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N-2 - USD ($) |  |  | 3 Months Ended
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Aug. 22, 2022 | Aug. 18, 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, 2019 | Sep. 30, 2019
Cover [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Central Index Key |  | 0001070732 |  |  |  |  |  |  |  |  |  |  |  |  |
Amendment Flag |  | true |  |  |  |  |  |  |  |  |  |  |  |  |
Amendment Description |  | AMENDMENT NO. 26 |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Inv Company Type |  | N-2 |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Company Act File Number |  | 811-09013 |  |  |  |  |  |  |  |  |  |  |  |  |
Document Type |  | N-2/A |  |  |  |  |  |  |  |  |  |  |  |  |
Document Registration Statement |  | false |  |  |  |  |  |  |  |  |  |  |  |  |
Pre-Effective Amendment |  | true |  |  |  |  |  |  |  |  |  |  |  |  |
Pre-Effective Amendment Number |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |
Post-Effective Amendment |  | false |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Company Act Registration |  | true |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Company Registration Amendment |  | true |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Company Registration Amendment Number |  | 26 |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Registrant Name |  | EATON VANCE SENIOR INCOME TRUST |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Address Line One |  | Two International Place |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, City or Town |  | Boston |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, State or Province |  | MA |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Postal Zip Code |  | 02110 |  |  |  |  |  |  |  |  |  |  |  |  |
City Area Code |  | (617) |  |  |  |  |  |  |  |  |  |  |  |  |
Local Phone Number |  | 482-8260 |  |  |  |  |  |  |  |  |  |  |  |  |
Approximate Date of Commencement of Proposed Sale to Public |  | As soon as practicable 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) |  | false |  |  |  |  |  |  |  |  |  |  |  |  |
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 |  | No |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Emerging Growth Company |  | false |  |  |  |  |  |  |  |  |  |  |  |  |
New CEF or BDC Registrant [Flag] |  | false |  |  |  |  |  |  |  |  |  |  |  |  |
Fee Table [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shareholder Transaction Expenses [Table Text Block] |  |
Common Shareholder transaction expenses |
Sales load paid by you (as a percentage of offering price) | --%(1)
Offering expenses (as a percentage of offering price) | None(2)
Dividend reinvestment plan fees | $5.00(3)
Sales Load [Percent] | [1] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend Reinvestment and Cash Purchase Fees | [2] | $ 5 |  |  |  |  |  |  |  |  |  |  |  |  |
Other Transaction Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Transaction Expense 1 [Percent] | [3] | 0.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Annual Expenses [Table Text Block] |  |
Annual expenses | Percentage of net assets attributable to Common Shares(4)
Investment advisory fee | 1.10 %(5)
Interest payments on borrowed funds | 0.48 %(6)
Other expenses | 0.80%
Acquired fund fees and expenses | 0.06 %
Total annual Trust operating expenses | 2.44 %
Dividends on preferred shares | 0.09 %(6)
Total annual Trust operating expenses and dividends on preferred shares | 2.53 %
Interest Expenses on Borrowings [Percent] | [4],[5] | 0.48% |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend Expenses on Preferred Shares [Percent] | [4],[5] | 0.09% |  |  |  |  |  |  |  |  |  |  |  |  |
Incentive Fees [Percent] | [5],[6] | 1.10% |  |  |  |  |  |  |  |  |  |  |  |  |
Acquired Fund Fees and Expenses [Percent] | [5] | 0.06% |  |  |  |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Percent] | [5] | 0.80% |  |  |  |  |  |  |  |  |  |  |  |  |
Total Annual Expenses [Percent] | [5] | 2.44% |  |  |  |  |  |  |  |  |  |  |  |  |
Expense Example [Table Text Block] |  | EXAMPLE The following example illustrates the expenses that Common Shareholders would pay on a $1,000 investment in Common Shares, assuming (i) total annual expenses of 2.53 % of net assets attributable to Common Shares in years 1 through 10; (ii) a 5% annual return; and (iii) all distributions are reinvested at NAV:
1 Year | 3 Years | 5 Years | 10 Years
$26 | $79 | $135 | $287
Expense Example, Year 01 |  | $ 26 |  |  |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 3 |  | 79 |  |  |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 5 |  | 135 |  |  |  |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 10 |  | $ 287 |  |  |  |  |  |  |  |  |  |  |  |  |
Purpose of Fee Table , Note [Text Block] |  | The purpose of the table below is to help you understand all fees and expenses that you, as a holder of Common Shares (“Common Shareholder”), would bear directly or indirectly. The table reflects the issuance of preferred shares and borrowings, and shows Trust expenses as a percentage of net assets attributable to Common Shares for the year ended June 30, 2022. |  |  |  |  |  |  |  |  |  |  |  |  |
Basis of Transaction Fees, Note [Text Block] |  | Summary of Trust Expenses The purpose of the table below is to help you understand all fees and expenses that you, as a holder of Common Shares (“Common Shareholder”), would bear directly or indirectly. The table reflects the issuance of preferred shares and borrowings, and shows Trust expenses as a percentage of net assets attributable to Common Shares for the year ended June 30, 2022.
Common Shareholder transaction expenses |
Sales load paid by you (as a percentage of offering price) | --%(1)
Offering expenses (as a percentage of offering price) | None(2)
Dividend reinvestment plan fees | $5.00(3)
Annual expenses | Percentage of net assets attributable to Common Shares(4)
Investment advisory fee | 1.10 %(5)
Interest payments on borrowed funds | 0.48 %(6)
Other expenses | 0.80%
Acquired fund fees and expenses | 0.06 %
Total annual Trust operating expenses | 2.44 %
Dividends on preferred shares | 0.09 %(6)
Total annual Trust operating expenses and dividends on preferred shares | 2.53 %
Management Fee not based on Net Assets, Note [Text Block] |  | `(5)`The investment adviser fee paid by the Trust to the Adviser is based on the average weekly gross assets of the Trust, including all assets attributable to any form of investment leverage that the Trust may utilize. Accordingly, if the Trust were to increase investment leverage in the future, the investment adviser fee will increase as a percentage of net assets. Pursuant to the investment advisory agreement, the investment adviser fee was computed at an annual rate of 0.73% of the Trust’s average weekly gross assets through April 30, 2022 and beginning May 1, 2022, at 0.72% of the Trust’s average weekly gross assets, and is payable monthly. The annual investment adviser fee rate shall be reduced to the following as of the stated date: May 1, 2023: 0.71%, May 1, 2024: 0.70%, May 1, 2025: 0.69% and May 1, 2026: 0.55%. |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investment Objectives and Practices [Text Block] |  | Investment Objective, Policies and Risks INVESTMENT OBJECTIVE The Trust's investment objective is to provide shareholders with a high level of current income, consistent with the preservation of capital. The Trust pursues its objective by investing its assets primarily in senior, secured floating-rate loans (“Senior Loans”). Senior Loans are loans in which the interest rate paid fluctuates based on a reference rate. Senior Loans typically are secured with specific collateral and have a claim on the assets and/or stock that is senior to subordinated debtholders and stockholders of the borrower. Senior Loans are made to corporations, partnerships and other business entities (“Borrowers”) that operate in a variety of industries and geographical regions. Senior Loans pay interest at rates that are reset periodically by reference to a base lending rate, primarily LIBOR, plus a premium. PRIMARY INVESTMENT POLICIES General Composition of the Trust. Under normal market conditions, the Trust will invest at least 80% of its total assets in Senior Loans of domestic and foreign borrowers that are denominated in U.S. dollars, euros, British pounds, Swiss francs, Canadian dollars and Australian dollars (each, an “Authorized Foreign Currency”) making payments in such Authorized Foreign Currency. For the purposes of the 80% test, total assets is defined as net assets plus any borrowings for investment purposes, including any outstanding preferred shares. The Trust may also invest up to 15% of its net assets in foreign Senior Loans denominated in an Authorized Foreign Currency. For all foreign Senior Loan investments denominated in an Authorized Foreign Currency, the Adviser currently intends to hedge against foreign currency fluctuations through the use of currency exchange contracts and other appropriate permitted hedging strategies.  The Trust may invest up to 20% of its total assets in (i) loan interests which have (a) a second lien on collateral, (b) no security interest in the collateral, or (c) lower than a senior claim on collateral; (ii) other income-producing securities, such as investment and non-investment grade corporate debt securities and U.S. government and U.S. dollar-denominated foreign government or supranational debt securities; and (iii) warrants and equity securities issued by a Borrower or its affiliates as part of a package of investments in the Borrower or its affiliates. During unusual market conditions, the Trust may invest up to 100% of assets in cash or cash equivalents which may be inconsistent with its investment objective and other policies. Corporate bonds of below investment grade quality (“Non-Investment Grade Bonds”), commonly referred to as “junk bonds,” which are bonds that are rated below investment grade by each of the Rating Agencies who cover the security, or, if unrated, are determined to be of comparable quality by the Adviser. S&P and Fitch consider securities rated below BBB- to be below investment grade and Moody’s considers securities rated below Baa3 to be below investment grade. The Trust’s credit quality policies apply only at the time a security is purchased, and the Trust is not required to dispose of a security in the event of a downgrade of an assessment of credit quality, the withdrawal of a rating, or in the event of a default. In determining whether to retain or sell such a security, Eaton Vance may consider such factors as Eaton Vance’s assessment of the credit quality of the issuers of such security, the price at which such security could be sold and the rating, if any, assigned to such security by other Rating Agencies. Securities rated in the lowest investment grade rating (BBB- or Baa3) may have certain speculative characteristics. Below investment grade quality securities are considered to be predominantly speculative because of the credit risk of the issuers. See “Investment Objective, Policies and Risks - Risk Considerations - Non-Investment Grade Bonds Risk.” The Trust’s policy of investing, under normal market conditions, at least 80% of its total assets in Senior Loans is not considered to be fundamental by the Trust and can be changed without a vote of the Trust’s shareholders. However, this policy may only be changed by the Trust’s Board following the provision of 60 days prior written notice to the Trust’s shareholders. The Trust is not subject to any restrictions with respect to the maturity of Senior Loans held in its portfolio. A lender may have certain obligations pursuant to a loan agreement relating to Senior Loans, which may include the obligation to make additional loans in certain circumstances. The Trust generally will reserve against such contingent obligations by segregating a sufficient amount of cash, liquid securities and liquid Senior Loans, subject to the Trust's borrowing limitations. The Trust will not purchase interests in Senior Loans that would require the Trust to make any such additional loans if such additional loan commitments in the aggregate would exceed 20% of the Trust's total assets or would cause the Trust to fail to meet its tax diversification requirements. The Adviser’s staff monitors the credit quality and the price of Senior Loans and other securities held by the Trust, as well as other securities that are available to the Trust. The Trust may invest in Senior Loans and other securities of any credit quality. Although the Adviser considers ratings when making investment decisions, it generally performs its own credit and investment analysis and does not rely primarily on the ratings assigned by the Rating Agencies. In evaluating the quality of a particular security, whether rated or unrated, the Adviser will normally take into consideration, among other things, the issuer’s financial resources and operating history, its sensitivity to economic conditions and trends, the ability of its management, its debt maturity schedules and borrowing requirements, and relative values based on anticipated cash flow, interest and asset coverage, and earnings prospects. The Adviser will attempt to reduce the risks of investing in lower rated or unrated debt instruments through active portfolio management, credit analysis and attention to current developments and trends in the economy and the financial markets. The Trust is not required to dispose of a security in the event that a Rating Agency downgrades its assessment of the credit characteristics of a particular issue or withdraws its assessment, including in the event of a default. In determining whether to retain or sell such a security, Eaton Vance may consider such factors as Eaton Vance's assessment of the credit quality of the issuers of such security, the price at which such security could be sold and the rating, if any, assigned to such security by other Rating Agencies. The Trust may invest up to 15% of net assets in Senior Loans denominated in Authorized Foreign Currencies and may invest in other securities of non-United States issuers. The Trust’s investments may have significant exposure to certain sectors of the economy and thus may react differently to political or economic developments than the market as a whole. The Trust may accept equity securities in connection with a debt restructuring or reorganization of a Borrower either inside or outside of bankruptcy. The Trust may hold equity securities issued in exchange for a Senior Loan or issued in connection with the debt restructuring or reorganization of a Borrower. The Trust may also acquire additional equity securities of such Borrower or its affiliates if, in the judgment of the Adviser, such an investment may enhance the value of a Senior Loan held or would otherwise be consistent with the Trust’s investment policies. The Trust will not invest more than 10% of its assets in securities (including interests in Senior Loans) of any single Borrower. The Trust may purchase shares of other investment companies, including open- and closed-end investment companies and exchange-traded funds, with a similar investment objective and policies as permitted under the 1940 Act. Such investments are limited to 10% of total assets overall, with no more than 5% invested in any one issuer. The value of shares of other closed-end investment companies and exchange-traded funds is affected by risks similar to those of the Trust, such as demand for those securities regardless of the demand for the underlying portfolio assets. Investment companies bear fees and expenses that the Trust will bear indirectly, so investors in the Trust will be subject to duplication of fees. The Trust also may invest up to 5% of its total assets in structured notes with rates of return determined by reference to the total rate of return on one or more Senior Loans referenced in such notes. The rate of return on the structured note may be determined by applying a multiplier to the rate of total return on the referenced Senior Loan or Loans. Application of a multiplier is comparable to the use of financial leverage, a speculative technique. Leverage magnifies the potential for gain and the risk of loss; as a result, a relatively small decline in the value of a referenced Senior Loan could result in a relatively large loss in the value of a structured note. Common Shares of other investment companies and structured notes as discussed above that invest in Senior Loans or baskets of Senior Loans will be treated as Senior Loans for purposes of the Trust’s policy of normally investing at least 80% of its assets in Senior Loans, and may be subject to the Trust’s leverage limitations. Senior Loans. Senior Loans hold a senior position in the capital structure of a Borrower, are typically secured with specific collateral and have a claim on the assets and/or stock of the Borrower that is senior to that held by subordinated debt holders and stockholders of the Borrower. The capital structure of a Borrower may include Senior Loans, senior and junior subordinated debt, preferred stock and common stock issued by the Borrower, typically in descending order of seniority with respect to claims on the Borrower’s assets. Senior Loans are typically secured by specific collateral. As also discussed above, the proceeds of Senior Loans primarily are used to finance leveraged buyouts, recapitalizations, mergers, acquisitions, stock repurchases, refinancing and internal growth and for other corporate purposes. Senior Loans in which the Trust will invest generally pay interest at rates, which are reset periodically by reference to a base lending rate, plus a premium. Senior Loans typically have rates of interest which are reset either daily, monthly, quarterly or semi-annually by reference to a base lending rate, plus a premium or credit spread. These base lending rates are primarily LIBOR, and secondarily the prime rate offered by one or more major United States banks (the “Prime Rate”) and the certificate of deposit (“CD”) rate or other base lending rates used by commercial lenders. Floating-rate loans typically have rates of interest which are re-determined daily, monthly, quarterly or semi-annually by reference to a base lending rate, plus a premium. As floating-rate loans, the frequency of how often a loan resets its interest rate will impact how closely such loans track current market interest rate. The floating-rate loans held by the Trust will have a dollar-weighted average period until the next interest rate adjustment of approximately 90 days or less. As a result, as short-term interest rates increase, interest payable to the Trust from its investments in Senior Loans should increase, and as short-term interest rates decrease, interest payable to the Trust from its investments in Senior Loans should decrease. The Trust may utilize derivative instruments to shorten the effective interest rate redetermination period of Senior Loans in its portfolio. Senior Loans typically have a stated term of between one and ten years. In the experience of the Adviser over the last decade, however, the average life of Senior Loans has been two to four years because of prepayments. Junior Loans are secured and unsecured subordinated loans, second lien loans and subordinate bridge loans. Senior Loans and Junior Loans are referred to together herein as “loans.” Loans may be primary, direct investments or investments in loan assignments or participation interests. A loan assignment represents a portion of the entirety of a loan and a portion of the entirety of a position previously attributable to a different lender. The purchaser of an assignment typically succeeds to all the rights and obligations under the loan agreement and has the same rights and obligations as the assigning investor. However, assignments through private negotiations may cause the purchaser of an assignment to have different and more limited rights than those held by the assigning investor. Loan participation interests are interests issued by a lender or other entity and represent a fractional interest in a loan. The Trust typically will have a contractual relationship only with the financial institution that issued the participation interest. As a result, the Trust may have the right to receive payments of principal, interest and any fees to which it is entitled only from the financial institution and only upon receipt by such entity of such payments from the borrower. In connection with purchasing a participation interest, the Trust generally will have no right to enforce compliance by the borrower with the terms of the loan agreement, nor any rights with respect to any funds acquired by other investors through set-off against the borrower and the Trust may not directly benefit from the collateral supporting the loan in which it has purchased the participation interest. As a result, the Trust may assume the credit risk of both the borrower and the financial institution issuing the participation interest. In the event of the insolvency of the entity issuing a participation interest, the Trust may be treated as a general creditor of such entity. No active trading market may exist for certain loans, which may impair the ability of the Trust to realize full value in the event of the need to sell a loan and which may make it difficult to value the loan. To the extent that a secondary market does exist for certain loans, the market may be subject to irregular trading activity, wide bid/ask spreads and extended trade settlement periods. Most loans are rated below investment grade or, if unrated, are of similar credit quality. Loan investments may be made at par or at a discount or premium to par. The interest payable on a loan may be fixed or floating rate, and paid in cash or in-kind. In connection with transactions in loans, the Trust may be subject to facility or other fees. Loans may be secured by specific collateral or other assets of the borrower, guaranteed by a third party, unsecured or subordinated. During the term of a loan, the value of any collateral securing the loan may decline in value, causing the loan to be under collateralized. Collateral may consist of assets that may not be readily liquidated, and there is no assurance that the liquidation of such assets would satisfy fully a borrower’s obligations under the loan. In addition, if a loan is foreclosed, the Trust could become part owner of the collateral and would bear the costs and liabilities associated with owning and disposing of such collateral. A lender’s repayment and other rights primarily are determined by governing loan, assignment or participation documents, which (among other things) typically establish the priority of payment on the loan relative to other indebtedness and obligations of the borrower. A borrower typically is required to comply with certain covenants contained in a loan agreement between the borrower and the holders of the loan. The types of covenants included in loan agreements generally vary depending on market conditions, the creditworthiness of the issuer, and the nature of the collateral securing the loan. Loans with fewer covenants that restrict activities of the borrower may provide the borrower with more flexibility to take actions that may be detrimental to the loan holders and provide fewer investor protections in the event covenants are breached. The Trust may experience relatively greater realized or unrealized losses or delays and expense in enforcing its rights with respect to loans with fewer restrictive covenants. Loans to entities located outside of the U.S. have substantially different lender protections and covenants as compared to loans to U.S. entities and may involve greater risks. In the event of bankruptcy, applicable law may impact a lender’s ability to enforce its rights. Bankruptcy laws in foreign jurisdictions, including emerging markets, may differ significantly from U.S. bankruptcy law and the Trust’s rights with respect to a loan governed by the laws of a foreign jurisdiction may be more limited. Loans may be originated by a lending agent, such as a financial institution or other entity, on behalf of a group or “syndicate” of loan investors (the “Loan Investors”). In such a case, the agent administers the terms of the loan agreement and is responsible for the collection of principal, and interest payments from the borrower and the apportionment of these payments to the Loan Investors. Failure by the agent to fulfill its obligations may delay or adversely affect receipt of payment by the Trust. Furthermore, unless under the terms of a loan agreement or participation (as applicable) the Trust has direct recourse against the borrower, the Trust must rely on the agent and the other Loan Investors to pursue appropriate remedies against the borrower. The Trust expects primarily to purchase Senior Loans by assignment from a participant in the original syndicate of lenders or from subsequent assignees of such interests. The purchaser of an assignment typically succeeds to all the rights and obligations under the loan agreement and has the same rights and obligations as the assigning investor. However, assignments through private negotiations may cause the purchaser of an assignment to have different and more limited rights than those held by the assigning investor. The Trust may also purchase participations in the original syndicate making Senior Loans. Such indebtedness may be secured or unsecured. Loan participations typically represent direct participations in a loan to a corporate borrower, and generally are offered by banks or other financial institutions or lending syndicates. The Trust may participate in such syndications, or can buy part of