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N-2 - USD ($) |  |  | 3 Months Ended | 12 Months Ended
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Aug. 10, 2022 | Jun. 30, 2022 | Jun. 30, 2022 | Mar. 31, 2022 | Dec. 31, 2021 | Sep. 30, 2021 | Jun. 30, 2021 | Mar. 31, 2021 | Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | May 31, 2015 | May 31, 2014 | May 31, 2013 | May 31, 2012
Cover [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Central Index Key |  | 0001170299 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amendment Flag |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Inv Company Type |  | N-2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Securities Act File Number |  | 811-21076 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Company Act File Number |  | 333-000000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Document Type |  | N-2ASR |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Document Registration Statement |  | true |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Pre-Effective Amendment |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Post-Effective Amendment |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Company Act Registration |  | true |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Company Registration Amendment |  | true |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Company Registration Amendment Number |  | 7 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Registrant Name |  | PIMCO MUNICIPAL INCOME FUND II |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Address Line One |  | 1633 Broadway |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, City or Town |  | New York |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, State or Province |  | NY |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Postal Zip Code |  | 10019 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
City Area Code |  | 888 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Local Phone Number |  | 877-4626 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Approximate Date of Commencement of Proposed Sale to Public |  | From time to time after the effective date of this Registration Statement. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend or Interest Reinvestment Plan Only |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Delayed or Continuous Offering |  | true |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Primary Shelf [Flag] |  | true |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Effective Upon Filing, 462(e) |  | true |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Additional Securities Effective, 413(b) |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Effective when Declared, Section 8(c) |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
New Effective Date for Previous Filing |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Additional Securities. 462(b) |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
No Substantive Changes, 462(c) |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Exhibits Only, 462(d) |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Registered Closed-End Fund [Flag] |  | true |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Development Company [Flag] |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interval Fund [Flag] |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Primary Shelf Qualified [Flag] |  | true |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Well-known Seasoned Issuer |  | Yes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Emerging Growth Company |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
New CEF or BDC Registrant [Flag] |  | false |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fee Table [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shareholder Transaction Expenses [Table Text Block] |  |
Shareholder Transaction Expenses |  | Percentage of Offering Price |
Sales Load (as a percentage of offering price) (1) |  |  | [- | ]%
Offering Expenses Borne by Common Shareholders (as a percentage of offering price) (2) |  |  | [- | ]%
Dividend Reinvestment Plan Fees (3) |  |  | None |
(1) | In the event that the Common Shares to which this prospectus relates are sold to or through underwriters or dealer managers, a corresponding prospectus supplement will disclose the applicable sales load and/or commission.
(2) | The related prospectus supplement will disclose the estimated amount of offering expenses, the offering price and the offering expenses borne by the Fund and indirectly by all of its Common Shareholders as a percentage of the offering price.
(3) | You will pay brokerage charges if you direct your broker or the plan agent to sell your Common Shares that you acquired pursuant to a dividend reinvestment plan. You may also pay a pro rata share of brokerage commissions incurred in connection with open-market purchases pursuant to the Fund’s Dividend Reinvestment Plan. See “Dividend Reinvestment Plan.”
Sales Load [Percent] | [1] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend Reinvestment and Cash Purchase Fees | [2] | $ 0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Transaction Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Transaction Expense 1 [Percent] | [3] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual Expenses [Table Text Block] |  |
Annual Expenses |  | Percentage of Net Assets Attributable to Common Shares (reflecting leverage attributable to Preferred Shares and TOBs) |
Management Fees (1) |  |  | 1.00 | %
Dividend Cost on Preferred Shares (2) |  |  | 0.94 | %
Interest Payments on Borrowed Funds (3) |  |  | 0.22 | %
Other Expenses (4) |  |  | 0.03 | %
Total Annual Expenses (5) |  |  | 2.19 | %
(1) | Management Fees include fees payable to the Investment Manager for advisory services and for supervisory, administrative and other services. The Fund pays for the advisory, supervisory and administrative services it requires under what is essentially an all-in fee structure (the “unified management fee”). Pursuant to an investment management agreement, PIMCO is paid a Management Fee of 0.685% of the Fund’s average daily net assets (including daily net assets attributable to any Preferred Shares). The Fund (and not PIMCO) will be responsible for certain fees and expenses, which are reflected in the table above, that are not covered by the unified management fee under the investment management agreement. Please see
| “Management of the Fund–Investment Management Agreement” for an explanation of the unified management fee.
(2) | Restated to reflect the Fund’s outstanding ARPS and RVMTP averaged over the year ended December 31, 2021, which represented 22.02% and 5.07%, respectively, of the Fund’s total average managed assets (including the liquidation preference of outstanding Preferred Shares and assets attributable to TOBs), at an annual estimated dividend cost to the Fund of 1 .9 3 % for ARPS and 1.83% for RVMTP as of June 30, 2022, and assumes the Fund will continue to pay dividends on the ARPS at the “maximum applicable rate” called for under the Fund’s Bylaws due to the ongoing failure of auctions for the ARPS. The actual dividend rate paid on the Preferred Shares will vary over time in accordance with variations in market interest rates. See “Use of Leverage” and “Description of Capital Structure.”
(3) | Restated to reflect the Fund’s use of leverage in the form of TOBs averaged over the year ended December 31, 2021, which represented 14.89% of the Fund’s total average managed assets (including assets attributable to Preferred Shares and TOBs), at an estimated annual interest rate cost to the Fund of 0.84% as of June 30, 2022. See “Use of Leverage—Effects of Leverage.” The actual amount of interest expense borne by the Fund will vary over time in accordance with the level of the Fund’s use of Preferred Shares, TOBs and/or other forms of borrowing and variations in market interest rates. Borrowing expense is required to be treated as an expense of the Fund for accounting purposes. Any associated income or gains (or losses) realized from leverage obtained through such instruments is not reflected in the Annual Expenses table above, but would be reflected in the Fund’s performance results.
(4) | “Other Expenses” are estimated for the Fund’s current fiscal year ending December 31, 2022.
(5) | “Dividend Cost on Preferred Shares”, including distributions on Preferred Shares, and “Interest Payments on Borrowed Funds” are borne by the Fund separately from the management fees paid to PIMCO. Excluding such expenses, Total Annual Expenses are 1.03%.
Management Fees [Percent] | [4] | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend Expenses on Preferred Shares [Percent] | [5] | 0.94% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend and Interest Expenses on Short Sales [Percent] | [6] | 0.22% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Annual Expense 1 [Percent] | [7] | 0.03% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total Annual Expenses [Percent] | [8] | 2.19% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expense Example [Table Text Block] |  | The following example illustrates the expenses that you would pay on a $1,000 investment in Common Shares of the Fund, assuming (1) that the Fund’s net assets do not increase or decrease, (2) that the Fund incurs total annual expenses of 2.19% of net assets attributable to Common Shares in years 1 through 10 (assuming outstanding Preferred Shares and TOBs representing 41.98% of the Fund’s total managed assets) and (3) a 5% annual return (1) :
|  | 1 Year |  | 3 Years |  | 5 Years |  | 10 Years
Total Expenses Incurred |  | $22 |  | $69 |  | $117 |  | $252
(1) | The example above should not be considered a representation of future expenses. Actual expenses may be higher or lower than those shown. The example assumes that the estimated Interest Payments on Borrowed Funds, Dividend Cost on Preferred Shares and Other Expenses set forth in the Annual Expenses table are accurate, that the rate listed under Total Annual Expenses remains the same each year and that all dividends and distributions are reinvested at NAV. Actual expenses may be greater or less than those assumed. Moreover, the Fund’s actual rate of return may be greater or less than the hypothetical 5% annual return shown in the example. The example does not include commissions or estimated offering expenses, which would cause the expenses shown in the example to increase. In connection with an offering of Common Shares, the prospectus supplement will set forth an example including sales load and estimated offering costs.
Expense Example, Year 01 | [9] | $ 22 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 3 | [9] | 69 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 5 | [9] | 117 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 10 | [9] | $ 252 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purpose of Fee Table , Note [Text Block] |  | The following table is intended to assist investors in understanding the fees and expenses (annualized) that an investor in Common Shares of the Fund would bear, directly or indirectly, as a result of an offering. The table reflects the use of leverage attributable to the Fund’s outstanding Preferred Shares and TOBs in an amount equal to 41.98% of the Fund’s total managed assets (including assets attributable to such leverage), which reflects approximately the percentage of the Fund’s total average managed assets attributable to such leverage averaged over the year ended December 31, 2021, and shows Fund expenses as a percentage of net assets attributable to Common Shares. The percentage above and information below do not reflect the Fund’s use of other forms of economic leverage, such as credit default swaps or other derivative instruments. The table and example below are based on the Fund’s capital structure as of December 31, 2021. The extent of the Fund’s assets attributable to leverage following an offering, and the Fund’s associated expenses, are likely to vary (perhaps significantly) from these assumptions. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis of Transaction Fees, Note [Text Block] |  | as a percentage of offering price |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Expenses, Note [Text Block] |  | “Other Expenses” are estimated for the Fund’s current fiscal year ending December 31, 2022. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management Fee not based on Net Assets, Note [Text Block] |  | Management Fees include fees payable to the Investment Manager for advisory services and for supervisory, administrative and other services. The Fund pays for the advisory, supervisory and administrative services it requires under what is essentially an all-in fee structure (the “unified management fee”). Pursuant to an investment management agreement, PIMCO is paid a Management Fee of 0.685% of the Fund’s average daily net assets (including daily net assets attributable to any Preferred Shares). The Fund (and not PIMCO) will be responsible for certain fees and expenses, which are reflected in the table above, that are not covered by the unified management fee under the investment management agreement. Please see
| “Management of the Fund–Investment Management Agreement” for an explanation of the unified management fee.
Financial Highlights [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Securities [Table Text Block] |  |
|  | ARPS |  |  |  |  |  | RVMTP (5) |
Selected Per Share Data for the Year Ended^: |  | Total Amount Outstanding |  |  | Asset Coverage per Preferred Share (1) |  |  | Involuntary Liquidating Preference per Preferred Share (2) |  |  | Average Market Value per ARPS (3) |  |  |  |  |  | Total Amount Outstanding |  |  | Asset Coverage per Preferred Share (1) |  |  | Involuntary Liquidating Preference per Preferred Share (2) |  |  | Average Market Value per RVMTP (4) |
12/31/2021 |  | $ | 298,275,000 |  |  | $ | 78,363 |  |  |  | $25,000 |  |  |  | N/A |  |  |  |  |  |  |  | $68,700,000 |  |  | $ | 313,450 |  |  |  | $100,000 |  |  |  | N/A |
12/31/2020 |  |  | 298,275,000 |  |  |  | 78,293 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  | 68,700,000 |  |  |  | 313,170 |  |  |  | 100,000 |  |  |  | N/A |
12/31/2019 |  |  | 298,275,000 |  |  |  | 78,308 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  | 68,700,000 |  |  |  | 313,230 |  |  |  | 100,000 |  |  |  | N/A |
12/31/2018 |  |  | 298,275,000 |  |  |  | 74,285 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  | 68,700,000 |  |  |  | 297,110 |  |  |  | 100,000 |  |  |  | N/A |
12/31/2017 |  |  | 367,000,000 |  |  |  | 76,136 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  | N/A |  |  |  | N/A |  |  |  | 100,000 |  |  |  | N/A |
12/31/2016 |  |  | 367,000,000 |  |  |  | 74,548 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
06/01/2015 - 12/31/2015 (g) |  |  | 367,000,000 |  |  |  | 76,782 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
05/31/2015 |  |  | 367,000,000 |  |  |  | 75,553 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
05/31/2014 |  |  | 367,000,000 |  |  |  | 74,733 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
05/31/2013 |  |  | 367,000,000 |  |  |  | 75,501 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
05/31/2012 |  |  | 367,000,000 |  |  |  | 74,192 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
1 | “Asset Coverage per Preferred Share” means the ratio that the value of the total assets of the Fund, less all liabilities and indebtedness not represented by ARPS or RVMTP, bears to the aggregate of the involuntary liquidation preference of ARPS or RVMTP, expressed as a dollar amount per ARPS or RVMTP.
2 | “Involuntary Liquidating Preference” means the amount to which a holder of ARPS or RVMTP would be entitled upon the involuntary liquidation of the Fund in preference to the Common Shareholders, expressed as a dollar amount per Preferred Share.
3 | The ARPS have no readily ascertainable market value. Auctions for the ARPS have failed since February 2008, there is currently no active trading market for the ARPS and the Fund is not able to reliably estimate what their value would be in a third-party market sale. The liquidation value of the ARPS represents its liquidation preference, which approximates fair value of the shares less any accumulated unpaid dividends.
4 | The RVMTP have no readily ascertainable market value. The liquidation value of the RVMTP represents its liquidation preference, which approximates fair value of the shares less any unamortized debt issuance costs.
5 | Prior to July 14, 2021, RVMTP Shares were VMTP Shares.
Senior Securities, Note [Text Block] |  | Financial Highlights
|  | ARPS |  |  |  |  |  | RVMTP (5) |
Selected Per Share Data for the Year Ended^: |  | Total Amount Outstanding |  |  | Asset Coverage per Preferred Share (1) |  |  | Involuntary Liquidating Preference per Preferred Share (2) |  |  | Average Market Value per ARPS (3) |  |  |  |  |  | Total Amount Outstanding |  |  | Asset Coverage per Preferred Share (1) |  |  | Involuntary Liquidating Preference per Preferred Share (2) |  |  | Average Market Value per RVMTP (4) |
12/31/2021 |  | $ | 298,275,000 |  |  | $ | 78,363 |  |  |  | $25,000 |  |  |  | N/A |  |  |  |  |  |  |  | $68,700,000 |  |  | $ | 313,450 |  |  |  | $100,000 |  |  |  | N/A |
12/31/2020 |  |  | 298,275,000 |  |  |  | 78,293 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  | 68,700,000 |  |  |  | 313,170 |  |  |  | 100,000 |  |  |  | N/A |
12/31/2019 |  |  | 298,275,000 |  |  |  | 78,308 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  | 68,700,000 |  |  |  | 313,230 |  |  |  | 100,000 |  |  |  | N/A |
12/31/2018 |  |  | 298,275,000 |  |  |  | 74,285 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  | 68,700,000 |  |  |  | 297,110 |  |  |  | 100,000 |  |  |  | N/A |
12/31/2017 |  |  | 367,000,000 |  |  |  | 76,136 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  | N/A |  |  |  | N/A |  |  |  | 100,000 |  |  |  | N/A |
12/31/2016 |  |  | 367,000,000 |  |  |  | 74,548 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
06/01/2015 - 12/31/2015 (g) |  |  | 367,000,000 |  |  |  | 76,782 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
05/31/2015 |  |  | 367,000,000 |  |  |  | 75,553 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
05/31/2014 |  |  | 367,000,000 |  |  |  | 74,733 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
05/31/2013 |  |  | 367,000,000 |  |  |  | 75,501 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
05/31/2012 |  |  | 367,000,000 |  |  |  | 74,192 |  |  |  | 25,000 |  |  |  | N/A |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
1 | “Asset Coverage per Preferred Share” means the ratio that the value of the total assets of the Fund, less all liabilities and indebtedness not represented by ARPS or RVMTP, bears to the aggregate of the involuntary liquidation preference of ARPS or RVMTP, expressed as a dollar amount per ARPS or RVMTP.
2 | “Involuntary Liquidating Preference” means the amount to which a holder of ARPS or RVMTP would be entitled upon the involuntary liquidation of the Fund in preference to the Common Shareholders, expressed as a dollar amount per Preferred Share.
3 | The ARPS have no readily ascertainable market value. Auctions for the ARPS have failed since February 2008, there is currently no active trading market for the ARPS and the Fund is not able to reliably estimate what their value would be in a third-party market sale. The liquidation value of the ARPS represents its liquidation preference, which approximates fair value of the shares less any accumulated unpaid dividends.
4 | The RVMTP have no readily ascertainable market value. The liquidation value of the RVMTP represents its liquidation preference, which approximates fair value of the shares less any unamortized debt issuance costs.
5 | Prior to July 14, 2021, RVMTP Shares were VMTP Shares.
Senior Securities Averaging Method, Note [Text Block] |  | The ARPS have no readily ascertainable market value. Auctions for the ARPS have failed since February 2008, there is currently no active trading market for the ARPS and the Fund is not able to reliably estimate what their value would be in a third-party market sale. The liquidation value of the ARPS represents its liquidation preference, which approximates fair value of the shares less any accumulated unpaid dividends. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Objectives and Practices [Text Block] |  | Investment Objective and Policies The Fund seeks to provide current income exempt from federal income tax. In pursuing the Fund’s investment objective, the Fund’s investment manager, Pacific Investment Management Company LLC (“PIMCO or the “Investment Manager”), also seeks to preserve and enhance the value of the Fund’s holdings relative to the municipal bond market generally, using proprietary analytical models that test and evaluate the sensitivity of those holdings to changes in interest rates and yield relationships. The Fund cannot assure you that it will achieve its investment objective, and you could lose all of your investment in the Fund. Portfolio Investment Strategies Under normal circumstances, the Fund expects to invest at least 90% of its net assets in municipal bonds which pay interest that, in the opinion of bond counsel to the issuer (or on the basis of other authority believed by PIMCO to be reliable), is exempt from regular federal income taxes (i.e., excluded from gross income for federal income tax purposes but not necessarily exempt from the federal alternative minimum tax). Subject to its other investment policies, the Fund may invest up to 20% of its total assets in investments the interest from which is subject to the federal alternative minimum tax. The Fund invests at least 80% of its net assets in municipal bonds that at the time of investment are investment grade quality. Investment grade quality bonds are bonds rated within the four highest grades (Baa by Moody’s or BBB or better by S&P or Fitch), or bonds that are unrated but determined to be of comparable quality by PIMCO. The Fund may invest up to 20% of its net assets in municipal bonds that are, at the time of investment, rated Ba/BB or B or lower by Moody’s, S&P or Fitch or that are unrated but judged to be of comparable quality by PIMCO. Bonds of below investment grade quality are regarded as having predominantly speculative characteristics with respect to capacity to pay interest and repay principal, and are commonly referred to as “junk bonds.” Bonds in the lowest investment grade category may also be considered to possess some speculative characteristics. The Fund’s investment in municipal bonds may be based on PIMCO’s belief that they have attractive yield and/or total return potential. The Fund attempts to produce returns relative to the municipal bond market generally by prudent selection of municipal bonds. The Fund may invest in bonds associated with a particular municipal market sector (for example, electric utilities), issued by a particular municipal issuer, or having particular structural characteristics, that PIMCO believes may be undervalued. PIMCO may purchase such a bond for the Fund’s portfolio because it represents a market sector or issuer that PIMCO considers undervalued. For example, municipal bonds of particular types (e.g., hospital bonds, industrial revenue bonds or bonds issued by a particular municipal issuer) could be undervalued if there is a temporary excess of supply in that market sector, or because of a general decline in the market price of municipal bonds of the market sector for reasons that do not apply to the particular municipal bonds that are considered undervalued. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk Factors [Table Text Block] |  | Principal Risks of the Fund The Fund is subject to the principal risks noted below, whether through the Fund’s direct investments or derivatives positions. Market Discount Risk The price of the Fund’s Common Shares will fluctuate with market conditions and other factors. If you sell your Common Shares, the price received may be more or less than your original investment. The Common Shares are designed for long-term investors and should not be treated as trading vehicles. Shares of closed-end management investment companies frequently trade at a discount from their NAV. The Common Shares may trade at a price that is less than the offering price for Common Shares issued pursuant to an offering. This risk may be greater for investors who sell their Common Shares relatively shortly after completion of an offering. The sale of Common Shares by the Fund (or the perception that such sales may occur), particularly if sold at a discount to the then current market price of the Common Shares, may have an adverse effect on the market price of the Common Shares. Market Risk The market price of securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. Securities may decline in value due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of a security may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates, adverse changes to credit markets or adverse investor sentiment generally. The value of a security may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Equity securities generally have greater price volatility than fixed income securities. Credit ratings downgrades may also negatively affect securities held by the Fund. Even when markets perform well, there is no assurance that the investments held by the Fund will increase in value along with the broader market. In addition, market risk includes the risk that geopolitical and other events will disrupt the economy on a national or global level. For instance, war, terrorism, market manipulation, government defaults, government shutdowns, political changes or diplomatic developments, public health emergencies (such as the spread of infectious diseases, pandemics and epidemics) and natural/environmental disasters can all negatively impact the securities markets, which could cause the Fund to lose value. These events could reduce consumer demand or economic output, result in market closures, travel restrictions or quarantines, and significantly adversely impact the economy. The current contentious domestic political environment, as well as political and diplomatic events within the United States and abroad, such as presidential elections in the United States or abroad or the U.S. government’s inability at times to agree on a long-term budget and deficit reduction plan, has in the past resulted, and may in the future result, in a government shutdown or otherwise adversely affect the U.S. regulatory landscape, the general market environment and/or investor sentiment, which could have an adverse impact on the Fund’s investments and operations. Additional and/or prolonged U.S. federal government shutdowns may affect investor and consumer confidence and may adversely impact financial markets and the broader economy, perhaps suddenly and to a significant degree. Governmental and quasi-governmental authorities and regulators throughout the world have previously responded to serious economic disruptions with a variety of significant fiscal and monetary policy changes, including but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates. An unexpected or sudden reversal of these policies, or the ineffectiveness of these policies, could increase volatility in securities markets, which could adversely affect the Fund’s investments. Any market disruptions could also prevent the Fund from executing advantageous investment decisions in a timely manner. Funds that have focused their investments in a region enduring geopolitical market disruption, it will face higher risks of loss. Thus, investors should closely monitor current market conditions to determine whether the Fund meets their individual financial needs and tolerance for risk. Current market conditions may pose heightened risks with respect to the Fund’s investment in fixed income securities. As such, fixed income securities markets may experience heightened levels of interest rate, volatility and liquidity risk. Any interest rate increases in the future could cause the value of any Fund, such as the Fund, that invests in fixed income securities to decrease. Exchanges and securities markets may close early, close late or issue trading halts on specific securities, which may result in, among other things, the Fund being unable to buy or sell certain securities or financial instruments at an advantageous time or accurately price its portfolio investments. Municipal Bond Risk The ability of municipal issuers to make timely payments of interest and principal may be diminished during general economic downturns, by litigation, legislation or political events, or by the bankruptcy of the issuer. Laws, referenda, ordinances or regulations enacted in the future by Congress or state legislatures or the applicable governmental entity could extend the time for payment of principal and/or interest, or impose other constraints on enforcement of such obligations, or on the ability of municipal issuers to levy taxes. Issuers of municipal securities also might seek protection under the bankruptcy laws. In the event of bankruptcy of such an issuer, the Fund could experience delays in collecting principal and interest and the Fund may not, in all circumstances, be able to collect all principal and interest to which it is entitled. To enforce its rights in the event of a default in the payment of interest or repayment of principal, or both, the Fund may take possession of and manage the assets securing the issuer’s obligations on such securities, which may increase the Fund’s operating expenses. The Fund may invest in revenue bonds, which are typically issued to fund a wide variety of capital projects including electric, gas, water and sewer systems; highways, bridges and tunnels; port and airport facilities; colleges and universities; and hospitals. Because the principal security for a revenue bond is generally the net revenues derived from a particular facility or group of facilities or, in some cases, from the proceeds of a special excise or other specific revenue source, there is no guarantee that the particular project will generate enough revenue to pay its obligations, in which case the Fund’s performance may be adversely affected. The Fund may invest in taxable municipal bonds, such as Build America Bonds. Build America Bonds are tax credit bonds created by the American Recovery and Reinvestment Act of 2009, which authorized state and local governments to issue Build America Bonds as taxable bonds in 2009 and 2010, without volume limitations, to finance any capital expenditures for which such issuers could otherwise issue traditional tax-exempt bonds. The Fund’s investments in Build America Bonds or similar taxable municipal bonds will result in taxable income and the Fund may elect to pass through to holders of the Fund’s common shares (“Common Shares”) the corresponding tax credits. The tax credits can generally be used to offset federal income taxes and the alternative minimum tax, but such credits are generally not refundable. Taxable municipal bonds involve similar risks as tax-exempt municipal bonds, including credit and market risk. Municipal securities are also subject to interest rate, credit, and liquidity risk, which are discussed generally elsewhere in this section, and elaborated upon below with respect to municipal bonds. Interest Rate Risk. The value of municipal securities, similar to other fixed income securities, will likely drop as interest rates rise in the general market. Conversely, when rates decline, bond prices generally rise. Credit Risk. The risk that a borrower may be unable to make interest or principal payments when they are due. A fund that invests in municipal securities relies on the ability of the issuer to service its debt. This subjects the Fund to credit risk in that the municipal issuer may be fiscally unstable or exposed to large liabilities that could impair its ability to honor its obligations. Municipal issuers with significant debt service requirements, in the near-to mid-term; unrated issuers and those with less capital and liquidity to absorb additional expenses may be most at risk. To the extent the Fund invests in lower quality or high yield municipal securities, it may be more sensitive to the adverse credit events in the municipal market. The treatment of municipalities in bankruptcy is more uncertain, and potentially more adverse to debt holders, than for corporate issues. Liquidity Risk. The risk that investors may have difficulty finding a buyer when they seek to sell, and therefore, may be forced to sell at a discount to the market value. Liquidity may sometimes be impaired in the municipal market and because the Fund primarily invests in municipal securities, it may find it difficult to purchase or sell such securities at opportune times. Liquidity can be impaired due to interest rate concerns, credit events, or general supply and demand imbalances. Depending on the particular issuer and current economic conditions, municipal securities could be deemed more volatile investments. In addition to general municipal market risks, different municipal sectors may face different risks. For instance, general obligation bonds are secured by the full faith, credit, and taxing power of the municipality issuing the obligation. As such, timely payment depends on the municipality’s ability to raise tax revenue and maintain a fiscally sound budget. The timely payments may also be influenced by any unfunded pension liabilities or other post-employee benefit plan (OPEB) liabilities. Revenue bonds are secured by special tax revenues or other revenue sources. If the specified revenues do not materialize, then the bonds may not be repaid. Private activity bonds are yet another type of municipal security. Municipalities use private activity bonds to finance the development of industrial facilities for use by private enterprise. Principal and interest payments are to be made by the private enterprise benefitting from the development, which means that the holder of the bond is exposed to the risk that the private issuer may default on the bond. Moral obligation bonds are usually issued by special purpose public entities. If the public entity defaults, repayment becomes a “moral obligation” instead of a legal one. The lack of a legally enforceable right to payment in the event of default poses a special risk for a holder of the bond because it has little or no ability to seek recourse in the event of default. In addition, a significant restructuring of federal income tax rates or even serious discussion on the topic in Congress could cause municipal bond prices to fall. The demand for municipal securities is strongly influenced by the value of tax-exempt income to investors. Lower income tax rates could reduce the advantage of owning municipal securities. Municipal notes are similar to general municipal debt obligations, but they generally possess shorter terms. Municipal notes can be used to provide interim financing and may not be repaid if anticipated revenues are not realized. Municipal Project-Specific Risk The Fund may be more sensitive to adverse economic, business or political developments if it invests a substantial portion of its assets in the bonds of specific projects (such as those relating to education, health care, housing, transportation, and utilities), industrial development bonds, or in general obligation bonds, particularly if there is a large concentration from issuers in a single state. This is because the value of municipal securities can be significantly affected by the political, economic, legal, and legislative realities of the particular issuer’s locality or municipal sector events. Similarly, changes to state or federal regulation tied to a specific sector, such as the hospital sector, could have an impact on the revenue stream for a given subset of the market. U.S. Government Securities Risk Certain U.S. government securities, such as U.S. Treasury bills, notes, bonds and mortgage-related securities guaranteed by the GNMA, are supported by the full faith and credit of the United States; others, such as those of the FHLBs or the FHLMC, are supported by the right of the issuer to borrow from the U.S. Treasury; others, such as those of the FNMA, are supported by the discretionary authority of the U.S. government to purchase the agency’s obligations; and still others are supported only by the credit of the agency, instrumentality or corporation. Although legislation has been enacted to support certain government sponsored entities, including the FHLBs, FHLMC and FNMA, there is no assurance that the obligations of such entities will be