a loan, becoming a part lender. When purchasing loan participations, the Trust assumes the credit risk associated with the corporate Borrower and may assume the credit risk associated with an interposed bank or other financial intermediary. The participation interests in which the Trust intends to invest may not be rated by any Rating Agency. The Trust may purchase and retain in its portfolio loans where the Borrowers have experienced, or may be perceived to be likely to experience, credit problems, including default, involvement in or recent emergence from bankruptcy reorganization proceedings or other forms of debt restructuring. At times, in connection with the restructuring of a loan either outside of bankruptcy court or in the context of bankruptcy court proceedings, the Trust may determine or be required to accept equity securities or junior debt securities in exchange for all or a portion of a loan. The Trust may also purchase unsecured loans, other floating-rate debt securities such as notes, bonds and asset-backed securities (such as special purpose trusts investing in bank loans), credit-linked notes, tranches of collateralized loan obligations, investment grade fixed-income debt obligations and money market instruments, such as commercial paper. Loans are subject to the risk that a court, pursuant to fraudulent conveyance or other similar laws, could subordinate a loan to presently existing or future indebtedness of the borrower, or take other action detrimental to the holders of a loan including, in certain circumstances, invalidating the loans or causing interest previously paid to be returned to the borrower. Any such actions by a court could negatively affect the Trust’s performance. Loans that are secured and senior to other debtholders of a borrower tend to have more favorable loss recovery rates as compared to more junior types of below investment grade debt obligations. Due to their lower place in the borrower’s capital structure and, in some cases, their unsecured status, junior loans involve a higher degree of overall risk than senior loans of the same borrower. Investing in loans involves the risk of default by the borrower or other party obligated to repay the loan. In the event of insolvency of the borrower or other obligated party, the Trust may be treated as a general creditor of such entity unless it has rights that are senior to that of other creditors or secured by specific collateral or assets of the borrower. Fixed rate loans are also subject to the risk that their value will decline in a rising interest rate environment. This risk is mitigated for floating-rate loans, where the interest rate payable on the loan resets periodically by reference to a base lending rate. Many loans in which the Trust will invest may not be rated by a Rating Agency, will not be registered with the SEC or any state securities commission and will not be listed on any national securities exchange. In evaluating the creditworthiness of Borrowers, the Adviser will consider, and may rely in part, on analyses performed by others. Borrowers may have outstanding debt obligations that are rated below investment grade by a Rating Agency. Many of the loans held by the Trust will have been assigned ratings below investment grade by Rating Agencies. In the event loans are not rated, they are likely to be the equivalent of below investment grade quality. Because of the protective features of Senior Loans, the Adviser believes, based on its experience, that Senior Loans tend to have more favorable loss recovery rates as compared to more junior types of below investment grade debt obligations. U.S. federal securities laws afford certain protections against fraud and misrepresentation in connection with the offering or sale of a security, as well as against manipulation of trading markets for securities. The typical practice of a lender in relying exclusively or primarily on reports from the borrower may involve the risk of fraud, misrepresentation, or market manipulation by the borrower. It is unclear whether U.S. federal securities law protections are available to an investment in a loan. In certain circumstances, loans may not be deemed to be securities, and in the event of fraud or misrepresentation by a borrower, lenders may not have the protection of the anti-fraud provisions of the federal securities laws. However, contractual provisions in the loan documents may offer some protections, and lenders may also avail themselves of common-law fraud protections under applicable state law. In addition to the risks generally associated with debt instruments, such as credit, market, interest rate and liquidity risks, loans are also subject to the risk that the value of any collateral securing a loan may decline, be insufficient to meet the obligations of the borrower or be difficult to liquidate. The specific collateral used to secure a loan may decline in value or become illiquid, which would adversely affect the loan’s value. The Trust’s access to collateral may be limited by bankruptcy, other insolvency laws or by the type of loan the Trust has purchased. For example, if the Trust purchases a participation instead of an assignment, it would not have direct access to collateral of the borrower. As a result, a floating rate loan may not be fully collateralized and can decline significantly in value. Additionally, collateral on loan instruments may not be readily liquidated, and there is no assurance that the liquidation of such assets will satisfy a borrower’s obligations under the investment. When interest rates decline, the value of a fund invested in fixed-rate obligations can be expected to rise. Conversely, when interest rates rise, the value of a fund invested in fixed-rate obligations can be expected to decline. Although changes in prevailing interest rates can be expected to cause some fluctuations in the value of Senior Loans (due to the fact that floating-rates on Senior Loans only reset periodically), the value of Senior Loans is less sensitive to changes in market interest rates than fixed-rate instruments. As a result, the Adviser expects the Trust’s policy of investing a portion of its assets in floating-rate Senior Loans will make the Trust less volatile and less sensitive to changes in market interest rates than if the Trust invested exclusively in fixed-rate obligations. Similarly, a sudden and significant increase in market interest rates may cause a decline in the value of these investments and in the Trust’s net asset value. Other factors (including, but not limited to, rating downgrades, credit deterioration, a large downward movement in stock prices, a disparity in supply and demand of certain Senior Loans and other securities or market conditions that reduce liquidity) can reduce the value of Senior Loans and other debt obligations, impairing the Trust’s net asset value. Although the overall size and number of participants in the market for loans has grown over the past decade, loans continue to trade in a private, unregulated inter-dealer or inter-bank secondary market. The amount of public information available with respect to Senior Loans will generally be less extensive than that available for registered or exchange listed securities. With limited exceptions, the adviser will take steps intended to ensure that it does not receive material nonpublic information about the issuers of Senior Loans that also issue publicly traded securities. Therefore the adviser may have less information than other investors about certain of the Senior Loans in which it seeks to invest. Purchases and sales of loans are generally subject to contractual restrictions that must be satisfied before a loan can be bought or sold. These restrictions may (i) impede the Trust’s ability to buy or sell loans, (ii) negatively impact the transaction price, (iii) impact the counterparty credit risk borne by the Trust, (iv) impede the Trust’s ability to timely vote or otherwise act with respect to loans, (v) expose the Trust to adverse tax or regulatory consequences and (vi) result in delayed settlement of loan transactions. It may take longer than seven days for transactions in loans to settle. This is partly due to the nature of loans and the contractual restrictions noted above, which require a written assignment agreement and various ancillary documents for each transfer, and frequently require discretionary consents from both the borrower and the administrative agent. In light of the foregoing, the Trust may hold cash, sell securities or temporarily borrow from banks or other lenders to meet short-term liquidity needs due to the extended loan settlement process. The Adviser uses an independent pricing service to value most loans and other debt securities at their market value. The Adviser may use the fair value method to value loans or other securities if a security or a loan is not priced by a pricing service, a pricing service’s price is deemed unreliable, or if events occur after the close of a securities market (usually a foreign market) and before the Trust values its assets would materially affect net asset value. A security that is fair valued may be valued at a price higher or lower than actual market quotations or the value determined by other funds using their own fair valuation procedures. Because foreign securities trade on days when the Common Shares are not priced, net asset value can change at times when Common Shares cannot be sold. ADDITIONAL INVESTMENT PRACTICES Second Lien Loans and Debt Securities. The Trust may invest in loans and other debt securities that have the same characteristics as Senior Loans except that such loans are second in lien priority rather than first. Such “second lien” loans and securities like Senior Loans typically have adjustable floating-rate interest payments. Accordingly, the risks associated with “second lien” loans are higher than the risks of loans with first priority over the collateral. In the event of default on a “second lien” loan, the first priority lien holder has first claim to the underlying collateral of the loan. It is possible that no collateral value would remain for the second priority lien holder, and therefore result in a loss of investment to the Trust. Collateralized Loan Obligations (“CLOs”). The Trust may invest in certain asset-backed securities as discussed below. Asset-backed securities are payment claims that are securitized in the form of negotiable paper that is issued by a financing company (generically called a Special Purpose Vehicle or “SPV”). These securitized payment claims are, as a rule, corporate financial assets brought into a pool according to specific diversification rules. The SPV is a company founded solely for the purpose of securitizing these claims and its only asset is the risk arising out of this diversified asset pool. On this basis, marketable securities are issued which, due to the diversification of the underlying risk, generally represent a lower level of risk than the original assets. The redemption of the securities issued by the SPV takes place at maturity out of the cash flow generated by the collected claims. A CLO is a structured credit security issued by an SPV that was created to reapportion the risk and return characteristics of a pool of assets. The assets, typically Senior Loans, are used as collateral supporting the various debt tranches issued by the SPV. The key feature of the CLO structure is the prioritization of the cash flows from a pool of debt securities among the several classes of CLO holders, thereby creating a series of obligations with varying rates and maturities appealing to a wide range of investors. CLOs generally are secured by an assignment to a trustee under the indenture pursuant to which the bonds are issued of collateral consisting of a pool of debt instruments, usually, non-investment grade bank loans. Payments with respect to the underlying debt securities generally are made to the trustee under the indenture. CLOs are designed to be retired as the underlying debt instruments are repaid. In the event of sufficient early prepayments on such debt instruments, the class or series of CLO first to mature generally will be retired prior to maturity. Therefore, although in most cases the issuer of CLOs will not supply additional collateral in the event of such prepayments, there will be sufficient collateral to secure their priority with respect to other CLO tranches that remain outstanding. The credit quality of these securities depends primarily upon the quality of the underlying assets, their priority with respect to other CLO tranches and the level of credit support and/or enhancement provided. The underlying assets (e.g., loans) are subject to prepayments which shorten the securities’ weighted average maturity and may lower their return. If the credit support or enhancement is exhausted, losses or delays in payment may result if the required payments of principal and interest are not made. The value of these securities also may change because of changes in market value, that is changes in the market’s perception of the creditworthiness of the servicing agent for the pool, the originator of the pool, or the financial institution or fund providing the credit support or enhancement. The Trust will indirectly bear any management fees and expenses incurred by a CLO. Collateralized Debt Obligations (“CDOs”). The Trust may invest in CDOs. A CDO is a structured credit security issued by an SPV that was created to reapportion the risk and return characteristics of a pool of assets. The assets, typically non-investment grade bonds, leveraged loans, and other asset-backed obligations, are used as collateral supporting the various debt and equity tranches issued by the SPV. The key feature of the CDO structure is the prioritization of the cash flows from a pool of debt securities among the several classes of CDO holders, thereby creating a series of obligations with varying rates and maturities appealing to a wide range of investors. CDOs generally are secured by an assignment to a trustee under the indenture pursuant to which the bonds are issued of collateral consisting of a pool of debt securities, usually, non-investment grade bonds. Payments with respect to the underlying debt securities generally are made to the trustee under the indenture. CDOs are designed to be retired as the underlying debt securities are repaid. In the event of sufficient early prepayments on such debt securities, the class or series of CDO first to mature generally will be retired prior to maturity. Therefore, although in most cases the issuer of CDOs will not supply additional collateral in the event of such prepayments, there will be sufficient collateral to secure CDOs that remain outstanding. The credit quality of these securities depends primarily upon the quality of the underlying assets and the level of credit support and/or enhancement provided. CDOs operate similarly to CLOs and are subject to the same inherent risks. Foreign Securities. The Trust may invest in Senior Loans and other debt securities of non-U.S. issuers. Investment in securities of non-U.S. issuers involves special risks, including that non-U.S. issuers may be subject to less rigorous accounting and reporting requirements than U.S. issuers, less rigorous regulatory requirements, differing legal systems and laws relating to creditors’ rights, the potential inability to enforce legal judgments and the potential for political, social and economic adversity. The willingness and ability of sovereign issuers to pay principal and interest on government securities depends on various economic factors, including among others the issuer’s balance of payments, overall debt level, and cash flow considerations related to the availability of tax or other revenues to satisfy the issuer’s obligations. The securities of some foreign issuers are less liquid and at times more volatile than securities of comparable U.S. issuers. Foreign settlement procedures and trade regulations may involve certain risks (such as delay in the payment or delivery of securities and interest or in the recovery of assets held abroad) and expenses not present in the settlement of domestic investments. Investments may include securities issued by the governments of lesser-developed countries, which are sometimes referred to as “emerging markets.” There may be a possibility of nationalization or expropriation of assets, imposition of currency exchange controls, confiscatory taxation, political or financial instability, armed conflict and diplomatic developments which could affect the value of the Trust’s investments in certain foreign countries. Foreign issuers may become subject to sanctions imposed by the United States or another country, which could result in the immediate freeze of the foreign issuers’ assets or securities. The imposition of such sanctions could impair the market value of the securities of such foreign issuers and limit the Trust’s ability to buy, sell, receive or deliver the securities. Trading in certain foreign markets is also subject to liquidity risks. The value of foreign assets and currencies as measured in U.S. dollars may be affected favorably or unfavorably by changes in foreign currency rates and exchange control regulations, application of foreign tax laws (including withholding tax), governmental administration of economic or monetary policies (in this country or abroad), and relations between nations and trading. Foreign currencies also are subject to settlement, custodial and other operational risks. Currency exchange rates can be affected unpredictably by intervention, or the failure to intervene, by U.S. or foreign governments or central banks or by currency controls or political developments in the United States or abroad. If the U.S. dollar rises in value relative to a foreign currency, a security denominated in that foreign currency will be worth less in U.S. dollars. If the U.S. dollar decreases in value relative to a foreign currency, a security denominated in that foreign currency will be worth more in U.S. dollars. A devaluation of a currency by a country’s government or banking authority will have a significant impact on the value of any investments denominated in that currency. Costs are incurred in connection with conversions between currencies. The Trust may invest in securities and other instruments (including loans) issued, guaranteed, or backed by sovereign or government entities. Economic data as reported by sovereign or government entities and other issuers may be delayed, inaccurate or fraudulent. Many sovereign or government debt obligations may be rated below investment grade. Any restructuring of a sovereign or government debt obligation held by the Trust will likely have a significant adverse effect on the value of the obligation. In the event of default of a sovereign or government debt, the Trust may be unable to pursue legal action against the issuer or secure collateral on the debt, as there are typically no assets to be seized or cash flows to be attached. Furthermore, the willingness or ability of a sovereign or government entity to restructure defaulted debt may be limited. Therefore, losses on sovereign or government defaults may far exceed the losses from the default of a similarly rated U.S. corporate debt issuer. Political events in foreign countries may cause market disruptions. In June 2016, the United Kingdom (“UK”) voted in a referendum to leave the European Union (“EU”) (“Brexit”). Effective January 31, 2020, the UK ceased to be a member of the EU and, following a transition period during which the EU and the UK Government engaged in a series of negotiations regarding the terms of the UK’s future relationship with the EU, the EU and the UK Government signed an agreement on December 30, 2020 regarding the economic relationship between the UK and the EU. This agreement became effective on a provisional basis on January 1, 2021 and entered into full force on May 1, 2021. There remains significant market uncertainty regarding Brexit’s ramifications, and the range and potential implications of the possible political, regulatory, economic, and market outcomes in the UK, EU and beyond are difficult to predict. The end of the Brexit transition period may cause greater market volatility and illiquidity, currency fluctuations, deterioration in economic activity, a decrease in business confidence, and an increased likelihood of a recession in the UK. If one or more additional countries leave the EU or the EU dissolves, the world’s securities markets likely will be significantly disrupted. Corporate Bonds and Other Debt Securities. The Trust may invest in a wide variety of bonds, debentures and similar debt securities of varying maturities and durations issued by corporations and other business entities, including limited liability companies. Debt securities in which the Trust may invest may pay fixed or variable rates of interest. Bonds and other debt securities generally are issued by corporations and other issuers to borrow money from investors. The issuer pays the investor a fixed or variable rate of interest and normally must repay the amount borrowed on or before maturity. Certain debt securities are “perpetual” in that they have no maturity date. The Trust may invest in bonds and other debt securities of any quality. As discussed below, Non-Investment Grade Bonds, commonly known as “junk bonds,” are considered to be predominantly speculative in nature because of the credit risk of the issuers. Non-Investment Grade Bonds. As indicated above, Non-Investment Grade Bonds are those rated lower than investment grade (i.e., bonds rated lower than Baa3 by Moody’s and lower than BBB- by S&P and Fitch) or are unrated and of comparable quality as determined by the Adviser. Non-Investment Grade Bonds rated BB and Ba have speculative characteristics, while lower rated Non-Investment Grade Bonds are predominantly speculative. The Trust may hold securities that are unrated or in the lowest rating categories (rated C by Moody’s or D by S&P or Fitch). Bonds rated C by Moody’s are regarded as having extremely poor prospects of ever attaining any real investment standing. Bonds rated D by S&P or Fitch are in payment default or a bankruptcy petition has been filed and debt service payments are jeopardized. In order to enforce its rights with defaulted securities, the Trust may be required to retain legal counsel and/or a financial adviser. This may increase the Trust’s operating expenses and adversely affect net asset value. The credit quality of most securities held by the Trust reflects a greater than average possibility that adverse changes in the financial condition of an issuer, or in general economic conditions, or both, may impair the ability of the issuer to make payments of interest and principal. The inability (or perceived inability) of issuers to make timely payment of interest and principal would likely make the values of securities held by the Trust more volatile and could limit the Trust’s ability to sell its securities at favorable prices. In the absence of a liquid trading market for securities held by it, the Trust may have difficulties determining the fair market value of such securities. Because of the greater number of investment considerations involved in investing in investments that receive lower ratings, investing in lower rated investments depends more on the Adviser’s judgment and analytical abilities than may be the case for investing in investments with higher ratings. While the Adviser will attempt to reduce the risks of investing in lower rated or unrated securities through, among other things, active portfolio management, credit analysis and attention to current developments and trends in the economy and the financial markets, there can be no assurance that the investment adviser will be successful in doing so. Investments in obligations rated below investment grade and comparable unrated securities (sometimes referred to as “junk”) generally entail greater economic, credit and liquidity risks than investment grade securities. Lower rated investments have speculative characteristics because of the credit risk associated with their issuers. Changes in economic conditions or other circumstances typically have a greater effect on the ability of issuers of lower rated investments to make principal and interest payments than they do on issuers of higher rated investments. An economic downturn generally leads to a higher non-payment rate, and a lower rated investment may lose significant value before a default occurs. Lower rated investments generally are subject to greater price volatility and illiquidity than higher rated investments. Lower rated investments are considered primarily speculative with respect to the issuer’s capacity to pay interest and repay principal. The Trust’s high yield securities may have fixed or variable principal payments and all types of interest rate and dividend payment and reset terms, including fixed rate, adjustable rate, zero coupon, contingent, deferred, and payment in kind features. Convertible Securities. The Trust may invest in convertible securities. A convertible security is a bond, debenture, note, preferred security, or other security that entitles the holder to acquire common stock or other equity securities of the same or a different issuer. A convertible security entitles the holder to receive interest paid or accrued or dividends paid until the convertible security matures or is redeemed, converted or exchanged. Before conversion, convertible securities have characteristics similar to nonconvertible income securities. The Trust may invest in convertible securities of any rating. Holders of convertible securities generally have a claim on the assets of the