satisfied in full, or that such obligations will not decrease in value or default. It is difficult, if not impossible, to predict the future political, regulatory or economic changes that could impact the government sponsored entities and the values of their related securities or obligations. In addition, certain governmental entities, including FNMA and FHLMC, have been subject to regulatory scrutiny regarding their accounting policies and practices and other concerns that may result in legislation, changes in regulatory oversight and/or other consequences that could adversely affect the credit quality, availability or investment character of securities issued by these entities. Yields available from U.S. government debt securities are generally lower than the yields available from other debt securities. The values of U.S. government securities change as interest rates fluctuate. Asset Allocation Risk The Fund’s investment performance depends upon how its assets are allocated and reallocated. A principal risk of investing in the Fund is that PIMCO may make less than optimal or poor asset allocation decisions. PIMCO employs an active approach to allocation among multiple fixed-income sectors, but there is no guarantee that such allocation techniques will produce the desired results. It is possible that PIMCO will focus on an investment that performs poorly or underperforms other investments under various market conditions. You could lose money on your investment in the Fund as a result of these allocation decisions. Management Risk The Fund is subject to management risk because it is an actively managed investment portfolio. PIMCO and each individual portfolio manager will apply investment techniques and risk analysis in making investment decisions for the Fund, but there can be no guarantee that these decisions will produce the desired results. Certain securities or other instruments in which the Fund seeks to invest may not be available in the quantities desired. In addition, regulatory restrictions, actual or potential conflicts of interest or other considerations may cause PIMCO to restrict or prohibit participation in certain investments. In such circumstances, PIMCO or the individual portfolio managers may determine to purchase other securities or instruments as substitutes. Such substitute securities or instruments may not perform as intended, which could result in losses to the Fund. The Fund is also subject to the risk that deficiencies in the internal systems or controls of PIMCO or another service provider will cause losses for the Fund or hinder Fund operations. For example, trading delays or errors (both human and systemic) could prevent the Fund from purchasing a security expected to appreciate in value. To the extent the Fund employs strategies targeting perceived pricing inefficiencies, arbitrage strategies or similar strategies, it is subject to the risk that the pricing or valuation of the securities and instruments involved in such strategies may change unexpectedly, which may result in reduced returns or losses to the Fund. Additionally, actual or potential conflicts of interest, legislative, regulatory, or tax restrictions, policies or developments may affect the investment techniques available to PIMCO and each individual portfolio manager in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. There also can be no assurance that all of the personnel of PIMCO will continue to be associated with PIMCO for any length of time. The loss of the services of one or more key employees of PIMCO could have an adverse impact on the Fund’s ability to realize its investment objective. In addition, the Fund may rely on various third-party sources to calculate its NAV. As a result, the Fund is subject to certain operational risks associated with reliance on service providers and service providers’ data sources. In particular, errors or systems failures and other technological issues may adversely impact the Fund’s calculations of its NAV, and such NAV calculation issues may result in inaccurately calculated NAV, delays in NAV calculation and/or the inability to calculate NAVs over extended periods. The Fund may be unable to recover any losses associated with such failures. Issuer Risk The value of a security may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods or services, as well as the historical and prospective earnings of the issuer and the value of its assets. A change in the financial condition of a single issuer may affect securities markets as a whole. These risks can apply to the Common Shares issued by the Fund and to the issuers of securities and other instruments in which the Fund invests. Interest Rate Risk Interest rate risk is the risk that fixed income securities and other instruments in the Fund’s portfolio will decline in value because of a change in interest rates. As nominal interest rates rise, the value of certain fixed income securities held by the Fund is likely to decrease. A nominal interest rate can be described as the sum of a real interest rate and an expected inflation rate. Interest rate changes can be sudden and unpredictable, and the Fund may lose money as a result of movements in interest rates. The Fund may not be able to effectively hedge against changes in interest rates or may choose not to do so for cost or other reasons. A wide variety of factors can cause interest rates or yields of U.S. Treasury securities (or yields of other types of bonds) to rise (e.g., central bank monetary policies, inflation rates, general economic conditions). Recently, there have been signs of inflationary price movements. As such, fixed income securities markets may experience heightened levels of interest rate, volatility and liquidity risk. Fixed income securities with longer durations tend to be more sensitive to changes in interest rates, usually making them more volatile. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates that incorporates a security’s yield, coupon, final maturity and call features, among other characteristics. Duration is useful primarily as a measure of the sensitivity of a fixed income security’s market price to interest rate (i.e., yield) movements. All other things remaining equal, for each one percentage point increase in interest rates, the value of a portfolio of fixed income investments would generally be expected to decline by one percent for every year of the portfolio’s average duration above zero. For example, the value of a portfolio of fixed income securities with an average duration of fourteen years would generally be expected to decline by approximately 14% if interest rates rose by one percentage point. Variable and floating rate securities may decline in value if their interest rates do not rise as much, or as quickly, as interest rates in general. Conversely, floating rate securities will not generally increase in value if interest rates decline. Inverse floating rate securities may decrease in value if interest rates increase. Inverse floating rate securities may also exhibit greater price volatility than a fixed rate obligation with similar credit quality. When the Fund holds variable or floating rate securities, a decrease (or, in the case of inverse floating rate securities, an increase) in market interest rates will adversely affect the income received from such securities and the NAV of the Fund’s shares. During periods of very low or negative interest rates, the Fund may be unable to maintain positive returns. Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, may result in heightened market volatility and may detract from Fund performance to the extent the Fund is exposed to such interest rates. Measures such as average duration may not accurately reflect the true interest rate sensitivity of the Fund. This is especially the case if the Fund consists of securities with widely varying durations. Therefore, if the Fund has an average duration that suggests a certain level of interest rate risk, the Fund may in fact be subject to greater interest rate risk than the average would suggest. This risk is greater to the extent the Fund uses leverage or derivatives. Convexity is an additional measure used to understand a security’s or Fund’s interest rate sensitivity. Convexity measures the rate of change of duration in response to changes in interest rates. With respect to a security’s price, a larger convexity (positive or negative) may imply more dramatic price changes in response to changing interest rates. Convexity may be positive or negative. Negative convexity implies that interest rate increases result in increased duration, meaning increased sensitivity in prices in response to rising interest rates. Thus, securities with negative convexity, which may include bonds with traditional call features and certain mortgage-backed securities, may experience greater losses in periods of rising interest rates. Accordingly, if the Fund holds such securities, the Fund may be subject to a greater risk of losses in periods of rising interest rates. Rising interest rates may result in periods of volatility and a decline in value of the Fund’s fixed income investments. Further, while U.S. bond markets have steadily grown over the past three decades, dealer “market making ability has remained relatively stagnant. As a result, dealer inventories of certain types of bonds and similar instruments, which provide a core indication of the ability of financial intermediaries to “make markets,” are at or near historic lows in relation to market size. Because market makers provide stability to a market through their intermediary services, a significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty. All of these factors, collectively and/or individually, could cause the Fund to lose value. Credit Risk The Fund could lose money if the issuer or guarantor of a fixed income security, or the counterparty to a derivatives contract, repurchase agreement or a loan of portfolio securities, is unable or unwilling, or is perceived as unable or unwilling, to make timely principal and/or interest payments or to otherwise honor its obligations. The downgrade of the credit of a security held by the Fund may decrease its value. Measures such as average credit quality may not accurately reflect the true credit risk of the Fund. This is especially the case if the Fund consists of securities with widely varying credit ratings. This risk is greater to the extent the Fund uses leverage or derivatives. Municipal bonds are subject to the risk that litigation, legislation or other political events, local business or economic conditions, or the bankruptcy of the issuer could have a significant effect on an issuer’s ability to make payments of principal and/or interest. Mortgage-Related and Other Asset-Backed Instruments Risk The mortgage-related assets in which the Fund may invest include, but are not limited to, any security, instrument or other asset that is related to U.S. or non-U.S. mortgages, including those issued by private originators or issuers, or issued or guaranteed as to principal or interest by the U.S. government or its agencies or instrumentalities or by non-U.S. governments or authorities, such as, without limitation, assets representing interests in, collateralized or backed by, or whose values are determined in whole or in part by reference to any number of mortgages or pools of mortgages or the payment experience of such mortgages or pools of mortgages, including REMICs, which could include Re-REMICs, mortgage pass-through securities, inverse floaters, CMOs, CLOs, multiclass pass-through securities, private mortgage pass-through securities, stripped mortgage securities (generally interest-only and principal-only securities), mortgage-related asset backed securities and mortgage-related loans (including through participations, assignments, originations and whole loans), including commercial and residential mortgage loans. Exposures to mortgage-related assets through derivatives or other financial instruments will be considered investments in mortgage-related assets. The Fund may also invest in other types of ABS, including CDOs, CBOs and CLOs and other similarly structured securities See “The Fund’s Investment Objective and Strategies-Portfolio Contents and Other Information-Mortgage-Related and Other Asset-Backed Instruments” in this prospectus and “Investment Objective and Policies-Mortgage-Related and Other Asset- Backed Instruments” in the Statement of Additional Information for a description of the various mortgage-related and other asset-backed instruments in which the Fund may invest and their related risks. Mortgage-related and other asset-backed instruments represent interests in “pools” of mortgages or other assets such as consumer loans or receivables held in trust and often involve risks that are different from or possibly more acute than risks associated with other types of debt instruments. Generally, rising interest rates tend to extend the duration of fixed rate mortgage-related assets, making them more sensitive to changes in interest rates. As a result, in a period of rising interest rates, the Fund may exhibit additional volatility since individual mortgage holders are less likely to exercise prepayment options, thereby putting additional downward pressure on the value of these securities and potentially causing the Fund to lose money. This is known as extension risk. Mortgage-backed securities can be highly sensitive to rising interest rates, such that even small movements can cause the Fund to lose value. Mortgage-backed securities, and in particular those not backed by a government guarantee, are subject to credit risk. When interest rates decline, borrowers may pay off their mortgages sooner than expected. This can reduce the returns of the Fund because the Fund may have to reinvest that money at the lower prevailing interest rates. The Fund’s investments in other asset-backed instruments are subject to risks similar to those associated with mortgage-related assets, as well as additional risks associated with the nature of the assets and the servicing of those assets. Payment of principal and interest on asset-backed instruments may be largely dependent upon the cash flows generated by the assets backing the instruments, and asset-backed instruments may not have the benefit of any security interest in the related assets. Subordinate mortgage-backed or asset-backed instruments are paid interest only to the extent that there are funds available to make payments. To the extent the collateral pool includes a large percentage of delinquent loans, there is a risk that interest payments on subordinate mortgage-backed or asset-backed instruments will not be fully paid. There are multiple tranches of mortgage-backed and asset-backed instruments, offering investors various maturity and credit risk characteristics. Tranches are categorized as senior, mezzanine, and subordinated/equity or “first loss,” according to their degree of risk. The most senior tranche of a mortgage-backed or asset-backed instrument has the greatest collateralization and pays the lowest interest rate. If there are defaults or the collateral otherwise underperforms, scheduled payments to senior tranches take precedence over those of mezzanine tranches, and scheduled payments to mezzanine tranches take precedence over those to subordinated/equity tranches. Lower tranches represent lower degrees of credit quality and pay higher interest rates intended to compensate for the attendant risks. The return on the lower tranches is especially sensitive to the rate of defaults in the collateral pool. The lowest tranche (i.e., the “equity” or “residual” tranche) specifically receives the residual interest payments (i.e., money that is left over after the higher tranches have been paid and expenses of the issuing entities have been paid) rather than a fixed interest rate. The Fund may also invest in the residual or equity tranches of mortgage-related and other asset-backed instruments, which may be referred to as subordinate mortgage-backed or asset-backed instruments and interest-only mortgage-backed or asset-backed instruments. The Fund expects that investments in subordinate mortgage-backed and other asset-backed instruments will be subject to risks arising from delinquencies and foreclosures, thereby exposing its investment portfolio to potential losses. Subordinate securities of mortgage-backed and other asset-backed instruments are also subject to greater credit risk than those mortgage-backed or other asset-backed instruments that are more highly rated. The mortgage markets in the United States and in various foreign countries have experienced extreme difficulties in the past that adversely affected the performance and market value of certain mortgage-related investments. Delinquencies and losses on residential and commercial mortgage loans (especially subprime and second-lien mortgage loans) may increase, and a decline in or flattening of housing and other real property values may exacerbate such delinquencies and losses. In addition, reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen. Mortgage-Related Derivative Instruments Risk The Fund may engage in derivative transactions related to mortgage-backed securities, including purchasing and selling exchange-listed and OTC put and call options, futures and forwards on mortgages and mortgage-backed securities. The Fund may also invest in mortgage-backed securities credit default swaps, which include swaps the reference obligation for which is a mortgage-backed security or related index, such as the CMBX Index (a tradeable index referencing a basket of commercial mortgage-backed securities), the TRX Index (a tradeable index referencing total return swaps based on commercial mortgage-backed securities) or the ABX (a tradeable index referencing a basket of sub-prime mortgage backed securities). The Fund may invest in newly developed mortgage related derivatives that may hereafter become available. Derivative mortgage-backed securities (such as principal-only (“POs”), interest-only (“IOs”) or inverse floating rate securities) are particularly exposed to call and extension risks. Small changes in mortgage prepayments can significantly impact the cash flows and the market value of these derivative instruments. In general, the risk of faster than anticipated prepayments adversely affects IOs, super floaters and premium priced mortgage-backed securities. The risk of slower than anticipated prepayments generally affects POs, floating-rate securities subject to interest rate caps, support tranches and discount priced mortgage-backed securities. In addition, particular derivative instruments may be leveraged such that their exposure (i.e., price sensitivity) to interest rate and/or prepayment risk is magnified. Mortgage-related derivative instruments involve risks associated with mortgage-related and other asset-backed instruments, privately-issued mortgage-related securities, the mortgage market, the real estate industry, derivatives and credit default swaps. See “Mortgage-Related and Other Asset-Backed Instruments Risk”, “Privately-Issued Mortgage-Related Securities Risk,” “Derivatives Risk,” and “Credit Default Swaps Risk.” Mortgage-related derivative instruments involve risks associated with mortgage-related and other asset-backed instruments, privately-issued mortgage-related securities, the mortgage market, the real estate industry, derivatives and credit default swaps. See “Mortgage-Related and Other Asset-Backed Instruments Risk,” “Privately-Issued Mortgage-Related Securities Risk,” “Derivatives Risk,” and “Credit Default Swaps Risk.” High Yield Securities Risk To the extent that the Fund invests in high yield securities and unrated securities of similar credit quality (commonly known as “high yield securities” or “junk bonds”), the Fund will be subject to greater levels of credit risk, call risk and liquidity risk than funds that do not invest in such securities, which could have a negative effect on the NAV and market price of the Fund’s Common Shares or Common Share dividends. These securities are considered predominantly speculative with respect to an issuer’s continuing ability to make principal and interest payments, and may be more volatile than other types of securities. An economic downturn or individual corporate developments could adversely affect the market for these securities and reduce the Fund’s ability to sell these securities at an advantageous time or price. The Fund may purchase distressed securities that are in default or the issuers of which are in bankruptcy, which involve heightened risks. Issuers of high yield securities may have the right to “call or redeem the issue prior to maturity, which may result in the Fund having to reinvest the proceeds in other high yield securities or similar instruments that may pay lower interest rates. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in high yield securities. Consequently, transactions in high yield securities may involve greater costs than transactions in more actively traded securities. To the extent that the Fund invests in high yield securities and unrated securities of similar credit quality (commonly known as “high yield securities” or “junk bonds”), the Fund may be subject to greater levels of credit risk, call risk and liquidity risk than funds that do not invest in such securities, which could have a negative effect on the NAV and market price of the Fund’s Common Shares or Common Share dividends. These securities are considered predominantly speculative with respect to an issuer’s continuing ability to make principal and interest payments, and may be more volatile than other types of securities. An economic downturn or individual corporate developments could adversely affect the market for these securities and reduce the Fund’s ability to sell these securities at an advantageous time or price. The Fund may purchase distressed securities that are in default or the issuers of which are in bankruptcy, which involve heightened risks. Issuers of high yield securities may have the right to “call” or redeem the issue prior to maturity, which may result in the Fund having to reinvest the proceeds in other high yield securities or similar instruments that may pay lower interest rates. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in high yield securities. Consequently, transactions in high yield securities may involve greater costs than transactions in more actively traded securities. These factors may result in the Fund being unable to realize full value for these securities and/or may result in the Fund not receiving the proceeds from a sale of a high yield security for an extended period after such sale, each of which could result in losses to the Fund. Because of the risks involved in investing in high yield securities, an investment in the Fund should be considered speculative. In general, lower rated debt securities carry a greater degree of risk that the issuer will lose its ability to make interest and principal payments, which could have a negative effect on the Fund. Securities of below investment grade quality are regarded as having predominantly speculative characteristics with respect to capacity to pay interest and repay principal and are commonly referred to as “high yield” securities or “junk bonds.” High yield securities involve a greater risk of default and their prices are generally more volatile and sensitive to actual or perceived negative developments. Debt securities in the lowest investment grade category also may be considered to possess some speculative characteristics by certain rating agencies. The Fund may purchase stressed or distressed securities that are in default or the issuers of which are in bankruptcy, which involve heightened risks. An economic downturn could severely affect the ability of issuers (particularly those that are highly leveraged) to service or repay their debt obligations. Lower-rated securities are generally less liquid than higher-rated securities, which may have an adverse effect on the Fund’s ability to dispose of them. For example, under adverse market or economic conditions, the secondary market for below investment grade securities could contract further, independent of any specific adverse changes in the condition of a particular issuer, and certain securities in the Fund’s portfolio may become illiquid or less liquid. As a result, the Fund could find it more difficult to sell these securities or may be able to sell these securities only at prices lower than if such securities were widely traded. To the extent the Fund focuses on below investment grade debt obligations, PIMCO’s capabilities in analyzing credit quality and associated risks will be particularly important, and there can be no assurance that PIMCO will be successful in this regard. Due to the risks involved in investing in high yield securities, an investment in the Fund should be considered speculative. The Fund’s credit quality policies apply only at the time a security is purchased, and the Fund is not required to dispose of a security in the event that a rating agency or PIMCO downgrades its assessment of the credit characteristics of a particular issue. Analysis of creditworthiness may be more complex for issuers of high yield securities than for issuers of higher quality debt securities. Reinvestment Risk Income from the Fund’s portfolio will decline if and when the Fund invests the proceeds from matured, traded or called debt obligations at market interest rates that are below the portfolio’s current earnings rate. For instance, during periods of declining interest rates, an issuer of debt obligations may exercise an option to redeem securities prior to maturity, forcing the Fund to invest in lower-yielding securities The Fund also may choose to sell higher yielding portfolio securities and to purchase lower yielding securities to achieve greater portfolio diversification, because the portfolio managers believe the current holdings are overvalued or for other investment-related reasons. A decline in income received by the Fund from its investments is likely to have a negative effect on dividend levels and the market price, NAV and/or overall return of the Common Shares. Securities Lending Risk. For the purpose of achieving income, the Fund may lend its portfolio securities to brokers, dealers, and other financial institutions provided a number of conditions are satisfied, including that the loan is fully collateralized. Please see “Investment Objectives and Policies—Loans of Portfolio Securities” in the Statement of Additional Information for more details. When the Fund lends portfolio securities, its investment performance will continue to reflect changes in the value of the securities loaned, and the Fund will also receive a fee or interest on the collateral. Securities lending involves the risk of loss of rights in the collateral or delay in recovery of the collateral if the borrower fails to return the security loaned or becomes insolvent. The Fund may pay lending fees to a party arranging the loan. Cash collateral received by the Fund in securities lending transactions may be invested in short-term liquid fixed income instruments or in money market or short-term mutual funds, or similar investment vehicles, including affiliated money market or short-term mutual funds. The Fund bears the risk of such investments. Call Risk Call risk refers to the possibility that an issuer may exercise its right to redeem a fixed income security earlier than expected. Issuers may call outstanding securities prior to their maturity for a number of reasons. If an issuer calls a security in which the Fund has invested, the Fund may not recoup the full amount of its initial investment and may be forced to reinvest in lower-yielding securities, securities with greater credit risks or securities with other, less favorable features. U.S. Government Securities Risk Certain U.S. government securities, such as U.S. Treasury bills, notes, bonds and mortgage-related securities guaranteed by the GNMA, are supported by the full faith and credit of the United States; others, such as those of the FHLBs or the FHLMC, are supported by the right of the issuer to borrow from the U.S. Treasury; others, such as those of the FNMA, are supported by the discretionary authority of the U.S. government to purchase the agency’s obligations; and still others are supported only by the credit of the agency, instrumentality or corporation. Although legislation has been enacted to support certain government sponsored entities, including the FHLBs, FHLMC and FNMA, there is no assurance that the obligations of such entities will be satisfied in full, or that such obligations will not decrease in value or default. It is difficult, if not impossible, to predict the future political, regulatory or economic changes that could impact the government sponsored entities and the values of their related securities or obligations. In addition, certain governmental entities, including FNMA and FHLMC, have been subject to regulatory scrutiny regarding their accounting policies and practices and other concerns that may result in legislation, changes in regulatory oversight and/or other consequences that could adversely affect the credit quality, availability or investment character of securities issued by these entities. Yields available from U.S. government debt securities are generally lower than the yields available from other debt securities. The values of U.S. government securities change as interest rates fluctuate. California State-Specific Risk The Fund may be affected significantly by economic, regulatory or political developments affecting the ability of California issuers to pay interest or repay principal. Certain issuers of California municipal bonds have experienced serious financial difficulties in the past and reoccurrence of these difficulties may impair the ability of certain California issuers to pay principal or interest on their obligations. Provisions of the California Constitution and State statutes which limit the taxing and spending authority of California governmental entities may impair the ability of California issuers to pay principal and/or interest on their obligations. While California’s economy is broad, it does have major concentrations in advanced technology, aerospace and defense-related manufacturing, trade, entertainment, real estate and financial services, and may be sensitive to economic problems affecting those industries. Future California political and economic developments, constitutional amendments, legislative measures, executive orders, administrative regulations, litigation and voter initiatives could have an adverse effect on the debt obligations of California issuers. New York State-Specific Risk The Fund may be affected significantly by economic, regulatory or political developments affecting the ability of New York issuers to pay interest or repay principal. Certain issuers of New York municipal bonds have experienced serious financial difficulties in the past and reoccurrence of these difficulties may impair the ability of certain New York issuers to pay principal or interest on their obligations. Provisions of the New York Constitution and State statutes which limit the taxing and spending authority of New York governmental entities may impair the ability of New York issuers to pay principal and/or interest on their obligations. While New York’s economy is broad, it does have major concentrations in certain industries, such as financial services, and may be sensitive to economic problems affecting those industries. Future New York political and economic developments, constitutional amendments, legislative measures, executive orders, administrative regulations, litigation and voter initiatives could have an adverse effect on the debt obligations of New York issuers. Puerto Rico-Specific Risk The Fund may be affected significantly by economic, regulatory, restructuring or political developments affecting the ability of Puerto Rico issuers to pay interest or repay principal. Certain issuers of Puerto Rico municipal bonds have experienced serious financial difficulties in the past and reoccurrence of these difficulties may impair the ability of certain Puerto Rico issuers to pay principal or interest on their obligations. Provisions of the Puerto Rico Constitution and Commonwealth laws, including a federally-appointed oversight board to oversee the Commonwealth’s financial operations, which limit the taxing and spending authority of Puerto Rico governmental entities may impair the ability of Puerto Rico issuers to pay principal and/or interest on their obligations. While Puerto Rico’s economy is broad, it does have major concentrations in certain industries, such as manufacturing and service, and may be sensitive to economic problems affecting those industries. Future Puerto Rico political and economic developments, constitutional amendments, legislative measures, executive orders, administrative regulations, litigation, debt restructuring, and voter initiatives could have an adverse effect on the debt obligations of Puerto Rico issuers. Valuation Risk Certain securities in which the Fund invests may be less liquid and more difficult to value than other types of securities. When market quotations or pricing service prices are not readily available or are deemed to be unreliable, the Fund values its investments at fair value as determined in good faith pursuant to policies and procedures approved by the Board. Fair value pricing may require subjective determinations about the value of a security or other asset. As a result, there can be no assurance that fair value pricing will result in adjustments to the prices of securities or other assets or that fair value pricing will reflect actual market value, and it is possible that the fair value determined for a security or other asset will be materially different from quoted or published prices, from the prices used by others for the same security or other asset and/or from the value that actually could be or is realized upon the sale of that security or other asset. Leverage Risk The Fund’s use of leverage (as described under “Use of Leverage” in the body of this prospectus) creates the opportunity for increased Common Share net income, but also creates special risks for Common Shareholders. To the extent used, there is no assurance that the Fund’s leveraging strategies will be successful. Leverage is a speculative technique that may expose the Fund to greater risk and increased costs. The Fund’s assets attributable to any outstanding Preferred Shares or the net proceeds that the Fund obtains from its use of TOBs, derivatives or other forms of leverage, if any, will be invested in accordance with the Fund’s investment objective and policies as described in this prospectus. Dividends payable with respect to Preferred Shares outstanding and interest expense payable by the Fund with respect to any TOBs, derivatives and other forms of leverage will generally be based on shorter-term interest rates that would be periodically reset. If shorter-term interest rates rise relative to the rate of return on the Fund’s portfolio, the interest and other costs to the Fund of leverage (including interest expenses on TOBs and the dividend rate on any outstanding Preferred Shares s, including the Preferred Shareholder Gross-Up (as defined below)) could exceed the rate of return on the debt obligations and other investments held by the Fund, thereby reducing return to Common Shareholders. In addition, fees and expenses of any form of leverage used by the Fund will be borne entirely by the Common Shareholders (and not by preferred shareholders) and will reduce the investment return of the Common Shares. Therefore, there can be no assurance that the Fund’s use of leverage will result in a higher yield on the Common Shares, and it may result in losses. In addition, Preferred Shares issued by the Fund pay cumulative dividends, which may tend to increase leverage risk. Leverage creates several major types of risks for Common Shareholders, including:
| ∎ | the likelihood of greater volatility of NAV and market price of Common Shares, and of the investment return to Common Shareholders, than a comparable portfolio without leverage;
| ∎ | the possibility either that Common Share dividends will fall if the interest and other costs of leverage rise, or that dividends paid on Common Shares will fluctuate because such costs vary over time; and
| ∎ | the effects of leverage in a declining market or a rising interest rate environment, as leverage is likely to cause a greater decline in the NAV of the Common Shares than if the Fund were not leveraged and may result in a greater decline in the market value of the Common Shares.
In addition, the counterparties to the Fund’s leveraging transactions and preferred shareholders of the Fund will have priority of payment over the Fund’s Common Shareholders. The Fund is required to satisfy certain asset coverage requirements in connection with its use of Preferred Shares, including those imposed by regulatory and rating agency requirements. Accordingly, any decline in the net asset value of the Fund’s investments could result in the risk that the Fund will fail to meet its asset coverage requirements for Preferred Shares or the risk of the Preferred Shares being downgraded by a rating agency. In an extreme case, the Fund’s current investment income might not be sufficient to meet the dividend requirements on Preferred Shares outstanding. In order to address these types of events, the Fund might need to dispose of investments in order to fund a redemption of some or all of the Preferred Shares. Dispositions at times of adverse economic conditions may result in a loss to the Fund. At other times, these dispositions may result in gain at the Fund level and thus in additional taxable distributions to Common Shareholders. See “Tax Matters” for more information. Any Preferred Shares, TOBs, loans of portfolio securities, short sales and when-issued, delayed delivery and forward commitment transactions, credit default swaps, reverse repurchases, or other derivatives by the Fund or counterparties to the Fund’s other leveraging transactions, if any, would have, seniority over the Fund’s Common Shares. In connection with the adoption of Rule 18f-4 under the 1940 Act, the SEC eliminated the asset segregation framework arising from prior SEC guidance for covering derivatives and certain financial instruments, such as TOBs. Accordingly, all disclosure in this Prospectus and the Statement of Additional Information regarding how the Fund will segregate, cover or earmark for derivative investments, including TOBs, will be superseded by the requirements of Rule 18f-4 as of the compliance date, August 19, 2022. See “The New SEC Derivatives Rule and Potential Implications for the Fund” in the Statement of Additional Information for a discussion of how these regulatory changes will affect the Fund’s use of leverage, derivatives and certain related instruments. When the Fund issues Preferred Shares, the Fund pays (and the Common Shareholders bear) all costs and expenses relating to the issuance and ongoing maintenance of Preferred Shares. In addition, holders of Preferred Shares issued by the Fund would have complete priority over Common Shareholders in the distribution of the Fund’s assets. Furthermore, preferred shareholders, voting separately as a single class, have the right to elect two members of the Board at all times and to elect a majority of the trustees in the event two full years’ dividends on the Preferred Shares are unpaid, and also have separate class voting rights on certain matters. Accordingly, preferred shareholders may have interests that differ from those of Common Shareholders, and may at times have disproportionate influence over the Fund’s affairs. Because the fees received by the Investment Manager are based on the average daily net asset value of the Fund (including daily net assets attributable to any Preferred Shares), the Investment Manager has a financial incentive for the Fund to utilize Preferred Shares, which may create a conflict of interest between the Investment Manager, on the one hand, and the Common Shareholders, on the other hand. Segregation and Coverage Risk Certain portfolio management techniques, such as, among other things, entering into TOBs, reverse repurchase agreement transactions, swap agreements, futures contracts or other derivative transactions, purchasing securities on a when-issued or delayed delivery basis or engaging in short sales currently may be considered senior securities unless steps are taken to segregate the Fund’s assets or otherwise cover its obligations. To avoid having these instruments considered senior securities, the Fund may segregate liquid assets with a value equal (on a daily mark-to-market basis) to its obligations under these types of leveraged transactions, enter into offsetting transactions or otherwise cover such transactions. At times, all or a substantial portion of the Fund’s liquid assets may be segregated for purposes of various portfolio transactions. The Fund may be unable to use such segregated assets for certain other purposes, which could result in the Fund earning a lower return on its portfolio than it might otherwise earn if it did not have to segregate those assets in respect of, or otherwise cover, such portfolio positions. To the extent the Fund’s assets are segregated or committed as cover, it could limit the Fund’s investment flexibility. Segregating assets and covering positions will not limit or offset losses on related positions. In connection with the adoption of Rule 18f-4 under the 1940 Act, the SEC eliminated the asset segregation framework arising from prior SEC guidance for covering derivatives and certain financial instruments, such as TOBs. Accordingly, all disclosure in this Prospectus and the Statement of Additional Information regarding how the Fund will segregate, cover or earmark for derivative investments, including TOBs, will be superseded by the requirements of Rule 18f-4 as of the compliance date, August 19, 2022. See “The New SEC Derivatives Rule and Potential Implications for the Fund” in the Statement of Additional Information for a discussion of how these regulatory changes will affect the Fund’s use of leverage, derivatives and certain related instruments. Short Exposure Risk The Fund’s short sales, if any, are subject to special risks. A short sale involves the sale by the Fund of a security that it does not own with the hope of purchasing the same security at a later date at a lower price. The Fund may also enter into a short position through a forward commitment or a short derivative position through a futures contract or swap agreement. If the price of the security or derivative has increased during this time, then the Fund will incur a loss equal to the increase in price from the time that the short sale was entered into plus any transaction costs (i.e., premiums and interest) paid to the broker-dealer to borrow securities. Therefore, short sales involve the risk that losses may be exaggerated, potentially losing more money than the actual cost of the investment. By contrast, a loss on a long position arises from decreases in the value of the security and is limited by the fact that a security’s value cannot decrease below zero. By investing the proceeds received from selling securities short, the Fund could be deemed to be employing a form of leverage, which creates special risks. The use of leverage may increase the Fund’s exposure to long security positions and make any change in the Fund’s NAV greater than it would be without the use of leverage. This could result in increased volatility of returns. There is no guarantee that any leveraging strategy the Fund employs will be successful during any period in which it is employed. In times of unusual or adverse market, economic, regulatory or political conditions, the Fund may not be able, fully or partially, to implement its short selling strategy. Periods of unusual or adverse market, economic, regulatory or political conditions generally may exist for long periods of time. Also, there is the risk that the third party to the short sale will not fulfill its contractual obligations, causing a loss to the Fund. Derivatives Risk The use of derivative instruments involves risks different from, and possibly greater than, the risks associated with investing directly in securities and other traditional investments. Derivatives are subject to a number of risks, such as liquidity risk (which may be heightened for highly-customized derivatives), interest rate risk, market risk, credit risk, leveraging risk, counterparty risk, tax risk and management risk, as well as risks arising from changes in applicable requirements. They also involve the risk of mispricing, the risk of unfavorable or ambiguous documentation and the risk that changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index. If the Fund invests in a derivative instrument, the Fund could lose more than the amount invested and derivatives may increase the volatility of the Fund, especially in unusual or extreme market conditions. Also, suitable derivative transactions may not be available in all circumstances and there can be no assurance that the Fund will engage in these transactions to reduce exposure to other risks when that would be beneficial or that, if used, such strategies will be successful. The Fund’s use of derivatives may increase or accelerate the amount of taxes payable by Common Shareholders. Over-the-counter (“OTC”) derivatives are also subject to the risk that a counterparty to the transaction will not fulfill its contractual obligations to the other party, as many of the protections afforded to centrally-cleared derivative transactions might not be available for OTC derivative transactions. For derivatives traded on an exchange or through a central counterparty, credit risk resides with the Fund’s clearing broker, or the clearinghouse, rather than with a counterparty in an OTC derivative transaction. The primary credit risk on derivatives that are exchange-traded or traded through a central clearing counterparty resides with the Fund’s clearing broker, or the clearinghouse. Participation in the markets for derivative instruments involves investment risks and transaction costs to which the Fund may not be subject absent the use of these strategies. The skills needed to successfully execute derivative strategies may be different from those needed for other types of transactions. If the Fund incorrectly forecasts the value and/or creditworthiness of securities, currencies, interest rates, counterparties or other economic factors involved in a derivative transaction, the Fund might have been in a better position if the Fund had not entered into such derivative transaction. In evaluating the risks and contractual obligations associated with particular derivative instruments, it is important to consider that certain derivative transactions may be modified or terminated only by mutual consent of the Fund and its counterparty. Therefore, it may not be possible for the Fund to modify, terminate, or offset the Fund’s obligations or the Fund’s exposure to the risks associated with a derivative transaction prior to its scheduled termination or maturity date, which may create a possibility of increased volatility and/or decreased liquidity to the Fund. Because the markets for certain derivative instruments (including markets located in foreign countries) are relatively new and still developing, appropriate derivative transactions may not be available in all circumstances for risk management or other purposes. Upon the expiration of a particular contract, the Fund may wish to retain the Fund’s position in the derivative instrument by entering into a similar contract, but may be unable to do so if the counterparty to the original contract is unwilling to enter into the new contract and no other appropriate counterparty can be found. When such markets are unavailable, the Fund will be subject to increased liquidity and investment risk. The Fund may enter into opposite sides of interest rate swap and other derivatives for the principal purpose of generating distributable gains on the one side (characterized as ordinary income for tax purposes) that are not part of the Fund’s duration or yield curve management strategies (“paired swap transactions”), and with a substantial possibility that the Fund will experience a corresponding capital loss and decline in NAV with respect to the opposite side transaction (to the extent it does not have corresponding offsetting capital gains). Consequently, Common Shareholders may receive distributions and owe tax on amounts that are effectively a taxable return of the shareholder’s investment in the Fund, at a time when their investment in the Fund has declined in value, which tax may be at ordinary income rates. The tax treatment of certain derivatives in which the Fund invests may be unclear and thus subject to recharacterization. Any recharacterization of payments made or received by the Fund pursuant to derivatives potentially could affect the amount, timing or character of Fund distributions. In addition, the tax treatment of such investment strategies may be changed by regulation or otherwise. When a derivative is used as a hedge against a position that the Fund holds, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. Although hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying instrument, and there can be no assurance that the Fund’s hedging transactions will be effective. In such case, the Fund may lose money. The regulation of the derivatives markets has increased over the past several years, and additional future regulation of the derivatives markets may make derivatives more costly, may limit the availability or reduce the liquidity of derivatives or may otherwise adversely affect the value or performance of derivatives. Any such adverse future developments could impair the effectiveness or raise the costs of the Fund’s derivative transactions, impede the employment of the Fund’s derivatives strategies, or adversely affect the Fund’s performance and cause the Fund to lose value. For instance, on October 28, 2020, the SEC adopted Rule 18f-4 under the 1940 Act providing for the regulation of a registered investment company’s use of derivatives and certain related instruments. Among other things, Rule 18f-4 limits the Fund’s derivatives exposure through a value-at-risk test and requires the adoption and implementation of a derivatives risk management program for certain derivatives users. Subject to certain conditions, limited derivatives users (as defined in Rule 18f-4), however, would not be subject to the full requirements of Rule 18f-4. In connection with the adoption of Rule 18f-4 under the 1940 Act, the SEC also eliminated the asset segregation framework arising from prior SEC guidance for covering derivatives and certain financial instruments, such as TOBs. Accordingly, all disclosure in this Prospectus and the Statement of Additional Information regarding how the Fund will segregate, cover or earmark for derivative investments, including TOBs, will be superseded by the requirements of Rule 18f-4 as of the compliance date, August 19, 2022. As the Fund comes into compliance, the Fund’s approach to asset segregation and coverage requirements will be impacted. In addition, Rule 18f-4 could restrict the Fund’s ability to engage in certain derivatives transactions and/or increase the costs of such derivatives transactions, which could adversely affect the value or performance of the Fund and the Common Shares and/or the Fund’s distribution rate. See “The New SEC Derivatives Rule and Potential Implications for the Fund” in the Statement of Additional Information for a discussion of how these regulatory changes will affect the Fund’s use of leverage, derivatives and certain related instruments. Counterparty Risk The Fund will be subject to credit risk with respect to the counterparties to the derivative contracts and other instruments entered into by the Fund or held by special purpose or structured vehicles in which the Fund invests. In the event that the Fund enters into a derivative transaction with a counterparty that subsequently becomes insolvent or becomes the subject of a bankruptcy case, the derivative transaction may be terminated in accordance with its terms and the Fund’s ability to realize its rights under the derivative instrument and its ability to distribute the proceeds could be adversely affected. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery (including recovery of any collateral it has provided to the counterparty) in a dissolution, assignment for the benefit of creditors, liquidation, winding-up, bankruptcy or other analogous proceeding. In addition, in the event of the insolvency of a counterparty to a derivative transaction, the derivative transaction would typically be terminated at its fair market value. If the Fund is owed this fair market value in the termination of the derivative transaction and its claim is unsecured, the Fund will be treated as a general creditor of such counterparty and will not have any claim with respect to any underlying security or asset. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances. While the Fund may seek to manage its counterparty risk by transacting with a number of counterparties, concerns about the solvency of, or a default by, one large market participant could lead to significant impairment of liquidity and other adverse consequences for other counterparties. Additional Risks Associated with the Fund’s Preferred Shares Although the Fund’s ARPS ordinarily would pay dividends at rates set at periodic auctions, the weekly auctions for the ARPS (and auctions for similar preferred shares issued by closed-end funds in the U.S.) have failed since 2008. The dividend rates on the ARPS since that time have been paid, and the Fund expects that they will continue to be paid for the foreseeable future, at the “maximum applicable rate.” The maximum applicable rate for the ARPS and the RVMTP Share Dividend Rate (as defined below) is based in part on a multiple of or a spread plus a reference rate. An increase in market interest rates generally, therefore, could increase substantially the dividend rate required to be paid by the Fund to the holders of Preferred Shares, which would increase the costs associated with the Fund’s leverage and reduce the Fund’s net income available for distribution to holders of Common Shares. In addition, the multiple or spread used to calculate the maximum applicable rate for the ARPS and the RVMTP Share Dividend Rate is based in part on the credit rating assigned to the ARPS or RVMTP Shares by the applicable rating agency(ies), with the multiple or spread generally increasing as the rating declines. Accordingly, future ratings downgrades may result in increases to the maximum applicable rate for the ARPS or to the RVMTP Share Dividend Rate. Therefore, it is possible that a substantial rise in market interest rates and/or further ratings downgrades of the Preferred Shares could, by reducing income available for distribution to the holders of Common Shares and otherwise detracting from the Fund’s investment performance, make the Fund’s continued use of Preferred Shares for leverage purposes less attractive than such use is currently considered to be. In such case, the Fund may elect to redeem some or all of the Preferred Shares outstanding, which may require it to dispose of investments at inopportune times and to incur losses on such dispositions. Such dispositions may adversely affect the Fund’s investment performance generally, and the resultant loss of leverage may materially and adversely affect the Fund’s investment returns. The Fund is also subject to certain asset coverage tests associated with the rating agencies that rate the Preferred Shares. Failure by the Fund to maintain the asset coverages (or to cure such failure in a timely manner) may require the Fund to redeem Preferred Shares and could preclude the Fund from declaring or paying any dividends or distributions to holders of Common Shares. Failure to satisfy ratings agency asset coverage tests or other guidelines could also result in the applicable ratings agency downgrading its then-current ratings on the Preferred Shares, as described above. Moreover, the rating agency guidelines impose restrictions or limitations on the Fund’s use of certain financial instruments or investment techniques that the Fund might otherwise utilize in order to achieve its investment objective, which may adversely affect the Fund’s investment performance. Rating agency guidelines may be modified by the rating agencies in the future and such modifications may make such guidelines substantially more restrictive or otherwise result in downgrades, which could further negatively affect the Fund’s investment performance. The ratings agencies that have assigned ratings to the Fund’s Preferred Shares may change their rating methodologies, perhaps substantially. Such a change could adversely affect the ratings assigned to the Fund’s Preferred Shares, the dividend rates paid thereon, and the expenses borne by holders of Common Shares. For instance, Fitch Ratings published ratings criteria relating to closed-end funds on December 4, 2020, which effectively result in a rating cap of “AA” for debt and preferred stock issued by all closed-end funds and a rating cap of “A” for debt and preferred shares issued by (i) closed-end funds exposed to emerging market debt, below-investment-grade and unrated debt, structured securities and equity, and (ii) closed-end funds with material exposure to “BBB” category rated assets. On December 6, 2021, Fitch affirmed “AA” long-term ratings of the Fund’s RVMTP Shares. Fitch does not currently rate the Fund’s ARPS. In addition, future ratings downgrades by Moody’s or Fitch, as applicable, may result in an increase to the Fund’s Preferred Shares dividend rates. Confidential Information Access Risk In managing the Fund (and other PIMCO clients), PIMCO may from time to time have the opportunity to receive material, non-public information (“Confidential Information”) about the issuers of certain investments, including, without limitation, senior floating rate loans, other loans and related investments being considered for acquisition by the Fund or held in the Fund’s portfolio. For example, an issuer of privately placed loans considered by the Fund may offer to provide PIMCO with financial information and related documentation regarding the issuer that is not publicly available. Pursuant to applicable policies and procedures, PIMCO may (but is not required to) seek to avoid receipt of Confidential Information from the issuer so as to avoid possible restrictions on its ability to purchase and sell investments on behalf of the Fund and other clients to which such Confidential Information relates. In such circumstances, the Fund (and other PIMCO clients) may be disadvantaged in comparison to other investors, including with respect to the price the Fund pays or receives when it buys or sells an investment. Further, PIMCO’s and the Fund’s abilities to assess the desirability of proposed consents, waivers or amendments with respect to certain investments may be compromised if they are not privy to available Confidential Information. PIMCO may also determine to receive such Confidential Information in certain circumstances under its applicable policies and procedures. If PIMCO intentionally or unintentionally comes into possession of Confidential Information, it may be unable, potentially for a substantial period of time, to purchase or sell investments to which such Confidential Information relates. Private Placements and Restricted Securities Risk A private placement involves the sale of securities that have not been registered under the Securities Act or relevant provisions of applicable non-U.S. law to certain institutional and qualified individual purchasers, such as the Fund. In addition to the general risks to which all securities are subject, securities received in a private placement generally are subject to strict restrictions on resale, and there may be no liquid secondary market or ready purchaser for such securities. See “Principal Risks of the Fund—Liquidity Risk.” Therefore, the Fund may be unable to dispose of such securities when it desires to do so, or at the most favorable time or price. Private placements may also raise valuation risks. Restricted securities are often purchased at a discount from the market price of unrestricted securities of the same issuer reflecting the fact that such securities may not be readily marketable without some time delay. Such securities are often more difficult to value and the sale of such securities often requires more time and results in higher brokerage charges or dealer discounts and other selling expenses than does the sale of securities trading on national securities exchanges or in the over-the-counter markets. Until the Fund can sell such securities into the public markets, its holdings may be less liquid and any sales will need to be made pursuant to an exemption under the Securities Act. Inflation/Deflation Risk Inflation risk is the risk that the value of assets or income from the Fund’s investments will be worth less in the future as inflation decreases the value of payments at future dates. As inflation increases, the real value of the Fund’s portfolio could decline. Inflation has recently increased and it cannot be predicted whether it may decline. Deflation risk is the risk that prices throughout the economy decline over time. Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result in a decline in the value of the Fund’s portfolio and Common Shares. Regulatory Changes Risk Financial entities, such as investment companies and investment advisers, are generally subject to extensive government regulation and intervention. Government regulation and/or intervention may change the way the Fund is regulated, affect the expenses incurred directly by the Fund and the value of its investments, and limit and /or preclude the Fund’s ability to achieve its investment objective. Government regulation may change frequently and may have significant adverse consequences. The Fund and the Investment Manager have historically been eligible for exemptions from certain regulations. However, there is no assurance that the Fund and the Investment Manager will continue to be eligible for such exemptions. Actions by governmental entities may also impact certain instruments in which the Fund invests. Moreover, government regulation may have unpredictable and unintended effects. Legislative or regulatory actions to address perceived liquidity or other issues in fixed income markets generally, or in particular markets such as the municipal securities market, may alter or impair the Fund’s ability to pursue its investment objective or utilize certain investment strategies and techniques. Current rules related to credit risk retention requirements for ABS may increase the cost to originators, securitizers and, in certain cases, asset managers of securitization vehicles in which the Fund may invest. The impact of the risk retention rules on the securitization markets is uncertain. These requirements may increase the costs to originators, securitizers, and, in certain cases, collateral managers of securitization vehicles in which the Fund may invest, which costs could be passed along to the Fund as an investor in such vehicles. In addition, the costs imposed by the risk retention rules on originators, securitizers and/or collateral managers may result in a reduction of the number of new offerings of ABS and thus in fewer investment opportunities for the Fund. A reduction in the number of new securitizations could also reduce liquidity in the markets for certain types of financial assets, which in turn could negatively affect the returns on the Fund’s investment. Regulatory Risk – London Interbank Offered Rate (“LIBOR”) The Fund’s investments (including, but not limited to, repurchase agreements, collateralized loan obligations and mortgage-backed securities), payment obligations and financing terms may rely in some fashion on the London Interbank Offered Rate (“LIBOR”). LIBOR is an average interest rate, determined by the ICE Benchmark Administration that banks charge one another for the use of short-term money. ,On July 27, 2017, the Chief Executive of the FCA announced that after 2021 it would cease its active encouragement of banks to provide the quotations needed to sustain LIBOR due to the absence of an active market for interbank unsecured lending and other reasons. On March 5, 2021, the FCA publicly announced that all U.S. Dollar LIBOR settings will either cease to be provided by any administrator or will no longer be representative (i) immediately after December 31, 2021 for one-week and two-month U.S. Dollar LIBOR settings and (ii) immediately after June 30, 2023 for the remaining U.S. Dollar LIBOR settings. As of January 1, 2022, as a result of supervisory guidance from U.S. regulators, some U.S. regulated entities have ceased entering into new LIBOR contracts with limited exceptions. While publication of the one-, three- and six- month Sterling and Japanese yen LIBOR settings will continue at least through calendar year 2022 on the basis of a changed methodology (known as “synthetic LIBOR”), these rates have been designated by the FCA as unrepresentative of the underlying market they seek to measure and are solely available for use in legacy transactions. Certain bank-sponsored committees in other jurisdictions, including Europe, the United Kingdom, Japan and Switzerland, have selected alternative reference rates denominated in other currencies. Although the transition process away from LIBOR has become increasingly well-defined in advance of the anticipated discontinuation date, there remains uncertainty regarding the future utilization of LIBOR and the nature of any replacement rate (e.g., the Secured Overnight Financing Rate, which is intended to replace U.S. dollar LIBOR and measures the cost of overnight borrowings through repurchase agreement transactions collateralized with U.S. Treasury securities). Any potential effects of the transition away from LIBOR on the Fund or on certain instruments in which the Fund invests can be difficult to ascertain, and they may vary depending on factors that include, but are not limited to: (i) existing fallback or termination provisions in individual contracts and (ii) whether, how, and when industry participants develop and adopt new reference rates and fallbacks for both legacy and new products and instruments. For example, certain of the Fund’s investments may involve individual contracts that have no existing fallback provision or language that contemplates the discontinuation of LIBOR, and those investments could experience increased volatility or illiquidity as a result of the transition process. In addition, interest rate provisions included in such contracts, or in contracts or other arrangements entered into by the Fund, may need to be renegotiated. On March 15, 2022, the Adjustable Interest Rate (LIBOR) Act was signed into law. This law provides a statutory fallback mechanism on a nationwide basis to replace LIBOR with a benchmark rate that is selected by the Board of Governors of the Federal Reserve System and based on the Secured Overnight Financing Rate for certain contracts that reference LIBOR and contain no, or insufficient, fallback provisions. It is expected that implementing regulations in respect of the law will follow. The transition of investments from LIBOR to a replacement rate as a result of amendment, application of existing fallbacks, statutory requirements or otherwise may also result in a reduction in the value of certain instruments held by the Fund, a change in the cost of borrowing or the dividend rate for any Preferred Shares that may be issued by the Fund, or a reduction in the effectiveness of related Fund transactions such as hedges. Any such effects of the transition away from LIBOR, as well as other unforeseen effects, could result in losses to the Fund.​​​​​​​ Regulatory Risk – Commodity Pool Operator The CFTC has adopted regulations that subject registered investment companies and their investment advisers to regulation by the CFTC if the registered investment company invests more than a prescribed level of its liquidation value in futures, options on futures or commodities, swaps, or other financial instruments regulated under the CEA and the rules thereunder (“commodity interests”), or if the Fund markets itself as providing investment exposure to such instruments. The Investment Manager is registered with the CFTC as a CPO. However, with respect to the Fund, the Investment Manager has claimed an exclusion from registration as a CPO pursuant to CFTC Rule 4.5. For the Investment Manager to remain eligible for this exclusion, the Fund must comply with certain limitations, including limits on its ability to use any commodity interests and limits on the manner in which the Fund holds out its use of such commodity interests. These limitations may restrict the Fund’s ability to pursue its investment objective and strategies increase the costs of implementing its strategies, result in higher expenses for the Fund, and/or adversely affect the Fund’s total return. To the extent the Fund becomes ineligible for this exclusion from CFTC regulation, the Fund may consider steps in order to continue to qualify for exemption from CFTC regulation, or may determine to operate subject to CFTC regulation. Liquidity Risk Liquidity risk exists when particular investments are difficult to purchase or sell. Illiquid investments are investments that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. Illiquid investments may become harder to value, especially in changing markets. The Fund’s investments in illiquid investments may reduce the returns of the Fund because it may be unable to sell the illiquid investments at an advantageous time or price or possibly require the Fund to dispose of other investments at unfavorable times or prices in order to satisfy its obligations, which could prevent the Fund from taking advantage of other investment opportunities. Additionally, the market for certain investments may become illiquid under adverse market or economic conditions independent of any specific adverse changes in the conditions of a particular issuer. Bond markets have consistently grown over the past three decades while the capacity for traditional dealer counterparties to engage in fixed income trading has not kept pace and in some cases has decreased. As a result, dealer inventories of corporate bonds, which provide a core indication of the ability of financial intermediaries to “make markets,” are at or near historic lows in relation to market size. Because market makers seek to provide stability to a market through their intermediary services, a significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty. In such cases, the Fund, due to the difficulty in purchasing and selling such securities or instruments, may be unable to achieve its desired level of exposure to a certain sector. To the extent that the Fund invests in securities of companies with smaller market capitalizations, foreign (non-U.S.) securities, Rule 144A securities, illiquid sectors of fixed income securities, derivatives or securities with substantial market and/or credit risk, the Fund will tend to have greater exposure to liquidity risk. Further fixed income securities with longer durations until maturity face heightened levels of liquidity risk as compared to fixed income securities with shorter durations until maturity. The risks associated with illiquid instruments may be particularly acute in situations in which the Fund’s operations require cash (such as in connection with tender offers) and could result in the Fund borrowing to meet its short-term needs or incurring losses on the sale of illiquid instruments. It may also be the case that other market participants may be attempting to liquidate fixed income holdings at the same time as the Fund, causing increased supply in the market and contributing to liquidity risk and downward pricing pressure. Tax Risk The Fund has elected to be treated as a RIC under the Code and intends each year to qualify and be eligible to be treated as such, so that it generally will not be subject to U.S. federal income tax on its net investment income or net short-term or long-term capital gains, that are distributed to shareholders. In order to qualify and be eligible for such treatment, the Fund must meet certain asset diversification tests, derive at least 90% of its gross income for such year from certain types of qualifying income, and distribute to its shareholders at least 90% of its “investment company taxable income” as that term is defined in the Code (which includes, among other things, dividends, taxable interest and the excess of any net short-term capital gains over net long-term capital losses, as reduced by certain deductible expenses). The Fund’s investment strategy will potentially be limited by its intention to continue qualifying for treatment as a RIC, and can limit the Fund’s ability to continue qualifying as such. The tax treatment of certain of the Fund’s investments under one or more of the qualification or distribution tests applicable to RICs is uncertain. An adverse determination or future guidance by the IRS or a change in law might affect the Fund’s ability to qualify or be eligible for treatment as a RIC. Income and gains from certain of the Fund’s activities may not constitute qualifying income to a RIC for purposes of the 90% gross income test. If the Fund were to treat income or gain from a particular investment or activity as qualifying income and the income or gain were later determined not to constitute qualifying income and, together with any other nonqualifying income, caused the Fund’s nonqualifying income to exceed 10% of its gross income in any taxable year, the Fund would fail to qualify as a RIC unless it is eligible to and does pay a tax at the Fund level. If, in any year, the Fund were to fail to qualify for treatment as a RIC under the Code, and were ineligible to or did not otherwise cure such failure, the Fund would be subject to tax on its taxable income at corporate rates and, when such income is distributed, shareholders would be subject to further tax on such distributions to the extent of the Fund’s current or accumulated earnings and profits. Portfolio Turnover Risk The Investment Manager manages the Fund without regard generally to restrictions on portfolio turnover. The use of futures contracts and other derivative instruments with relatively short maturities may tend to exaggerate the portfolio turnover rate for the Fund. Trading in fixed income securities does not generally involve the payment of brokerage commissions, but does involve indirect transaction costs. The use of futures contracts and other derivative instruments may involve the payment of commissions to futures commission merchants or other intermediaries. Higher portfolio turnover involves correspondingly greater expenses to the Fund, including brokerage commissions or dealer mark-ups and other transaction costs on the sale of securities and reinvestments in other securities. The higher the rate of portfolio turnover of the Fund, the higher these transaction costs borne by the Fund generally will be. Such sales may result in realization of taxable capital gains (including short-term capital gains, which are generally taxed to shareholders at ordinary income tax rates when distributed net of short-term capital losses and net long-term capital losses), and may adversely impact the Fund’s after-tax returns. Operational Risk An investment in the Fund, like any fund, involves operational risks arising from factors such as processing errors, human errors, inadequate or failed internal or external processes, failures in systems and technology, changes in personnel and errors caused by third-party service providers. The occurrence of any of these failures, errors or breaches could result in a loss of information, regulatory scrutiny, reputational damage or other events, any of which could have a material adverse effect on the Fund. While the Fund seeks to minimize such events through controls and oversight, there may still be failures that could cause losses to the Fund. Other Investment Companies Risk When investing in an investment company, the Fund generally will bear its ratable share of that investment company’s expenses and remain subject to payment of the Fund’s management fees and other expenses with respect to assets so invested. Common Shareholders could therefore be subject to duplicative expenses to the extent the Fund invests in other investment companies. In addition, the securities of other investment companies may also be leveraged and will therefore be subject to the same leverage risks. Cybersecurity Risk As the use of technology has become more prevalent in the course of business, the Fund is potentially more susceptible to operational and information security risks resulting from breaches in cyber security. A breach in cyber security refers to both intentional and unintentional cyber events from outside threat actors or internal resources that may, among other things, cause the Fund to lose proprietary information, suffer data corruption and/or destruction, lose operational capacity, result in the unauthorized release or other misuse of confidential information, or otherwise disrupt normal business operations. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems (e.g., through “hacking” or malicious software coding), and may come from multiple sources, including outside attacks such as denial-of-service attacks (i.e., efforts to make network services unavailable to intended users) or cyber extortion, including exfiltration of data held for ransom and/or “ransomware” attacks that renders systems inoperable until ransom is paid, or insider actions. In addition, cyber security breaches involving the Fund’s third party service providers (including but not limited to advisers, sub-advisers, administrators, transfer agents, custodians, vendors, suppliers, distributors and other third parties), trading counterparties or issuers in which the Fund invests can also subject the Fund to many of the same risks associated with direct cyber security breaches or extortion of company data. Moreover, cyber security breaches involving trading counterparties or issuers in which the Fund invests could adversely impact such counterparties or issuers and cause the Fund’s investment to lose value. Cyber security failures or breaches may result in financial losses to the Fund and its shareholders. These failures or breaches may also result in disruptions to business operations, potentially resulting in financial losses; interference with the Fund’s ability to calculate its NAV, process shareholder transactions or otherwise transact business with shareholders; impediments to trading; violations of applicable privacy and other laws; regulatory fines; penalties; third party claims in litigation; reputational damage; reimbursement or other compensation costs; additional compliance and cyber security risk management costs and other adverse consequences. In addition, substantial costs may be incurred in order to prevent any cyber incidents in the future. Like with operational risk in general, the Fund has established business continuity plans and risk management systems designed to reduce the risks associated with cyber security. However, there are inherent limitations in these plans and systems, including that certain risks may not have been identified, in large part because different or unknown threats may emerge in the future. As such, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers in which the Fund may invest, trading counterparties or third party service providers to the Fund. Such entities have experienced cyber attacks and other attempts to gain unauthorized access to systems from time to time, and there is no guarantee that efforts to prevent or mitigate the effects of such attacks or other attempts to gain unauthorized access will be successful. There is also a risk that cyber security breaches may not be detected. The Fund and its shareholders may suffer losses as a result of a cyber security breach related to the Fund, its service providers, trading counterparties or the issuers in which the Fund invests.