issuer prior to the common stockholders but may be subordinated to other debt securities of the same issuer. Certain convertible debt securities may provide a put option to the holder, which entitles the holder to cause the securities to be redeemed by the issuer at a premium over the stated principal amount of the debt securities under certain circumstances. Certain convertible securities may include loss absorption characteristics that make the securities more debt-like. This is particularly true of convertible securities issued by companies in the financial services sector. The value of a convertible security may be influenced by changes in interest rates, with investment value declining as interest rates increase and increasing as interest rates decline. The credit standing of the issuer and other factors also may have an effect on the convertible security’s investment value. A convertible security may be subject to redemption at the option of the issuer at a price established in the convertible security’s governing instrument. Government Securities. U.S. Government securities include (1) U.S. Treasury obligations, which differ in their interest rates, maturities and times of issuance: U.S. Treasury bills (maturities of one year or less), U.S. Treasury notes (maturities of one year to ten years) and U.S. Treasury bonds (generally maturities of greater than ten years) and (2) obligations issued or guaranteed by U.S. Government agencies and instrumentalities that are supported by any of the following: (a) the full faith and credit of the U.S. Treasury, (b) the right of the issuer to borrow an amount limited to a specific line of credit from the U.S. Treasury, (c) discretionary authority of the U.S. Government to purchase certain obligations of the U.S. Government agency or instrumentality or (d) the credit of the agency or instrumentality. The Trust may also invest in any other security or agreement collateralized or otherwise secured by U.S. Government securities. Agencies and instrumentalities of the U.S. Government include but are not limited to: Federal Land Banks, Federal Financing Banks, Banks for Cooperatives, Federal Intermediate Credit Banks, Farm Credit Banks, Federal Home Loan Banks, Federal Home Loan Mortgage Corporation, Federal National Mortgage Association, Government National Mortgage Association, Student Loan Marketing Association, United States Postal Service, Small Business Administration, Tennessee Valley Authority and any other enterprise established or sponsored by the U.S. Government. Because the U.S. Government generally is not obligated to provide support to its instrumentalities, the Trust will invest in obligations issued by these instrumentalities only if the Adviser determines that the credit risk with respect to such obligations is minimal. The principal of and/or interest on certain U.S. Government securities which may be purchased by the Trust could be (a) payable in foreign currencies rather than U.S. dollars or (b) increased or diminished as a result of changes in the value of the U.S. dollar relative to the value of foreign currencies. The value of such portfolio securities may be affected favorably by changes in the exchange rate between foreign currencies and the U.S. dollar. Because of their high credit quality and market liquidity, U.S. Treasury and Agency Securities generally provide a lower current return than obligations of other issuers. While the U.S. Government has provided financial support to Fannie Mae and Freddie Mac in the past, but there can be no assurance that it will support these or other government-sponsored enterprises in the future. Commercial Paper. Commercial paper represents short-term unsecured promissory notes issued in bearer form by corporations such as banks or bank holding companies and finance companies. The rate of return on commercial paper may be linked or indexed to the level of exchange rates between the U.S. dollar and a foreign currency or currencies. Forward Commitments and When-Issued Securities. The Trust may purchase securities on a “forward commitment” or “when-issued” basis (meaning securities are purchased or sold with payment and delivery taking place in the future). In such a transaction, the Trust is securing what is considered to be an advantageous price and yield at the time of entering into the transaction. The yield on a comparable security when the transaction is consummated may vary from the yield on the security at the time that the forward commitment or when-issued transaction was made. From the time of entering into the transaction until delivery and payment is made at a later date, the securities that are the subject of the transaction are subject to market fluctuations. In forward commitment or when-issued transactions, if the seller or buyer, as the case may be, fails to consummate the transaction, the counterparty may miss the opportunity of obtaining a price or yield considered to be advantageous. Forward commitment or when-issued transactions may be expected to occur a month or more before delivery is due. No payment or delivery is made, however, until payment is received or delivery is made from the other party to the transaction. These transactions may create leverage in the Trust. Restricted Securities. Securities held by the Trust may be legally restricted as to resale (such as those issued in private placements), including commercial paper issued pursuant to Section 4(a)(2) of the 1933 Act and securities eligible for resale pursuant to Rule 144A thereunder, and securities of U.S. and non- U.S. issuers initially offered and sold outside the United States pursuant to Regulation S thereunder. Restricted securities may not be listed on an exchange and may have no active trading market. The Trust may incur additional expense when disposing of restricted securities, including all or a portion of the cost to register the securities. The Trust also may acquire securities through private placements under which it may agree to contractual restrictions on the resale of such securities that are in addition to applicable legal restrictions. In addition, if the Adviser receives material non-public information about the issuer, the Trust may as a result be unable to sell the securities. Restricted securities may be difficult to value properly and may involve greater risks than securities that are not subject to restrictions on resale. It may be difficult to sell restricted securities at a price representing fair value until such time as the securities may be sold publicly. Under adverse market or economic conditions or in the event of adverse changes in the financial condition of the issuer, the Trust could find it more difficult to sell such securities when the Adviser believes it advisable to do so or may be able to sell such securities only at prices lower than if such securities were more widely held. Holdings of restricted securities may increase the level of Trust illiquidity if eligible buyers become uninterested in purchasing them. Restricted securities may involve a high degree of business and financial risk, which may result in substantial losses. Illiquid Investments. The Trust may invest without limitation in investments for which there is no readily available trading market or are otherwise illiquid. It may be difficult to sell illiquid investments at a price representing their fair value until such time as such investments may be sold publicly. Where registration is required, a considerable period may elapse between a decision by the Trust to sell the investments and the time when it would be permitted to sell. Thus, the Trust may not be able to obtain as favorable a price as that prevailing at the time of the decision to sell. The Trust may also acquire investments through private placements under which it may agree to contractual restrictions on the resale of such investments. Such restrictions might prevent their sale at a time when such sale would otherwise be desirable. At times, a portion of the Trust’s assets may be invested in investments as to which the Trust, by itself or together with other accounts managed by the Adviser and its affiliates, holds a major portion or all of such investments. Under adverse market or economic conditions or in the event of adverse changes in the financial condition of the issuer, the Trust could find it more difficult to sell such investments when the Adviser believes it advisable to do so or may be able to sell such investments only at prices lower than if such investments were more widely held. It may also be more difficult to determine the fair value of such investments for purposes of computing the Trust’s net asset value. Equity Securities. Equity securities include: common stocks; preferred stocks, including convertible and contingent convertible preferred stocks; equity interests in trusts, partnerships, joint ventures and other unincorporated entities or enterprises; depositary receipts, rights and warrants in underlying equity interests; and other securities that are treated as equity for U.S. federal income tax purposes. The Trust cannot predict the income it might receive from equity securities because issuers generally have discretion as to the payment of any dividends or distributions. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer- and sector-specific considerations; and other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. Although stock prices can rebound, there is no assurance that values will return to previous levels. Pooled Investment Vehicles. Pooled investment vehicles include other open-end or closed-end investment companies affiliated or unaffiliated with the investment adviser, exchange-traded funds and other collective investment pools in accordance with the requirements of the 1940 Act, and the rules, regulations and interpretations . Closed-end investment company securities are usually traded on an exchange. The demand for a closed-end fund’s securities is independent of the demand for the underlying portfolio assets, and accordingly, such securities can trade at a discount from, or a premium over, their net asset value. The Trust generally will indirectly bear its proportionate share of any management fees paid by a pooled investment vehicle in which it invests in addition to the investment advisory fee paid by the Trust. Warrants. Equity warrants are securities that give the holder the right, but not the obligation, to subscribe for equity issues of the issuing company or a related company at a fixed price either on a certain date or during a set period. Changes in the value of a warrant do not necessarily correspond to changes in the value of its underlying security. The price of a warrant may be more volatile than the price of its underlying security, and a warrant may offer greater potential for capital appreciation as well as capital loss. Warrants do not entitle a holder to dividends or voting rights with respect to the underlying security and do not represent any rights in the assets of the issuing company. A warrant ceases to have value if it is not exercised prior to its expiration date. These factors can make warrants more speculative than other types of investments. The sale of a warrant results in a long or short term capital gain or loss depending on the period for which a warrant is held. Cash and Money Market Instruments; Temporary Defensive Positions . The Trust may invest in cash or money market instruments, including high quality short-term instruments. During unusual market conditions, including for temporary defensive purposes, the Trust may invest up to 100% of its assets in cash or money market instruments, which may be inconsistent with its investment objective(s) and other policies, and as such, the Trust may not achieve its investment objective(s) during this period . Money market instruments may be adversely affected by market and economic events, such as a sharp rise in prevailing short-term interest rates; adverse developments in the banking industry, which issues or guarantees many money market instruments; adverse economic, political or other developments affecting issuers of money market instruments; changes in the credit quality of issuers; and default by a counterparty. Derivatives. Generally, derivatives can be characterized as financial instruments whose performance is derived at least in part from the performance of an underlying reference instrument. Derivative instruments may be acquired in the United States or abroad consistent with the Trust’s investment strategy and may include the various types of exchange-traded and over-the-counter (“OTC”) instruments described herein and other instruments with substantially similar characteristics and risks. Trust obligations created pursuant to derivative instruments may give rise to leverage, which would subject the Trust to the requirements described under “Asset Coverage” in the Trust’s SAI. The Trust may invest in a derivative transaction if it is permitted to own, invest in, or otherwise have economic exposure to the reference instrument. Depending on the type of derivative instrument and the Trust’s investment strategy, a reference instrument could be a security, instrument, index, currency, commodity, economic indicator or event (“reference instruments”). As described more specifically below, the Trust may purchase or sell derivative instruments (which are instruments that derive their value from another instrument, security or index) to seek to hedge against fluctuations in securities prices or interest rates or for the purpose of leveraging the Trust. The Trust’s transactions in derivatives instruments may include the purchase or sale of futures contracts on securities, indices and other financial instruments, credit-linked notes, tranches of collateralized loan obligations and/or collateralized debt obligations, options on futures contracts, forward foreign currency contracts, and exchange-traded and over-the-counter options on securities or indices, index-linked securities, and interest rate, total return and credit default swaps. The Trust may trade in the specific type(s) and/or combinations of derivative transactions listed below. Derivative instruments are subject to a number of risks, including adverse or unexpected movements in the price of the reference instrument, and counterparty, credit, interest rate, liquidity, market, tax and leverage risks. In addition, derivatives also involve the risk that changes in their value may not correlate perfectly with the assets, rates, indices or instruments they are designed to hedge or closely track. Use of derivative instruments may cause the realization of higher amounts of short-term capital gains (generally taxed at ordinary income tax rates) than if such instruments had not been used. Success in using derivative instruments to hedge portfolio assets depends on the degree of price correlation between the derivative instruments and the hedged asset. Imperfect correlation may be caused by several factors, including temporary price disparities among the trading markets for the derivative instrument, the reference instrument and the Trust’s assets. To the extent that a derivative instrument is intended to hedge against an event that does not occur, the Trust may realize losses. OTC derivative instruments involve an additional risk in that the issuer or counterparty may fail to perform its contractual obligations. Some derivative instruments are not readily marketable or may become illiquid under adverse market conditions. In addition, during periods of market volatility, an option or commodity exchange or swap execution facility or clearinghouse may suspend or limit trading in an exchange-traded derivative instrument, which may make the contract temporarily illiquid and difficult to price. Commodity exchanges may also establish daily limits on the amount that the price of a futures contract or futures option can vary from the previous day’s settlement price. Once the daily limit is reached, no trades may be made that day at a price beyond the limit. This may prevent the closing out of positions to limit losses. The ability to terminate OTC derivative instruments may depend on the cooperation of the counterparties to such contracts. For thinly traded derivative instruments, the only source of price quotations may be the selling dealer or counterparty. In addition, certain provisions of the Internal Revenue Code of 1986, as amended (the “Code”), limit the use of derivative instruments. Derivatives permit the Trust to increase or decrease the level of risk, or change the character of the risk, to which its portfolio is exposed in much the same way as the Trust can increase or decrease the level of risk, or change the character of the risk, of its portfolio by making investments in specific securities. There can be no assurance that the use of derivative instruments will benefit the Trust. The U.S. and non-U.S. derivatives markets have undergone substantial changes in recent years as a result of changes under the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”) in the United States and regulatory changes in Europe, Asia and other non-U.S. jurisdictions. In particular, the Dodd-Frank Act and related regulations require many derivatives to be cleared and traded on an exchange, expand entity registration requirements, impose business conduct requirements on counterparties, and impose other regulatory requirements that will continue to change derivatives markets as regulations are implemented. As of October 28, 2020, the SEC has adopted new regulations that may significantly alter the Trust’s regulatory obligations with regard to its derivatives usage. In particular, the new regulations will, upon implementation, eliminate the current asset segregation framework for covering derivatives and certain other financial instruments, impose new responsibilities on the Board and establish new reporting and recordkeeping requirements for the Trust and may, depending on the extent to which the Trust uses derivatives, impose value at risk limitations on the Trust’s use of derivatives, and require the Trust’s Board to adopt a derivative risk management program. The implementation of these requirements may limit the ability of the Trust to use derivative instruments as part of its investment strategy, increase the costs of using these instruments or make them less effective. Additional future regulation of the derivatives markets may make the use of derivatives more costly, may limit the availability or reduce the liquidity of derivatives, and may impose limits or restrictions on the counterparties with which the Trust engages in derivative transactions. Trust management cannot predict the effects of any new governmental regulation that may be implemented, and there can be no assurance that any new government regulation will not adversely affect the Trust’s performance or ability to achieve its investment objective. Futures Contracts. Futures are standardized, exchange-traded contracts. Futures contracts on securities obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of the financial instrument called for in the contract at a specified future date at a specified price. An index futures contract obligates the purchaser to take, and a seller to deliver, an amount of cash equal to a specific dollar amount times the difference between the value of a specific index at the close of the last trading day of the contract and the price at which the agreement is made. No physical delivery of the underlying securities in the index is made. It is the practice of holders of futures contracts to close out their positions on or before the expiration date by use of offsetting contract positions, and physical delivery of financial instruments or delivery of cash, as applicable, is thereby avoided. An option on a futures contract gives the holder the right to enter into a specified futures contract. Credit-Linked Notes. The Trust may invest in credit-linked notes (“CLN”) for risk management purposes, including diversification. A CLN is a type of hybrid instrument in which a special purpose entity issues a structured note (the “note issuer”) with respect to which the reference instrument is a single bond, a portfolio of bonds or the unsecured credit of an issuer, in general (each a “reference credit”). The purchaser of the CLN (the “note purchaser”) invests a par amount and receives a payment during the term of the CLN that equals a fixed or floating rate of interest equivalent to a high-rated funded asset (such as a bank certificate of deposit) plus an additional premium that relates to taking on the credit risk of the reference credit. Upon maturity of the CLN, the note purchaser will receive a payment equal to: (i) the original par amount paid to the note issuer, if there is no occurrence of a designated event of default, restructuring or other credit event (each a “credit event”) with respect to the issuer of the reference credit; or (ii) the market value of the reference credit, if a credit event has occurred. Depending upon the terms of the CLN, it is also possible that the note purchaser may be required to take physical delivery of the reference credit in the event of credit event. Most CLNs use a corporate bond (or a portfolio of corporate bonds) as the reference credit. However, almost any type of fixed-income security (including foreign government securities), index or derivative contract (such as a credit default swap) can be used as the reference credit. Swaps. Swap contracts may be purchased or sold to hedge against fluctuations in securities prices, interest rates or market conditions, to change the duration of the overall portfolio, or to mitigate default risk. In a standard “swap” transaction, two parties agree to exchange the returns (or differentials in rates of return) to be exchanged or “swapped” between the parties, which returns are calculated with respect to a “notional amount,” i.e., the return on or increase in value of a particular dollar amount invested at a particular interest rate or in a “basket” of securities representing a particular index. Interest Rate Swaps. The Trust will enter into interest rate and total return swaps only on a net basis, i.e., the two payment streams are netted out, with the Trust receiving or paying, as the case may be, only the net amount of the two payments. Interest rate swaps involve the exchange by the Trust with another party of their respective commitments to pay or receive interest (e.g., an exchange of fixed rate payments for floating-rate payments). The Trust will only enter into interest rate swaps on a net basis. If the other party to an interest rate swap defaults, the Trust’s risk of loss consists of the net amount of payments that the Trust is contractually entitled to receive. The net amount of the excess, if any, of the Trust’s obligations over its entitlements will be maintained in a segregated account by the Trust’s custodian. The Trust will not enter into any interest rate swap unless the claims-paying ability of the other party thereto is considered to be investment grade by the Adviser. If there is a default by the other party to such a transaction, the Trust will have contractual remedies pursuant to the agreements related to the transaction. These instruments are traded in the over-the-counter market. The Trust may use interest rate swaps for risk management purposes only and not as a speculative investment and would typically use interest rate swaps to shorten the average interest rate reset time of the Trust’s holdings. Interest rate swaps involve the exchange by the Trust with another party of their respective commitments to pay or receive interest (e.g., an exchange of fixed rate payments for floating-rate payments). The use of interest rate swaps is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. If the Adviser is incorrect in its forecasts of market values, interest rates and other applicable factors, the investment performance of the Trust would be unfavorably affected. Total Return Swaps. As stated above, the Trust will enter into total return swaps only on a net basis. A total return swap is a contract in which one party agrees to make periodic payments to another party based on the change in market value of a reference instrument during the specified period, in return for periodic payments from the other party that are based on a fixed or variable interest rate or the total return of the reference instrument or another reference instrument. Total return swap agreements may be used to obtain exposure to a security or market without owning or taking physical custody of such security or investing directly in such market. Credit Default Swaps. The Trust may enter into credit default swap contracts for risk management purposes, including diversification. When the Trust is the buyer of a credit default swap contract, the Trust is entitled to receive the par (or other agreed-upon) value of a referenced debt obligation from the counterparty to the contract in the event of a default by a third party, such as a U.S. or foreign corporate issuer, on the debt obligation. In return, the Trust would pay the counterparty a periodic stream of payments over the term of the contract provided that no event of default has occurred. If no default occurs, the Trust would have spent the stream of payments and received no benefit from the contract. When the Trust is the seller of a credit default swap contract, it receives the stream of payments, but is obligated to pay upon default of the referenced debt obligation. As the seller, the Trust would effectively add leverage to its portfolio because, in addition to its total net assets, the Trust would be subject to investment exposure on the notional amount of the swap. These