​​​​​​​ Potential Conflicts of Interest Risk—Allocation of Investment Opportunities The Investment Manager and its affiliates are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. The Investment Manager may provide investment management services to other funds and discretionary managed accounts that follow an investment program similar to that of the Fund. Subject to the requirements of the 1940 Act, the Investment Manager intends to engage in such activities and may receive compensation from third parties for its services. The results of the Fund’s investment activities may differ from those of other accounts managed by the Investment Manager or its affiliates, and it is possible that the Fund could sustain losses during periods in which one or more other accounts managed by the Investment Manager or its affiliates, including proprietary accounts, achieve profits on their trading. Repurchase Agreements Risk The Fund may enter into repurchase agreements, in which the Fund purchases a security from a bank or broker-dealer, which agrees to repurchase the security at the Fund’s cost plus interest within a specified time. If the party agreeing to repurchase should default, the Fund will seek to sell the securities which it holds. This could involve procedural costs or delays in addition to a loss on the securities if their value should fall below their repurchase price. Repurchase agreements may be or become illiquid. These events could also trigger adverse tax consequences for the Fund. Structured Investments Risk Holders of structured products, including structured notes, credit-linked notes and other types of structured products, bear the risks of the underlying investments, index or reference obligation and are subject to counterparty risk. The Fund may have the right to receive payments only from the structured product, and generally does not have direct rights against the issuer or the entity that sold the assets to be securitized. While certain structured products enable the investor to acquire interests in a pool of securities without the brokerage and other expenses associated with directly holding the same securities, investors in structured products generally pay their share of the structured product’s administrative and other expenses. Although it is difficult to predict whether the prices of indices and securities underlying structured products will rise or fall, these prices (and, therefore, the prices of structured products) are generally influenced by the same types of political and economic events that affect issuers of securities and capital markets generally. If the issuer of a structured product uses shorter term financing to purchase longer term securities, the issuer may be forced to sell its securities at below market prices if it experiences difficulty in obtaining such financing, which may adversely affect the value of the structured products owned by the Fund. Structured products generally entail risks associated with derivative instruments. Market Disruptions Risk The Fund is subject to investment and operational risks associated with financial, economic and other global market developments and disruptions, including those arising from war, terrorism, market manipulation, government interventions, defaults and shutdowns, political changes or diplomatic developments, public health emergencies (such as the spread of infectious diseases, pandemics and epidemics) and natural/environmental disasters, which can all negatively impact the securities markets, interest rates, secondary trading, ratings, credit risk, inflation, deflation, other factors relating to the Fund’s investments or the Investment Manager’s operations and the value of an investment in the Fund, its distributions and its returns. These events can also impair the technology and other operational systems upon which the Fund’s service providers, including PIMCO as the Fund’s investment adviser, rely, and could otherwise disrupt the Fund’s service providers’ ability to fulfill their obligations to the Fund. For example, the recent spread of an infectious respiratory illness caused by a novel strain of coronavirus (known as COVID-19) has caused volatility, severe market dislocations and liquidity constraints in many markets, including markets for the securities the Fund holds, and may adversely affect the Fund’s investments and operations. The U.S. Federal Reserve made emergency interest-rate cuts, moving short-term rates to near zero, issued forward guidance that rates would remain low until the economy weathers the COVID-19 crisis, and resumed quantitative easing. Additionally, Congress approved stimulus to offset the severity and duration of the adverse economic effects of COVID-19 and related disruptions in economic and business activity. Dozens of central banks across Europe, Asia, and elsewhere have announced and/or adopted similar economic relief packages. The end of any such programs could cause market downturns, disruptions and volatility, particularly if markets view the ending as premature. Certain Affiliations Certain broker-dealers may be considered to be affiliated persons of the Fund and/or the Investment Manager due to their possible affiliations with Allianz SE, the ultimate parent of the Investment Manager. Absent an exemption from the SEC or other regulatory relief, the Fund is generally precluded from effecting certain principal transactions with affiliated brokers, and its ability to purchase securities being underwritten by an affiliated broker or a syndicate including an affiliated broker, or to utilize affiliated brokers for agency transactions, is subject to restrictions. This could limit the Fund’s ability to engage in securities transactions and take advantage of market opportunities. Anti-Takeover Provisions The Declaration includes provisions that could limit the ability of other entities or persons to acquire control of the Fund or to convert the Fund to open-end status. See “Anti-Takeover and Other Provisions in the Declaration of Trust and Bylaws.” These provisions in the Declaration could have the effect of depriving the Common Shareholders of opportunities to sell their Common Shares at a premium over the then-current market price of the Common Shares or at NAV. Distribution Rate Risk Although the Fund may seek to maintain level distributions, the Fund’s distribution rates may be affected by numerous factors, including but not limited to changes in realized and projected market returns, fluctuations in market interest rates, Fund performance, and other factors. There can be no assurance that a change in market conditions or other factors will not result in a change in the Fund’s distribution rate or that the rate will be sustainable in the future. For instance, during periods of low or declining interest rates, the Fund’s distributable income and dividend levels may decline for many reasons. For example, the Fund may have to deploy uninvested assets (whether from purchases of Fund shares, proceeds from matured, traded or called debt obligations or other sources) in new, lower yielding instruments. Additionally, payments from certain instruments that may be held by the Fund (such as variable and floating rate securities) may be negatively impacted by declining interest rates, which may also lead to a decline in the Fund’s distributable income and dividend levels. AMT Bonds Risk Investments by the Fund in AMT Bonds may expose the Fund to certain risks in addition to those typically associated with municipal bonds. Interest or principal on AMT Bonds paid out of current or anticipated revenues from a specific project or specific asset may be adversely impacted by declines in revenue from the project or asset. Declines in general business activity could also affect the economic viability of facilities that are the sole source of revenue to support AMT Bonds. In this regard, AMT Bonds may entail greater risks than general obligation municipal bonds. For shareholders subject to the federal alternative minimum tax, a portion of the Fund’s distributions may not be exempt from gross federal income, which may give rise to alternative minimum tax liability. Focused Investment Risk Substantial exposure to municipal bonds of particular issuers, geographies and/or jurisdictions will result in susceptibility to political, economic, regulatory and other factors affecting issuers of such bonds, their ability to meet their obligations and the economic condition of the facility or specific revenue source from whose revenues payments of obligations may be made. The ability of state, county, or local governments or other issuers to meet their obligations will depend primarily on the availability of tax and other revenues to those entities. The amounts of tax and other revenues available to issuers may be affected from time to time by economic, political and demographic conditions that specifically impact such issuers. In addition, there are constitutional and statutory restrictions that limit the power of certain issuers to raise revenues or increase taxes. The availability of federal, state and local aid to issuers may also affect their ability to meet their obligations. The creditworthiness of obligations issued by local issuers within a given state may be unrelated to the creditworthiness of obligations issued by the state and there is no obligation on the part of the state to make payment on such local obligations in the event of default. Any reduction in the actual or perceived ability of an issuer to meet its obligations (including a reduction in the rating of its outstanding securities) would likely affect adversely the market value and marketability of its obligations and could adversely affect the values of other bonds as well. Moreover, in such circumstances, the value of the Fund’s shares may fluctuate more widely than the value of shares of a more diversified fund. Many factors, including national economic, social and environmental policies and conditions, which are not within the control of issuers, could affect or could have an adverse impact on the financial condition of the issuers. The Fund is unable to predict whether or to what extent such factors or other factors may affect issuers, the market value or marketability of such bonds or the ability of the respective issuers of the bonds acquired by the Fund to pay interest on or principal of such bonds. CSDR Related Risk The European Union has adopted a settlement discipline regime under Regulation (EU) No 909/2014 and the Settlement Discipline RTS as they may be modified from time to time (“CSDR”), which will have phased compliance dates. It aims to reduce the number of settlement fails that occur in EEA central securities depositories (“CSDs”) and address settlement fails where they occur. The key elements of the regime are: (i) mandatory buy-ins—if a settlement fail continues for a specified period of time after the intended settlement date, a buy-in process must be initiated to effect the settlement; (ii) cash penalties—EEA CSDs are required to impose cash penalties on participants that cause settlement fails and distribute these to receiving participants; and (iii) allocations and confirmations—EEA investment firms are required to take measures to prevent settlement fails, including putting in place arrangements with their professional clients to communicate securities allocations and transaction confirmations. These requirements apply to transactions in transferable securities (e.g., shares and bonds), money market instruments, units in funds and emission allowances that are to be settled via an EEA CSD and, in the case of cash penalties and buy-in requirements only, are admitted to trading or traded on an EEA trading venue or cleared by an EEA central counterparty. The implementation of the CSDR settlement discipline regime for funds that enter into in-scope transactions may result in increased operational and compliance costs being borne directly or indirectly by the Fund. CSDR may also affect liquidity and increase trading costs associated with relevant securities. If in-scope transactions are subject to additional expenses and penalties as a consequence of the CSDR settlement discipline regime, such expenses and penalties may be charged to the relevant Fund depending upon their characterization under the Fund’s Investment Management Agreement.​​​​​​​ Insurance Risk The Fund may purchase municipal securities that are secured by insurance, bank credit agreements or escrow accounts. The credit quality of the companies that provide such credit enhancements will affect the value of those securities. Certain significant providers of insurance for municipal securities have incurred significant losses as a result of exposure to sub-prime mortgages and other lower credit quality investments that have experienced recent defaults or otherwise suffered extreme credit deterioration. As a result, such losses reduced the insurers’ capital and called into question their continued ability to perform their obligations under such insurance if they are called upon to do so in the future. If the insurer of a municipal security suffers a downgrade in its credit rating or the market discounts the value of the insurance provided by the insurer, the rating of the underlying municipal security will be more relevant and the value of the municipal security would more closely, if not entirely, reflect such rating. In such a case, the value of insurance associated with a municipal security would decline and may not add any value. The insurance feature of a municipal security does not guarantee the full payment of principal and interest through the life of an insured obligation, the market value of the insured obligation or the net asset value of the common shares represented by such insured obligation. Investing in the municipal bond market involves the risks of investing in debt securities generally and certain other risks. The amount of public information available about the municipal bonds in which the Fund may invest is generally less than that for corporate equities or bonds, and the investment performance of the Fund’s investment in municipal bonds may therefore be more dependent on the analytical abilities of PIMCO than its investments in taxable bonds. The secondary market for municipal bonds also tends to be less well developed or liquid than many other securities markets, which may adversely affect the Fund’s ability to sell municipal bonds at attractive prices. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Effects of Leverage [Text Block] |  | Effects of Leverage The following table is furnished in response to requirements of the SEC. It is designed to illustrate the effects of leverage through the use of senior securities, as that term is defined under Section 18 of the 1940 Act, on Common Share total return, assuming investment portfolio total returns (consisting of income and changes in the value of investments held in the Fund’s portfolio) of -10%, -5%, 0%, 5% and 10%. The table below assumes the Fund’s continued use of Preferred Shares averaged over the year ended December 31, 2021, representing approximately 27.09% of the Fund’s total managed assets, and, although not senior securities under the 1940 Act, the Fund’s use of TOBs averaged over the year ended December 31, 2021, representing approximately 14.89% of the Fund’s total average managed assets. The table below also assumes that the Fund will pay dividends on Preferred Shares at an estimated annual effective Preferred Share dividend rate of 1 .9 3 % for ARPS and 1.83% for RVMTP (as of June 30, 2022) and interest on TOBs at an estimated annual effective interest expense rate of 0.84% (as of June 30, 2022). Based on such estimates, the annual return that the Fund’s portfolio must experience (net of expenses) in order to cover such costs is 0.64%. The information below does not reflect any Fund’s use of certain other forms of economic leverage achieved through the use of other instruments or transactions not considered to be senior securities under the 1940 Act, such as covered credit default swaps or other derivative instruments. The assumed investment portfolio returns in the table below are hypothetical figures and are not necessarily indicative of the investment portfolio returns experienced or expected to be experienced by the Fund. Your actual returns may be greater or less than those appearing below. In addition, the actual Preferred Share dividend rate and the actual borrowing expenses associated with TOBs (or other forms of leverage, if any) used by the Fund may vary frequently and may be significantly higher or lower than the rates used for the example below.
Assumed Portfolio Total Return |  |  | (10.00 | )% |  |  | (5.00 | )% |  |  | 0.00 | % |  |  | 5.00 | % |  |  | 10.00 | %
Common Share Total Return |  |  | (18.34 | )% |  |  | (9.73 | )% |  |  | (1.11 | )% |  |  | 7.51 | % |  |  | 16.13 | %
Common Share total return is composed of two elements—the Common Share dividends paid by the Fund (the amount of which is largely determined by the net investment income of the Fund after paying dividends on Preferred Shares and expenses on any forms of leverage outstanding, including TOBs) and gains or losses on the value of the securities and other instruments the Fund owns. As required by SEC rules, the table assumes that the Fund is more likely to suffer capital losses than to enjoy capital appreciation. For example, to assume a portfolio total return of 0%, the Fund must assume that the income it receives on its investments is entirely offset by losses in the value of those investments. This table reflects hypothetical performance of the Fund’s portfolio and not the actual performance of the Fund’s Common Shares, the value of which is determined by market forces and other factors. Should the Fund elect to add additional leverage to its portfolio following an offering, any benefits of such additional leverage cannot be fully achieved until the proceeds resulting from the use of such leverage have been received by the Fund and invested in accordance with the Fund’s investment objective and policies. As noted above, the Fund’s willingness to use additional leverage, and the extent to which leverage is used at any time, will depend on many factors, including, among other things, PIMCO’s assessment of the yield curve environment, interest rate trends, market conditions and other factors. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Effects of Leverage [Table Text Block] |  |
Assumed Portfolio Total Return |  |  | (10.00 | )% |  |  | (5.00 | )% |  |  | 0.00 | % |  |  | 5.00 | % |  |  | 10.00 | %
Common Share Total Return |  |  | (18.34 | )% |  |  | (9.73 | )% |  |  | (1.11 | )% |  |  | 7.51 | % |  |  | 16.13 | %
Return at Minus Ten [Percent] |  | (18.34%) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Return at Minus Five [Percent] |  | (9.73%) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Return at Zero [Percent] |  | (1.11%) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Return at Plus Five [Percent] |  | 7.51% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Return at Plus Ten [Percent] |  | 16.13% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share Price [Table Text Block] |  | The following table sets forth, for each of the periods indicated, the high and low closing market prices of the Fund’s Common Shares on the NYSE, the high and low NAV per Common Share and the high and low premium/discount to NAV per Common Share. See “Net Asset Value” for information as to how the Fund’s NAV is determined.
|  | Common share market price (1) |  |  | Common share net asset value |  |  | Premium (discount) as a % of net asset value |
Quarter |  | High |  |  | Low |  |  | High |  |  | Low |  |  | High |  |  | Low |
Quarter ended June 30, 2022 |  |  | $11.82 |  |  |  | $10.12 |  |  |  | $10.78 |  |  |  | $ 9.14 |  |  |  | 16.48 | % |  |  | 2.22 | %
Quarter ended March 31, 2022 |  |  | $14.55 |  |  |  | $11.20 |  |  |  | $12.37 |  |  |  | $10.70 |  |  |  | 19.55 | % |  |  | 3.99 | %
Quarter ended December 31, 2021 |  |  | $14.83 |  |  |  | $13.86 |  |  |  | $12.42 |  |  |  | $12.15 |  |  |  | 19.58 | % |  |  | 13.51 | %
|  | Common share market price (1) |  |  | Common share net asset value |  |  | Premium (discount) as a % of net asset value |
Quarter |  | High |  |  | Low |  |  | High |  |  | Low |  |  | High |  |  | Low |
Quarter ended September 30, 2021 |  |  | $15.31 |  |  |  | $14.74 |  |  |  | $12.77 |  |  |  | $12.32 |  |  |  | 20.72 | % |  |  | 16.72 | %
Quarter ended June 30, 2021 |  |  | $15.08 |  |  |  | $14.53 |  |  |  | $12.68 |  |  |  | $12.26 |  |  |  | 22.02 | % |  |  | 16.48 | %
Quarter ended March 31, 2021 |  |  | $15.35 |  |  |  | $14.15 |  |  |  | $12.65 |  |  |  | $12.14 |  |  |  | 21.67 | % |  |  | 13.63 | %
Quarter ended December 31, 2020 |  |  | $14.71 |  |  |  | $13.09 |  |  |  | $12.42 |  |  |  | $11.87 |  |  |  | 18.92 | % |  |  | 9.91 | %
Quarter ended September 30, 2020 |  |  | $14.28 |  |  |  | $13.14 |  |  |  | $12.44 |  |  |  | $11.95 |  |  |  | 14.93 | % |  |  | 8.86 | %
Quarter ended June 30, 2020 |  |  | $13.45 |  |  |  | $11.59 |  |  |  | $11.95 |  |  |  | $10.95 |  |  |  | 13.64 | % |  |  | 4.70 | %
Quarter ended March 31, 2020 |  |  | $15.97 |  |  |  | $10.10 |  |  |  | $13.30 |  |  |  | $10.12 |  |  |  | 27.45 | % |  |  | (11.79 | )%
1 | Such prices reflect inter-dealer prices, without retail mark-up, mark-down or commission and may not represent actual transactions.​​​​​​​
The Fund’s NAV per Common share at the close of business on June 30, 2022 was $9.52 and the last reported sale price of a Common Share on the NYSE on that day was $10.74, representing a 12.82% premium to such NAV. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Highest Price or Bid, Premium (Discount) to NAV [Percent] |  |  |  | 16.48% | 19.55% | 19.58% | 20.72% | 22.02% | 21.67% | 18.92% | 14.93% | 13.64% | 27.45% |  |  |  |  |  |  |  |  |  |  |
Lowest Price or Bid, Premium (Discount) to NAV [Percent] |  |  |  | 2.22% | 3.99% | 13.51% | 16.72% | 16.48% | 13.63% | 9.91% | 8.86% | 4.70% | (11.79%) |  |  |  |  |  |  |  |  |  |  |
Share Prices Not Actual Transactions [Text Block] |  | Such prices reflect inter-dealer prices, without retail mark-up, mark-down or commission and may not represent actual transactions. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Latest Share Price |  |  |  | $ 10.74 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Latest Premium (Discount) to NAV [Percent] |  |  |  | 12.82% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Latest NAV |  |  |  | $ 9.52 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock [Table Text Block] |  | Description of Capital Structure The following is a brief description of the capital structure of the Fund. This description does not purport to be complete and is subject to and qualified in its entirety by reference to the Declaration and the Fund’s Bylaws, as amended and restated through the date hereof (the “Bylaws”). The Declaration and Bylaws are each exhibits to the registration statement of which this prospectus is a part. The Fund is an unincorporated voluntary association with transferable shares of beneficial interest (commonly referred to as a “Massachusetts business trust”) established under the laws of the Commonwealth of Massachusetts by the Declaration. The Declaration provides that the Trustees of the Fund may authorize separate classes of shares of beneficial interest. Preferred shares (such as the ARPS and the RVMTP Shares) are permitted to be issued in one or more series, with such par value and with such rights as determined by the Board, by action of the Board without the approval of the Common Shareholders. The following table shows, for each class of authorized securities of the Fund, the amount of (i) shares authorized and (ii) shares outstanding, each as of June 30, 2022.
Title of Class |  | Amount Authorized |  | Amount Outstanding
Common Shares |  | Unlimited |  | 63,519,359
Preferred Shares |  |  |  |
Series A ARPS |  | 4,040 |  | 2,279
Series B ARPS |  | 4,040 |  | 2,577
Series C ARPS |  | 4,040 |  | 2,422
Series D ARPS |  | 4,040 |  | 2,300
Series E ARPS |  | 4,040 |  | 2,353
Series 2051 RVMTP Shares |  | Unlimited |  | 687
The Common Shares of the Fund commenced trading on the NYSE in June 2002, under the trading or “ticker” symbol “PML.” As of the close of trading on the NYSE on June 30, 2022, the NAV per Common Share was $9.52, and the closing price per Common Share on the NYSE was $10.74, representing a premium to NAV of 12.82%. Common Shareholders will be entitled to the payment of dividends and other distributions when, as and if declared by the Board after payment of preferential amounts payable to holders of Preferred Shares.​​​​​​​ All Common Shares have equal rights to the payment of dividends and the distribution of assets upon liquidation after payment of the preferential amounts payable to holders of Preferred Shares. Common Shares will, when issued, be fully paid and, subject to matters discussed in “Anti-Takeover and Other Provisions in the Declaration of Trust,” non-assessable, and will have no pre-emptive or conversion rights or rights to cumulative voting.​​​​​​​ Upon liquidation of the Fund, after paying or adequately providing for the payment of all liabilities of the Fund and the liquidation preference with respect to any outstanding Preferred Shares, and upon receipt of such releases, indemnities and refunding agreements as they deem necessary for their protection, the Trustees may distribute the remaining assets of the Fund among the Fund’s Common Shareholders.​​​​​​​ Preferred Shares The Declaration authorizes the issuance of an unlimited number of preferred shares. Preferred shares may be issued in one or more classes or series, with such par value and rights as determined by the Board of Trustees, by action of the Board of Trustees without the approval of the Common Shareholders. The Fund initially issued ARPS in five series (Series A, Series B, Series C, Series D and Series E) in August 2002, in the amount of 4,040 shares per series. The ARPS have a par value of $0.00001 and liquidation value of $25,000 per share. The ARPS have various rights determined by action of the Board without the approval of Common Shareholders, most of which are specified in Article 11 of the Bylaws. On September 18, 2018, the Fund issued 687 variable municipal term preferred shares in a single series (the “VMTP Shares”). On June 30, 2021, pursuant to the authority expressly vested in the Board, the Board authorized the redesignation of the Fund’s VMTP Shares as Remarketable Variable Rate MuniFund Term Preferred Shares, Series 2051 (the “RVMTP Shares” and, together with the ARPS and any other preferred shares the Fund may have outstanding, the “Preferred Shares”), effective July 14, 2021. For so long as any Preferred Shares are outstanding, the Fund generally may not declare, pay or set apart for payment any dividend or other distribution (other than a dividend or distribution paid in shares of additional Common Shares or options, warrants or rights to subscribe for or purchase Common Shares or other shares ranking junior to the Preferred Shares as to dividends or upon liquidation) in respect of Common Shares or any other shares of the Fund ranking junior to or on a parity with the Preferred Shares as to dividends or upon liquidation, or call for redemption, redeem, purchase or otherwise acquire for consideration any Common Shares or any other such junior shares (except by conversion into or exchange for shares of beneficial interest of the Fund ranking junior to Preferred Shares as to dividends and upon liquidation) or any such parity shares (except by conversion into or exchange for shares of beneficial interest of the Fund ranking junior to or on a parity with Preferred Shares as to dividends and upon liquidation), unless and only if: (i) immediately after such transaction, the Fund would satisfy Moody’s Ratings Agency Preferred Shares Asset Coverage and 1940 Act Preferred Shares Asset Coverage (each as defined and described under “—Rating Agency Guidelines and Asset Coverage”); (ii) full cumulative dividends on the Preferred Shares due on or prior to the date of the transaction have been declared and paid or shall have been declared and sufficient funds for the payment thereof deposited with the auction agent for the Preferred Shares; and (iii) the Fund has redeemed the full number of Preferred Shares required to be redeemed by any provision for mandatory redemption contained in the Bylaws. See “Preferred Shares Redemption.” Further, so long as any Preferred Shares are outstanding, the Fund generally may not declare, pay or set apart for payment any dividend or other distribution on any parity shares other than the Preferred Shares unless the Fund contemporaneously declares, pays or sets apart for payment, as the case may be, the same proportionate share of dividends on the Preferred Shares. The Fund expects that similar restrictions would apply to any other classes of Preferred Shares that the Fund might choose to issue in the future. In addition, if the Fund has outstanding any senior security representing indebtedness, the 1940 Act prohibits the Fund from declaring any dividend or distribution on the Fund’s Common Shares (other than a dividend or distribution paid in shares of additional Common Shares) unless such senior securities representing indebtedness have, at the time of the declaration, asset coverage of at least 300% after deducting the amount of such dividend or distribution. See “Use of Leverage.” Shareholders of each class are entitled to one vote for each share held. Common Shareholders will vote with the holders of any outstanding Preferred Shares as a single class on each matter submitted to a vote of holders of Common Shares, except as otherwise provided by the Declaration, the Bylaws or applicable law. Except as otherwise provided by the Declaration, the Bylaws or applicable law, holders of Preferred Shares, voting as a separate class, are entitled to elect two of the Fund’s Trustees. The remaining Trustees are elected by Common Shareholders and holders of Preferred Shares, voting together as a single class. In the unlikely event that two full years of accrued dividends are unpaid on the Preferred Shares, the holders of all outstanding Preferred Shares, voting as a separate class, will be entitled to elect a majority of the Fund’s Trustees until all dividends in arrears have been paid or declared and set apart for payment. The holders of Preferred Shares also have the right to elect a majority of the Fund’s Trustees as may be required under the 1940 Act. The Preferred Shares have various rights that were approved by the Board without the approval of Common Shareholders, which are specified in the Fund’s Bylaws. Certain rights, terms and conditions the Preferred Shares are summarized below: Distribution Preference. Any Preferred Shares, including, without limitation, the ARPS and the RVMTP Shares, have complete priority over the Common Shares as to distribution of assets. Voting Rights. Under the 1940 Act, Preferred Shares (including, without limitation, the ARPS and the RVMTP Shares) are required to be voting shares and to have equal voting rights with Common Shares. Except as otherwise indicated in the Prospectus or this Statement of Additional Information, and except as otherwise required by applicable law, Preferred Shares vote together with Common Shareholders as a single class. In addition, holders of Preferred Shares, including the ARPS and the RVMTP Shares, voting as a separate class, are entitled to elect two of the Fund’s trustees. The remaining trustees are elected by Common Shareholders and Preferred Shareholders, voting together as a single class. In the unlikely event that two full years of accrued dividends are unpaid on the Preferred Shares, the holders of all outstanding Preferred Shares voting as a separate class, are entitled to elect a majority of the Fund’s trustees until all dividends in arrears with respect to the Preferred Shares have been paid or declared and set apart for payment. In order for the Fund to take certain actions or enter into certain transactions, a separate class vote of Preferred Shareholders is required, in addition to the single class vote of the holders of Preferred Shares and Common Shares. Liquidation Preference. Subject to the rights of holders of any series or class or classes of shares ranking on a parity with the Preferred Shares with respect to the distribution of assets upon liquidation of the Fund, upon a liquidation of the Fund (whether voluntary or involuntary), the holders of Preferred Shares then outstanding would be entitled to receive and to be paid, out of the assets of the Fund available for distribution to its shareholders, before any payment or distribution would be made on the Fund’s Common Shares or any other class of shares of the Fund ranking junior in right of payment upon liquidation to the Preferred Shares, an amount equal to the liquidation preference with respect to such Preferred Shares ($25,000 per share for the ARPS and $100,000 per share for the RVMTP Shares), plus an amount equal to all dividends thereon (whether or not earned or declared by the Fund, but excluding the interest thereon) accumulated but unpaid to (but not including) the date of final distribution in same-day funds in connection with the liquidation of the Fund. If such assets of the Fund are insufficient to make the full liquidation payment on outstanding Preferred Shares, then such assets will be distributed among the holders of Preferred Shares and the holders of shares of such other class or series ratably in proportion to the respective preferential amounts to which they are entitled. After the payment to the holders of Preferred Shares of the full preferential amounts provided for as described herein, the holders of Preferred Shares as such would have no right or claim to any of the remaining assets of the Fund. For these purposes, a liquidation of the Fund does not include the sale of all or any portion of the assets of the Fund or the merger, consolidation or statutory share exchange of the Fund into or with any trust or other entity. As used in this prospectus, unless otherwise noted, the Fund’s “net assets” include assets of the Fund attributable to any outstanding Preferred Shares, with no deduction for the liquidation preference of the Preferred Shares. Solely for financial reporting purposes, however, the Fund is required to exclude the liquidation preference of the Preferred Shares from “net assets,” so long as the Preferred Shares have redemption features that are not solely within the control of the Fund. For all regulatory and tax purposes, the Fund’s Preferred Shares will be treated as stock (rather than indebtedness). 1940 Act Asset Coverage. In accordance with the Fund’s governing documents and the 1940 Act, the Fund is required to maintain certain asset coverage with respect to all outstanding senior securities of the Fund which are stocks for purposes of the 1940 Act, including the ARPS and the RVMTP Shares. Under the 1940 Act, the Fund is not permitted to issue preferred shares unless, immediately after such issuance, the Fund has “asset coverage,” as defined in Section 18(h) of the 1940 Act (“1940 Act Asset Coverage”) with respect to at least 200% of the liquidation value of any outstanding preferred shares and the newly issued preferred shares plus the aggregate amount of any senior securities of the Fund representing indebtedness (i.e., such liquidation value plus the aggregate amount of senior securities representing indebtedness may not exceed 50% of the Fund’s total net assets). In addition, the Fund is not permitted to declare or pay common share dividends unless immediately thereafter the Fund has a minimum asset coverage ratio of 200% with respect to all outstanding senior securities of the Fund which are stocks for purposes of the 1940 Act after deducting the amount of such common share dividends. Issuance of Additional Preferred Shares. So long as any Preferred Shares are outstanding, the Fund may, without the vote or consent of the holders thereof, authorize, establish and create and issue and sell shares of one or more series of Preferred Shares ranking on a parity with the ARPS and the RVMTP Shares as to the payment of dividends and the distribution of assets upon dissolution, liquidation or the winding up of the affairs of the Fund, in addition to then outstanding series of Preferred Shares, including additional series of RVMTP Shares, and authorize, issue and sell additional shares of any such Series of Preferred Shares then outstanding or so established or created, including additional series of RVMTP Shares, in each case in accordance with applicable law, provided that the Fund shall, immediately after giving effect to the issuance of such Preferred Shares and to its receipt and application of the proceeds thereof, including to the redemption of Preferred Shares with such proceeds, have “asset coverage,” as defined for the purposes of Section 18(h) of the Act, of at least 200%. Redemption. Although the Preferred Shares are subject to redemption under certain circumstances as described below, unlike the shares of an open-end mutual fund, the Preferred Shares may not be redeemed at a shareholder’s option at NAV or otherwise. RVMTP SHARES Dividends. The dividend rate paid on the RVMTP Shares is determined over the course of “Rate Period,” which generally begins each Thursday and ends the following Wednesday. The dividends per share for the RVMTP Shares for a given Rate Period are dependent on the RVMTP Share dividend rate (the “RVMTP Share Dividend Rate”) for that Rate Period. The RVMTP Share Dividend Rate for the RMVTP Shares is equal to the greater of (i) the sum of the “Index Rate” 1 plus an “Applicable Spread” 2 for the Rate Period plus the “Failed Remarketing Spread,” 3 if applicable, and (ii) the sum of (a) the product of the Index Rate multiplied by the “Applicable Multiplier” 4 for such Rate Period plus (b) 0.92% plus (c) the Failed Remarketing Spread, if applicable. The dividend per RVMTP Share for the Rate Period is then determined as described in the table below. 5
Dividend Rate |  |  |  | Rate Period Fraction |  |  |  | RVMTP Shares Liquidation Preference |  |  |  | Dividend
|  |  |  | Number of days in the Rate Period (or a part thereof) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend Rate |  | X |  | Divided by |  |  |  | X |  |  |  |  | 100,000 |  |  |  |  | = |  |  | Dividends per RVMTP Share
|  |  |  | Total number of days in the year |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
RVMTP Special Terms Period. The Fund, at its option, may designate special terms applicable to all of the outstanding RVMTP Shares for a certain period (a “Special Terms Period”) pursuant to a notice of special terms. Such special terms may differ from those provided in the current governing documents of the RVMTP Shares and may include, without limitation, changes to the RVMTP Dividend Rate, dividend payment dates, redemption provisions (including, without limitation, the RVMTP Term Redemption Date or the RVMTP Early Term Redemption Date), required Effective Leverage Ratio, and the Preferred Shareholder Gross-Up (each as defined below); provided that such special terms do not affect the parity ranking of the RVMTP Shares to any other class or series of Preferred Shares then outstanding with respect to dividends or distribution of assets upon dissolution, liquidation, or winding up of the affairs of the Fund. No Special Terms Period with respect to the RVMTP Shares will become effective unless certain conditions are satisfied, including that all of the RVMTP Shares are remarketed (except with respect to any RVMTP Shares whose holders have elected to retain their RVMTP Shares for the Special Terms Period). A Special Terms Period will not become effective before the 12-month anniversary of the date of original issue of the RVMTP Shares. Preferred Shareholder Gross-Up. As noted above, RVMTP Shares each pay dividend distributions at stated rates, which rates are based generally on the assumption that such dividend distributions consist entirely of “exempt-interest dividends” (as defined below under “Taxation—Exempt-Interest Dividends”). The terms of the RVMTP Shares provide further that, in the event less than the entire amount of any particular dividend distribution paid pursuant to the stated rate were to consist of “exempt-interest dividends” (i.e., if a portion of any particular dividend were to derive from ordinary
1 | The "Index Rate" means the Securities Industry and Financial Markets Association ("SIFMA") Municipal Swap Index, or such other weekly, high-grade index comprised of seven-day, tax-exempt variable rate demand notes produced by Municipal Market Data, Inc. or its successor, or as otherwise designated by the Securities Industry and Financial Markets Association; provided that if the SIFMA Municipal Swap Index is less than zero (0), the SIFMA Municipal Swap Index will be deemed to be zero (0) for purposes of the determination of the Index Rate.
2 | For the RVMTP Shares, the Applicable Spread for a Rate Period is a percentage per annum that is based on the long-term rating most recently assigned by the applicable ratings agency to such RVMTP Shares.
3 | With respect to the RVMTP Shares, a Failed Remarketing Spread means (a) in the case of a Failed Special Terms Period Remarketing (as defined below): (i) for so long as two or more Failed Special Terms Period Remarketings have not occurred, 0.05%, and (ii) following the second occurrence of a Failed Special Terms Period Remarketing, 0.10% multiplied by the number of Failed Special Terms Period Remarketings that have occurred after the first Failed Special Terms Period Remarketing, and (b) in the case of a Failed Early Term Redemption Date Remarketing (as defined below): (i) 0.75% for the first 59 days following the applicable Early Term Redemption Date, (ii) 1.00% for the 60th to the 89th day following such Early Term Redemption Date, (iii) 1.25% for the 90th to the 119th day following such Early Term Redemption Date, (iv) 1.50% for the 120th to the 149th day following such Early Term Redemption Date, and (v) 1.75% for the 150th day following such Early Term Redemption Date to the date of the associated mandatory redemption of the Series 2052-A RVMTP Shares. With respect to the RVMTP Shares, a “Failed Special Terms Period Remarketing” will occur if any RVMTP Shares subject to a Mandatory Tender Event due to the Fund designating a Special Terms Period have not been either retained by the holders or successfully remarketed by the Mandatory Tender Date. In addition, with respect to the RVMTP Shares, a “Failed Early Term Redemption Date Remarketing” will occur if any RVMTP Shares subject to a Mandatory Tender Event have not been either retained by the holders or successfully remarketed by the Early Term Redemption Date.
4 | The Applicable Multiplier for a Rate Period is a percentage that is based on the long-term rating most recently assigned by the applicable ratings agency to such series of the RVMTP Shares.
5 | An increased RVMTP Share Dividend Rate could be triggered by the Fund’s failure to comply with certain requirements relating to the RVMTP Shares, certain actions taken by the applicable ratings agency or certain determinations regarding the tax status of such series of the RVMTP Shares made by a court or other applicable governmental authority. The RVMTP Share Dividend Rate will in no event exceed 15% per year.
income or capital gain, including short-term capital gain taxable as ordinary income when distributed), the amount of such dividend would increase by an amount (the “Preferred Shareholder Gross-Up”) such that the after-tax amount of such dividend, as increased by the Preferred Shareholder Gross-Up, would equal the total amount the holder of such RVMTP Shares would have received if the dividend at the stated rate had consisted entirely of “exempt-interest dividends.” The Preferred Shareholder Gross-Up is calculated (i) without consideration being given to the time value of money, (ii) assuming that no holder of RVMTP Shares is subject to the federal alternative minimum tax, and (iii) assuming that the portion of any dividend distribution (including the amount of the Preferred Shareholder Gross-Up) that is not an exempt interest dividend would be taxable (x), in the hands of the initial purchaser of the RVMTP Shares (or certain of its affiliates), at the maximum marginal regular federal corporate income tax rate, and (y) in the case of any other holder, at the greater of (a) the maximum marginal regular federal individual income tax rate (taking into account the 3.8% Medicare contribution tax on net investment income) applicable to ordinary income or net capital gain, as applicable, or (b) the maximum marginal regular federal corporate income tax rate applicable to ordinary income or net capital gain, as applicable, in each case disregarding the effect of any state or local taxes. Any Preferred Shareholder Gross-Up will reduce the amount that would otherwise be distributable to Common Shareholders. Additional Investment Limitations. Under the terms of purchase agreement between the Fund and the initial investor in the RVMTP Shares, the Fund is subject to various investment limitations. These investment limitations are in addition to, and may be more restrictive than, those to which the Fund is subject in accordance with its investment objective and policies as described herein and in the Prospectus. Effective Leverage Ratio Requirement. In accordance with the Bylaws, without the prior written consent of the holders of RVMTP Shares, the Fund’s Effective Leverage Ratio may not exceed 50% (or 51% solely by reason of fluctuations in the market value of the Fund’s portfolio securities) as of the close of business on any business day. If the Fund fails to comply with any additional requirements relating to the calculation of the Effective Leverage Ratio requirement applicable to the RVMTP Shares and, in any such case, such failure is not cured as of the close of business on the date that is ten business days following the business day on which such non-compliance is first determined (the “Effective Leverage Ratio Cure Date”), the Fund shall cause the Effective Leverage Ratio to not exceed 42.5% (or 43.5% solely by reason of fluctuations in the market value of the Fund’s portfolio securities), by (i) not later than the close of business on the business day next following the Effective Leverage Ratio Cure Date, engaging in transactions involving or relating to any floating rate securities not owned by the Fund and/or any inverse floating rate securities owned by the Fund, including the purchase, sale or retirement thereof, (ii) to the extent permitted by law, not later than the close of business on the second business day next following the Effective Leverage Ratio Cure Date, causing a notice of redemption to be issued for the redemption of a sufficient number of Preferred Shares, in accordance with the terms of the Preferred Shares, or (iii) engaging in any combination, in the Fund’s discretion, of the actions contemplated by clauses (i) and (ii). Calculation of Effective Leverage Ratio. For purposes of determining whether the effective leverage requirement discussed above is satisfied, the “Effective Leverage Ratio” on any date shall mean the quotient of: (i) The sum of (A) the aggregate liquidation preference of the Fund’s “senior securities” (as that term is defined in the Act) that are stock for purposes of the Act, excluding, without duplication, (1) any such senior securities for which the Fund has issued a notice of redemption and either has delivered deposit securities or sufficient securities or funds, (as applicable in accordance with the terms of such senior securities) to the paying agent for such senior securities or otherwise has adequate deposit securities or sufficient securities or funds on hand for the purpose of such redemption (as applicable in accordance with the terms of such senior securities) and (2) any such senior securities that are to be redeemed with net proceeds from the sale of the RVMTP Shares, for which the Fund has delivered deposit securities or sufficient securities or funds (as applicable in accordance with the terms of such senior securities) to the paying agent for such senior securities or otherwise has adequate deposit securities or sufficient securities or funds on hand (as applicable in accordance with the terms of such senior securities) for the purpose of such redemption; (B) the aggregate principal amount of the Fund’s “senior securities representing indebtedness” (as that term is defined in the 1940 Act giving effect to any interpretations thereof by the SEC or its staff); and (C) the aggregate principal amount of floating rate securities corresponding to any associated residual floating rate securities not owned by the Fund (less the aggregate principal amount of any such floating rate securities owned by the Fund and corresponding to the associated residual floating rate securities owned by the Fund). Ratings Agency Guidelines. The Fund has obtained ratings for the RVMTP Shares from Fitch. For so long as Fitch is rating the RVMTP Shares, the Fund has agreed to adhere to separate guidelines and asset coverage requirements specific to Fitch (“Fitch Preferred Shares Asset Coverage”) as described in Fitch’s published Closed-End Funds and Market Value Structures Rating Criteria (“Fitch Rating Criteria”). These guidelines may be changed by Fitch, in its sole discretion, from time to time. These guidelines impose asset coverage or portfolio composition requirements that may be more stringent than those imposed on the Fund by the 1940 Act. Satisfaction of Fitch Preferred Shares Asset Coverage for the RVMTP Shares requires that the Fund satisfy both a “Fitch Total Overcollateralization Test” (“Fitch Total OC”) and a “Fitch Net Over Collateralization Test” (“Fitch Net OC”, and together with Fitch Total OC, the “Fitch OC Tests”), in each case to be consistent with the then-current rating of the RVMTP Shares assigned by Fitch using the calculations set forth in the Fitch Rating Criteria, including information therein relating to diversification guidelines as applied to the Fund. The Fund has agreed that it will adhere to the Fitch OC Tests as described above as of the close of business on the last business day of each month for so long as Fitch is rating the RVMTP Shares. If the Fund fails to adhere to the Fitch OC Tests as described in the preceding sentence, the Fund will cure such failure (including, without limitation, by causing a notice of redemption to be issued for the redemption of a sufficient number of the Fund’s Preferred Shares) within ten days following the business day on which such failure is first determined. Fitch may change its rating methodologies for evaluating and providing ratings for shares of closed-end funds at any time and in its sole discretion, perhaps substantially. Such a change could adversely affect the ratings assigned to the Fund’s Preferred Shares (including the RVMTP Shares), the dividend rates paid thereon, and the expenses borne by the Fund’s Common Shareholders. Mandatory Redemptions. The RVMTP Shares are subject to a mandatory term redemption date on July 14, 2051, subject to the Fund’s right to extend the term with the consent of the holders of the RVMTP Shares (the “RVMTP Share Term Redemption Date”). There is no assurance that the term of the RVMTP Shares will be extended. In addition, with respect to the RVMTP Shares, a “Mandatory Tender Event” will occur on each date that is (i) 20 business days before each three-year anniversary of the date of original issue of such series of the RVMTP Shares, (ii) the date the Fund delivers a notice designating a Special Terms Period, and (iii) 20 business days before the end of a Special Terms Period (provided that no subsequent Terms Period is designated). If any RVMTP Shares subject to a Mandatory Tender Event upon a three-year anniversary of the date of original issue of the RVMTP Shares or upon the end of a Special Terms Period (each, an “RVMTP Early Term Redemption Date”) have not been either retained by the holders or remarketed by the Mandatory Tender Date, the Fund will redeem such RVMTP Shares on the RVMTP Early Term Redemption Date. 6 The RVMTP Shares are also subject to mandatory redemption by the Fund, in whole or in part, in certain circumstances, such as the failure by the Fund to comply with asset coverage and/or effective leverage ratio requirements described above (and the failure to cure any such failure within the applicable cure period) or certain actions taken by the applicable ratings agency. Term Redemption and Early Term Redemption Liquidity Account. At least six months prior to the RVMTP Share Redemption Date, or the RVMTP Early Term Redemption Date (each, a “Redemption Date”), the Fund will maintain segregated assets of a minimum credit rating quality with a market value equal to at least 110% of the redemption price of all outstanding RVMTP Shares to be redeemed until the redemption of all such outstanding RVMTP Shares, as applicable. The Fund will include certain liquid and/or highly rated assets in an amount equal to 20% of such segregated assets with five months remaining to the Redemption Date, which amount will increase monthly by 20% and reach 100% with one month remaining to the Redemption Date. Optional redemption. The Fund may redeem, in whole or from time to time in part, the outstanding RVMTP Shares at a redemption price per share equal to (i) the liquidation preference of the RVMTP Shares, as applicable, plus (ii) an amount equal to all unpaid dividends and other distributions on such RVMTP Shares, as applicable, accumulated from and including the date of issuance to (but excluding) the date of redemption (whether or not earned or declared by the Fund, but without interest thereon) plus (iii) any applicable optional redemption premium. RVMTP Mandatory Tender. Upon the occurrence of a Mandatory Tender Event with respect to a series of RVMTP Shares, all RVMTP Shares in such series will be subject to mandatory tender (subject to the holders’ election to retain their RVMTP Shares) and the Fund will issue or cause to be issued a notice of mandatory tender to the holders of such RVMTP Shares for remarketing on the Mandatory Tender Date. ARPS Dividends. The ARPS have complete priority over the Common Shares as to distribution of assets and equal priority with the RVMTP Shares. The terms of the ARPS provide that they would ordinarily pay dividends at a rate set at auctions held every seven days, normally payable on the first business day following the end of the rate period, subject to a “maximum applicable rate” calculated as a function of the ARPS’ then-current ratings and a reference interest rate as described below. However, the weekly auctions for the ARPS, as well as auctions for similar preferred shares issued by closed-end funds in the U.S., have failed since February 2008, and the dividend rates on the ARPS since that time have been paid at the maximum applicable rate under the Bylaws. Ratings agencies may change their methodologies for evaluating and providing ratings for shares of closed-end funds at any time and in their sole discretion, which may affect the rating (if any) of the Fund’s shares. Fitch Ratings published ratings criteria relating to closed-end funds on December 4, 2020, which effectively result in a rating cap of “AA” for debt and preferred stock issued by all closed-end funds and a rating cap of “A” for (i) debt and preferred shares issued by closed-end funds exposed to emerging market debt, below-investment-grade and unrated debt, structured securities and equity, (ii) and closed-end funds with material exposure to “BBB” category rated assets. The long-term rating actions were driven by changes in the updated ratings criteria for closed-end funds rather than by any fundamental changes to the Fund’s credit profile. The Fund expects that the ARPS will continue to pay dividends at the maximum applicable rate for the foreseeable future and cannot predict whether or when the auction markets for the ARPS may resume normal functioning.
6 | With respect to the Mandatory Tender Events described in clauses (i), (ii) and (iii) above, the corresponding “Mandatory Tender Date” means, respectively: (i) the date that is 180 calendar days following the Early Redemption Date, (ii) the date on which the related Special Terms Period becomes effective, and (iii) the last day of the related Special Terms Period (subject, in each case, to the holders’ election to retain their RVMTP Shares).
As noted, the “maximum applicable rate” for each series of ARPS depends on the credit ratings assigned to such shares. The maximum applicable rate for any regular rate period (i.e., any rate period other than a non-payment period) will be the applicable percentage of the reference rate. The reference rate is the applicable “AA” Financial Composite Commercial Paper Rate (for a Dividend Period of fewer than 184 days) or the applicable Treasury Index Rate (for a Dividend Period of 184 days or more). The applicable percentage for any Dividend Period is generally determined based on the lower of the credit ratings assigned to the ARPS by Moody’s or Fitch on the auction date for such period (as set forth in the table below).
Moody’s Credit Rating |  | Fitch Credit Rating |  | Applicable Percentage
Aa3 or above |  | AA- or above |  | 150%
A3 to A1 |  | A- to A+ |  | 160%
Baa3 to Baa1 |  | BBB- to BBB+ |  | 250%
Below Baa3 |  | Below BBB- |  | 275%
Ratings Agency Preferred Shares Asset Coverage. The Fund is required under the Bylaws to satisfy separate asset coverage tests specific to each rating agency (the “Ratings Agency Preferred Shares Asset Coverage”). Moody’s Preferred Shares Asset Coverage. Satisfaction of Moody’s Ratings Agency Preferred Shares Asset Coverage generally requires the Fund to have eligible assets having in the aggregate a discounted value equal to or in excess of a “Preferred Shares Basic Maintenance Amount.” Generally, the Preferred Shares Basic Maintenance Amount includes the sum of (a) the aggregate liquidation preference of the Fund’s Preferred Shares then outstanding (including the ARPS) and (b) certain accrued and projected payment obligations of the Fund, including without limit any accrued and projected dividends on its Preferred Shares then outstanding (including the ARPS). Article 11 of the Bylaws includes Moody’s-specific guidelines for calculating discounted value for purposes of determining whether the Moody’s Ratings Agency Preferred Shares Asset Coverage test is satisfied. These guidelines specify discount factors that the Fund must apply to various types of securities in its portfolio for purposes of calculating whether the discounted value of the Fund’s eligible assets is at least equal to the Preferred Shares Basic Maintenance Amount (with the level of discount generally becoming greater as the credit quality of a security becomes lower). In addition, under the Moody’s guidelines, certain types of securities (including securities in which the Fund may otherwise invest) are not eligible for inclusion in the calculation of the discounted value of the Fund’s portfolio. The Moody’s guidelines for calculating discounted value do not impose any limitations on the percentage of the Fund’s assets that may be invested in ineligible assets, and the amount of ineligible assets included in the Fund’s portfolio at any time may vary depending upon the rating, diversification and other characteristics of the Moody’s eligible assets included in the portfolio. Fitch Preferred Shares Asset Coverage. Satisfaction of Fitch Preferred Shares Asset Coverage requires that the Fund satisfy both a “Fitch Total Overcollateralization Test (“Fitch Total OC”) and a “Fitch Net Over Collateralization Test (“Fitch Net OC”), in each case to be consistent with the then-current rating from Fitch. Under the Bylaws, Fitch Preferred Shares Asset Coverage is satisfied if, as of a particular date or time, the Fund has sufficient asset coverage with respect to the Preferred Shares such that the Fund satisfies both the (i) Fitch Total OC test and the (ii) Fitch Net OC test as of such date or time. The Fitch Total OC test and the Fitch Net OC test are satisfied if the Fund has Fitch Total OC or Fitch Net OC, as the case may be, in excess of one-hundred percent (100%) pursuant to the applicable formula below. The Fund’s Bylaws incorporate by reference the Closed-End Fund Criteria Report issued by Fitch entitled “Rating Closed-End Fund and Market Value Structures Rating Criteria” or similar future report most recently published by Fitch and approved for use by the Trust by resolution of the Board of Trustees of the Trust (the “Fitch Criteria”). The Fitch Criteria include, among other things, the current formulations for satisfaction of the Fitch Total OC test and the Fitch Net OC test, asset discount factors (used in part to calculate Fitch Total OC and Fitch Net OC), issuer and industry diversification and concentration thresholds and guidelines and a description of other rating considerations. The Fitch Criteria define Fitch Total OC and Fitch Net OC as follows:
Fitch Total OC |  | = |  | Total Net Discounted Assets at MV*
| Fitch Rated Liability + Other Liabilities Pari Passu and Senior to Rated Liability
In the event the Fund does not timely cure a failure to maintain (a) both Moody’s Ratings Agency Preferred Shares Asset Coverage and Fitch Preferred shares Asset Coverage or (b) 1940 Act Preferred Shares Asset Coverage, in each case in accordance with the requirements of the rating agency or agencies then rating the ARPS, the Fund will be required to redeem ARPS as described under “Mandatory Redemption” below. In addition to the requirements described above, the rating agency guidelines impose restrictions or limitations on the Fund’s use of certain financial instruments or investment techniques that the Fund might otherwise utilize in order to obtain and maintain a rating from Moody’s and Fitch on the ARPS. It is not currently anticipated that these guidelines will materially impede PIMCO from managing the Fund’s portfolio in accordance with the Fund’s investment objective and policies. The Fund may, but is not required to, adopt any modifications to the guidelines that may be established by Moody’s and/or Fitch with respect to their ratings of the ARPS. Failure to adopt any such modifications, however, may result in a reduction in the rating described above or a withdrawal of rating altogether. In addition, any rating agency providing a rating for the ARPS may, at any time, change or withdraw any such rating. The Board may, without shareholder approval, amend, alter or repeal various definitions and related provisions that have been adopted by the Fund pursuant to the rating agency guidelines in the event the Fund receives written confirmation from Moody’s or Fitch (or any substitute rating agency) that any such amendment, alteration or repeal would not impair the rating then assigned by the rating agency to the ARPS. The ratings of the ARPS are based on current information furnished to Moody’s and Fitch by the Fund or the Investment Manager or information obtained from other sources. The ratings may be changed, suspended or withdrawn as a result of changes in, or the unavailability of, such information. The Common Shares have not been rated by any nationally recognized statistical rating organizations (“NRSROs”). A rating agency’s guidelines will apply to the ARPS Shares only so long as the rating agency is rating the shares. The Fund pays certain fees to Moody’s and Fitch for rating the ARPS. The foregoing description of the rating agency guidelines and asset coverage requirements applicable to the ARPS is intended only as a summary and is qualified in its entirety by reference to the actual terms of Article 11 and other relevant provisions of the Bylaws and Exhibit 1 thereto. Mandatory redemption . As noted above, the Fund is required under the Bylaws to maintain (a) Moody’s Ratings Agency Preferred Shares Asset Coverage, (b) Fitch Preferred Shares Asset Coverage, and (c) 1940 Act Asset Coverage. Eligible portfolio securities for the purposes of (a) and (b) above will be determined from time to time by the rating agency then rating the then outstanding ARPS. If the Fund fails to maintain such asset coverage amounts and does not timely cure such failure in accordance with the Bylaws, the Fund would be required to redeem all or a portion of the ARPS. This mandatory redemption would take place on a date that the Board specifies out of legally available funds in accordance with the Declaration, the Bylaws and applicable law, at the redemption price of $25,000 per share, plus accumulated but unpaid dividends (whether or not earned or declared) to (but not including) the date fixed for redemption. In determining the number of Preferred Shares required to be redeemed in accordance with the foregoing, the Fund would redeem the lesser of (a) the minimum number of ARPS necessary to satisfy the Ratings Agency Preferred Shares Asset Coverage or 1940 Act Preferred Shares Asset Coverage, as the case may be, and (b) the maximum number of ARPS and any other Preferred Shares of the Fund subject to redemption or retirement that can be redeemed out of funds expected to be legally available therefor at the time of redemption, and in any case will redeem such Preferred Shares pro rata among the Preferred Shares subject to redemption or retirement. The mandatory redemption will be limited to the number of ARPS and any other Preferred Shares necessary to restore the required Ratings Agency Preferred Shares Asset Coverage or 1940 Act Preferred Shares Asset Coverage, as the case may be. Optional redemption . To the extent permitted under the 1940 Act and under Massachusetts law, upon giving notice of redemption, as provided below, the Fund, at its option, may redeem Preferred Shares, in whole or in part, out of funds legally available therefore, at the Optional Redemption Price (as defined below) per share on any dividend payment date, provided that no Preferred Shares may be redeemed at the option of the Fund during (a) the initial rate period with respect to the Preferred Shares or (b) a non-call period to which such shares are subject. “Optional Redemption Price” means $25,000 per Preferred Share plus an amount equal to accumulated but unpaid dividends (whether or not earned or declared) to the date fixed for redemption plus the applicable redemption premium, if any. The Fund has the authority to redeem Preferred Shares for any reason and may redeem all or part of the outstanding Preferred Shares if it anticipates that the Fund’s leveraged capital structure will result, for a significant period of time, in a lower rate of return to Common Shareholders than that obtainable if the Common Shares were not so leveraged. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Security Title [Text Block] |  | Common Shareholders will be entitled to the payment of dividends and other distributions when, as and if declared by the Board after payment of preferential amounts payable to holders of Preferred Shares.​​​​​​​ All Common Shares have equal rights to the payment of dividends and the distribution of assets upon liquidation after payment of the preferential amounts payable to holders of Preferred Shares. Common Shares will, when issued, be fully paid and, subject to matters discussed in “Anti-Takeover and Other Provisions in the Declaration of Trust,” non-assessable, and will have no pre-emptive or conversion rights or rights to cumulative voting.​​​​​​​ Upon liquidation of the Fund, after paying or adequately providing for the payment of all liabilities of the Fund and the liquidation preference with respect to any outstanding Preferred Shares, and upon receipt of such releases, indemnities and refunding agreements as they deem necessary for their protection, the Trustees may distribute the remaining assets of the Fund among the Fund’s Common Shareholders.​​​​​​​ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Security Dividends [Text Block] |  | Common Shareholders will be entitled to the payment of dividends and other distributions when, as and if declared by the Board after payment of preferential amounts payable to holders of Preferred Shares. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Security Voting Rights [Text Block] |  | Common Shares will, when issued, be fully paid and, subject to matters discussed in “Anti-Takeover and Other Provisions in the Declaration of Trust,” non-assessable, and will have no pre-emptive or conversion rights or rights to cumulative voting. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Security Liquidation Rights [Text Block] |  | All Common Shares have equal rights to the payment of dividends and the distribution of assets upon liquidation after payment of the preferential amounts payable to holders of Preferred Shares. Common Shares will, when issued, be fully paid and, subject to matters discussed in “Anti-Takeover and Other Provisions in the Declaration of Trust,” non-assessable, and will have no pre-emptive or conversion rights or rights to cumulative voting.​​​​​​​ Upon liquidation of the Fund, after paying or adequately providing for the payment of all liabilities of the Fund and the liquidation preference with respect to any outstanding Preferred Shares, and upon receipt of such releases, indemnities and refunding agreements as they deem necessary for their protection, the Trustees may distribute the remaining assets of the Fund among the Fund’s Common Shareholders. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Distributions May Reduce Principal [Text Block] |  | The Fund may sell Common Shares through underwriters or dealers, directly to one or more purchasers (including existing shareholders in a rights offering), through agents, to or through underwriters or dealers, or through a combination of any such methods of sale. The applicable prospectus supplement will identify any underwriter or agent involved in the offer and sale of the Common Shares, any sales loads, discounts, commissions, fees or other compensation paid to any underwriter, dealer or agent, the offering price, net proceeds and use of proceeds and the terms of any sale. The distribution of the Common Shares may be effected from time to time in one or more transactions at a fixed price or prices, which may be changed, at prevailing market prices at the time of sale, at prices related to such prevailing market prices, or at negotiated prices. The sale of Common Shares by the Fund (or the perception that such sales may occur), particularly if sold at a discount to the then-current market price of the Common Shares, may have an adverse effect on the market price of the Common Shares. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Securities [Table Text Block] |  | The following table shows, for each class of authorized securities of the Fund, the amount of (i) shares authorized and (ii) shares outstanding, each as of June 30, 2022.