transactions involve certain risks, including the risk that the seller may be unable to fulfill the transaction. Credit default swap agreements (“CDS”) enable the Trust to buy or sell credit protection on an individual issuer or basket of issuers (i.e., the reference instrument). The Trust may enter into CDS to gain or short exposure to a reference instrument. Long CDS positions are utilized to gain exposure to a reference instrument (similar to buying the instrument) and are akin to selling insurance on the instrument. Short CDS positions are utilized to short exposure to a reference instrument (similar to shorting the instrument) and are akin to buying insurance on the instrument. Under a CDS, the protection “buyer” in a credit default contract is generally obligated to pay the protection “seller” an upfront or a periodic stream of payments over the term of the contract, provided that no credit event, such as a default, on a reference instrument has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (full notional value) of the reference instrument in exchange for an equal face amount of the reference instrument described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. If the Trust is a buyer and no credit event occurs, the Trust may recover nothing if the swap is held through its termination date. As a seller, the Trust generally receives an upfront payment or a fixed rate of income throughout the term of the swap provided that there is no credit event. The Trust’s obligations under a CDS will be accrued daily (offset against any amounts owed to the Trust). In response to market events, federal and certain state regulators have proposed regulation of the CDS market. These regulations may limit the Trust’s ability to use CDS and/or the benefits of CDS. CDS may be difficult to value and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The Trust may have difficulty, be unable or may incur additional costs to acquire any securities or instruments it is required to deliver under a CDS. The Trust may have limited ability to eliminate its exposure under a CDS either by assignment or other disposition, or by entering into an offsetting swap agreement. The Trust also may have limited ability to eliminate its exposure under a CDS if the reference instrument has declined in value. Futures and Options on Futures. The Trust may purchase and sell various kinds of financial futures contracts and options thereon to seek to hedge against changes in interest rates or for other risk management purposes. Futures contracts may be based on various debt securities and securities indices. Such transactions involve a risk of loss or depreciation due to unanticipated adverse changes in securities prices, which may exceed the Trust’s initial investment in these contracts. The Trust will only purchase or sell futures contracts or related options in compliance with the rules of the CFTC. These transactions involve transaction costs. There can be no assurance that Eaton Vance’s use of futures will be advantageous to the Trust. Rating Agency guidelines on any preferred shares issued by the Trust, including APS, may limit use of these transactions. Options. Options may be traded on an exchange and OTC. By buying a put option on a particular instrument, the Trust acquires a right to sell the underlying instrument at the exercise price. By buying a put option on an index, the Trust acquires a right to receive the cash difference between the strike price of the option and the index price at expiration. A purchased put position also typically can be sold at any time by selling at prevailing market prices. Purchased put options generally are expected to limit the Trust's risk of loss through a decline in the market value of the underlying security or index until the put option expires. When buying a put, the Trust pays a premium to the seller of the option. If the price of the underlying security or index is above the exercise price of the option as of the option valuation date, the option expires worthless and the Trust will not be able to recover the option premium paid to the seller. The Trust may purchase uncovered put options on securities, meaning it will not own the securities underlying the option. The Trust may also write (i.e., sell) put options. The Trust will receive a premium for selling a put option, which may increase the Trust's return. In selling a put option on a security, the Trust has the obligation to buy the security at an agreed upon price if the price of such instrument decreases below the exercise price. By selling a put option on an index, the Trust has an obligation to make a payment to the buyer to the extent that the value of the index decreases below the exercise price as of the option valuation date. If the value of the underlying security or index on the option’s expiration date is above the exercise price, the option will generally expire worthless and the Trust, as option seller, will have no obligation to the option holder. The Trust may purchase call options. By purchasing a call option on a security, the Trust has the right to buy the security at the option’s exercise price. By buying a call option on an index, the Trust acquires the right to receive the cash difference between the market price of the index and strike price at expiration. Call options typically can be exercised any time prior to option maturity or, sold at the prevailing market price. The Trust may also write (i.e., sell) a call option on a security or index in return for a premium. A call written on a security obligates the Trust to deliver the underlying security at the option exercise price. Written index call options obligate the Trust to make a cash payment to the buyer at expiration if the market price of the index is above the option strike price. Calls typically can also be bought back by the Trust at prevailing market prices and the Trust also may enter into closing purchase transactions with respect to written call options. The Trust’s options positions are marked to market daily. The value of options is affected by changes in the value and dividend rates of their underlying instruments, changes in interest rates, changes in the actual or perceived volatility of the relevant index or market and the remaining time to the options’ expiration, as well as trading conditions in the options market. The hours of trading for options may not conform to the hours during which the underlying instruments are traded. To the extent that the options markets close before markets for the underlying instruments, significant price and rate movements can take place in the markets that would not be reflected concurrently in the options markets. The Trust's ability to sell the instrument underlying a call option may be limited while the option is in effect unless the Trust enters into a closing purchase transaction. Uncovered call options have speculative characteristics and are riskier than covered call options because there is no underlying instrument held by the Trust that can act as a partial hedge. As the seller of a covered call option or an index call option, the Trust may forego, during the option’s life, the opportunity to profit from increases in the market value of the underlying instrument covering the call option above the sum of the premium received by the Trust and the exercise price of the call. The Trust also retains the risk of loss, minus the option premium received, should the price of the underlying instrument decline. Participants in OTC markets are typically not subject to the same credit evaluation and regulatory oversight as are members of “exchange-based” markets. OTC option contracts generally carry greater liquidity risk than exchange-traded contracts. This risk may be increased in times of financial stress, if the trading market for OTC options becomes restricted. The ability of the Trust to transact business with any one or a number of counterparties may increase the potential for losses to the Trust, due to the lack of any independent evaluation of the counterparties or their financial capabilities, and the absence of a regulated market to facilitate settlement of the options. Forward Foreign Currency Exchange Contracts. A forward foreign currency exchange contract (“currency forward”) involves an obligation to purchase or sell a specific currency at a future date, which may be any fixed number of days from the date of the contract agreed upon by the parties, at a price set at the time of the contract. These contracts may be bought or sold to protect against an adverse change in the relationship between currencies or to increase exposure to a particular foreign currency. Certain currency forwards may be individually negotiated and privately traded, exposing them to credit and counterparty risks. The precise matching of the currency forward amounts and the value of the instruments denominated in the corresponding currencies will not generally be possible because the future value of such securities in foreign currencies will change as a consequence of market movements in the value of those securities between the date on which the contract is entered into and the date it matures. There is additional risk that the use of currency forwards may reduce or preclude the opportunity for gain if the value of the currency should move in the direction opposite to the position taken and that currency forwards may create exposure to currencies in which the Trust’s securities are not denominated. In addition, it may not be possible to hedge against long-term currency changes. Currency forwards are subject to the risk of political and economic factors applicable to the countries issuing the underlying currencies. Furthermore, unlike trading in most other types of instruments, there is no systematic reporting of last sale information with respect to the foreign currencies underlying currency forwards. As a result, available information may not be complete. Counterparty Risk. A financial institution or other counterparty with whom the Trust does business (such as trading or as a derivatives counterparty), or that underwrites, distributes or guarantees any instruments that the Trust owns or is otherwise exposed to, may decline in financial condition and become unable to honor its commitments. This could cause the value of Trust shares to decline or could delay the return or delivery of collateral or other assets to the Trust. Counterparty risk is increased for contracts with longer maturities. Securities Lending. The Trust may lend its portfolio securities to broker-dealers and other institutional borrowers. During the existence of a loan, the Trust will continue to receive the equivalent of the interest paid by the issuer on the securities loaned, or all or a portion of the interest on investment of the collateral, if any. The Trust may pay lending fees to such borrowers. Loans will only be made to firms that have been approved by the investment adviser, and the investment adviser or the securities lending agent will periodically monitor the financial condition of such firms while such loans are outstanding. Securities loans will only be made when the investment adviser believes that the expected returns, net of expenses, justify the attendant risks. Securities loans currently are required to be secured continuously by collateral in cash, cash equivalents (such as money market instruments) or other liquid securities held by the custodian and maintained in an amount at least equal to the market value of the securities loaned. The Trust may engage in securities lending to generate income. Upon return of the loaned securities, the Trust would be required to return the related collateral to the borrower and may be required to liquidate portfolio securities in order to do so. The Trust may lend up to one-third of the value of its total assets or such other amount as may be permitted by law. As with other extensions of credit, there are risks of delay in recovery or even loss of rights in the securities loaned if the borrower of the securities fails financially. To the extent that the portfolio securities acquired with such collateral have decreased in value, it may result in the Trust realizing a loss at a time when it would not otherwise do so. As such, securities lending may introduce leverage into the Trust. The Trust also may incur losses if the returns on securities that it acquires with cash collateral are less than the applicable rebate rates paid to borrowers and related administrative costs. Borrowings. The Trust may borrow money to the extent permitted under the 1940 Act as interpreted, modified or otherwise permitted by the regulatory authority having jurisdiction. Under the 1940 Act, the Trust is not permitted to incur indebtedness, including through the issuance of debt securities, unless immediately thereafter the total asset value of the Trust’s portfolio is at least 300% of the liquidation value of the outstanding indebtedness (i.e., such liquidation value may not exceed 33 1/3% of the Trust’s total assets). The Trust may also borrow money for temporary administrative purposes. The Trust has entered into a Revolving Credit and Security Agreement (the Agreement) with conduit lenders and a bank to borrow up to $50 million ($125 million prior to September 29, 2021). Borrowings under the Agreement are secured by the assets of the Trust. Interest is charged at a rate above the conduits’ commercial paper issuance rate and is payable monthly. Under the terms of the Agreement, in effect through March 6, 2023 , the Trust also pays a program fee of 0.90% per annum on its outstanding borrowings to administer the facility and a liquidity fee of 0.15% (0.25% if the outstanding loan amount is less than or equal to 60% of the total facility size) per annum on the unused portion of the total commitment under the Agreement. Program and liquidity fees for the year ended June 30, 2022 totaled $351,954 . In connection with the renewal of the Agreement on March 7, 2022 , the Trust paid upfront fees of $75,000 , which is being amortized to interest expense over a period of one year through March 6, 2023 . The Trust is required to maintain certain net asset levels during the term of the Agreement. At June 30, 2022, the Trust had borrowings outstanding under the Agreement of $26 million at an interest rate of 1.62%. Based on the short-term nature of the borrowings under the Agreement and the variable interest rate, the carrying amount of the borrowings at June 30, 2022 approximated its fair value. For the year ended June 30, 2022, the average borrowings under the Agreement and the average interest rate (excluding fees) were $26,572,603 and 0.36 %, respectively. In addition, the credit facility may in the future be replaced or refinanced by one or more credit facilities having substantially different terms or by the issuance of preferred shares or debt securities. Repurchase Agreements. The Trust may enter into repurchase agreements (the purchase of a security coupled with an agreement to resell at a higher price) with respect to its permitted investments. A repurchase agreement is the purchase by the Trust of securities from a counterparty in exchange for cash that is coupled with an agreement to resell those securities to the counterparty at a specified date and price. Repurchase agreements maturing in more than seven days that the investment adviser believes may not be terminated within seven days at approximately the amount at which the Trust has valued the agreements are considered illiquid securities. When a repurchase agreement is entered into, the Trust typically receives securities with a value that equals or exceeds the repurchase price, including any accrued interest earned on the agreement. The value of such securities will be marked to market daily, and cash or additional securities will be exchanged between the parties as needed. Except in the case of a repurchase agreement entered into to settle a short sale, the value of the securities delivered to the Trust will be at least equal to repurchase price during the term of the repurchase agreement. The terms of a repurchase agreement entered into to settle a short sale may provide that the cash purchase price paid by the Trust is more than the value of purchased securities that effectively collateralize the repurchase price payable by the counterparty. Since in such a transaction the Trust normally will have used the purchased securities to settle the short sale, the Trust will segregate liquid assets equal to the marked to market value of the purchased securities that it is obligated to return to the counterparty under the repurchase agreement. In the event of the insolvency of the counterparty to a repurchase agreement, recovery of the repurchase price owed to the Trust may be delayed. In a repurchase agreement, such an insolvency may result in a loss to the extent that the value of the purchased securities decreases during the delay or that value has otherwise not been maintained at an amount equal to the repurchase price. Repurchase agreements may create leverage in the Trust. Reverse Repurchase Agreements. While the Trust has no current intention to enter into reverse repurchase agreements, the Trust reserves the right to enter into reverse repurchase agreements in the future, at levels that may vary over time. Under a reverse repurchase agreement, the Trust temporarily transfers possession of a portfolio instrument to another party, such as a bank or broker-dealer, in return for cash. At the same time, the Trust agrees to repurchase the instrument at an agreed upon time and price, which reflects an interest payment. The Trust may enter into such agreements when it is able to invest the cash acquired at a rate higher than the cost of the agreement, which would increase earned income. In the event of the insolvency of the counterparty to a reverse repurchase agreement, recovery of the securities sold by the Trust may be delayed. In a reverse repurchase agreement, the counterparty’s insolvency may result in a loss equal to the amount by which the value of the securities sold by the Trust exceeds the repurchase price payable by the Trust. When the Trust enters into a reverse repurchase agreement, any fluctuations in the market value of either the securities transferred to another party or the securities in which the proceeds may be invested would affect the market value of the Trust’s assets. As a result, such transactions may increase fluctuations in the market value of the Trust’s assets. While there is a risk that large fluctuations in the market value of the Trust’s assets could affect net asset value, this risk is not significantly increased by entering into reverse repurchase agreements, in the opinion of the Adviser. Because reverse repurchase agreements may be considered to be the practical equivalent of borrowing funds, they constitute a form of leverage. The SEC views reverse repurchase transactions as collateralized borrowings by a fund. Such agreements will be treated as subject to investment restrictions regarding “borrowings.” If the Trust reinvests the proceeds of a reverse repurchase agreement at a rate lower than the cost of the agreement, entering into the agreement will lower the Trust’s yield. Research Process. The Trust’s portfolio management utilizes the information provided by, and the expertise of, the research staff of the investment adviser and/or certain of its affiliates in making investment decisions. As part of the research process, portfolio management may consider financially material environmental, social and governance (“ESG”) factors. Such factors, alongside other relevant factors, may be taken into account in the Trust’s securities selection process. Temporary Investments. During unusual market conditions, the Trust may invest up to 100% of its assets in cash or cash equivalents temporarily, which may be inconsistent with its investment objectives, principal strategies and other policies. Cash equivalents are highly liquid, short-term securities such as commercial paper, time deposits, certificates of deposit, short-term notes and short-term U.S. government obligations. In moving to a substantial temporary investments position and in transitioning from such a position back into conformity with the Trust’s normal investment policies, the Trust may incur transaction costs that would not be incurred if the Trust had remained fully invested in accordance with such normal policies. The Trust’s investment in such temporary investments under unusual market circumstances may not be in furtherance of the Trust’s investment objectives. Portfolio Turnover. The Trust cannot accurately predict its portfolio turnover rate, but the annual turnover rate may exceed 100% (excluding turnover of securities having a maturity of one year or less). A high turnover rate (100% or more) necessarily involves greater expenses to the Trust. The portfolio turnover rate(s) for the Trust for the fiscal years ended June 30, 2022 and 2021 were 43 % and 40 %, respectively. |  |  |  |  |  |  |  |  |  |  |  |  |
Risk Factors [Table Text Block] |  | ADDITIONAL RISK CONSIDERATIONS Risk is inherent in all investing. Investing in any investment company security involves risk, including the risk that you may receive little or no return on your investment or even that you may lose part or all of your investment. Discount From or Premium to NAV. The Offering will be conducted only when Common Shares of the Trust are trading at a price equal to or above the Trust’s NAV per Common Share plus the per Common Share amount of commissions. As with any security, the market value of the Common Shares may increase or decrease from the amount initially paid for the Common Shares. The Trust’s Common Shares have traded both at a premium and at a discount relative to net asset value. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Trust’s NAV may decrease. Market Discount Risk. As with any security, the market value of the Common Shares may increase or decrease from the amount initially paid for the Common Shares. The Trust’s Common Shares have traded both at a premium and at a discount relative to NAV. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Trust’s NAV may decrease. Secondary Market for the Common Shares. The issuance of Common Shares through the Offering may have an adverse effect on the secondary market for the Common Shares. The increase in the amount of the Trust’s outstanding Common Shares resulting from the Offering may put downward pressure on the market price for the Common Shares of the Trust. Common Shares will not be issued pursuant to the Offering at any time when Common Shares are trading at a price lower than a price equal to the Trust’s NAV per Common Share plus the per Common Share amount of commissions. The Trust also issues Common Shares of the Trust through its dividend reinvestment plan. See “Dividend Reinvestment Plan.” Common Shares may be issued under the plan at a discount to the market price for such Common Shares, which may put downward pressure on the market price for Common Shares of the Trust. When the Common Shares are trading at a premium, the Trust may also issue Common Shares of the Trust that are sold through transactions effected on the NYSE. The increase in the amount of the Trust’s outstanding Common Shares resulting from that offering may also put downward pressure on the market price for the Common Shares of the Trust. The voting power of current shareholders will be diluted to the extent that such shareholders do not purchase shares in any future Common Share offerings or do not purchase sufficient shares to maintain their percentage interest. In addition, if the Adviser is unable to invest the proceeds of such offering as intended, the Trust’s per share distribution may decrease (or may consist of return of capital) and the Trust may not participate in market advances to the same extent as if such proceeds were fully invested as planned. Income Risk. The income investors receive from the Trust is based primarily on the interest it earns from its investments, which can vary widely over the short and long-term. If prevailing market interest rates drop, investors’ income from the Trust could drop as well. The Trust’s income could also be affected adversely when prevailing short-term interest rates increase and the Trust is utilizing leverage, although this risk is mitigated by the Trust’s investment in Senior Loans, which pay floating-rates of interest. Market Risk. The value of investments held by the Trust may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include such events as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest . These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Trust. The frequency and magnitude of resulting changes in the value of the Trust‘s investments cannot be predicted. Certain securities and other investments held by the Trust may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to higher market volatility. No active trading market may exist for certain investments held by the Trust, which may impair the ability of the Trust to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets. Senior Loans Risk. The risks associated with Senior Loans are similar to the risks of Non-Investment Grade Bonds (discussed below), although Senior Loans are typically senior and secured in contrast to Non-Investment Grade Bonds, which are often subordinated and unsecured. Senior Loans’ higher standing has historically resulted in generally higher recoveries in the event of a corporate reorganization or other restructuring. In addition, because their interest rates are adjusted for changes in short-term interest rates, Senior Loans generally have less interest rate risk than Non-Investment Grade Bonds, which are typically fixed rate. The Trust’s investments in Senior Loans are typically below investment grade and are considered speculative because of the credit risk of their issuers. Such companies are more likely to default on their payments of interest and principal owed to the Trust, and such defaults could reduce the Trust’s net asset value and income distributions. An economic downturn generally leads to a higher non-payment rate, and a debt obligation may lose significant value before a default occurs. Moreover, any specific collateral used to secure a loan may decline in value or lose all its value or become illiquid, which would adversely affect the loan’s value. “Junior Loans” are secured and unsecured subordinated loans, second lien loans and subordinate bridge loans. Senior Loans and Junior Loans are referred to together herein as “loans.” Loans and other debt securities are also subject to the risk of price declines and to increases in prevailing interest rates, although floating-rate debt instruments are less exposed to this risk than fixed-rate debt instruments. Interest rate changes may also increase prepayments of debt obligations and require the Trust to invest assets at lower yields. Loans are traded in a private, unregulated inter-dealer or inter-bank resale market and are generally subject to contractual restrictions that must be satisfied before a loan can be bought or sold. These restrictions may impede the Trust’s ability to buy or sell loans (thus affecting their liquidity) and may negatively impact the transaction price. See also “Market Risk” above. It also may take longer than seven days for transactions in loans to settle. The types of covenants included in loan agreements generally vary depending on market conditions, the creditworthiness of the issuer, the nature of the collateral securing the loan and possibly other factors. Loans with fewer covenants that restrict activities of the borrower may provide the borrower with more flexibility to take actions that may be detrimental to the loan holders and provide fewer investor protections in the event of such actions or if covenants are breached. The Trust may experience relatively greater realized or unrealized losses or delays and expense in enforcing its rights with respect to loans with fewer restrictive covenants. Loans to entities located outside of the U.S. may have substantially different lender protections and covenants as compared to loans to U.S. entities and may involve greater risks. The Trust may have difficulties and incur expense enforcing its rights with respect to non-U.S. loans and such loans could be subject to bankruptcy laws that are materially different than in the U.S. Loans may be structured such that they are not securities under securities law, and in the event of fraud or misrepresentation by a borrower, lenders may not have the protection of the anti-fraud provisions of the federal securities laws. Loans are also subject to risks associated with other types of income investments, including credit risk and risks of lower rated investments. Credit Risk. Investments in loans and other debt obligations (referred to below as “debt instruments”) are subject to the risk of non-payment of scheduled principal and interest. Changes in economic conditions or other circumstances may reduce the capacity of the party obligated to make principal and interest payments on such instruments and may lead to defaults. Such non-payments and defaults may reduce the value of Trust shares and income distributions. The value of debt instruments also may decline because of concerns about the issuer’s ability to make principal and interest payments. In addition, the credit ratings of debt instruments may be lowered if the financial condition of the party obligated to make payments with respect to such instruments deteriorates. In the event of bankruptcy of the issuer of a debt instrument, the Trust could experience delays or limitations with respect to its ability to realize the benefits of any collateral securing the instrument. In order to enforce its rights in the event of a default, bankruptcy or similar situation, the Trust may be required to retain legal or similar counsel, which may increase the Trust’s operating expenses and adversely affect net asset value. See “Lower Rated Investments Risk.” The Trust is also exposed to credit risk when it engages in certain types of derivatives transactions and when it engages in transactions that expose the Trust to counterparty risk. See “Derivatives.” Due to their lower place in the borrower’s capital structure, Junior Loans involve a higher degree of overall risk than Senior Loans to the same borrower. In evaluating the quality of a particular instrument, the investment adviser may take into consideration, among other things, a credit rating assigned by a credit rating agency, the issuer’s financial resources and operating history, its sensitivity to economic conditions and trends, the ability of its management, its debt maturity schedules and borrowing requirements, and relative values based on anticipated cash flow, interest and asset coverage, and earnings prospects. Credit rating agencies are private services that provide ratings of the credit quality of certain investments. Credit ratings issued by rating agencies are based on a number of factors including, but not limited to, the issuer’s financial condition and the rating agency’s credit analysis, if applicable, at the time of rating. As such, the rating assigned to any particular security is not necessarily a reflection of the issuer’s current financial condition. The ratings assigned are not absolute standards of credit quality and do not evaluate market risks or necessarily reflect the issuer’s current financial condition or the volatility or liquidity of the security. A credit rating may have a modifier (such as plus, minus or a numerical modifier) to denote its relative status within the rating. The presence of a modifier does not change the security credit rating (for example, BBB- and Baa3 are within the investment grade rating) for purposes of the Trust’s investment limitations. Interest Rate Risk. In general, the value of income securities will fluctuate based on changes in interest rates. The value of these securities is likely to increase when interest rates fall and decline when interest rates rise. Duration measures the time-weighted expected cash flows of a fixed-income security, while maturity refers to the amount of time until a fixed-income security matures. Generally, securities with longer durations or maturities are more sensitive to changes in interest rates than securities with shorter durations or maturities, causing them to be more volatile. Conversely, fixed-income securities with shorter durations or maturities will be less volatile but may provide lower returns than fixed-income securities with longer durations or maturities. In a rising interest rate environment, the duration of income securities that have the ability to be prepaid or called by the issuer may be extended. In a declining interest rate environment, the proceeds from prepaid or maturing instruments may have to be reinvested at a lower interest rate. The impact of interest rate changes is significantly less for floating-rate instruments that have relatively short periodic rate resets (e.g., ninety days or less). Variable and floating-rate loans and securities generally are less sensitive to interest rate changes, but may decline in value if their interest rates do not rise as much or as quickly as interest rates in general. Conversely, variable and floating-rate loans and securities generally will not increase in value as much as fixed rate debt instruments if interest rates decline. Because the Trust holds variable and floating-rate loans and securities, a decrease in market interest rates will reduce the interest income to be received from such securities. In the event that the Trust has a negative average portfolio duration, the value of the Trust may decline in a declining interest rate environment. Because floating or variable rates on loans only reset periodically, changes in prevailing interest rates may cause some fluctuations in the Trust’s net asset value. Similarly, a sudden and significant increase in market interest rates may cause a decline in the Trust’s net asset value. A material decline in the Trust’s net asset value may impair the Trust’s ability to maintain required levels of asset coverage. Certain countries and regulatory bodies may use negative interest rates as a monetary policy tool to encourage economic growth during periods of deflation. In a negative interest rate environment, debt instruments may trade at negative yields, which means the purchaser of the instrument may receive at maturity less than the total amount invested. LIBOR Transition and Associated Risk. The London Interbank Offered Rate or LIBOR is the average offered rate for various maturities of short-term loans between major international banks who are members of the British Bankers Association. It is used throughout global banking and financial industries to determine interest rates for a variety of financial instruments (such as debt instruments and derivatives) and borrowing arrangements. In July 2017, the Financial Conduct Authority (the “FCA”), the United Kingdom financial regulatory body, announced a desire to phase out the use of LIBOR. The ICE Benchmark Administration Limited, the administrator of LIBOR, ceased publishing certain LIBOR settings on December 31, 2021, and is expected to cease publishing the remaining LIBOR settings on June 30, 2023. Many market participants are in the process of transitioning to the use of alternative reference or benchmark rates. On September 29, 2021 the FCA announced that it will compel the ICE Benchmark Administration Limited (the “IBA”) to publish a subset of non-U.S. LIBOR maturities after December 31, 2021 using a “synthetic” methodology that is not based on panel bank contributions and has indicated that it may also require IBA to publish a subset of U.S. LIBOR maturities after June 30, 2023, using a similar synthetic methodology. However, these synthetic publications are expected to be published for a limited period of time and would be considered non-representative of the underlying market. Although the transition process away from LIBOR has become increasingly well-defined, the impact on certain debt securities, derivatives and other financial instruments that utilize LIBOR remains uncertain. The transition process may involve, among other things, increased volatility or illiquidity in markets for instruments that currently rely on LIBOR. The transition may also result in a change in (i) the value of certain instruments held by the Trust, (ii) the cost of borrowing or the dividend rate for preferred shares, or (iii) the effectiveness of related Trust transactions such as hedges, as applicable. Various financial industry groups are planning for the transition away from LIBOR, but there are obstacles to converting certain longer term securities and transactions to a new benchmark. In June 2017, the Alternative Reference Rates Committee, a group of large U.S. banks working with the Federal Reserve, announced its selection of a new Secured Overnight Financing Rate (“SOFR”), which is intended to be a broad measure of secured overnight U.S. Treasury repo rates, as an appropriate replacement for LIBOR. Bank working groups and regulators in other countries have suggested other alternatives for their markets, including the Sterling Overnight Interbank Average Rate (“SONIA”) in England. Both SOFR and SONIA, as well as certain other proposed replacement rates, are materially different from LIBOR, and changes in the applicable spread for financial instruments transitioning away from LIBOR need to be made to accommodate the differences. Liquid markets for newly-issued instruments that use an alternative reference rate are still developing. Consequently, there may be challenges for a Trust to enter into hedging transactions against instruments tied to alternative reference rates until a market for such hedging transactions develops. Additionally, while some existing LIBOR-based instruments may contemplate a scenario where LIBOR is no longer available by providing for an alternative or “fallback” rate-setting methodology, there may be significant uncertainty regarding the effectiveness of any such alternative methodologies to replicate LIBOR. Not all existing LIBOR-based instruments have such fallback provisions, and many that do, do not contemplate the permanent cessation of LIBOR. While it is expected that market participants will amend legacy financial instruments referencing LIBOR to include fallback provisions to alternative reference rates, there remains uncertainty regarding the willingness and ability of parties to add or amend such fallback provisions in legacy instruments maturing after the end of 2021, particularly with respect to legacy cash products. Although there are ongoing efforts among certain government entities and other organizations to address these uncertainties, the ultimate effectiveness of such efforts is not yet known. Any effects of the transition away from LIBOR and the adoption of alternative reference rates, as well as other unforeseen effects, could result in losses to the Trust, and such effects may occur prior to the discontinuation of the remaining LIBOR settings in 2023. Furthermore, the risks associated with the discontinuation of LIBOR and transition to replacement rates may be exacerbated if an orderly transition to an alternative reference rate is not completed in a timely manner. Non-Investment Grade Bonds Risk. The Trust’s investments in Non-Investment Grade Bonds, commonly referred to as “junk bonds,” are predominantly speculative because of the credit risk of their issuers. While offering a greater potential opportunity for capital appreciation and higher yields, Non-Investment Grade Bonds typically entail greater potential price volatility and may be less liquid than higher-rated securities. Issuers of Non-Investment Grade Bonds are more likely to default on their payments of interest and principal owed to the Trust, and such defaults will reduce the Trust’s net asset value and income distributions. The prices of these lower rated obligations are more sensitive to negative developments than higher rated securities. Adverse business conditions, such as a decline in the issuer’s revenues or an economic downturn, generally lead to a higher non-payment rate. In addition, a security may lose significant value before a default occurs as the market adjusts to expected higher non-payment rates. Lower Rated Investments Risk. Investments rated below investment grade and comparable unrated investments (sometimes referred to as “junk”) have speculative characteristics because of the credit risk associated with their issuers. Changes in economic conditions or other circumstances typically have a greater effect on the ability of issuers of lower rated investments to make principal and interest payments than they do on issuers of higher rated investments. An economic downturn generally leads to a higher non-payment rate, and a lower rated investment may lose significant value before a default occurs. Lower rated investments typically are subject to greater price volatility and illiquidity than higher rated investments. Lower rated investments are considered primarily speculative with respect to the issuer’s capacity to pay interest and repay principal. Prepayment Risk. During periods of declining interest rates or for other purposes, Borrowers may exercise their option to prepay principal earlier than scheduled. For fixed-income securities, such payments often occur during periods of declining interest rates, forcing the Trust to reinvest in lower yielding securities. This is known as call or prepayment risk. Non-Investment Grade Bonds frequently have call features that allow the issuer to redeem the security at dates prior to its stated maturity at a specified price (typically greater than par) only if certain prescribed conditions are met (“call protection”). An issuer may redeem a Non-Investment Grade Bond if, for example, the issuer can refinance the debt at a lower cost due to declining interest rates or an improvement in the credit standing of the issuer. Senior Loans typically have no such call protection. For premium bonds (bonds acquired at prices that exceed their par or principal value) purchased by the Trust, prepayment risk may be enhanced. Issuer Risk. The value of corporate income-producing securities held by the Trust may decline for a number of reasons, which directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. Derivatives Risk. The Trust’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instruments”), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Trust, which represents a non-cash exposure to the reference instrument. Leverage can increase both the risk and return potential of the Trust. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Trust. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Trust shares may decline and the Trust could experience delays in the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment, particularly when there is no stated limit on the Trust’s use of derivatives. A derivative investment also involves the risks relating to the reference instrument underlying the investment. Leverage Risk. Certain fund transactions may give rise to leverage. Leverage can result from a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Trust. The Trust is required to segregate liquid assets or otherwise cover the Trust’s obligation created by a transaction that may give rise to leverage. The use of leverage may cause the Trust to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet segregation requirements. Leverage may cause the Trust’s share price to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the value of the Trust’s portfolio securities. The loss on leveraged investments may substantially exceed the initial investment. As discussed above, the Trust currently uses leverage created by issuing APS and borrowings. On June 27, 2001, the Trust issued 2,200 Series A APS and 2,200 Series B APS, with a liquidation preference per share of $25,000 plus accumulated but unpaid dividends. On September 23, 2016, the Trust repurchased 968 Series A APS and 968 Series B APS and on September 14, 2018, the Trust repurchased 480 Series A APS and 480 Series B APS. The Trust has entered into a Revolving Credit and Security Agreement, as amended (the Agreement) with conduit lenders and a bank to borrow up to $50 million ($125 million prior to September 29, 2021). The Trust is required to maintain certain net asset levels during the term of the Agreement. As of June 30, 2022 , the Trust had $26 million in outstanding borrowings under the Agreement , at an interest rate of 1.62 %, in addition to outstanding APS. The Adviser anticipates that the use of leverage (from the issuance of APS and borrowings) may result in higher income to Common Shareholders over time. Leverage creates risks for Common Shareholders, including the likelihood of greater volatility of NAV and market price of the Common Shares and the risk that fluctuations in dividend rates on APS and costs of borrowings may affect the return to Common Shareholders. See also “LIBOR Transition and Associated Risk.” To the extent the income derived from investments purchased with funds received from leverage exceeds the cost of leverage, the Trust’s distributions will be greater than if leverage had not been used. Conversely, if the income from the investments purchased with such funds is not sufficient to cover the cost of leverage, the amount available for distribution to Common Shareholders will be less than if leverage had not been used. In the latter case, Eaton Vance, in its best judgment, may nevertheless determine to maintain the Trust’s leveraged position if it deems such action to be appropriate. While the Trust has preferred shares outstanding, an increase in short-term rates would also result in an increased cost of leverage, which would adversely affect the Trust’s income available for distribution. There can be no assurance that a leveraging strategy will be successful. In addition, under current federal income tax law, the Trust is required to allocate a portion of any net realized capital gains or other taxable income to APS holders. The terms of the Trust’s APS require the Trust to pay to any APS holders additional dividends intended to compensate such holders for taxes payable on any capital gains or other taxable income allocated to such holders. Any such additional dividends will reduce the amount available for distribution to Common Shareholders. As discussed under “Management of the Trust,” the fee paid to Eaton Vance is calculated on the basis of the Trust’s gross assets, including proceeds from the issuance of APS and borrowings, so the fees will be higher when leverage is utilized. In this regard, holders of APS do not bear the investment advisory fee. Rather, Common Shareholders bear the portion of the investment advisory fee attributable to the assets purchased with the proceeds, which means that Common Shareholders effectively bear the entire advisory fee. The APS have been rated Aa3 by Moody's. The Trust currently intends to seek to maintain this rating or an equivalent credit rating on the APS or any preferred shares it issues. The Rating Agencies which rate the preferred shares and any bank lender in connection with a credit facility or commercial paper program may also impose specific restrictions as a condition to borrowing. Such restrictions may include asset coverage or portfolio composition requirements that are more stringent than those imposed on the Trust by the 1940 Act. These covenants or guidelines do not currently and are not expected to impede Eaton Vance in managing the Trust’s portfolio in accordance with its investment objective and policies and it is not anticipated that they will so impede Eaton Vance in the future. See “Description of Capital Structure - Preferred Shares.” Financial leverage may also be achieved through the purchase of certain derivative instruments. The Trust’s use of derivative instruments exposes the Trust to special risks. See “Investment Objective, Policies and Risks - Additional Investment Practices” and “Investment Objective, Policies, and Risks - Additional Risk Considerations.” Foreign Investment Risk. Investments in foreign issuers could be affected by factors not present in the United States, including expropriation, armed conflict, confiscatory taxation, lack of uniform accounting and auditing standards, less publicly available financial and other information, and potential difficulties in enforcing contractual obligations. Because foreign issuers may not be subject to uniform accounting, auditing and financial reporting standard practices and requirements and regulatory measures comparable to those in the United States, there may be less publicly available information about such foreign issuers. Settlements of securities transactions in foreign countries are subject to risk of loss, may be delayed and are generally less frequent than in the United States, which could affect the liquidity of the Trust’s assets. Evidence of ownership of certain foreign investments may be held outside the United States, and the Trust may be subject to the risks associated with the holding of such property overseas. Trading in certain foreign markets is also subject to liquidity risk. Foreign investments in the securities markets of certain foreign countries is restricted or controlled to varying degrees. Foreign issuers may become subject to sanctions imposed by the United States or another country, which could result in the immediate freeze of the foreign issuers’ assets or securities. The imposition of such sanctions could impair the market value of the securities of such foreign issuers and limit the Trust’s ability to buy, sell, receive or deliver the securities. In addition, as a result of economic sanctions, the Trust may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Trust and increased transaction costs. If a deterioration occurs in a country's balance of payments, the country could impose temporary restrictions on foreign capital remittances. The Trust could also be adversely affected by delays in, or a refusal to grant, any required governmental approval for repatriation, as well as by other restrictions on investment. The risks posed by such actions with respect to a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Trust invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Political events in foreign countries may cause market disruptions. In June 2016, the United Kingdom (“UK”) voted in a referendum to leave the European Union (“EU”) (“Brexit”). Effective January 31, 2020, the UK ceased to be a member of the EU and, following a transition period during which the EU and the UK Government engaged in a series of negotiations regarding the terms of the UK’s future relationship with the EU, the EU and the UK Government signed an agreement on December 30, 2020 regarding the economic relationship between the UK and the EU. This agreement became effective on a provisional basis on January 1, 2021 and entered into full force on May 1, 2021. There remains significant market uncertainty regarding Brexit’s ramifications, and the range and potential implications of the possible political, regulatory, economic, and market outcomes in the UK, EU and beyond are difficult to predict. The end of the Brexit transition period may cause greater market volatility and illiquidity, currency fluctuations, deterioration in economic activity, a decrease in business confidence, and an increased likelihood of a recession in the UK. If one or more additional countries leave the EU or the EU dissolves, the world’s securities markets likely will be significantly disrupted. The Trust may invest in securities and other instruments (including loans) issued, guaranteed, or backed by sovereign or government entities. Economic data as reported by sovereign or government entities and other issuers may be delayed, inaccurate or fraudulent. Many sovereign or government debt obligations may be rated below investment grade. Any restructuring of a sovereign or government debt obligation held by the Trust will likely have a significant adverse effect on the value of the obligation. In the event of default of a sovereign or government debt, the Trust may be unable to pursue legal action against the issuer or secure collateral on the debt, there are typically no assets to be seized or cash flows to be attached. Furthermore, the willingness or ability of a sovereign or government entity to restructure defaulted debt may be limited. Therefore, losses on sovereign or government defaults may far exceed the losses from the default of a similarly rated U.S. corporate debt issuer. Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks. U.S. Government Securities Risk. Although certain U.S. Government-sponsored agencies (such as the Federal Home Loan Mortgage Corporation and the Federal National Mortgage Association) may be chartered or sponsored by acts of Congress, their securities are neither issued nor guaranteed by the U.S. Treasury. U.S. Treasury securities generally have a lower return than other obligations because of their higher credit quality and market liquidity. Pooled Investment Vehicles Risk. Pooled investment vehicles are open- and closed-end investment companies and exchange-traded funds (“ETFs”). Pooled investment vehicles are subject to the risks of investing in the underlying securities or other investments. Shares of closed-end investment companies and ETFs may trade at a premium or discount to net asset value and are subject to secondary market trading risks. In addition, the Trust will bear a pro rata portion of the operating expenses of a pooled investment vehicle in which it invests. Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; unexpected trading activity among retail investors; or other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Trust's equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels. Liquidity Risk. The Trust is exposed to liquidity risk when trading volume, lack of a market maker, or legal restrictions impair the Trust’s ability to sell particular investments or close derivative positions at an advantageous market price. Trading opportunities are also more limited for securities and other instruments that are not widely held or are traded in less developed markets. These factors may make it more difficult to sell or buy a security at a favorable price or time. Consequently, the Trust may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Trust’s performance. It also may be more difficult to value less liquid investments. These effects may be exacerbated during times of financial or political stress. In addition, the limited liquidity could affect the market price of the investments, thereby adversely affecting the Trust's net asset value and ability to make dividend distributions. The Trust has no limitation on the amount of its assets which may be invested in illiquid investments. Money Market Instrument Risk. Money market instruments may be adversely affected by market and economic events, such as a sharp rise in prevailing short-term interest rates; adverse developments in the banking industry, which issues or guarantees many money market instruments; adverse economic, political or other developments affecting issuers of money market instruments; changes in the credit quality of issuers; and default by a counterparty. Reinvestment Risk. Income from the Trust’s portfolio will decline if and when the Trust invests the proceeds from matured, traded or called debt obligations into lower yielding instruments. Inflation Risk. Inflation risk is the risk that the value of assets or income from investments will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value of the Common Shares and distributions thereon can decline. In addition, during any periods of rising inflation, dividend rates of preferred shares would likely increase, which would tend to further reduce returns to Common Shareholders. This risk is mitigated to some degree by the Trust's investments in Senior Loans. Management Risk. The Trust is subject to management risk because it is actively managed. Eaton Vance and the individual portfolio managers invest the assets of the Trust as they deem appropriate in implementing the Trust’s investment strategy. Accordingly, the success of the Trust depends upon the investment skills and analytical abilities of Eaton Vance and the individual portfolio managers to develop and effectively implement strategies that achieve the Trust’s investment objective. There is no assurance that Eaton Vance and the individual portfolio managers will be successful in developing and implementing the Trust’s investment strategy. Subjective decisions made by Eaton Vance and the individual portfolio managers may cause the Trust to incur losses or to miss profit opportunities. Cybersecurity Risk. With the increased use of technologies by Trust service providers to conduct business, such as the Internet, the Trust is susceptible to operational, information security and related risks. The Trust relies on communications technology, systems, and networks to engage with clients, employees, accounts, shareholders, and service providers, and a cyber incident may inhibit the Trust’s ability to use these technologies. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber attacks include, but are not limited to, gaining unauthorized access to digital systems (e.g., through “hacking” or malicious software coding) for purposes of misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber attacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of-service attacks on websites or via “ransomware” that renders the systems inoperable until appropriate actions are taken. A denial-of-service attack is an effort to make network services unavailable to intended users, which could cause shareholders to lose access to their electronic accounts, potentially indefinitely. Employees and service providers also may not be able to access electronic systems to perform critical duties for the Trust, such as trading NAV calculation, shareholder accounting or fulfillment of Trust share purchases and redemptions, during a denial-of-service attack. There is also the possibility for systems failures due to malfunctions, user error and misconduct by employees and agents, natural disasters, or other foreseeable and unforeseeable events. Because technology is consistently changing, new ways to carry out cyber attacks are always developing. Therefore, there is a chance that some risks have not been identified or prepared for, or that an attack may not be detected, which puts limitations on the Trust's ability to plan for or respond to a cyber attack. Like other Trusts and business enterprises, the Trust and its service providers have experienced, and will continue to experience, cyber incidents consistently. In addition to deliberate cyber attacks, unintentional cyber incidents can occur, such as the inadvertent release of confidential information by the Trust or its service providers. The Trust uses third party service providers who are also heavily dependent on computers and technology for their operations. Cybersecurity failures or breaches by the Trust’s investment adviser or administrator and other service providers (including, but not limited to, the custodian or transfer agent), and the issuers of securities in which the Trust invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Trust, impede Trust trading, interfere with the Trust’s ability to calculate its NAV, or cause violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, litigation costs, or additional compliance costs. While many of the Trust service providers have established business continuity plans and risk management systems intended to identify and mitigate cyber attacks, there are inherent limitations in such plans and systems including the possibility that certain risks have not been identified. The Trust cannot control the cybersecurity plans and systems put in place by service providers to the Trust and issuers in which the Trust invests. The Trust and its shareholders could be negatively impacted as a result. Recent Market Conditions. An outbreak of respiratory disease caused by a novel coronavirus was first detected in China in late 2019 and subsequently spread internationally. This coronavirus has resulted in closing borders, enhanced health screenings, changes to healthcare service preparation and delivery, quarantines, cancellations, disruptions to supply chains and customer activity, as well as general concern and uncertainty. The impact of this coronavirus has resulted in a substantial economic downturn, which may continue for an extended period of time. Health crises caused by outbreaks of disease, such as the coronavirus outbreak, may exacerbate other pre-existing political, social and economic risks and disrupt normal market conditions and operations. The impact of this outbreak has negatively affected the worldwide economy, as well as the economies of individual countries and industries, and could continue to affect the market in significant and unforeseen ways. Other epidemics and pandemics that may arise in the future may have similar effects. For example, a global pandemic or other widespread health crisis could cause substantial market volatility and exchange trading suspensions and closures. In addition, the increasing interconnectedness of markets around the world may result in many markets being affected by events or conditions in a single country or region or events affecting a single or small number of issuers. The coronavirus outbreak and public and private sector responses thereto have led to large portions of the populations of many countries working from home for indefinite periods of time, temporary or permanent layoffs, disruptions in supply chains, and lack of availability of certain goods. The impact of such responses could adversely affect the information technology and operational systems upon which the Trust and the Trust’s service providers rely, and could otherwise disrupt the ability of the employees of the Trust’s service providers to perform critical tasks relating to the Trust. Any such impact could adversely affect the Trust’s performance, or the performance of the securities in which the Trust invests and may lead to losses on your investment in the Trust. Geopolitical Risk. The increasing interconnectivity between global economies and financial markets increases the likelihood that events or conditions in one region or financial market may adversely impact issuers in a different country, region or financial market. Securities in a Trust’s portfolio may underperform due to inflation (or expectations for inflation), interest rates, global demand for particular products or resources, natural disasters, health emergencies (such as epidemics and pandemics), terrorism, regulatory events and governmental or quasi-governmental actions. The occurrence of global events similar to those in recent years, such as terrorist attacks around the world, natural disasters, health emergencies, social and political discord, war or debt crises and downgrades, among others, may result in market volatility and may have long term effects on both the U.S. and global financial markets. Other financial, economic and other global market and social developments or disruptions may result in similar adverse circumstances, and it is difficult to predict when similar events affecting the U.S. or global financial markets may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). Such global events may negatively impact broad segments of businesses and populations, cause a significant negative impact on the performance of the Trust’s investments, adversely affect and increase the volatility of the Trust’s share price and/or exacerbate preexisting political, social and economic risks to the Trust. The Trust’s operations may be interrupted and any such event(s) could have a significant adverse impact on the value and risk profile of the Trust’s portfolio. There is a risk that you may lose money by investing in the Trust. Regulatory Risk. To the extent that legislation or state or federal regulators that regulate certain financial institutions impose additional requirements or restrictions with respect to the ability of such institutions to make loans, particularly in connection with highly leveraged transactions, the availability of Senior Loans for investment may be adversely affected. Further, such legislation or regulation could depress the market value of Senior Loans. Market Disruption. Global instability, war, geopolitical tensions and terrorist attacks in the United States and around the world have previously resulted, and may in the future result in market volatility and may have long-term effects on the United States and worldwide financial markets and may cause further economic uncertainties in the United States and worldwide. The Trust cannot predict the effects of significant future events on the global economy and securities markets. A similar disruption of the financial markets could impact interest rates, auctions, secondary trading, ratings, credit risk, inflation and other factors relating to the Common Shares. In particular, Non-Investment Grade Bonds and Senior Loans tend to be more volatile than higher rated fixed-income securities so that these events and any actions resulting from them may have a greater impact on the prices and volatility of Non-Investment Grade Bonds and Senior Loans than on higher rated fixed-income securities. Anti-Takeover Provisions. The Trust’s Agreement and Declaration of Trust (the “Declaration of Trust”) and Amended and Restated By-Laws (the “By-Laws” and together with the Declaration of Trust, the “Organizational Documents”) include provisions that could have the effect of limiting the ability of other persons or entities to acquire control of the Trust or to change the composition of its Board. For example, pursuant to the Trust's Declaration of Trust, the Board is divided into three classes of Trustees with each class serving for a three-year term and certain types of transactions require the favorable vote of holders of at least 75% of the outstanding shares of the Trust. See “Description of Capital Structure - Certain Provisions of the Organizational Documents - Anti-Takeover Provisions in the Organizational Documents.” |  |  |  |  |  |  |  |  |  |  |  |  |
Effects of Leverage [Text Block] |  | USE OF LEVERAGE AND RELATED RISKS Generally, leverage involves the use of proceeds from the issuance of preferred shares, borrowed funds or various financial instruments (such as derivatives) to seek to increase a trust’s potential returns. The Trust currently uses leverage created by issuing APS as well as by loans acquired with borrowings. The Trust currently uses leverage created by issuing APS. On June 27, 2001, the Trust issued 2,200 Series A APS and 2,200 Series B APS, with a liquidation preference per share of $25,000 plus accumulated but unpaid dividends. The APS have seniority over the Common Shares. On September 23, 2016, the Trust repurchased 968 Series A APS and 968 Series B APS and on September 14, 2018, the Trust repurchased 480 Series A APS and 480 Series B APS. The Trust has entered into a Revolving Credit and Security Agreement, as amended (the Agreement) with conduit lenders and a bank to borrow up to $50 million ($125 million prior to September 29, 2021). Borrowings under the Agreement are secured by the assets of the Trust. Interest is charged at a rate above the conduits’ commercial paper issuance rate and is payable monthly. Under the terms of the Agreement, in effect through March 6, 2023 , the Trust also pays a program fee of 0.90% per annum on its outstanding borrowings to administer the facility and a liquidity fee of 0.15% (0.25% if the outstanding loan amount is less than or equal to 60% of the total facility size) per annum on the unused portion of the total commitment under the Agreement. Program and liquidity fees for the year ended June 30, 2022 totaled $351,954 . In connection with the renewal of the Agreement on March 7, 2022 , the Trust paid upfront fees of $75,000 , which is being amortized to interest expense over a period of one year through March 6, 2023 . The Trust is required to maintain certain net asset levels during the term of the Agreement. As of June 30, 2022 , the Trust had $26 million in outstanding borrowings under the Agreement , at an interest rate of 1.62 %, in addition to outstanding APS. The Adviser anticipates that the use of leverage (from such issuance of APS and any borrowings) may result in higher income to Common Shareholders over time. Use of financial leverage creates an opportunity for increased income but, at the same time, creates special risks. There can be no assurance that a leveraging strategy will be successful. The costs of the financial leverage program (from any issuance of preferred shares and any borrowings) are borne by Common Shareholders and consequently result in a reduction of the NAV of Common Shares. During periods in which the Trust is using leverage, the fees paid to Eaton Vance for investment advisory services will be higher than if the Trust did not use leverage because the fees paid will be calculated on the basis of the Trust’s gross assets, including proceeds from the issuance of preferred shares and any borrowings. In this regard, holders of debt or preferred securities do not bear the investment advisory fee. Rather, Common Shareholders bear the portion of the investment advisory fee attributable to the assets purchased with the proceeds, which means that Common Shareholders effectively bear the entire advisory fee. Leverage creates risks for holders of the Common Shares, including the likelihood of greater volatility of NAV and market price of the Common Shares. There is a risk that fluctuations in the distribution rates on any outstanding preferred shares may adversely affect the return to the holders of the Common Shares. If the income from the investments purchased with the proceeds of leverage is not sufficient to cover the cost of leverage, the return on the Trust will be less than if leverage had not been used, and, therefore, the amount available for distribution to Common Shareholders will be reduced. The Adviser in its best judgment nevertheless may determine to maintain the Trust’s leveraged position if it deems such action to be appropriate in the circumstances. Changes in the value of the Trust’s investment portfolio (including investments bought with the proceeds of leverage) will be borne entirely by the Common Shareholders. If there is a net decrease (or increase) in the value of the Trust’s investment portfolio, the leverage will decrease (or increase) the NAV per Common Share to a greater extent than if the Trust were not leveraged. During periods in which the Trust is using leverage, the fees paid to Eaton Vance for investment advisory services will be higher than if the Trust did not use leverage because the fees paid will be calculated on the basis of the Trust’s gross assets, including the proceeds from the issuance of preferred shares and any borrowings. As discussed under “Description of Capital Structure,” the Trust’s issuance of preferred shares may alter the voting power of Common Shareholders. Capital raised through leverage will be subject to distribution and/or interest payments, which may exceed the income and appreciation on the assets purchased. The issuance of preferred shares involves offering expenses and other costs and may limit the Trust’s freedom to pay distributions on Common Shares or to engage in other activities. The issuance of a class of preferred shares having priority over the Common Shares creates an opportunity for greater return per Common Share, but at the same time such leveraging is a speculative technique that will increase the Trust’s exposure to capital risk. Unless the income and appreciation, if any, on assets acquired with offering proceeds exceed the cost of issuing additional classes of securities (and other Trust expenses), the use of leverage will diminish the investment performance of the Common Shares compared with what it would have been without leverage. The Trust is subject to certain restrictions on investments imposed by guidelines of one or more Rating Agencies that issued ratings for preferred shares issued by the Trust. These guidelines impose asset coverage or Trust composition requirements that are more stringent than those imposed on the Trust by the 1940 Act. These covenants or guidelines do not currently and are not expected to impede Eaton Vance in managing the Trust’s portfolio in accordance with its investment objective and policies and it is not anticipated that they will so impede Eaton Vance in the future. Under the 1940 Act, the Trust is not permitted to issue preferred shares unless immediately after such issuance the total asset value of the Trust’s portfolio is at least 200% of the liquidation value of the outstanding preferred shares plus the amount of any senior security representing indebtedness (i.e., such liquidation value and amount of indebtedness may not exceed 50% of the Trust’s total assets). In addition, the Trust is not permitted to declare any cash distribution on its Common Shares unless, at the time of such declaration, the NAV of the Trust’s portfolio (determined after deducting the amount of such distribution) is at least 200% of such liquidation value plus amount of indebtedness. The Trust intends, to the extent possible, to purchase or redeem preferred shares, from time to time, to maintain coverage of any preferred shares of at least 200%. As of June 30, 2022 , the outstanding APS and the outstanding borrowings represented 37.45 % leverage, and there was an asset coverage of the APS of 267%. Holders of preferred shares, voting as a class, shall be entitled to elect two of the Trust’s Trustees. The holders of both the Common Shares and the preferred shares (voting together as a single class with each share entitling its holder to one vote) shall be entitled to elect the remaining Trustees of the Trust. In the event the Trust fails to pay distributions on its preferred shares for two years, preferred shareholders would be entitled to elect a majority of the Trustees until the preferred distributions in arrears are paid. Under the 1940 Act, the Trust is not permitted to incur indebtedness, including through the issuance of debt securities, unless immediately thereafter the total asset value of the Trust’s portfolio is at least 300% of the liquidation value of the outstanding indebtedness (i.e., such liquidation value may not exceed 33 1/3% of the Trust’s total assets). In addition, the Trust is not permitted to declare any cash distribution on its Common Shares unless, at the time of such declaration, the NAV of the Trust’s portfolio (determined after deducting the amount of such distribution) is at least 300% of such liquidation value. If the Trust borrows money or enters into a commercial paper program, the Trust intends, to the extent possible, to retire outstanding debt, from time to time, to maintain coverage of any outstanding indebtedness of at least 300%. As of June 30, 2022 , there were $26 million in outstanding borrowings. To qualify for federal income taxation as a “regulated investment company,” the Trust must distribute in each taxable year at least 90% of its net investment income (including net interest income and net short-term gain). The Trust also will be required to distribute annually substantially all of its income and capital gain, if any, to avoid imposition of a nondeductible 4% federal excise tax. If the Trust is precluded from making distributions on the Common Shares because of any applicable asset coverage requirements, the terms of the preferred shares may provide that any amounts so precluded from being distributed, but required to be distributed for the Trust to meet the distribution requirements for qualification as a regulated investment company, will be paid to the holders of the preferred shares as a special distribution. This distribution can be expected to decrease the amount that holders of preferred shares would be entitled to receive upon redemption or liquidation of the shares. Successful use of a leveraging strategy may depend on the Adviser’s ability to predict correctly interest rates and market movements, and there is no assurance that a leveraging strategy will be successful during any period in which it is employed. The following table is designed to illustrate the effect on the return to a holder of the Common Shares of leverage in the amount of approximately 37.45 % of the Trust’s gross assets, assuming hypothetical annual returns of the Trust’s portfolio of minus 10% to plus 10%. As the table shows, leverage generally increases the return to Common Shareholders when portfolio return is positive and greater than the cost of leverage and decreases the return when the portfolio return is negative or less than the cost of leverage. The figures appearing in the table are hypothetical and actual returns may be greater or less than those appearing in the table.