Title of Class |  | Amount Authorized |  | Amount Outstanding
Common Shares |  | Unlimited |  | 63,519,359
Preferred Shares |  |  |  |
Series A ARPS |  | 4,040 |  | 2,279
Series B ARPS |  | 4,040 |  | 2,577
Series C ARPS |  | 4,040 |  | 2,422
Series D ARPS |  | 4,040 |  | 2,300
Series E ARPS |  | 4,040 |  | 2,353
Series 2051 RVMTP Shares |  | Unlimited |  | 687
Market Discount Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Market Discount Risk The price of the Fund’s Common Shares will fluctuate with market conditions and other factors. If you sell your Common Shares, the price received may be more or less than your original investment. The Common Shares are designed for long-term investors and should not be treated as trading vehicles. Shares of closed-end management investment companies frequently trade at a discount from their NAV. The Common Shares may trade at a price that is less than the offering price for Common Shares issued pursuant to an offering. This risk may be greater for investors who sell their Common Shares relatively shortly after completion of an offering. The sale of Common Shares by the Fund (or the perception that such sales may occur), particularly if sold at a discount to the then current market price of the Common Shares, may have an adverse effect on the market price of the Common Shares. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Market Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Market Risk The market price of securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. Securities may decline in value due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of a security may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates, adverse changes to credit markets or adverse investor sentiment generally. The value of a security may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Equity securities generally have greater price volatility than fixed income securities. Credit ratings downgrades may also negatively affect securities held by the Fund. Even when markets perform well, there is no assurance that the investments held by the Fund will increase in value along with the broader market. In addition, market risk includes the risk that geopolitical and other events will disrupt the economy on a national or global level. For instance, war, terrorism, market manipulation, government defaults, government shutdowns, political changes or diplomatic developments, public health emergencies (such as the spread of infectious diseases, pandemics and epidemics) and natural/environmental disasters can all negatively impact the securities markets, which could cause the Fund to lose value. These events could reduce consumer demand or economic output, result in market closures, travel restrictions or quarantines, and significantly adversely impact the economy. The current contentious domestic political environment, as well as political and diplomatic events within the United States and abroad, such as presidential elections in the United States or abroad or the U.S. government’s inability at times to agree on a long-term budget and deficit reduction plan, has in the past resulted, and may in the future result, in a government shutdown or otherwise adversely affect the U.S. regulatory landscape, the general market environment and/or investor sentiment, which could have an adverse impact on the Fund’s investments and operations. Additional and/or prolonged U.S. federal government shutdowns may affect investor and consumer confidence and may adversely impact financial markets and the broader economy, perhaps suddenly and to a significant degree. Governmental and quasi-governmental authorities and regulators throughout the world have previously responded to serious economic disruptions with a variety of significant fiscal and monetary policy changes, including but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates. An unexpected or sudden reversal of these policies, or the ineffectiveness of these policies, could increase volatility in securities markets, which could adversely affect the Fund’s investments. Any market disruptions could also prevent the Fund from executing advantageous investment decisions in a timely manner. Funds that have focused their investments in a region enduring geopolitical market disruption, it will face higher risks of loss. Thus, investors should closely monitor current market conditions to determine whether the Fund meets their individual financial needs and tolerance for risk. Current market conditions may pose heightened risks with respect to the Fund’s investment in fixed income securities. As such, fixed income securities markets may experience heightened levels of interest rate, volatility and liquidity risk. Any interest rate increases in the future could cause the value of any Fund, such as the Fund, that invests in fixed income securities to decrease. Exchanges and securities markets may close early, close late or issue trading halts on specific securities, which may result in, among other things, the Fund being unable to buy or sell certain securities or financial instruments at an advantageous time or accurately price its portfolio investments. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Municipal Bond Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Municipal Bond Risk The ability of municipal issuers to make timely payments of interest and principal may be diminished during general economic downturns, by litigation, legislation or political events, or by the bankruptcy of the issuer. Laws, referenda, ordinances or regulations enacted in the future by Congress or state legislatures or the applicable governmental entity could extend the time for payment of principal and/or interest, or impose other constraints on enforcement of such obligations, or on the ability of municipal issuers to levy taxes. Issuers of municipal securities also might seek protection under the bankruptcy laws. In the event of bankruptcy of such an issuer, the Fund could experience delays in collecting principal and interest and the Fund may not, in all circumstances, be able to collect all principal and interest to which it is entitled. To enforce its rights in the event of a default in the payment of interest or repayment of principal, or both, the Fund may take possession of and manage the assets securing the issuer’s obligations on such securities, which may increase the Fund’s operating expenses. The Fund may invest in revenue bonds, which are typically issued to fund a wide variety of capital projects including electric, gas, water and sewer systems; highways, bridges and tunnels; port and airport facilities; colleges and universities; and hospitals. Because the principal security for a revenue bond is generally the net revenues derived from a particular facility or group of facilities or, in some cases, from the proceeds of a special excise or other specific revenue source, there is no guarantee that the particular project will generate enough revenue to pay its obligations, in which case the Fund’s performance may be adversely affected. The Fund may invest in taxable municipal bonds, such as Build America Bonds. Build America Bonds are tax credit bonds created by the American Recovery and Reinvestment Act of 2009, which authorized state and local governments to issue Build America Bonds as taxable bonds in 2009 and 2010, without volume limitations, to finance any capital expenditures for which such issuers could otherwise issue traditional tax-exempt bonds. The Fund’s investments in Build America Bonds or similar taxable municipal bonds will result in taxable income and the Fund may elect to pass through to holders of the Fund’s common shares (“Common Shares”) the corresponding tax credits. The tax credits can generally be used to offset federal income taxes and the alternative minimum tax, but such credits are generally not refundable. Taxable municipal bonds involve similar risks as tax-exempt municipal bonds, including credit and market risk. Municipal securities are also subject to interest rate, credit, and liquidity risk, which are discussed generally elsewhere in this section, and elaborated upon below with respect to municipal bonds. Interest Rate Risk. The value of municipal securities, similar to other fixed income securities, will likely drop as interest rates rise in the general market. Conversely, when rates decline, bond prices generally rise. Credit Risk. The risk that a borrower may be unable to make interest or principal payments when they are due. A fund that invests in municipal securities relies on the ability of the issuer to service its debt. This subjects the Fund to credit risk in that the municipal issuer may be fiscally unstable or exposed to large liabilities that could impair its ability to honor its obligations. Municipal issuers with significant debt service requirements, in the near-to mid-term; unrated issuers and those with less capital and liquidity to absorb additional expenses may be most at risk. To the extent the Fund invests in lower quality or high yield municipal securities, it may be more sensitive to the adverse credit events in the municipal market. The treatment of municipalities in bankruptcy is more uncertain, and potentially more adverse to debt holders, than for corporate issues. Liquidity Risk. The risk that investors may have difficulty finding a buyer when they seek to sell, and therefore, may be forced to sell at a discount to the market value. Liquidity may sometimes be impaired in the municipal market and because the Fund primarily invests in municipal securities, it may find it difficult to purchase or sell such securities at opportune times. Liquidity can be impaired due to interest rate concerns, credit events, or general supply and demand imbalances. Depending on the particular issuer and current economic conditions, municipal securities could be deemed more volatile investments. In addition to general municipal market risks, different municipal sectors may face different risks. For instance, general obligation bonds are secured by the full faith, credit, and taxing power of the municipality issuing the obligation. As such, timely payment depends on the municipality’s ability to raise tax revenue and maintain a fiscally sound budget. The timely payments may also be influenced by any unfunded pension liabilities or other post-employee benefit plan (OPEB) liabilities. Revenue bonds are secured by special tax revenues or other revenue sources. If the specified revenues do not materialize, then the bonds may not be repaid. Private activity bonds are yet another type of municipal security. Municipalities use private activity bonds to finance the development of industrial facilities for use by private enterprise. Principal and interest payments are to be made by the private enterprise benefitting from the development, which means that the holder of the bond is exposed to the risk that the private issuer may default on the bond. Moral obligation bonds are usually issued by special purpose public entities. If the public entity defaults, repayment becomes a “moral obligation” instead of a legal one. The lack of a legally enforceable right to payment in the event of default poses a special risk for a holder of the bond because it has little or no ability to seek recourse in the event of default. In addition, a significant restructuring of federal income tax rates or even serious discussion on the topic in Congress could cause municipal bond prices to fall. The demand for municipal securities is strongly influenced by the value of tax-exempt income to investors. Lower income tax rates could reduce the advantage of owning municipal securities. Municipal notes are similar to general municipal debt obligations, but they generally possess shorter terms. Municipal notes can be used to provide interim financing and may not be repaid if anticipated revenues are not realized. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Municipal Project-Specific Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Municipal Project-Specific Risk The Fund may be more sensitive to adverse economic, business or political developments if it invests a substantial portion of its assets in the bonds of specific projects (such as those relating to education, health care, housing, transportation, and utilities), industrial development bonds, or in general obligation bonds, particularly if there is a large concentration from issuers in a single state. This is because the value of municipal securities can be significantly affected by the political, economic, legal, and legislative realities of the particular issuer’s locality or municipal sector events. Similarly, changes to state or federal regulation tied to a specific sector, such as the hospital sector, could have an impact on the revenue stream for a given subset of the market. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
U.S. Government Securities Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | U.S. Government Securities Risk Certain U.S. government securities, such as U.S. Treasury bills, notes, bonds and mortgage-related securities guaranteed by the GNMA, are supported by the full faith and credit of the United States; others, such as those of the FHLBs or the FHLMC, are supported by the right of the issuer to borrow from the U.S. Treasury; others, such as those of the FNMA, are supported by the discretionary authority of the U.S. government to purchase the agency’s obligations; and still others are supported only by the credit of the agency, instrumentality or corporation. Although legislation has been enacted to support certain government sponsored entities, including the FHLBs, FHLMC and FNMA, there is no assurance that the obligations of such entities will be satisfied in full, or that such obligations will not decrease in value or default. It is difficult, if not impossible, to predict the future political, regulatory or economic changes that could impact the government sponsored entities and the values of their related securities or obligations. In addition, certain governmental entities, including FNMA and FHLMC, have been subject to regulatory scrutiny regarding their accounting policies and practices and other concerns that may result in legislation, changes in regulatory oversight and/or other consequences that could adversely affect the credit quality, availability or investment character of securities issued by these entities. Yields available from U.S. government debt securities are generally lower than the yields available from other debt securities. The values of U.S. government securities change as interest rates fluctuate. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Asset Allocation Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Asset Allocation Risk The Fund’s investment performance depends upon how its assets are allocated and reallocated. A principal risk of investing in the Fund is that PIMCO may make less than optimal or poor asset allocation decisions. PIMCO employs an active approach to allocation among multiple fixed-income sectors, but there is no guarantee that such allocation techniques will produce the desired results. It is possible that PIMCO will focus on an investment that performs poorly or underperforms other investments under various market conditions. You could lose money on your investment in the Fund as a result of these allocation decisions. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Management Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Management Risk The Fund is subject to management risk because it is an actively managed investment portfolio. PIMCO and each individual portfolio manager will apply investment techniques and risk analysis in making investment decisions for the Fund, but there can be no guarantee that these decisions will produce the desired results. Certain securities or other instruments in which the Fund seeks to invest may not be available in the quantities desired. In addition, regulatory restrictions, actual or potential conflicts of interest or other considerations may cause PIMCO to restrict or prohibit participation in certain investments. In such circumstances, PIMCO or the individual portfolio managers may determine to purchase other securities or instruments as substitutes. Such substitute securities or instruments may not perform as intended, which could result in losses to the Fund. The Fund is also subject to the risk that deficiencies in the internal systems or controls of PIMCO or another service provider will cause losses for the Fund or hinder Fund operations. For example, trading delays or errors (both human and systemic) could prevent the Fund from purchasing a security expected to appreciate in value. To the extent the Fund employs strategies targeting perceived pricing inefficiencies, arbitrage strategies or similar strategies, it is subject to the risk that the pricing or valuation of the securities and instruments involved in such strategies may change unexpectedly, which may result in reduced returns or losses to the Fund. Additionally, actual or potential conflicts of interest, legislative, regulatory, or tax restrictions, policies or developments may affect the investment techniques available to PIMCO and each individual portfolio manager in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. There also can be no assurance that all of the personnel of PIMCO will continue to be associated with PIMCO for any length of time. The loss of the services of one or more key employees of PIMCO could have an adverse impact on the Fund’s ability to realize its investment objective. In addition, the Fund may rely on various third-party sources to calculate its NAV. As a result, the Fund is subject to certain operational risks associated with reliance on service providers and service providers’ data sources. In particular, errors or systems failures and other technological issues may adversely impact the Fund’s calculations of its NAV, and such NAV calculation issues may result in inaccurately calculated NAV, delays in NAV calculation and/or the inability to calculate NAVs over extended periods. The Fund may be unable to recover any losses associated with such failures. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Issuer Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Issuer Risk The value of a security may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods or services, as well as the historical and prospective earnings of the issuer and the value of its assets. A change in the financial condition of a single issuer may affect securities markets as a whole. These risks can apply to the Common Shares issued by the Fund and to the issuers of securities and other instruments in which the Fund invests. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest Rate Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Interest Rate Risk Interest rate risk is the risk that fixed income securities and other instruments in the Fund’s portfolio will decline in value because of a change in interest rates. As nominal interest rates rise, the value of certain fixed income securities held by the Fund is likely to decrease. A nominal interest rate can be described as the sum of a real interest rate and an expected inflation rate. Interest rate changes can be sudden and unpredictable, and the Fund may lose money as a result of movements in interest rates. The Fund may not be able to effectively hedge against changes in interest rates or may choose not to do so for cost or other reasons. A wide variety of factors can cause interest rates or yields of U.S. Treasury securities (or yields of other types of bonds) to rise (e.g., central bank monetary policies, inflation rates, general economic conditions). Recently, there have been signs of inflationary price movements. As such, fixed income securities markets may experience heightened levels of interest rate, volatility and liquidity risk. Fixed income securities with longer durations tend to be more sensitive to changes in interest rates, usually making them more volatile. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates that incorporates a security’s yield, coupon, final maturity and call features, among other characteristics. Duration is useful primarily as a measure of the sensitivity of a fixed income security’s market price to interest rate (i.e., yield) movements. All other things remaining equal, for each one percentage point increase in interest rates, the value of a portfolio of fixed income investments would generally be expected to decline by one percent for every year of the portfolio’s average duration above zero. For example, the value of a portfolio of fixed income securities with an average duration of fourteen years would generally be expected to decline by approximately 14% if interest rates rose by one percentage point. Variable and floating rate securities may decline in value if their interest rates do not rise as much, or as quickly, as interest rates in general. Conversely, floating rate securities will not generally increase in value if interest rates decline. Inverse floating rate securities may decrease in value if interest rates increase. Inverse floating rate securities may also exhibit greater price volatility than a fixed rate obligation with similar credit quality. When the Fund holds variable or floating rate securities, a decrease (or, in the case of inverse floating rate securities, an increase) in market interest rates will adversely affect the income received from such securities and the NAV of the Fund’s shares. During periods of very low or negative interest rates, the Fund may be unable to maintain positive returns. Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, may result in heightened market volatility and may detract from Fund performance to the extent the Fund is exposed to such interest rates. Measures such as average duration may not accurately reflect the true interest rate sensitivity of the Fund. This is especially the case if the Fund consists of securities with widely varying durations. Therefore, if the Fund has an average duration that suggests a certain level of interest rate risk, the Fund may in fact be subject to greater interest rate risk than the average would suggest. This risk is greater to the extent the Fund uses leverage or derivatives. Convexity is an additional measure used to understand a security’s or Fund’s interest rate sensitivity. Convexity measures the rate of change of duration in response to changes in interest rates. With respect to a security’s price, a larger convexity (positive or negative) may imply more dramatic price changes in response to changing interest rates. Convexity may be positive or negative. Negative convexity implies that interest rate increases result in increased duration, meaning increased sensitivity in prices in response to rising interest rates. Thus, securities with negative convexity, which may include bonds with traditional call features and certain mortgage-backed securities, may experience greater losses in periods of rising interest rates. Accordingly, if the Fund holds such securities, the Fund may be subject to a greater risk of losses in periods of rising interest rates. Rising interest rates may result in periods of volatility and a decline in value of the Fund’s fixed income investments. Further, while U.S. bond markets have steadily grown over the past three decades, dealer “market making ability has remained relatively stagnant. As a result, dealer inventories of certain types of bonds and similar instruments, which provide a core indication of the ability of financial intermediaries to “make markets,” are at or near historic lows in relation to market size. Because market makers provide stability to a market through their intermediary services, a significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty. All of these factors, collectively and/or individually, could cause the Fund to lose value. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Credit Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Credit Risk The Fund could lose money if the issuer or guarantor of a fixed income security, or the counterparty to a derivatives contract, repurchase agreement or a loan of portfolio securities, is unable or unwilling, or is perceived as unable or unwilling, to make timely principal and/or interest payments or to otherwise honor its obligations. The downgrade of the credit of a security held by the Fund may decrease its value. Measures such as average credit quality may not accurately reflect the true credit risk of the Fund. This is especially the case if the Fund consists of securities with widely varying credit ratings. This risk is greater to the extent the Fund uses leverage or derivatives. Municipal bonds are subject to the risk that litigation, legislation or other political events, local business or economic conditions, or the bankruptcy of the issuer could have a significant effect on an issuer’s ability to make payments of principal and/or interest. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage-Related and Other Asset-Backed Instruments Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Mortgage-Related and Other Asset-Backed Instruments Risk The mortgage-related assets in which the Fund may invest include, but are not limited to, any security, instrument or other asset that is related to U.S. or non-U.S. mortgages, including those issued by private originators or issuers, or issued or guaranteed as to principal or interest by the U.S. government or its agencies or instrumentalities or by non-U.S. governments or authorities, such as, without limitation, assets representing interests in, collateralized or backed by, or whose values are determined in whole or in part by reference to any number of mortgages or pools of mortgages or the payment experience of such mortgages or pools of mortgages, including REMICs, which could include Re-REMICs, mortgage pass-through securities, inverse floaters, CMOs, CLOs, multiclass pass-through securities, private mortgage pass-through securities, stripped mortgage securities (generally interest-only and principal-only securities), mortgage-related asset backed securities and mortgage-related loans (including through participations, assignments, originations and whole loans), including commercial and residential mortgage loans. Exposures to mortgage-related assets through derivatives or other financial instruments will be considered investments in mortgage-related assets. The Fund may also invest in other types of ABS, including CDOs, CBOs and CLOs and other similarly structured securities See “The Fund’s Investment Objective and Strategies-Portfolio Contents and Other Information-Mortgage-Related and Other Asset-Backed Instruments” in this prospectus and “Investment Objective and Policies-Mortgage-Related and Other Asset- Backed Instruments” in the Statement of Additional Information for a description of the various mortgage-related and other asset-backed instruments in which the Fund may invest and their related risks. Mortgage-related and other asset-backed instruments represent interests in “pools” of mortgages or other assets such as consumer loans or receivables held in trust and often involve risks that are different from or possibly more acute than risks associated with other types of debt instruments. Generally, rising interest rates tend to extend the duration of fixed rate mortgage-related assets, making them more sensitive to changes in interest rates. As a result, in a period of rising interest rates, the Fund may exhibit additional volatility since individual mortgage holders are less likely to exercise prepayment options, thereby putting additional downward pressure on the value of these securities and potentially causing the Fund to lose money. This is known as extension risk. Mortgage-backed securities can be highly sensitive to rising interest rates, such that even small movements can cause the Fund to lose value. Mortgage-backed securities, and in particular those not backed by a government guarantee, are subject to credit risk. When interest rates decline, borrowers may pay off their mortgages sooner than expected. This can reduce the returns of the Fund because the Fund may have to reinvest that money at the lower prevailing interest rates. The Fund’s investments in other asset-backed instruments are subject to risks similar to those associated with mortgage-related assets, as well as additional risks associated with the nature of the assets and the servicing of those assets. Payment of principal and interest on asset-backed instruments may be largely dependent upon the cash flows generated by the assets backing the instruments, and asset-backed instruments may not have the benefit of any security interest in the related assets. Subordinate mortgage-backed or asset-backed instruments are paid interest only to the extent that there are funds available to make payments. To the extent the collateral pool includes a large percentage of delinquent loans, there is a risk that interest payments on subordinate mortgage-backed or asset-backed instruments will not be fully paid. There are multiple tranches of mortgage-backed and asset-backed instruments, offering investors various maturity and credit risk characteristics. Tranches are categorized as senior, mezzanine, and subordinated/equity or “first loss,” according to their degree of risk. The most senior tranche of a mortgage-backed or asset-backed instrument has the greatest collateralization and pays the lowest interest rate. If there are defaults or the collateral otherwise underperforms, scheduled payments to senior tranches take precedence over those of mezzanine tranches, and scheduled payments to mezzanine tranches take precedence over those to subordinated/equity tranches. Lower tranches represent lower degrees of credit quality and pay higher interest rates intended to compensate for the attendant risks. The return on the lower tranches is especially sensitive to the rate of defaults in the collateral pool. The lowest tranche (i.e., the “equity” or “residual” tranche) specifically receives the residual interest payments (i.e., money that is left over after the higher tranches have been paid and expenses of the issuing entities have been paid) rather than a fixed interest rate. The Fund may also invest in the residual or equity tranches of mortgage-related and other asset-backed instruments, which may be referred to as subordinate mortgage-backed or asset-backed instruments and interest-only mortgage-backed or asset-backed instruments. The Fund expects that investments in subordinate mortgage-backed and other asset-backed instruments will be subject to risks arising from delinquencies and foreclosures, thereby exposing its investment portfolio to potential losses. Subordinate securities of mortgage-backed and other asset-backed instruments are also subject to greater credit risk than those mortgage-backed or other asset-backed instruments that are more highly rated. The mortgage markets in the United States and in various foreign countries have experienced extreme difficulties in the past that adversely affected the performance and market value of certain mortgage-related investments. Delinquencies and losses on residential and commercial mortgage loans (especially subprime and second-lien mortgage loans) may increase, and a decline in or flattening of housing and other real property values may exacerbate such delinquencies and losses. In addition, reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage-Related Derivative Instruments Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Mortgage-Related Derivative Instruments Risk The Fund may engage in derivative transactions related to mortgage-backed securities, including purchasing and selling exchange-listed and OTC put and call options, futures and forwards on mortgages and mortgage-backed securities. The Fund may also invest in mortgage-backed securities credit default swaps, which include swaps the reference obligation for which is a mortgage-backed security or related index, such as the CMBX Index (a tradeable index referencing a basket of commercial mortgage-backed securities), the TRX Index (a tradeable index referencing total return swaps based on commercial mortgage-backed securities) or the ABX (a tradeable index referencing a basket of sub-prime mortgage backed securities). The Fund may invest in newly developed mortgage related derivatives that may hereafter become available. Derivative mortgage-backed securities (such as principal-only (“POs”), interest-only (“IOs”) or inverse floating rate securities) are particularly exposed to call and extension risks. Small changes in mortgage prepayments can significantly impact the cash flows and the market value of these derivative instruments. In general, the risk of faster than anticipated prepayments adversely affects IOs, super floaters and premium priced mortgage-backed securities. The risk of slower than anticipated prepayments generally affects POs, floating-rate securities subject to interest rate caps, support tranches and discount priced mortgage-backed securities. In addition, particular derivative instruments may be leveraged such that their exposure (i.e., price sensitivity) to interest rate and/or prepayment risk is magnified. Mortgage-related derivative instruments involve risks associated with mortgage-related and other asset-backed instruments, privately-issued mortgage-related securities, the mortgage market, the real estate industry, derivatives and credit default swaps. See “Mortgage-Related and Other Asset-Backed Instruments Risk”, “Privately-Issued Mortgage-Related Securities Risk,” “Derivatives Risk,” and “Credit Default Swaps Risk.” Mortgage-related derivative instruments involve risks associated with mortgage-related and other asset-backed instruments, privately-issued mortgage-related securities, the mortgage market, the real estate industry, derivatives and credit default swaps. See “Mortgage-Related and Other Asset-Backed Instruments Risk,” “Privately-Issued Mortgage-Related Securities Risk,” “Derivatives Risk,” and “Credit Default Swaps Risk.” |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
High Yield Securities Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | High Yield Securities Risk To the extent that the Fund invests in high yield securities and unrated securities of similar credit quality (commonly known as “high yield securities” or “junk bonds”), the Fund will be subject to greater levels of credit risk, call risk and liquidity risk than funds that do not invest in such securities, which could have a negative effect on the NAV and market price of the Fund’s Common Shares or Common Share dividends. These securities are considered predominantly speculative with respect to an issuer’s continuing ability to make principal and interest payments, and may be more volatile than other types of securities. An economic downturn or individual corporate developments could adversely affect the market for these securities and reduce the Fund’s ability to sell these securities at an advantageous time or price. The Fund may purchase distressed securities that are in default or the issuers of which are in bankruptcy, which involve heightened risks. Issuers of high yield securities may have the right to “call or redeem the issue prior to maturity, which may result in the Fund having to reinvest the proceeds in other high yield securities or similar instruments that may pay lower interest rates. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in high yield securities. Consequently, transactions in high yield securities may involve greater costs than transactions in more actively traded securities. To the extent that the Fund invests in high yield securities and unrated securities of similar credit quality (commonly known as “high yield securities” or “junk bonds”), the Fund may be subject to greater levels of credit risk, call risk and liquidity risk than funds that do not invest in such securities, which could have a negative effect on the NAV and market price of the Fund’s Common Shares or Common Share dividends. These securities are considered predominantly speculative with respect to an issuer’s continuing ability to make principal and interest payments, and may be more volatile than other types of securities. An economic downturn or individual corporate developments could adversely affect the market for these securities and reduce the Fund’s ability to sell these securities at an advantageous time or price. The Fund may purchase distressed securities that are in default or the issuers of which are in bankruptcy, which involve heightened risks. Issuers of high yield securities may have the right to “call” or redeem the issue prior to maturity, which may result in the Fund having to reinvest the proceeds in other high yield securities or similar instruments that may pay lower interest rates. The Fund may also be subject to greater levels of liquidity risk than funds that do not invest in high yield securities. Consequently, transactions in high yield securities may involve greater costs than transactions in more actively traded securities. These factors may result in the Fund being unable to realize full value for these securities and/or may result in the Fund not receiving the proceeds from a sale of a high yield security for an extended period after such sale, each of which could result in losses to the Fund. Because of the risks involved in investing in high yield securities, an investment in the Fund should be considered speculative. In general, lower rated debt securities carry a greater degree of risk that the issuer will lose its ability to make interest and principal payments, which could have a negative effect on the Fund. Securities of below investment grade quality are regarded as having predominantly speculative characteristics with respect to capacity to pay interest and repay principal and are commonly referred to as “high yield” securities or “junk bonds.” High yield securities involve a greater risk of default and their prices are generally more volatile and sensitive to actual or perceived negative developments. Debt securities in the lowest investment grade category also may be considered to possess some speculative characteristics by certain rating agencies. The Fund may purchase stressed or distressed securities that are in default or the issuers of which are in bankruptcy, which involve heightened risks. An economic downturn could severely affect the ability of issuers (particularly those that are highly leveraged) to service or repay their debt obligations. Lower-rated securities are generally less liquid than higher-rated securities, which may have an adverse effect on the Fund’s ability to dispose of them. For example, under adverse market or economic conditions, the secondary market for below investment grade securities could contract further, independent of any specific adverse changes in the condition of a particular issuer, and certain securities in the Fund’s portfolio may become illiquid or less liquid. As a result, the Fund could find it more difficult to sell these securities or may be able to sell these securities only at prices lower than if such securities were widely traded. To the extent the Fund focuses on below investment grade debt obligations, PIMCO’s capabilities in analyzing credit quality and associated risks will be particularly important, and there can be no assurance that PIMCO will be successful in this regard. Due to the risks involved in investing in high yield securities, an investment in the Fund should be considered speculative. The Fund’s credit quality policies apply only at the time a security is purchased, and the Fund is not required to dispose of a security in the event that a rating agency or PIMCO downgrades its assessment of the credit characteristics of a particular issue. Analysis of creditworthiness may be more complex for issuers of high yield securities than for issuers of higher quality debt securities. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinvestment Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Reinvestment Risk Income from the Fund’s portfolio will decline if and when the Fund invests the proceeds from matured, traded or called debt obligations at market interest rates that are below the portfolio’s current earnings rate. For instance, during periods of declining interest rates, an issuer of debt obligations may exercise an option to redeem securities prior to maturity, forcing the Fund to invest in lower-yielding securities The Fund also may choose to sell higher yielding portfolio securities and to purchase lower yielding securities to achieve greater portfolio diversification, because the portfolio managers believe the current holdings are overvalued or for other investment-related reasons. A decline in income received by the Fund from its investments is likely to have a negative effect on dividend levels and the market price, NAV and/or overall return of the Common Shares. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Securities Lending Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Securities Lending Risk. For the purpose of achieving income, the Fund may lend its portfolio securities to brokers, dealers, and other financial institutions provided a number of conditions are satisfied, including that the loan is fully collateralized. Please see “Investment Objectives and Policies—Loans of Portfolio Securities” in the Statement of Additional Information for more details. When the Fund lends portfolio securities, its investment performance will continue to reflect changes in the value of the securities loaned, and the Fund will also receive a fee or interest on the collateral. Securities lending involves the risk of loss of rights in the collateral or delay in recovery of the collateral if the borrower fails to return the security loaned or becomes insolvent. The Fund may pay lending fees to a party arranging the loan. Cash collateral received by the Fund in securities lending transactions may be invested in short-term liquid fixed income instruments or in money market or short-term mutual funds, or similar investment vehicles, including affiliated money market or short-term mutual funds. The Fund bears the risk of such investments. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Call Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Call Risk Call risk refers to the possibility that an issuer may exercise its right to redeem a fixed income security earlier than expected. Issuers may call outstanding securities prior to their maturity for a number of reasons. If an issuer calls a security in which the Fund has invested, the Fund may not recoup the full amount of its initial investment and may be forced to reinvest in lower-yielding securities, securities with greater credit risks or securities with other, less favorable features. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
U.S. Government Securities Risk 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | U.S. Government Securities Risk Certain U.S. government securities, such as U.S. Treasury bills, notes, bonds and mortgage-related securities guaranteed by the GNMA, are supported by the full faith and credit of the United States; others, such as those of the FHLBs or the FHLMC, are supported by the right of the issuer to borrow from the U.S. Treasury; others, such as those of the FNMA, are supported by the discretionary authority of the U.S. government to purchase the agency’s obligations; and still others are supported only by the credit of the agency, instrumentality or corporation. Although legislation has been enacted to support certain government sponsored entities, including the FHLBs, FHLMC and FNMA, there is no assurance that the obligations of such entities will be satisfied in full, or that such obligations will not decrease in value or default. It is difficult, if not impossible, to predict the future political, regulatory or economic changes that could impact the government sponsored entities and the values of their related securities or obligations. In addition, certain governmental entities, including FNMA and FHLMC, have been subject to regulatory scrutiny regarding their accounting policies and practices and other concerns that may result in legislation, changes in regulatory oversight and/or other consequences that could adversely affect the credit quality, availability or investment character of securities issued by these entities. Yields available from U.S. government debt securities are generally lower than the yields available from other debt securities. The values of U.S. government securities change as interest rates fluctuate. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
California State-Specific Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | California State-Specific Risk The Fund may be affected significantly by economic, regulatory or political developments affecting the ability of California issuers to pay interest or repay principal. Certain issuers of California municipal bonds have experienced serious financial difficulties in the past and reoccurrence of these difficulties may impair the ability of certain California issuers to pay principal or interest on their obligations. Provisions of the California Constitution and State statutes which limit the taxing and spending authority of California governmental entities may impair the ability of California issuers to pay principal and/or interest on their obligations. While California’s economy is broad, it does have major concentrations in advanced technology, aerospace and defense-related manufacturing, trade, entertainment, real estate and financial services, and may be sensitive to economic problems affecting those industries. Future California political and economic developments, constitutional amendments, legislative measures, executive orders, administrative regulations, litigation and voter initiatives could have an adverse effect on the debt obligations of California issuers. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
New York State-Specific Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | New York State-Specific Risk The Fund may be affected significantly by economic, regulatory or political developments affecting the ability of New York issuers to pay interest or repay principal. Certain issuers of New York municipal bonds have experienced serious financial difficulties in the past and reoccurrence of these difficulties may impair the ability of certain New York issuers to pay principal or interest on their obligations. Provisions of the New York Constitution and State statutes which limit the taxing and spending authority of New York governmental entities may impair the ability of New York issuers to pay principal and/or interest on their obligations. While New York’s economy is broad, it does have major concentrations in certain industries, such as financial services, and may be sensitive to economic problems affecting those industries. Future New York political and economic developments, constitutional amendments, legislative measures, executive orders, administrative regulations, litigation and voter initiatives could have an adverse effect on the debt obligations of New York issuers. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Puerto Rico-Specific Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Puerto Rico-Specific Risk The Fund may be affected significantly by economic, regulatory, restructuring or political developments affecting the ability of Puerto Rico issuers to pay interest or repay principal. Certain issuers of Puerto Rico municipal bonds have experienced serious financial difficulties in the past and reoccurrence of these difficulties may impair the ability of certain Puerto Rico issuers to pay principal or interest on their obligations. Provisions of the Puerto Rico Constitution and Commonwealth laws, including a federally-appointed oversight board to oversee the Commonwealth’s financial operations, which limit the taxing and spending authority of Puerto Rico governmental entities may impair the ability of Puerto Rico issuers to pay principal and/or interest on their obligations. While Puerto Rico’s economy is broad, it does have major concentrations in certain industries, such as manufacturing and service, and may be sensitive to economic problems affecting those industries. Future Puerto Rico political and economic developments, constitutional amendments, legislative measures, executive orders, administrative regulations, litigation, debt restructuring, and voter initiatives could have an adverse effect on the debt obligations of Puerto Rico issuers. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Valuation Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Valuation Risk Certain securities in which the Fund invests may be less liquid and more difficult to value than other types of securities. When market quotations or pricing service prices are not readily available or are deemed to be unreliable, the Fund values its investments at fair value as determined in good faith pursuant to policies and procedures approved by the Board. Fair value pricing may require subjective determinations about the value of a security or other asset. As a result, there can be no assurance that fair value pricing will result in adjustments to the prices of securities or other assets or that fair value pricing will reflect actual market value, and it is possible that the fair value determined for a security or other asset will be materially different from quoted or published prices, from the prices used by others for the same security or other asset and/or from the value that actually could be or is realized upon the sale of that security or other asset. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Leverage Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Leverage Risk The Fund’s use of leverage (as described under “Use of Leverage” in the body of this prospectus) creates the opportunity for increased Common Share net income, but also creates special risks for Common Shareholders. To the extent used, there is no assurance that the Fund’s leveraging strategies will be successful. Leverage is a speculative technique that may expose the Fund to greater risk and increased costs. The Fund’s assets attributable to any outstanding Preferred Shares or the net proceeds that the Fund obtains from its use of TOBs, derivatives or other forms of leverage, if any, will be invested in accordance with the Fund’s investment objective and policies as described in this prospectus. Dividends payable with respect to Preferred Shares outstanding and interest expense payable by the Fund with respect to any TOBs, derivatives and other forms of leverage will generally be based on shorter-term interest rates that would be periodically reset. If shorter-term interest rates rise relative to the rate of return on the Fund’s portfolio, the interest and other costs to the Fund of leverage (including interest expenses on TOBs and the dividend rate on any outstanding Preferred Shares s, including the Preferred Shareholder Gross-Up (as defined below)) could exceed the rate of return on the debt obligations and other investments held by the Fund, thereby reducing return to Common Shareholders. In addition, fees and expenses of any form of leverage used by the Fund will be borne entirely by the Common Shareholders (and not by preferred shareholders) and will reduce the investment return of the Common Shares. Therefore, there can be no assurance that the Fund’s use of leverage will result in a higher yield on the Common Shares, and it may result in losses. In addition, Preferred Shares issued by the Fund pay cumulative dividends, which may tend to increase leverage risk. Leverage creates several major types of risks for Common Shareholders, including:
| ∎ | the likelihood of greater volatility of NAV and market price of Common Shares, and of the investment return to Common Shareholders, than a comparable portfolio without leverage;
| ∎ | the possibility either that Common Share dividends will fall if the interest and other costs of leverage rise, or that dividends paid on Common Shares will fluctuate because such costs vary over time; and
| ∎ | the effects of leverage in a declining market or a rising interest rate environment, as leverage is likely to cause a greater decline in the NAV of the Common Shares than if the Fund were not leveraged and may result in a greater decline in the market value of the Common Shares.
In addition, the counterparties to the Fund’s leveraging transactions and preferred shareholders of the Fund will have priority of payment over the Fund’s Common Shareholders. The Fund is required to satisfy certain asset coverage requirements in connection with its use of Preferred Shares, including those imposed by regulatory and rating agency requirements. Accordingly, any decline in the net asset value of the Fund’s investments could result in the risk that the Fund will fail to meet its asset coverage requirements for Preferred Shares or the risk of the Preferred Shares being downgraded by a rating agency. In an extreme case, the Fund’s current investment income might not be sufficient to meet the dividend requirements on Preferred Shares outstanding. In order to address these types of events, the Fund might need to dispose of investments in order to fund a redemption of some or all of the Preferred Shares. Dispositions at times of adverse economic conditions may result in a loss to the Fund. At other times, these dispositions may result in gain at the Fund level and thus in additional taxable distributions to Common Shareholders. See “Tax Matters” for more information. Any Preferred Shares, TOBs, loans of portfolio securities, short sales and when-issued, delayed delivery and forward commitment transactions, credit default swaps, reverse repurchases, or other derivatives by the Fund or counterparties to the Fund’s other leveraging transactions, if any, would have, seniority over the Fund’s Common Shares. In connection with the adoption of Rule 18f-4 under the 1940 Act, the SEC eliminated the asset segregation framework arising from prior SEC guidance for covering derivatives and certain financial instruments, such as TOBs. Accordingly, all disclosure in this Prospectus and the Statement of Additional Information regarding how the Fund will segregate, cover or earmark for derivative investments, including TOBs, will be superseded by the requirements of Rule 18f-4 as of the compliance date, August 19, 2022. See “The New SEC Derivatives Rule and Potential Implications for the Fund” in the Statement of Additional Information for a discussion of how these regulatory changes will affect the Fund’s use of leverage, derivatives and certain related instruments. When the Fund issues Preferred Shares, the Fund pays (and the Common Shareholders bear) all costs and expenses relating to the issuance and ongoing maintenance of Preferred Shares. In addition, holders of Preferred Shares issued by the Fund would have complete priority over Common Shareholders in the distribution of the Fund’s assets. Furthermore, preferred shareholders, voting separately as a single class, have the right to elect two members of the Board at all times and to elect a majority of the trustees in the event two full years’ dividends on the Preferred Shares are unpaid, and also have separate class voting rights on certain matters. Accordingly, preferred shareholders may have interests that differ from those of Common Shareholders, and may at times have disproportionate influence over the Fund’s affairs. Because the fees received by the Investment Manager are based on the average daily net asset value of the Fund (including daily net assets attributable to any Preferred Shares), the Investment Manager has a financial incentive for the Fund to utilize Preferred Shares, which may create a conflict of interest between the Investment Manager, on the one hand, and the Common Shareholders, on the other hand. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Segregation and Coverage Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Segregation and Coverage Risk Certain portfolio management techniques, such as, among other things, entering into TOBs, reverse repurchase agreement transactions, swap agreements, futures contracts or other derivative transactions, purchasing securities on a when-issued or delayed delivery basis or engaging in short sales currently may be considered senior securities unless steps are taken to segregate the Fund’s assets or otherwise cover its obligations. To avoid having these instruments considered senior securities, the Fund may segregate liquid assets with a value equal (on a daily mark-to-market basis) to its obligations under these types of leveraged transactions, enter into offsetting transactions or otherwise cover such transactions. At times, all or a substantial portion of the Fund’s liquid assets may be segregated for purposes of various portfolio transactions. The Fund may be unable to use such segregated assets for certain other purposes, which could result in the Fund earning a lower return on its portfolio than it might otherwise earn if it did not have to segregate those assets in respect of, or otherwise cover, such portfolio positions. To the extent the Fund’s assets are segregated or committed as cover, it could limit the Fund’s investment flexibility. Segregating assets and covering positions will not limit or offset losses on related positions. In connection with the adoption of Rule 18f-4 under the 1940 Act, the SEC eliminated the asset segregation framework arising from prior SEC guidance for covering derivatives and certain financial instruments, such as TOBs. Accordingly, all disclosure in this Prospectus and the Statement of Additional Information regarding how the Fund will segregate, cover or earmark for derivative investments, including TOBs, will be superseded by the requirements of Rule 18f-4 as of the compliance date, August 19, 2022. See “The New SEC Derivatives Rule and Potential Implications for the Fund” in the Statement of Additional Information for a discussion of how these regulatory changes will affect the Fund’s use of leverage, derivatives and certain related instruments. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Short Exposure Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Short Exposure Risk The Fund’s short sales, if any, are subject to special risks. A short sale involves the sale by the Fund of a security that it does not own with the hope of purchasing the same security at a later date at a lower price. The Fund may also enter into a short position through a forward commitment or a short derivative position through a futures contract or swap agreement. If the price of the security or derivative has increased during this time, then the Fund will incur a loss equal to the increase in price from the time that the short sale was entered into plus any transaction costs (i.e., premiums and interest) paid to the broker-dealer to borrow securities. Therefore, short sales involve the risk that losses may be exaggerated, potentially losing more money than the actual cost of the investment. By contrast, a loss on a long position arises from decreases in the value of the security and is limited by the fact that a security’s value cannot decrease below zero. By investing the proceeds received from selling securities short, the Fund could be deemed to be employing a form of leverage, which creates special risks. The use of leverage may increase the Fund’s exposure to long security positions and make any change in the Fund’s NAV greater than it would be without the use of leverage. This could result in increased volatility of returns. There is no guarantee that any leveraging strategy the Fund employs will be successful during any period in which it is employed. In times of unusual or adverse market, economic, regulatory or political conditions, the Fund may not be able, fully or partially, to implement its short selling strategy. Periods of unusual or adverse market, economic, regulatory or political conditions generally may exist for long periods of time. Also, there is the risk that the third party to the short sale will not fulfill its contractual obligations, causing a loss to the Fund. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivatives Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Derivatives Risk The use of derivative instruments involves risks different from, and possibly greater than, the risks associated with investing directly in securities and other traditional investments. Derivatives are subject to a number of risks, such as liquidity risk (which may be heightened for highly-customized derivatives), interest rate risk, market risk, credit risk, leveraging risk, counterparty risk, tax risk and management risk, as well as risks arising from changes in applicable requirements. They also involve the risk of mispricing, the risk of unfavorable or ambiguous documentation and the risk that changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index. If the Fund invests in a derivative instrument, the Fund could lose more than the amount invested and derivatives may increase the volatility of the Fund, especially in unusual or extreme market conditions. Also, suitable derivative transactions may not be available in all circumstances and there can be no assurance that the Fund will engage in these transactions to reduce exposure to other risks when that would be beneficial or that, if used, such strategies will be successful. The Fund’s use of derivatives may increase or accelerate the amount of taxes payable by Common Shareholders. Over-the-counter (“OTC”) derivatives are also subject to the risk that a counterparty to the transaction will not fulfill its contractual obligations to the other party, as many of the protections afforded to centrally-cleared derivative transactions might not be available for OTC derivative transactions. For derivatives traded on an exchange or through a central counterparty, credit risk resides with the Fund’s clearing broker, or the clearinghouse, rather than with a counterparty in an OTC derivative transaction. The primary credit risk on derivatives that are exchange-traded or traded through a central clearing counterparty resides with the Fund’s clearing broker, or the clearinghouse. Participation in the markets for derivative instruments involves investment risks and transaction costs to which the Fund may not be subject absent the use of these strategies. The skills needed to successfully execute derivative strategies may be different from those needed for other types of transactions. If the Fund incorrectly forecasts the value and/or creditworthiness of securities, currencies, interest rates, counterparties or other economic factors involved in a derivative transaction, the Fund might have been in a better position if the Fund had not entered into such derivative transaction. In evaluating the risks and contractual obligations associated with particular derivative instruments, it is important to consider that certain derivative transactions may be modified or terminated only by mutual consent of the Fund and its counterparty. Therefore, it may not be possible for the Fund to modify, terminate, or offset the Fund’s obligations or the Fund’s exposure to the risks associated with a derivative transaction prior to its scheduled termination or maturity date, which may create a possibility of increased volatility and/or decreased liquidity to the Fund. Because the markets for certain derivative instruments (including markets located in foreign countries) are relatively new and still developing, appropriate derivative transactions may not be available in all circumstances for risk management or other purposes. Upon the expiration of a particular contract, the Fund may wish to retain the Fund’s position in the derivative instrument by entering into a similar contract, but may be unable to do so if the counterparty to the original contract is unwilling to enter into the new contract and no other appropriate counterparty can be found. When such markets are unavailable, the Fund will be subject to increased liquidity and investment risk. The Fund may enter into opposite sides of interest rate swap and other derivatives for the principal purpose of generating distributable gains on the one side (characterized as ordinary income for tax purposes) that are not part of the Fund’s duration or yield curve management strategies (“paired swap transactions”), and with a substantial possibility that the Fund will experience a corresponding capital loss and decline in NAV with respect to the opposite side transaction (to the extent it does not have corresponding offsetting capital gains). Consequently, Common Shareholders may receive distributions and owe tax on amounts that are effectively a taxable return of the shareholder’s investment in the Fund, at a time when their investment in the Fund has declined in value, which tax may be at ordinary income rates. The tax treatment of certain derivatives in which the Fund invests may be unclear and thus subject to recharacterization. Any recharacterization of payments made or received by the Fund pursuant to derivatives potentially could affect the amount, timing or character of Fund distributions. In addition, the tax treatment of such investment strategies may be changed by regulation or otherwise. When a derivative is used as a hedge against a position that the Fund holds, any loss generated by the derivative generally should be substantially offset by gains on the hedged investment, and vice versa. Although hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the underlying instrument, and there can be no assurance that the Fund’s hedging transactions will be effective. In such case, the Fund may lose money. The regulation of the derivatives markets has increased over the past several years, and additional future regulation of the derivatives markets may make derivatives more costly, may limit the availability or reduce the liquidity of derivatives or may otherwise adversely affect the value or performance of derivatives. Any such adverse future developments could impair the effectiveness or raise the costs of the Fund’s derivative transactions, impede the employment of the Fund’s derivatives strategies, or adversely affect the Fund’s performance and cause the Fund to lose value. For instance, on October 28, 2020, the SEC adopted Rule 18f-4 under the 1940 Act providing for the regulation of a registered investment company’s use of derivatives and certain related instruments. Among other things, Rule 18f-4 limits the Fund’s derivatives exposure through a value-at-risk test and requires the adoption and implementation of a derivatives risk management program for certain derivatives users. Subject to certain conditions, limited derivatives users (as defined in Rule 18f-4), however, would not be subject to the full requirements of Rule 18f-4. In connection with the adoption of Rule 18f-4 under the 1940 Act, the SEC also eliminated the asset segregation framework arising from prior SEC guidance for covering derivatives and certain financial instruments, such as TOBs. Accordingly, all disclosure in this Prospectus and the Statement of Additional Information regarding how the Fund will segregate, cover or earmark for derivative investments, including TOBs, will be superseded by the requirements of Rule 18f-4 as of the compliance date, August 19, 2022. As the Fund comes into compliance, the Fund’s approach to asset segregation and coverage requirements will be impacted. In addition, Rule 18f-4 could restrict the Fund’s ability to engage in certain derivatives transactions and/or increase the costs of such derivatives transactions, which could adversely affect the value or performance of the Fund and the Common Shares and/or the Fund’s distribution rate. See “The New SEC Derivatives Rule and Potential Implications for the Fund” in the Statement of Additional Information for a discussion of how these regulatory changes will affect the Fund’s use of leverage, derivatives and certain related instruments. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Counterparty Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Counterparty Risk The Fund will be subject to credit risk with respect to the counterparties to the derivative contracts and other instruments entered into by the Fund or held by special purpose or structured vehicles in which the Fund invests. In the event that the Fund enters into a derivative transaction with a counterparty that subsequently becomes insolvent or becomes the subject of a bankruptcy case, the derivative transaction may be terminated in accordance with its terms and the Fund’s ability to realize its rights under the derivative instrument and its ability to distribute the proceeds could be adversely affected. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery (including recovery of any collateral it has provided to the counterparty) in a dissolution, assignment for the benefit of creditors, liquidation, winding-up, bankruptcy or other analogous proceeding. In addition, in the event of the insolvency of a counterparty to a derivative transaction, the derivative transaction would typically be terminated at its fair market value. If the Fund is owed this fair market value in the termination of the derivative transaction and its claim is unsecured, the Fund will be treated as a general creditor of such counterparty and will not have any claim with respect to any underlying security or asset. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances. While the Fund may seek to manage its counterparty risk by transacting with a number of counterparties, concerns about the solvency of, or a default by, one large market participant could lead to significant impairment of liquidity and other adverse consequences for other counterparties. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Additional Risks Associated with the Fund's Preferred Shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Additional Risks Associated with the Fund’s Preferred Shares Although the Fund’s ARPS ordinarily would pay dividends at rates set at periodic auctions, the weekly auctions for the ARPS (and auctions for similar preferred shares issued by closed-end funds in the U.S.) have failed since 2008. The dividend rates on the ARPS since that time have been paid, and the Fund expects that they will continue to be paid for the foreseeable future, at the “maximum applicable rate.” The maximum applicable rate for the ARPS and the RVMTP Share Dividend Rate (as defined below) is based in part on a multiple of or a spread plus a reference rate. An increase in market interest rates generally, therefore, could increase substantially the dividend rate required to be paid by the Fund to the holders of Preferred Shares, which would increase the costs associated with the Fund’s leverage and reduce the Fund’s net income available for distribution to holders of Common Shares. In addition, the multiple or spread used to calculate the maximum applicable rate for the ARPS and the RVMTP Share Dividend Rate is based in part on the credit rating assigned to the ARPS or RVMTP Shares by the applicable rating agency(ies), with the multiple or spread generally increasing as the rating declines. Accordingly, future ratings downgrades may result in increases to the maximum applicable rate for the ARPS or to the RVMTP Share Dividend Rate. Therefore, it is possible that a substantial rise in market interest rates and/or further ratings downgrades of the Preferred Shares could, by reducing income available for distribution to the holders of Common Shares and otherwise detracting from the Fund’s investment performance, make the Fund’s continued use of Preferred Shares for leverage purposes less attractive than such use is currently considered to be. In such case, the Fund may elect to redeem some or all of the Preferred Shares outstanding, which may require it to dispose of investments at inopportune times and to incur losses on such dispositions. Such dispositions may adversely affect the Fund’s investment performance generally, and the resultant loss of leverage may materially and adversely affect the Fund’s investment returns. The Fund is also subject to certain asset coverage tests associated with the rating agencies that rate the Preferred Shares. Failure by the Fund to maintain the asset coverages (or to cure such failure in a timely manner) may require the Fund to redeem Preferred Shares and could preclude the Fund from declaring or paying any dividends or distributions to holders of Common Shares. Failure to satisfy ratings agency asset coverage tests or other guidelines could also result in the applicable ratings agency downgrading its then-current ratings on the Preferred Shares, as described above. Moreover, the rating agency guidelines impose restrictions or limitations on the Fund’s use of certain financial instruments or investment techniques that the Fund might otherwise utilize in order to achieve its investment objective, which may adversely affect the Fund’s investment performance. Rating agency guidelines may be modified by the rating agencies in the future and such modifications may make such guidelines substantially more restrictive or otherwise result in downgrades, which could further negatively affect the Fund’s investment performance. The ratings agencies that have assigned ratings to the Fund’s Preferred Shares may change their rating methodologies, perhaps substantially. Such a change could adversely affect the ratings assigned to the Fund’s Preferred Shares, the dividend rates paid thereon, and the expenses borne by holders of Common Shares. For instance, Fitch Ratings published ratings criteria relating to closed-end funds on December 4, 2020, which effectively result in a rating cap of “AA” for debt and preferred stock issued by all closed-end funds and a rating cap of “A” for debt and preferred shares issued by (i) closed-end funds exposed to emerging market debt, below-investment-grade and unrated debt, structured securities and equity, and (ii) closed-end funds with material exposure to “BBB” category rated assets. On December 6, 2021, Fitch affirmed “AA” long-term ratings of the Fund’s RVMTP Shares. Fitch does not currently rate the Fund’s ARPS. In addition, future ratings downgrades by Moody’s or Fitch, as applicable, may result in an increase to the Fund’s Preferred Shares dividend rates. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Confidential Information Access Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Confidential Information Access Risk In managing the Fund (and other PIMCO clients), PIMCO may from time to time have the opportunity to receive material, non-public information (“Confidential Information”) about the issuers of certain investments, including, without limitation, senior floating rate loans, other loans and related investments being considered for acquisition by the Fund or held in the Fund’s portfolio. For example, an issuer of privately placed loans considered by the Fund may offer to provide PIMCO with financial information and related documentation regarding the issuer that is not publicly available. Pursuant to applicable policies and procedures, PIMCO may (but is not required to) seek to avoid receipt of Confidential Information from the issuer so as to avoid possible restrictions on its ability to purchase and sell investments on behalf of the Fund and other clients to which such Confidential Information relates. In such circumstances, the Fund (and other PIMCO clients) may be disadvantaged in comparison to other investors, including with respect to the price the Fund pays or receives when it buys or sells an investment. Further, PIMCO’s and the Fund’s abilities to assess the desirability of proposed consents, waivers or amendments with respect to certain investments may be compromised if they are not privy to available Confidential Information. PIMCO may also determine to receive such Confidential Information in certain circumstances under its applicable policies and procedures. If PIMCO intentionally or unintentionally comes into possession of Confidential Information, it may be unable, potentially for a substantial period of time, to purchase or sell investments to which such Confidential Information relates. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Private Placements and Restricted Securities Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Private Placements and Restricted Securities Risk A private placement involves the sale of securities that have not been registered under the Securities Act or relevant provisions of applicable non-U.S. law to certain institutional and qualified individual purchasers, such as the Fund. In addition to the general risks to which all securities are subject, securities received in a private placement generally are subject to strict restrictions on resale, and there may be no liquid secondary market or ready purchaser for such securities. See “Principal Risks of the Fund—Liquidity Risk.” Therefore, the Fund may be unable to dispose of such securities when it desires to do so, or at the most favorable time or price. Private placements may also raise valuation risks. Restricted securities are often purchased at a discount from the market price of unrestricted securities of the same issuer reflecting the fact that such securities may not be readily marketable without some time delay. Such securities are often more difficult to value and the sale of such securities often requires more time and results in higher brokerage charges or dealer discounts and other selling expenses than does the sale of securities trading on national securities exchanges or in the over-the-counter markets. Until the Fund can sell such securities into the public markets, its holdings may be less liquid and any sales will need to be made pursuant to an exemption under the Securities Act. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inflation/Deflation Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Inflation/Deflation Risk Inflation risk is the risk that the value of assets or income from the Fund’s investments will be worth less in the future as inflation decreases the value of payments at future dates. As inflation increases, the real value of the Fund’s portfolio could decline. Inflation has recently increased and it cannot be predicted whether it may decline. Deflation risk is the risk that prices throughout the economy decline over time. Deflation may have an adverse effect on the creditworthiness of issuers and may make issuer default more likely, which may result in a decline in the value of the Fund’s portfolio and Common Shares. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Changes Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Regulatory Changes Risk Financial entities, such as investment companies and investment advisers, are generally subject to extensive government regulation and intervention. Government regulation and/or intervention may change the way the Fund is regulated, affect the expenses incurred directly by the Fund and the value of its investments, and limit and /or preclude the Fund’s ability to achieve its investment objective. Government regulation may change frequently and may have significant adverse consequences. The Fund and the Investment Manager have historically been eligible for exemptions from certain regulations. However, there is no assurance that the Fund and the Investment Manager will continue to be eligible for such exemptions. Actions by governmental entities may also impact certain instruments in which the Fund invests. Moreover, government regulation may have unpredictable and unintended effects. Legislative or regulatory actions to address perceived liquidity or other issues in fixed income markets generally, or in particular markets such as the municipal securities market, may alter or impair the Fund’s ability to pursue its investment objective or utilize certain investment strategies and techniques. Current rules related to credit risk retention requirements for ABS may increase the cost to originators, securitizers and, in certain cases, asset managers of securitization vehicles in which the Fund may invest. The impact of the risk retention rules on the securitization markets is uncertain. These requirements may increase the costs to originators, securitizers, and, in certain cases, collateral managers of securitization vehicles in which the Fund may invest, which costs could be passed along to the Fund as an investor in such vehicles. In addition, the costs imposed by the risk retention rules on originators, securitizers and/or collateral managers may result in a reduction of the number of new offerings of ABS and thus in fewer investment opportunities for the Fund. A reduction in the number of new securitizations could also reduce liquidity in the markets for certain types of financial assets, which in turn could negatively affect the returns on the Fund’s investment. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Risk—London Interbank Offered Rate ("LIBOR") |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Regulatory Risk – London Interbank Offered Rate (“LIBOR”) The Fund’s investments (including, but not limited to, repurchase agreements, collateralized loan obligations and mortgage-backed securities), payment obligations and financing terms may rely in some fashion on the London Interbank Offered Rate (“LIBOR”). LIBOR is an average interest rate, determined by the ICE Benchmark Administration that banks charge one another for the use of short-term money. ,On July 27, 2017, the Chief Executive of the FCA announced that after 2021 it would cease its active encouragement of banks to provide the quotations needed to sustain LIBOR due to the absence of an active market for interbank unsecured lending and other reasons. On March 5, 2021, the FCA publicly announced that all U.S. Dollar LIBOR settings will either cease to be provided by any administrator or will no longer be representative (i) immediately after December 31, 2021 for one-week and two-month U.S. Dollar LIBOR settings and (ii) immediately after June 30, 2023 for the remaining U.S. Dollar LIBOR settings. As of January 1, 2022, as a result of supervisory guidance from U.S. regulators, some U.S. regulated entities have ceased entering into new LIBOR contracts with limited exceptions. While publication of the one-, three- and six- month Sterling and Japanese yen LIBOR settings will continue at least through calendar year 2022 on the basis of a changed methodology (known as “synthetic LIBOR”), these rates have been designated by the FCA as unrepresentative of the underlying market they seek to measure and are solely available for use in legacy transactions. Certain bank-sponsored committees in other jurisdictions, including Europe, the United Kingdom, Japan and Switzerland, have selected alternative reference rates denominated in other currencies. Although the transition process away from LIBOR has become increasingly well-defined in advance of the anticipated discontinuation date, there remains uncertainty regarding the future utilization of LIBOR and the nature of any replacement rate (e.g., the Secured Overnight Financing Rate, which is intended to replace U.S. dollar LIBOR and measures the cost of overnight borrowings through repurchase agreement transactions collateralized with U.S. Treasury securities). Any potential effects of the transition away from LIBOR on the Fund or on certain instruments in which the Fund invests can be difficult to ascertain, and they may vary depending on factors that include, but are not limited to: (i) existing fallback or termination provisions in individual contracts and (ii) whether, how, and when industry participants develop and adopt new reference rates and fallbacks for both legacy and new products and instruments. For example, certain of the Fund’s investments may involve individual contracts that have no existing fallback provision or language that contemplates the discontinuation of LIBOR, and those investments could experience increased volatility or illiquidity as a result of the transition process. In addition, interest rate provisions included in such contracts, or in contracts or other arrangements entered into by the Fund, may need to be renegotiated. On March 15, 2022, the Adjustable Interest Rate (LIBOR) Act was signed into law. This law provides a statutory fallback mechanism on a nationwide basis to replace LIBOR with a benchmark rate that is selected by the Board of Governors of the Federal Reserve System and based on the Secured Overnight Financing Rate for certain contracts that reference LIBOR and contain no, or insufficient, fallback provisions. It is expected that implementing regulations in respect of the law will follow. The transition of investments from LIBOR to a replacement rate as a result of amendment, application of existing fallbacks, statutory requirements or otherwise may also result in a reduction in the value of certain instruments held by the Fund, a change in the cost of borrowing or the dividend rate for any Preferred Shares that may be issued by the Fund, or a reduction in the effectiveness of related Fund transactions such as hedges. Any such effects of the transition away from LIBOR, as well as other unforeseen effects, could result in losses to the Fund. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Risk—Commodity Pool Operator |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Regulatory Risk – Commodity Pool Operator The CFTC has adopted regulations that subject registered investment companies and their investment advisers to regulation by the CFTC if the registered investment company invests more than a prescribed level of its liquidation value in futures, options on futures or commodities, swaps, or other financial instruments regulated under the CEA and the rules thereunder (“commodity interests”), or if the Fund markets itself as providing investment exposure to such instruments. The Investment Manager is registered with the CFTC as a CPO. However, with respect to the Fund, the Investment Manager has claimed an exclusion from registration as a CPO pursuant to CFTC Rule 4.5. For the Investment Manager to remain eligible for this exclusion, the Fund must comply with certain limitations, including limits on its ability to use any commodity interests and limits on the manner in which the Fund holds out its use of such commodity interests. These limitations may restrict the Fund’s ability to pursue its investment objective and strategies increase the costs of implementing its strategies, result in higher expenses for the Fund, and/or adversely affect the Fund’s total return. To the extent the Fund becomes ineligible for this exclusion from CFTC regulation, the Fund may consider steps in order to continue to qualify for exemption from CFTC regulation, or may determine to operate subject to CFTC regulation. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Liquidity Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Liquidity Risk Liquidity risk exists when particular investments are difficult to purchase or sell. Illiquid investments are investments that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. Illiquid investments may become harder to value, especially in changing markets. The Fund’s investments in illiquid investments may reduce the returns of the Fund because it may be unable to sell the illiquid investments at an advantageous time or price or possibly require the Fund to dispose of other investments at unfavorable times or prices in order to satisfy its obligations, which could prevent the Fund from taking advantage of other investment opportunities. Additionally, the market for certain investments may become illiquid under adverse market or economic conditions independent of any specific adverse changes in the conditions of a particular issuer. Bond markets have consistently grown over the past three decades while the capacity for traditional dealer counterparties to engage in fixed income trading has not kept pace and in some cases has decreased. As a result, dealer inventories of corporate bonds, which provide a core indication of the ability of financial intermediaries to “make markets,” are at or near historic lows in relation to market size. Because market makers seek to provide stability to a market through their intermediary services, a significant reduction in dealer inventories could potentially lead to decreased liquidity and increased volatility in the fixed income markets. Such issues may be exacerbated during periods of economic uncertainty. In such cases, the Fund, due to the difficulty in purchasing and selling such securities or instruments, may be unable to achieve its desired level of exposure to a certain sector. To the extent that the Fund invests in securities of companies with smaller market capitalizations, foreign (non-U.S.) securities, Rule 144A securities, illiquid sectors of fixed income securities, derivatives or securities with substantial market and/or credit risk, the Fund will tend to have greater exposure to liquidity risk. Further fixed income securities with longer durations until maturity face heightened levels of liquidity risk as compared to fixed income securities with shorter durations until maturity. The risks associated with illiquid instruments may be particularly acute in situations in which the Fund’s operations require cash (such as in connection with tender offers) and could result in the Fund borrowing to meet its short-term needs or incurring losses on the sale of illiquid instruments. It may also be the case that other market participants may be attempting to liquidate fixed income holdings at the same time as the Fund, causing increased supply in the market and contributing to liquidity risk and downward pricing pressure. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Tax Risk The Fund has elected to be treated as a RIC under the Code and intends each year to qualify and be eligible to be treated as such, so that it generally will not be subject to U.S. federal income tax on its net investment income or net short-term or long-term capital gains, that are distributed to shareholders. In order to qualify and be eligible for such treatment, the Fund must meet certain asset diversification tests, derive at least 90% of its gross income for such year from certain types of qualifying income, and distribute to its shareholders at least 90% of its “investment company taxable income” as that term is defined in the Code (which includes, among other things, dividends, taxable interest and the excess of any net short-term capital gains over net long-term capital losses, as reduced by certain deductible expenses). The Fund’s investment strategy will potentially be limited by its intention to continue qualifying for treatment as a RIC, and can limit the Fund’s ability to continue qualifying as such. The tax treatment of certain of the Fund’s investments under one or more of the qualification or distribution tests applicable to RICs is uncertain. An adverse determination or future guidance by the IRS or a change in law might affect the Fund’s ability to qualify or be eligible for treatment as a RIC. Income and gains from certain of the Fund’s activities may not constitute qualifying income to a RIC for purposes of the 90% gross income test. If the Fund were to treat income or gain from a particular investment or activity as qualifying income and the income or gain were later determined not to constitute qualifying income and, together with any other nonqualifying income, caused the Fund’s nonqualifying income to exceed 10% of its gross income in any taxable year, the Fund would fail to qualify as a RIC unless it is eligible to and does pay a tax at the Fund level. If, in any year, the Fund were to fail to qualify for treatment as a RIC under the Code, and were ineligible to or did not otherwise cure such failure, the Fund would be subject to tax on its taxable income at corporate rates and, when such income is distributed, shareholders would be subject to further tax on such distributions to the extent of the Fund’s current or accumulated earnings and profits. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Portfolio Turnover Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Portfolio Turnover Risk The Investment Manager manages the Fund without regard generally to restrictions on portfolio turnover. The use of futures contracts and other derivative instruments with relatively short maturities may tend to exaggerate the portfolio turnover rate for the Fund. Trading in fixed income securities does not generally involve the payment of brokerage commissions, but does involve indirect transaction costs. The use of futures contracts and other derivative instruments may involve the payment of commissions to futures commission merchants or other intermediaries. Higher portfolio turnover involves correspondingly greater expenses to the Fund, including brokerage commissions or dealer mark-ups and other transaction costs on the sale of securities and reinvestments in other securities. The higher the rate of portfolio turnover of the Fund, the higher these transaction costs borne by the Fund generally will be. Such sales may result in realization of taxable capital gains (including short-term capital gains, which are generally taxed to shareholders at ordinary income tax rates when distributed net of short-term capital losses and net long-term capital losses), and may adversely impact the Fund’s after-tax returns. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operational Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Operational Risk An investment in the Fund, like any fund, involves operational risks arising from factors such as processing errors, human errors, inadequate or failed internal or external processes, failures in systems and technology, changes in personnel and errors caused by third-party service providers. The occurrence of any of these failures, errors or breaches could result in a loss of information, regulatory scrutiny, reputational damage or other events, any of which could have a material adverse effect on the Fund. While the Fund seeks to minimize such events through controls and oversight, there may still be failures that could cause losses to the Fund. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Investment Companies Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Other Investment Companies Risk When investing in an investment company, the Fund generally will bear its ratable share of that investment company’s expenses and remain subject to payment of the Fund’s management fees and other expenses with respect to assets so invested. Common Shareholders could therefore be subject to duplicative expenses to the extent the Fund invests in other investment companies. In addition, the securities of other investment companies may also be leveraged and will therefore be subject to the same leverage risks. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cybersecurity Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Cybersecurity Risk As the use of technology has become more prevalent in the course of business, the Fund is potentially more susceptible to operational and information security risks resulting from breaches in cyber security. A breach in cyber security refers to both intentional and unintentional cyber events from outside threat actors or internal resources that may, among other things, cause the Fund to lose proprietary information, suffer data corruption and/or destruction, lose operational capacity, result in the unauthorized release or other misuse of confidential information, or otherwise disrupt normal business operations. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems (e.g., through “hacking” or malicious software coding), and may come from multiple sources, including outside attacks such as denial-of-service attacks (i.e., efforts to make network services unavailable to intended users) or cyber extortion, including exfiltration of data held for ransom and/or “ransomware” attacks that renders systems inoperable until ransom is paid, or insider actions. In addition, cyber security breaches involving the Fund’s third party service providers (including but not limited to advisers, sub-advisers, administrators, transfer agents, custodians, vendors, suppliers, distributors and other third parties), trading counterparties or issuers in which the Fund invests can also subject the Fund to many of the same risks associated with direct cyber security breaches or extortion of company data. Moreover, cyber security breaches involving trading counterparties or issuers in which the Fund invests could adversely impact such counterparties or issuers and cause the Fund’s investment to lose value. Cyber security failures or breaches may result in financial losses to the Fund and its shareholders. These failures or breaches may also result in disruptions to business operations, potentially resulting in financial losses; interference with the Fund’s ability to calculate its NAV, process shareholder transactions or otherwise transact business with shareholders; impediments to trading; violations of applicable privacy and other laws; regulatory fines; penalties; third party claims in litigation; reputational damage; reimbursement or other compensation costs; additional compliance and cyber security risk management costs and other adverse consequences. In addition, substantial costs may be incurred in order to prevent any cyber incidents in the future. Like with operational risk in general, the Fund has established business continuity plans and risk management systems designed to reduce the risks associated with cyber security. However, there are inherent limitations in these plans and systems, including that certain risks may not have been identified, in large part because different or unknown threats may emerge in the future. As such, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers in which the Fund may invest, trading counterparties or third party service providers to the Fund. Such entities have experienced cyber attacks and other attempts to gain unauthorized access to systems from time to time, and there is no guarantee that efforts to prevent or mitigate the effects of such attacks or other attempts to gain unauthorized access will be successful. There is also a risk that cyber security breaches may not be detected. The Fund and its shareholders may suffer losses as a result of a cyber security breach related to the Fund, its service providers, trading counterparties or the issuers in which the Fund invests. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Potential Conflicts of Interest Risk—Allocation of Investment Opportunities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Potential Conflicts of Interest Risk—Allocation of Investment Opportunities The Investment Manager and its affiliates are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. The Investment Manager may provide investment management services to other funds and discretionary managed accounts that follow an investment program similar to that of the Fund. Subject to the requirements of the 1940 Act, the Investment Manager intends to engage in such activities and may receive compensation from third parties for its services. The results of the Fund’s investment activities may differ from those of other accounts managed by the Investment Manager or its affiliates, and it is possible that the Fund could sustain losses during periods in which one or more other accounts managed by the Investment Manager or its affiliates, including proprietary accounts, achieve profits on their trading. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repurchase Agreements Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Repurchase Agreements Risk The Fund may enter into repurchase agreements, in which the Fund purchases a security from a bank or broker-dealer, which agrees to repurchase the security at the Fund’s cost plus interest within a specified time. If the party agreeing to repurchase should default, the Fund will seek to sell the securities which it holds. This could involve procedural costs or delays in addition to a loss on the securities if their value should fall below their repurchase price. Repurchase agreements may be or become illiquid. These events could also trigger adverse tax consequences for the Fund. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Structured Investments Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Structured Investments Risk Holders of structured products, including structured notes, credit-linked notes and other types of structured products, bear the risks of the underlying investments, index or reference obligation and are subject to counterparty risk. The Fund may have the right to receive payments only from the structured product, and generally does not have direct rights against the issuer or the entity that sold the assets to be securitized. While certain structured products enable the investor to acquire interests in a pool of securities without the brokerage and other expenses associated with directly holding the same securities, investors in structured products generally pay their share of the structured product’s administrative and other expenses. Although it is difficult to predict whether the prices of indices and securities underlying structured products will rise or fall, these prices (and, therefore, the prices of structured products) are generally influenced by the same types of political and economic events that affect issuers of securities and capital markets generally. If the issuer of a structured product uses shorter term financing to purchase longer term securities, the issuer may be forced to sell its securities at below market prices if it experiences difficulty in obtaining such financing, which may adversely affect the value of the structured products owned by the Fund. Structured products generally entail risks associated with derivative instruments. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Market Disruptions Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Market Disruptions Risk The Fund is subject to investment and operational risks associated with financial, economic and other global market developments and disruptions, including those arising from war, terrorism, market manipulation, government interventions, defaults and shutdowns, political changes or diplomatic developments, public health emergencies (such as the spread of infectious diseases, pandemics and epidemics) and natural/environmental disasters, which can all negatively impact the securities markets, interest rates, secondary trading, ratings, credit risk, inflation, deflation, other factors relating to the Fund’s investments or the Investment Manager’s operations and the value of an investment in the Fund, its distributions and its returns. These events can also impair the technology and other operational systems upon which the Fund’s service providers, including PIMCO as the Fund’s investment adviser, rely, and could otherwise disrupt the Fund’s service providers’ ability to fulfill their obligations to the Fund. For example, the recent spread of an infectious respiratory illness caused by a novel strain of coronavirus (known as COVID-19) has caused volatility, severe market dislocations and liquidity constraints in many markets, including markets for the securities the Fund holds, and may adversely affect the Fund’s investments and operations. The U.S. Federal Reserve made emergency interest-rate cuts, moving short-term rates to near zero, issued forward guidance that rates would remain low until the economy weathers the COVID-19 crisis, and resumed quantitative easing. Additionally, Congress approved stimulus to offset the severity and duration of the adverse economic effects of COVID-19 and related disruptions in economic and business activity. Dozens of central banks across Europe, Asia, and elsewhere have announced and/or adopted similar economic relief packages. The end of any such programs could cause market downturns, disruptions and volatility, particularly if markets view the ending as premature. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Certain Affiliations |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Certain Affiliations Certain broker-dealers may be considered to be affiliated persons of the Fund and/or the Investment Manager due to their possible affiliations with Allianz SE, the ultimate parent of the Investment Manager. Absent an exemption from the SEC or other regulatory relief, the Fund is generally precluded from effecting certain principal transactions with affiliated brokers, and its ability to purchase securities being underwritten by an affiliated broker or a syndicate including an affiliated broker, or to utilize affiliated brokers for agency transactions, is subject to restrictions. This could limit the Fund’s ability to engage in securities transactions and take advantage of market opportunities. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Anti-Takeover Provisions |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Anti-Takeover Provisions The Declaration includes provisions that could limit the ability of other entities or persons to acquire control of the Fund or to convert the Fund to open-end status. See “Anti-Takeover and Other Provisions in the Declaration of Trust and Bylaws.” These provisions in the Declaration could have the effect of depriving the Common Shareholders of opportunities to sell their Common Shares at a premium over the then-current market price of the Common Shares or at NAV. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Distribution Rate Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Distribution Rate Risk Although the Fund may seek to maintain level distributions, the Fund’s distribution rates may be affected by numerous factors, including but not limited to changes in realized and projected market returns, fluctuations in market interest rates, Fund performance, and other factors. There can be no assurance that a change in market conditions or other factors will not result in a change in the Fund’s distribution rate or that the rate will be sustainable in the future. For instance, during periods of low or declining interest rates, the Fund’s distributable income and dividend levels may decline for many reasons. For example, the Fund may have to deploy uninvested assets (whether from purchases of Fund shares, proceeds from matured, traded or called debt obligations or other sources) in new, lower yielding instruments. Additionally, payments from certain instruments that may be held by the Fund (such as variable and floating rate securities) may be negatively impacted by declining interest rates, which may also lead to a decline in the Fund’s distributable income and dividend levels. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
AMT Bonds Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | AMT Bonds Risk Investments by the Fund in AMT Bonds may expose the Fund to certain risks in addition to those typically associated with municipal bonds. Interest or principal on AMT Bonds paid out of current or anticipated revenues from a specific project or specific asset may be adversely impacted by declines in revenue from the project or asset. Declines in general business activity could also affect the economic viability of facilities that are the sole source of revenue to support AMT Bonds. In this regard, AMT Bonds may entail greater risks than general obligation municipal bonds. For shareholders subject to the federal alternative minimum tax, a portion of the Fund’s distributions may not be exempt from gross federal income, which may give rise to alternative minimum tax liability. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Focused Investment Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Focused Investment Risk Substantial exposure to municipal bonds of particular issuers, geographies and/or jurisdictions will result in susceptibility to political, economic, regulatory and other factors affecting issuers of such bonds, their ability to meet their obligations and the economic condition of the facility or specific revenue source from whose revenues payments of obligations may be made. The ability of state, county, or local governments or other issuers to meet their obligations will depend primarily on the availability of tax and other revenues to those entities. The amounts of tax and other revenues available to issuers may be affected from time to time by economic, political and demographic conditions that specifically impact such issuers. In addition, there are constitutional and statutory restrictions that limit the power of certain issuers to raise revenues or increase taxes. The availability of federal, state and local aid to issuers may also affect their ability to meet their obligations. The creditworthiness of obligations issued by local issuers within a given state may be unrelated to the creditworthiness of obligations issued by the state and there is no obligation on the part of the state to make payment on such local obligations in the event of default. Any reduction in the actual or perceived ability of an issuer to meet its obligations (including a reduction in the rating of its outstanding securities) would likely affect adversely the market value and marketability of its obligations and could adversely affect the values of other bonds as well. Moreover, in such circumstances, the value of the Fund’s shares may fluctuate more widely than the value of shares of a more diversified fund. Many factors, including national economic, social and environmental policies and conditions, which are not within the control of issuers, could affect or could have an adverse impact on the financial condition of the issuers. The Fund is unable to predict whether or to what extent such factors or other factors may affect issuers, the market value or marketability of such bonds or the ability of the respective issuers of the bonds acquired by the Fund to pay interest on or principal of such bonds. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
CSDR Related Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | CSDR Related Risk The European Union has adopted a settlement discipline regime under Regulation (EU) No 909/2014 and the Settlement Discipline RTS as they may be modified from time to time (“CSDR”), which will have phased compliance dates. It aims to reduce the number of settlement fails that occur in EEA central securities depositories (“CSDs”) and address settlement fails where they occur. The key elements of the regime are: (i) mandatory buy-ins—if a settlement fail continues for a specified period of time after the intended settlement date, a buy-in process must be initiated to effect the settlement; (ii) cash penalties—EEA CSDs are required to impose cash penalties on participants that cause settlement fails and distribute these to receiving participants; and (iii) allocations and confirmations—EEA investment firms are required to take measures to prevent settlement fails, including putting in place arrangements with their professional clients to communicate securities allocations and transaction confirmations. These requirements apply to transactions in transferable securities (e.g., shares and bonds), money market instruments, units in funds and emission allowances that are to be settled via an EEA CSD and, in the case of cash penalties and buy-in requirements only, are admitted to trading or traded on an EEA trading venue or cleared by an EEA central counterparty. The implementation of the CSDR settlement discipline regime for funds that enter into in-scope transactions may result in increased operational and compliance costs being borne directly or indirectly by the Fund. CSDR may also affect liquidity and increase trading costs associated with relevant securities. If in-scope transactions are subject to additional expenses and penalties as a consequence of the CSDR settlement discipline regime, such expenses and penalties may be charged to the relevant Fund depending upon their characterization under the Fund’s Investment Management Agreement. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Insurance Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Insurance Risk The Fund may purchase municipal securities that are secured by insurance, bank credit agreements or escrow accounts. The credit quality of the companies that provide such credit enhancements will affect the value of those securities. Certain significant providers of insurance for municipal securities have incurred significant losses as a result of exposure to sub-prime mortgages and other lower credit quality investments that have experienced recent defaults or otherwise suffered extreme credit deterioration. As a result, such losses reduced the insurers’ capital and called into question their continued ability to perform their obligations under such insurance if they are called upon to do so in the future. If the insurer of a municipal security suffers a downgrade in its credit rating or the market discounts the value of the insurance provided by the insurer, the rating of the underlying municipal security will be more relevant and the value of the municipal security would more closely, if not entirely, reflect such rating. In such a case, the value of insurance associated with a municipal security would decline and may not add any value. The insurance feature of a municipal security does not guarantee the full payment of principal and interest through the life of an insured obligation, the market value of the insured obligation or the net asset value of the common shares represented by such insured obligation. Investing in the municipal bond market involves the risks of investing in debt securities generally and certain other risks. The amount of public information available about the municipal bonds in which the Fund may invest is generally less than that for corporate equities or bonds, and the investment performance of the Fund’s investment in municipal bonds may therefore be more dependent on the analytical abilities of PIMCO than its investments in taxable bonds. The secondary market for municipal bonds also tends to be less well developed or liquid than many other securities markets, which may adversely affect the Fund’s ability to sell municipal bonds at attractive prices. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Contact [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cover [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Address Line One |  | 650 Newport Center Drive |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, City or Town |  | Newport Beach |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, State or Province |  | CA |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Postal Zip Code |  | 92660 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contact Personnel Name |  | Ryan G. Leshaw |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Financial Highlights [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Securities Amount |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 298,275,000 | $ 298,275,000 | $ 298,275,000 | $ 298,275,000 | $ 367,000,000 | $ 367,000,000 | $ 367,000,000 | $ 367,000,000 | $ 367,000,000 | $ 367,000,000 | $ 367,000,000
Senior Securities Coverage per Unit | [10] |  |  |  |  |  |  |  |  |  |  |  |  | $ 78,363 | $ 78,293 | $ 78,308 | $ 74,285 | $ 76,136 | $ 74,548 | $ 76,782 | $ 75,553 | $ 74,733 | $ 75,501 | $ 74,192
Senior Securities Involuntary Liquidating Preference per Unit | [11] |  |  |  |  |  |  |  |  |  |  |  |  | 25,000 | 25,000 | 25,000 | 25,000 | 25,000 | 25,000 | 25,000 | 25,000 | 25,000 | 25,000 | 25,000
Senior Securities Average Market Value per Unit | [12] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
RVMTP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Financial Highlights [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Securities Amount |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 68,700,000 | $ 68,700,000 | $ 68,700,000 | $ 68,700,000 |  |  |  |  |  |  |
Senior Securities Coverage per Unit | [10] |  |  |  |  |  |  |  |  |  |  |  |  | $ 313,450 | $ 313,170 | $ 313,230 | $ 297,110 |  |  |  |  |  |  |
Senior Securities Involuntary Liquidating Preference per Unit | [11] |  |  |  |  |  |  |  |  |  |  |  |  | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 |  |  |  |  |  |
Senior Securities Average Market Value per Unit | [13] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Lowest Price or Bid | [14] |  |  | 10.12 | $ 11.2 | $ 13.86 | $ 14.74 | $ 14.53 | $ 14.15 | $ 13.09 | $ 13.14 | $ 11.59 | $ 10.1 |  |  |  |  |  |  |  |  |  |  |
Highest Price or Bid | [14] |  |  | 11.82 | 14.55 | 14.83 | 15.31 | 15.08 | 15.35 | 14.71 | 14.28 | 13.45 | 15.97 |  |  |  |  |  |  |  |  |  |  |
Lowest Price or Bid, NAV |  |  |  | 9.14 | 10.7 | 12.15 | 12.32 | 12.26 | 12.14 | 11.87 | 11.95 | 10.95 | 10.12 |  |  |  |  |  |  |  |  |  |  |
Highest Price or Bid, NAV |  |  |  | $ 10.78 | $ 12.37 | $ 12.42 | $ 12.77 | $ 12.68 | $ 12.65 | $ 12.42 | $ 12.44 | $ 11.95 | $ 13.3 |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Common Shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 63,519,359 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series A ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Series A ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Authorized [Shares] |  |  | 4,040 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 2,279 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series B ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Series B ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Authorized [Shares] |  |  | 4,040 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 2,577 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series C ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Series C ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Authorized [Shares] |  |  | 4,040 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 2,422 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series D ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Series D ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Authorized [Shares] |  |  | 4,040 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 2,300 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series E ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Series E ARPS |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Authorized [Shares] |  |  | 4,040 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 2,353 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series 2051 RVMTP Shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Series 2051 RVMTP Shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 687 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
[1] | In the event that the Common Shares to which this prospectus relates are sold to or through underwriters or dealer managers, a corresponding prospectus supplement will disclose the applicable sales load and/or commission.
[2] | You will pay brokerage charges if you direct your broker or the plan agent to sell your Common Shares that you acquired pursuant to a dividend reinvestment plan. You may also pay a pro rata share of brokerage commissions incurred in connection with open-market purchases pursuant to the Fund’s Dividend Reinvestment Plan. See “Dividend Reinvestment Plan.”
[3] | The related prospectus supplement will disclose the estimated amount of offering expenses, the offering price and the offering expenses borne by the Fund and indirectly by all of its Common Shareholders as a percentage of the offering price.
[4] | Management Fees include fees payable to the Investment Manager for advisory services and for supervisory, administrative and other services. The Fund pays for the advisory, supervisory and administrative services it requires under what is essentially an all-in fee structure (the “unified management fee”). Pursuant to an investment management agreement, PIMCO is paid a Management Fee of 0.685% of the Fund’s average daily net assets (including daily net assets attributable to any Preferred Shares). The Fund (and not PIMCO) will be responsible for certain fees and expenses, which are reflected in the table above, that are not covered by the unified management fee under the investment management agreement. Please see “Management of the Fund–Investment Management Agreement” for an explanation of the unified management fee.
[5] | Restated to reflect the Fund’s outstanding ARPS and RVMTP averaged over the year ended December 31, 2021, which represented 22.02% and 5.07%, respectively, of the Fund’s total average managed assets (including the liquidation preference of outstanding Preferred Shares and assets attributable to TOBs), at an annual estimated dividend cost to the Fund of 1.93% for ARPS and 1.83% for RVMTP as of June 30, 2022, and assumes the Fund will continue to pay dividends on the ARPS at the “maximum applicable rate” called for under the Fund’s Bylaws due to the ongoing failure of auctions for the ARPS. The actual dividend rate paid on the Preferred Shares will vary over time in accordance with variations in market interest rates. See “Use of Leverage” and “Description of Capital Structure.”
[6] | Restated to reflect the Fund’s use of leverage in the form of TOBs averaged over the year ended December 31, 2021, which represented 14.89% of the Fund’s total average managed assets (including assets attributable to Preferred Shares and TOBs), at an estimated annual interest rate cost to the Fund of 0.84% as of June 30, 2022. See “Use of Leverage—Effects of Leverage.” The actual amount of interest expense borne by the Fund will vary over time in accordance with the level of the Fund’s use of Preferred Shares, TOBs and/or other forms of borrowing and variations in market interest rates. Borrowing expense is required to be treated as an expense of the Fund for accounting purposes. Any associated income or gains (or losses) realized from leverage obtained through such instruments is not reflected in the Annual Expenses table above, but would be reflected in the Fund’s performance results.
[7] | “Other Expenses” are estimated for the Fund’s current fiscal year ending December 31, 2022.
[8] | “Dividend Cost on Preferred Shares”, including distributions on Preferred Shares, and “Interest Payments on Borrowed Funds” are borne by the Fund separately from the management fees paid to PIMCO. Excluding such expenses, Total Annual Expenses are 1.03%.
[9] | The example above should not be considered a representation of future expenses. Actual expenses may be higher or lower than those shown. The example assumes that the estimated Interest Payments on Borrowed Funds, Dividend Cost on Preferred Shares and Other Expenses set forth in the Annual Expenses table are accurate, that the rate listed under Total Annual Expenses remains the same each year and that all dividends and distributions are reinvested at NAV. Actual expenses may be greater or less than those assumed. Moreover, the Fund’s actual rate of return may be greater or less than the hypothetical 5% annual return shown in the example. The example does not include commissions or estimated offering expenses, which would cause the expenses shown in the example to increase. In connection with an offering of Common Shares, the prospectus supplement will set forth an example including sales load and estimated offering costs.
[10] | “Asset Coverage per Preferred Share” means the ratio that the value of the total assets of the Fund, less all liabilities and indebtedness not represented by ARPS or RVMTP, bears to the aggregate of the involuntary liquidation preference of ARPS or RVMTP, expressed as a dollar amount per ARPS or RVMTP.
[11] | “Involuntary Liquidating Preference” means the amount to which a holder of ARPS or RVMTP would be entitled upon the involuntary liquidation of the Fund in preference to the Common Shareholders, expressed as a dollar amount per Preferred Share.
[12] | The ARPS have no readily ascertainable market value. Auctions for the ARPS have failed since February 2008, there is currently no active trading market for the ARPS and the Fund is not able to reliably estimate what their value would be in a third-party market sale. The liquidation value of the ARPS represents its liquidation preference, which approximates fair value of the shares less any accumulated unpaid dividends.
[13] | The RVMTP have no readily ascertainable market value. The liquidation value of the RVMTP represents its liquidation preference, which approximates fair value of the shares less any unamortized debt issuance costs.
[14] | Such prices reflect inter-dealer prices, without retail mark-up, mark-down or commission and may not represent actual transactions.

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