Assumed Portfolio Return (Net of Expenses) |  | (10)% | (5)% | 0% | 5% | 10%
Corresponding Common Share Total Return |  | (16.70 )% | (8.71 )% | (0.72 )% | 7.28 % | 15.27 %
Assuming the utilization of leverage in the amount of 37.45 % of the Trust’s gross assets, the cost of leverage is 1.20 %. The additional income that the Trust must earn (net of expenses) in order to cover such costs is approximately 0.45 % of net assets. The Trust’s actual costs of leverage will be based on market rates at the time the Trust undertakes a leveraging strategy, and such actual costs of leverage may be higher or lower than that assumed in the previous example. |  |  |  |  |  |  |  |  |  |  |  |  |
Annual Interest Rate [Percent] |  | 0.90% |  |  |  |  |  |  |  |  |  |  |  |  |
Annual Interest Rate, Current [Percent] |  | 1.62% |  |  |  |  |  |  |  |  |  |  |  |  |
Effects of Leverage [Table Text Block] |  |
Assumed Portfolio Return (Net of Expenses) |  | (10)% | (5)% | 0% | 5% | 10%
Corresponding Common Share Total Return |  | (16.70 )% | (8.71 )% | (0.72 )% | 7.28 % | 15.27 %
Return at Minus Ten [Percent] |  | (16.70%) |  |  |  |  |  |  |  |  |  |  |  |  |
Return at Minus Five [Percent] |  | (8.71%) |  |  |  |  |  |  |  |  |  |  |  |  |
Return at Zero [Percent] |  | (0.72%) |  |  |  |  |  |  |  |  |  |  |  |  |
Return at Plus Five [Percent] |  | 7.28% |  |  |  |  |  |  |  |  |  |  |  |  |
Return at Plus Ten [Percent] |  | 15.27% |  |  |  |  |  |  |  |  |  |  |  |  |
Effects of Leverage, Purpose [Text Block] |  | The following table is designed to illustrate the effect on the return to a holder of the Common Shares of leverage in the amount of approximately 37.45 % of the Trust’s gross assets, assuming hypothetical annual returns of the Trust’s portfolio of minus 10% to plus 10%. As the table shows, leverage generally increases the return to Common Shareholders when portfolio return is positive and greater than the cost of leverage and decreases the return when the portfolio return is negative or less than the cost of leverage. The figures appearing in the table are hypothetical and actual returns may be greater or less than those appearing in the table. |  |  |  |  |  |  |  |  |  |  |  |  |
Share Price [Table Text Block] |  | TRADING AND NAV INFORMATION The Trust’s Common Shares have traded both at a premium and a discount to NAV. The Trust cannot predict whether its shares will trade in the future at a premium or discount to NAV. The provisions of the 1940 Act generally require that the public offering price of Common Shares (less any underwriting commissions and discounts) must equal or exceed the NAV per share of a company’s common stock. The issuance of Common Shares may have an adverse effect on prices in the secondary market for the Trust’s Common Shares by increasing the number of Common Shares available, which may put downward pressure on the market price for the Trust’s Common Shares. Shares of common stock of closed-end investment companies frequently trade at a discount from NAV. See “Additional Risk Considerations - Discount from or Premium to NAV”. In addition, the Trust’s Board of Trustees has authorized the Trust to repurchase up to 10% of its outstanding Common Shares as of the last day of the prior calendar year-end at market prices when shares are trading at a discount to net asset value. The share repurchase program does not obligate the Trust to purchase a specific amount of shares. The results of the share repurchase program are disclosed in the Trust’s annual and semi-annual reports to shareholders. See “Description of Capital Structure - Repurchase of Common Shares and Other Discount Measures.” The following table sets forth for each of the periods indicated the high and low closing market prices for Common Shares on the NYSE, and the corresponding NAV per share and the premium or discount to NAV per share at which the Trust’s Common Shares were trading as of such date.
| Market Price | NAV per Share on Date of Market Price | NAV Premium/(Discount) on Date of Market Price
Fiscal Quarter Ended | High | Low | High | Low | High | Low
6/30/2022 | $6.44 | $5.37 | $6.80 | $6.21 | (5.29)% | (13.53)%
3/31/2022 | $7.00 | $6.07 | $6.94 | $6.64 | 0.86% | (8.58)%
12/31/2021 | $7.20 | $6.56 | $6.97 | $6.88 | 3.30% | (4.65)%
9/30/2021 | $7.12 | $6.63 | $6.99 | $6.94 | 1.86% | (4.42)%
6/30/2021 | $6.80 | $6.61 | $6.90 | $6.87 | (1.45)% | (3.78)%
3/31/2021 | $6.70 | $6.33 | $6.91 | $6.76 | (3.04)% | (6.36)%
12/31/2020 | $6.43 | $5.80 | $6.77 | $6.44 | (5.02)% | (9.94)%
9/30/2020 | $6.01 | $5.29 | $6.53 | $6.20 | (7.96)% | (14.68)%
6/30/2020 | $5.57 | $4.48 | $6.36 | $5.42 | (12.42)% | (17.34)%
3/31/2020 | $6.58 | $3.84 | $7.07 | $4.80 | (6.93)% | (20.00)%
12/31/2019 | $6.41 | $6.09 | $7.01 | $6.98 | (8.56)% | (12.75)%
9/30/2019 | $6.32 | $6.03 | $7.04 | $7.00 | (10.23)% | (13.86)%
On August 18, 2022, the last reported sale price, NAV per Common Share and percentage premium/(discount) to NAV per Common Share, were $5.81, $6.35 and (8.50)%, respectively. As of August 18, 2022, the Trust had 17,538,857 Common Shares outstanding and net assets of $111,396,079. |  |  |  |  |  |  |  |  |  |  |  |  |
Latest Share Price |  |  | $ 5.81 |  |  |  |  |  |  |  |  |  |  |  |
Latest Premium (Discount) to NAV [Percent] |  |  | (8.50%) |  |  |  |  |  |  |  |  |  |  |  |
Latest NAV |  |  | $ 6.35 |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock [Table Text Block] |  | Description of Capital Structure The Trust is an unincorporated business trust established under the laws of the Commonwealth of Massachusetts by the Declaration of Trust. The Declaration of Trust provides that the Board may authorize separate classes of shares of beneficial interest. The Board has authorized an unlimited number of Common Shares. The Trust will hold annual meetings of shareholders so long as the Common Shares are listed on a national securities exchange and annual meetings are required as a condition of such listing. COMMON SHARES The Declaration of Trust permits the Trust to issue an unlimited number of full and fractional Common Shares. Each Common Share represents an equal proportionate interest in the assets of the Trust with each other Common Share in the Trust. Common Shareholders are entitled to the payment of distributions when, as, and if declared by the Board. The 1940 Act or the terms of any future borrowings or issuance of preferred shares may limit the payment of distributions to the Common Shareholder. Each whole Common Share shall be entitled to one vote as to matters on which it is entitled to vote pursuant to the terms of the Declaration of Trust on file with the SEC. The By-Laws establish qualification criteria applicable to prospective Trustees and generally require that advance notice be given to the Trust in the event a shareholder desires to nominate a person for election to the Board or to transact any other business at a meeting of shareholders. Any notice by a shareholder must be accompanied by certain information as required by the By-Laws. No shareholder proposal will be considered at any meeting of shareholders of the Trust if such proposal is submitted by a shareholder who does not satisfy all applicable requirements set forth in the By-Laws. In the event of the liquidation of the Trust, after paying or adequately providing for the payment of all liabilities of the Trust 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 Board may distribute the remaining assets of the Trust among the Common Shareholders. The Declaration of Trust provides that Common Shareholders are not liable for any liabilities of the Trust and permits inclusion of a clause to that effect in every agreement entered into by the Trust and, in coordination with the Trust's By-Laws, indemnifies shareholders against any such liability. Although shareholders of an unincorporated business trust established under Massachusetts law may, in certain limited circumstances, be held personally liable for the obligations of the business trust as though they were general partners, the provisions of the Trust’s Organizational Documents described in the foregoing sentence make the likelihood of such personal liability remote. While there are any borrowings or preferred shares outstanding, the Trust may not be permitted to declare any cash dividend or other distribution on its Common Shares, unless at the time of such declaration, (i) all accrued dividends on preferred shares or accrued interest on borrowings have been paid and (ii) the value of the Trust's total assets (determined after deducting the amount of such dividend or other distribution), less all liabilities and indebtedness of the Trust not represented by senior securities, is at least 300% of the aggregate amount of such securities representing indebtedness and at least 200% of the aggregate amount of securities representing indebtedness plus the aggregate liquidation value of the outstanding preferred shares (expected to equal the aggregate original purchase price of the outstanding preferred shares plus redemption premium, if any, together with any accrued and unpaid dividends thereon, whether or not earned or declared and on a cumulative basis). In addition to the requirements of the 1940 Act, the Trust may be required to comply with other asset coverage requirements as a condition of the Trust obtaining a rating of the preferred shares from a Rating Agency. These requirements may include an asset coverage test more stringent than under the 1940 Act. This limitation on the Trust's ability to make distributions on its Common Shares could in certain circumstances impair the ability of the Trust to maintain its qualification for taxation as a regulated investment company for federal income tax purposes. The Trust intends, however, to the extent possible to purchase or redeem preferred shares or reduce borrowings from time to time to maintain compliance with such asset coverage requirements and may pay special dividends to the holders of the preferred shares in certain circumstances in connection with any such impairment of the Trust's status as a regulated investment company. See “Investment Objective, Policies and Risks,” “Distributions” and “Federal Income Tax Matters.” Depending on the timing of any such redemption or repayment, the Trust may be required to pay a premium in addition to the liquidation preference of the preferred shares to the holders thereof. The Trust has no present intention of offering additional Common Shares, except as described herein. Other offerings of its Common Shares, if made, will require approval of the Board. Any additional offering will not be sold at a price per Common Share below the then current NAV (exclusive of underwriting discounts and commissions) except in connection with an offering to existing Common Shareholders or with the consent of a majority of the outstanding Common Shares. The Common Shares have no preemptive rights. The Trust generally will not issue Common Share certificates. However, upon written request to the Trust’s transfer agent, a share certificate will be issued for any or all of the full Common Shares credited to an investor’s account. Common Share certificates that have been issued to an investor may be returned at any time. CREDIT FACILITY The Trust currently leverages through borrowings, and has entered into a Revolving Credit and Security Agreement, as amended (the Agreement) with conduit lenders and a bank to borrow up to $50 million ($125 million prior to September 29, 2021). Borrowings under the Agreement are secured by the assets of the Trust. Interest is charged at a rate above the conduits’ commercial paper issuance rate and is payable monthly. Under the terms of the Agreement, in effect through March 6, 2023 , the Trust also pays a program fee of 0.90% per annum on its outstanding borrowings to administer the facility and a liquidity fee of 0.15% (0.25% if the outstanding loan amount is less than or equal to 60% of the total facility size) per annum on the unused portion of the total commitment under the Agreement. Program and liquidity fees for the year ended June 30, 2022 totaled $351,954 . In connection with the renewal of the Agreement on March 7, 2022 , the Trust paid upfront fees of $75,000 , which is being amortized to interest expense over a period of one year through March 6, 2023 . The Trust is required to maintain certain net asset levels during the term of the Agreement. As of June 30, 2022 , the Trust had borrowings outstanding under the Agreement of $26 million at an interest rate 1.62 %, in addition to outstanding APS. Based on the short-term nature of the borrowings under the Agreement and the variable interest rate, the carrying amount of the borrowings at June 30, 2022 approximated its fair value. For the year ended June 30, 2022 , the average borrowings under the Agreement and the average interest rate (excluding fees) were $26,572,603 and 0.36 %, respectively. In addition, the credit facility/program contains covenants that, among other things, limit the Trust’s ability to pay dividends in certain circumstances, incur additional debt, enter into a new investment advisory agreement without the consent of the lenders, change its fundamental investment policies and engage in certain transactions, including mergers and consolidations, and may require asset coverage ratios in addition to those required by the 1940 Act. The Trust is required to pledge its assets and to maintain a portion of its assets in cash or high-grade securities as a reserve against interest or principal payments and expenses. The credit facility/program contains customary covenant, negative covenant and default provisions. In addition, any such credit facility/program entered into in the future may be replaced or refinanced by one or more credit facilities having substantially different terms or by the issuance of preferred shares or debt securities. REPURCHASE OF COMMON SHARES AND OTHER DISCOUNT MEASURES Because shares of closed-end management investment companies frequently trade at a discount to their NAVs, the Board has determined that from time to time it may be in the interest of shareholders for the Trust to take corrective actions. The Board, in consultation with Eaton Vance, will review at least annually the possibility of open market repurchases and/or tender offers for the Common Shares and will consider such factors as the market price of the Common Shares, the NAV of the Common Shares, the liquidity of the assets of the Trust, effect on the Trust's expenses, whether such transactions would impair the Trust's status as a regulated investment company or result in a failure to comply with applicable asset coverage requirements, general economic conditions and such other events or conditions which may have a material effect on the Trust's ability to consummate such transactions. There are no assurances that the Board will, in fact, decide to undertake either of these actions or if undertaken, that such actions will result in the Trust's Common Shares trading at a price which is equal to or approximates their NAV. In recognition of the possibility that the Common Shares might trade at a discount to NAV and that any such discount may not be in the interest of shareholders, the Board, in consultation with Eaton Vance, from time to time may review possible actions to reduce any such discount. On November 11, 2013, the Board of Trustees initially approved a share repurchase program for the Trust. Pursuant to the reauthorization of the share repurchase program by the Board of Trustees in March 2019, the Trust is authorized to repurchase up to 10% of its Common Shares outstanding as of the last day of the prior calendar year at market prices when shares are trading at a discount to net asset value. The share repurchase program does not obligate the Trust to purchase a specific amount of shares. Results of the share repurchase program will be disclosed in the Trust’s annual and semiannual reports to shareholders. PREFERRED SHARES The Declaration of Trust authorizes the issuance of an unlimited number of shares of beneficial interest with preference rights, including preferred shares, having a par value of $0.01 per share, in one or more series, with rights as determined by the Board, by action of the Board without the approval of the Common Shareholders On June 27, 2001, the Trust issued 2,200 Series A APS and 2,200 Series B APS, with a liquidation preference per share of $25,000 plus accumulated but unpaid dividends. On September 23, 2016, the Trust repurchased 968 Series A APS and 968 Series B APS and on September 14, 2018, the Trust repurchased 480 Series A APS and 480 Series B APS. The APS have seniority over the Common Shares. Under the requirements of the 1940 Act, the Trust must, immediately after the issuance of any preferred shares, have an “asset coverage” of at least 200%. Asset coverage means the ratio which the value of the total assets of the Trust, less all liability and indebtedness not represented by senior securities (as defined in the 1940 Act), bears to the aggregate amount of senior securities representing indebtedness of the Trust, if any, plus the aggregate liquidation preference of the preferred shares. The liquidation value of the preferred shares is expected to equal to their aggregate original purchase price plus the applicable redemption premium, if any, together with any accrued and unpaid distributions thereon (on a cumulative basis), whether or not earned or declared. The terms of the preferred shares, including their distribution rate, voting rights, liquidation preference and redemption provisions, are determined by the Board (subject to applicable law and the Trust’s Declaration of Trust). The Trust may issue preferred shares that provide for the periodic redetermination of the distribution rate at relatively short intervals through an auction or remarketing procedure, although the terms of such preferred shares may also enable the Trust to lengthen such intervals. At times, the distribution rate on any preferred shares may exceed the Trust’s return after expenses on the investment of proceeds from the preferred shares and the Trust’s leverage structure, resulting in a lower rate of return to Common Shareholders than if the preferred shares were not outstanding. In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Trust, the terms of any preferred shares may entitle the holders of preferred shares to receive a preferential liquidating distribution (expected to equal to the original purchase price per share plus the applicable redemption premium, if any, together with accrued and unpaid distributions, whether or not earned or declared and on a cumulative basis) before any distribution of assets is made to holders of Common Shares. After payment of the full amount of the liquidating distribution to which they are entitled, the preferred shareholders would not be entitled to any further participation in any distribution of assets by the Trust. Holders of preferred shares, voting as a class, would be entitled to elect two of the Trust’s Trustees. The holders of both the Common Shares and the preferred shares (voting together as a single class with each share entitling its holder to one vote) would be entitled to elect the remaining Trustees of the Trust. Under the 1940 Act, if at any time distributions on any preferred shares are unpaid in an amount equal to two full years’ distributions thereon, the holders of all outstanding preferred shares, voting as a class, will be allowed to elect a majority of the Trust’s Trustees until all distributions in arrears have been paid or declared and set apart for payment. In addition, if required by a Rating Agency rating any preferred shares or if the Board determines it to be in the best interests of the Common Shareholders, issuance of such preferred shares may result in more restrictive provisions than required by the 1940 Act being imposed. In this regard, holders of any preferred shares may be entitled to elect a majority of the Trust’s Board in other circumstances, for example, if one payment on the preferred shares is in arrears. The differing rights of the holders of preferred and Common Shares with respect to the election of Trustees do not affect the obligation of all Trustees to take actions they believe to be consistent with the best interests of the Trust. All such actions must be consistent with (i) the obligations of the Trust with respect to the holders of preferred shares (which obligations arise primarily from the contractual terms of the preferred shares, as specified in the Trust’s Organizational Documents) and (ii) the fiduciary duties owed to the Trust, which include the duties of loyalty and care. The APS have been rated Aa3 by Moody's. The Trust currently intends to seek to maintain this rating or an equivalent credit rating on the APS or any preferred shares it issues. The Rating Agencies which rate the preferred shares and any bank lender in connection with a credit facility or commercial paper program may also impose specific restrictions as a condition to borrowing. Such restrictions may include asset coverage or portfolio composition requirements that are more stringent than those imposed on the Trust by the 1940 Act. These covenants or guidelines do not currently and are not expected to impede Eaton Vance in managing the Trust’s portfolio in accordance with its investment objective and policies and it is not anticipated that they will so impede Eaton Vance in the future. |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Securities [Table Text Block] |  | The following table provides information about our outstanding Common Shares as of August 18, 2022:
Title of Class | Amount Authorized | Amount Held by the Trust for its Account | Amount Outstanding
Common Shares | Unlimited | 0 | 17,538,857
Outstanding Security, Title [Text Block] |  | Common Shares |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  | 0 |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding Security, Not Held [Shares] |  | 17,538,857 |  |  |  |  |  |  |  |  |  |  |  |  |
Anti-Takeover Provisions [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Anti-Takeover Provisions. The Trust’s Agreement and Declaration of Trust (the “Declaration of Trust”) and Amended and Restated By-Laws (the “By-Laws” and together with the Declaration of Trust, the “Organizational Documents”) include provisions that could have the effect of limiting the ability of other persons or entities to acquire control of the Trust or to change the composition of its Board. For example, pursuant to the Trust's Declaration of Trust, the Board is divided into three classes of Trustees with each class serving for a three-year term and certain types of transactions require the favorable vote of holders of at least 75% of the outstanding shares of the Trust. See “Description of Capital Structure - Certain Provisions of the Organizational Documents - Anti-Takeover Provisions in the Organizational Documents.” |  |  |  |  |  |  |  |  |  |  |  |  |
Credit Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Credit Risk. Investments in loans and other debt obligations (referred to below as “debt instruments”) are subject to the risk of non-payment of scheduled principal and interest. Changes in economic conditions or other circumstances may reduce the capacity of the party obligated to make principal and interest payments on such instruments and may lead to defaults. Such non-payments and defaults may reduce the value of Trust shares and income distributions. The value of debt instruments also may decline because of concerns about the issuer’s ability to make principal and interest payments. In addition, the credit ratings of debt instruments may be lowered if the financial condition of the party obligated to make payments with respect to such instruments deteriorates. In the event of bankruptcy of the issuer of a debt instrument, the Trust could experience delays or limitations with respect to its ability to realize the benefits of any collateral securing the instrument. In order to enforce its rights in the event of a default, bankruptcy or similar situation, the Trust may be required to retain legal or similar counsel, which may increase the Trust’s operating expenses and adversely affect net asset value. See “Lower Rated Investments Risk.” The Trust is also exposed to credit risk when it engages in certain types of derivatives transactions and when it engages in transactions that expose the Trust to counterparty risk. See “Derivatives.” Due to their lower place in the borrower’s capital structure, Junior Loans involve a higher degree of overall risk than Senior Loans to the same borrower. In evaluating the quality of a particular instrument, the investment adviser may take into consideration, among other things, a credit rating assigned by a credit rating agency, the issuer’s financial resources and operating history, its sensitivity to economic conditions and trends, the ability of its management, its debt maturity schedules and borrowing requirements, and relative values based on anticipated cash flow, interest and asset coverage, and earnings prospects. Credit rating agencies are private services that provide ratings of the credit quality of certain investments. Credit ratings issued by rating agencies are based on a number of factors including, but not limited to, the issuer’s financial condition and the rating agency’s credit analysis, if applicable, at the time of rating. As such, the rating assigned to any particular security is not necessarily a reflection of the issuer’s current financial condition. The ratings assigned are not absolute standards of credit quality and do not evaluate market risks or necessarily reflect the issuer’s current financial condition or the volatility or liquidity of the security. A credit rating may have a modifier (such as plus, minus or a numerical modifier) to denote its relative status within the rating. The presence of a modifier does not change the security credit rating (for example, BBB- and Baa3 are within the investment grade rating) for purposes of the Trust’s investment limitations. |  |  |  |  |  |  |  |  |  |  |  |  |
Currency Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks. |  |  |  |  |  |  |  |  |  |  |  |  |
Cybersecurity Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Cybersecurity Risk. With the increased use of technologies by Trust service providers to conduct business, such as the Internet, the Trust is susceptible to operational, information security and related risks. The Trust relies on communications technology, systems, and networks to engage with clients, employees, accounts, shareholders, and service providers, and a cyber incident may inhibit the Trust’s ability to use these technologies. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber attacks include, but are not limited to, gaining unauthorized access to digital systems (e.g., through “hacking” or malicious software coding) for purposes of misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber attacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of-service attacks on websites or via “ransomware” that renders the systems inoperable until appropriate actions are taken. A denial-of-service attack is an effort to make network services unavailable to intended users, which could cause shareholders to lose access to their electronic accounts, potentially indefinitely. Employees and service providers also may not be able to access electronic systems to perform critical duties for the Trust, such as trading NAV calculation, shareholder accounting or fulfillment of Trust share purchases and redemptions, during a denial-of-service attack. There is also the possibility for systems failures due to malfunctions, user error and misconduct by employees and agents, natural disasters, or other foreseeable and unforeseeable events. Because technology is consistently changing, new ways to carry out cyber attacks are always developing. Therefore, there is a chance that some risks have not been identified or prepared for, or that an attack may not be detected, which puts limitations on the Trust's ability to plan for or respond to a cyber attack. Like other Trusts and business enterprises, the Trust and its service providers have experienced, and will continue to experience, cyber incidents consistently. In addition to deliberate cyber attacks, unintentional cyber incidents can occur, such as the inadvertent release of confidential information by the Trust or its service providers. The Trust uses third party service providers who are also heavily dependent on computers and technology for their operations. Cybersecurity failures or breaches by the Trust’s investment adviser or administrator and other service providers (including, but not limited to, the custodian or transfer agent), and the issuers of securities in which the Trust invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Trust, impede Trust trading, interfere with the Trust’s ability to calculate its NAV, or cause violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, litigation costs, or additional compliance costs. While many of the Trust service providers have established business continuity plans and risk management systems intended to identify and mitigate cyber attacks, there are inherent limitations in such plans and systems including the possibility that certain risks have not been identified. The Trust cannot control the cybersecurity plans and systems put in place by service providers to the Trust and issuers in which the Trust invests. The Trust and its shareholders could be negatively impacted as a result. |  |  |  |  |  |  |  |  |  |  |  |  |
Derivatives Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Derivatives Risk. The Trust’s exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative (“reference instruments”), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Trust, which represents a non-cash exposure to the reference instrument. Leverage can increase both the risk and return potential of the Trust. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Trust. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative’s counterparty is unable to honor its commitments, the value of Trust shares may decline and the Trust could experience delays in the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment, particularly when there is no stated limit on the Trust’s use of derivatives. A derivative investment also involves the risks relating to the reference instrument underlying the investment. |  |  |  |  |  |  |  |  |  |  |  |  |
Discount From or Premium to NAV [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Discount From or Premium to NAV. The Offering will be conducted only when Common Shares of the Trust are trading at a price equal to or above the Trust’s NAV per Common Share plus the per Common Share amount of commissions. As with any security, the market value of the Common Shares may increase or decrease from the amount initially paid for the Common Shares. The Trust’s Common Shares have traded both at a premium and at a discount relative to net asset value. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Trust’s NAV may decrease. |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Securities Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Equity Securities Risk. The value of equity securities and related instruments may decline in response to adverse changes in the economy or the economic outlook; deterioration in investor sentiment; interest rate, currency, and commodity price fluctuations; adverse geopolitical, social or environmental developments; issuer and sector-specific considerations; unexpected trading activity among retail investors; or other factors. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines in value, the value of the Trust's equity securities will also likely decline. Although prices can rebound, there is no assurance that values will return to previous levels. |  |  |  |  |  |  |  |  |  |  |  |  |
Foreign Investment Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Foreign Investment Risk. Investments in foreign issuers could be affected by factors not present in the United States, including expropriation, armed conflict, confiscatory taxation, lack of uniform accounting and auditing standards, less publicly available financial and other information, and potential difficulties in enforcing contractual obligations. Because foreign issuers may not be subject to uniform accounting, auditing and financial reporting standard practices and requirements and regulatory measures comparable to those in the United States, there may be less publicly available information about such foreign issuers. Settlements of securities transactions in foreign countries are subject to risk of loss, may be delayed and are generally less frequent than in the United States, which could affect the liquidity of the Trust’s assets. Evidence of ownership of certain foreign investments may be held outside the United States, and the Trust may be subject to the risks associated with the holding of such property overseas. Trading in certain foreign markets is also subject to liquidity risk. Foreign investments in the securities markets of certain foreign countries is restricted or controlled to varying degrees. Foreign issuers may become subject to sanctions imposed by the United States or another country, which could result in the immediate freeze of the foreign issuers’ assets or securities. The imposition of such sanctions could impair the market value of the securities of such foreign issuers and limit the Trust’s ability to buy, sell, receive or deliver the securities. In addition, as a result of economic sanctions, the Trust may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Trust and increased transaction costs. If a deterioration occurs in a country's balance of payments, the country could impose temporary restrictions on foreign capital remittances. The Trust could also be adversely affected by delays in, or a refusal to grant, any required governmental approval for repatriation, as well as by other restrictions on investment. The risks posed by such actions with respect to a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Trust invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Political events in foreign countries may cause market disruptions. In June 2016, the United Kingdom (“UK”) voted in a referendum to leave the European Union (“EU”) (“Brexit”). Effective January 31, 2020, the UK ceased to be a member of the EU and, following a transition period during which the EU and the UK Government engaged in a series of negotiations regarding the terms of the UK’s future relationship with the EU, the EU and the UK Government signed an agreement on December 30, 2020 regarding the economic relationship between the UK and the EU. This agreement became effective on a provisional basis on January 1, 2021 and entered into full force on May 1, 2021. There remains significant market uncertainty regarding Brexit’s ramifications, and the range and potential implications of the possible political, regulatory, economic, and market outcomes in the UK, EU and beyond are difficult to predict. The end of the Brexit transition period may cause greater market volatility and illiquidity, currency fluctuations, deterioration in economic activity, a decrease in business confidence, and an increased likelihood of a recession in the UK. If one or more additional countries leave the EU or the EU dissolves, the world’s securities markets likely will be significantly disrupted. The Trust may invest in securities and other instruments (including loans) issued, guaranteed, or backed by sovereign or government entities. Economic data as reported by sovereign or government entities and other issuers may be delayed, inaccurate or fraudulent. Many sovereign or government debt obligations may be rated below investment grade. Any restructuring of a sovereign or government debt obligation held by the Trust will likely have a significant adverse effect on the value of the obligation. In the event of default of a sovereign or government debt, the Trust may be unable to pursue legal action against the issuer or secure collateral on the debt, there are typically no assets to be seized or cash flows to be attached. Furthermore, the willingness or ability of a sovereign or government entity to restructure defaulted debt may be limited. Therefore, losses on sovereign or government defaults may far exceed the losses from the default of a similarly rated U.S. corporate debt issuer. |  |  |  |  |  |  |  |  |  |  |  |  |
Geopolitical Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Geopolitical Risk. The increasing interconnectivity between global economies and financial markets increases the likelihood that events or conditions in one region or financial market may adversely impact issuers in a different country, region or financial market. Securities in a Trust’s portfolio may underperform due to inflation (or expectations for inflation), interest rates, global demand for particular products or resources, natural disasters, health emergencies (such as epidemics and pandemics), terrorism, regulatory events and governmental or quasi-governmental actions. The occurrence of global events similar to those in recent years, such as terrorist attacks around the world, natural disasters, health emergencies, social and political discord, war or debt crises and downgrades, among others, may result in market volatility and may have long term effects on both the U.S. and global financial markets. Other financial, economic and other global market and social developments or disruptions may result in similar adverse circumstances, and it is difficult to predict when similar events affecting the U.S. or global financial markets may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). Such global events may negatively impact broad segments of businesses and populations, cause a significant negative impact on the performance of the Trust’s investments, adversely affect and increase the volatility of the Trust’s share price and/or exacerbate preexisting political, social and economic risks to the Trust. The Trust’s operations may be interrupted and any such event(s) could have a significant adverse impact on the value and risk profile of the Trust’s portfolio. There is a risk that you may lose money by investing in the Trust. |  |  |  |  |  |  |  |  |  |  |  |  |
Income Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Income Risk. The income investors receive from the Trust is based primarily on the interest it earns from its investments, which can vary widely over the short and long-term. If prevailing market interest rates drop, investors’ income from the Trust could drop as well. The Trust’s income could also be affected adversely when prevailing short-term interest rates increase and the Trust is utilizing leverage, although this risk is mitigated by the Trust’s investment in Senior Loans, which pay floating-rates of interest. |  |  |  |  |  |  |  |  |  |  |  |  |
Inflation Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Inflation Risk. Inflation risk is the risk that the value of assets or income from investments will be worth less in the future as inflation decreases the value of money. As inflation increases, the real value of the Common Shares and distributions thereon can decline. In addition, during any periods of rising inflation, dividend rates of preferred shares would likely increase, which would tend to further reduce returns to Common Shareholders. This risk is mitigated to some degree by the Trust's investments in Senior Loans. |  |  |  |  |  |  |  |  |  |  |  |  |
Interest Rate Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Interest Rate Risk. In general, the value of income securities will fluctuate based on changes in interest rates. The value of these securities is likely to increase when interest rates fall and decline when interest rates rise. Duration measures the time-weighted expected cash flows of a fixed-income security, while maturity refers to the amount of time until a fixed-income security matures. Generally, securities with longer durations or maturities are more sensitive to changes in interest rates than securities with shorter durations or maturities, causing them to be more volatile. Conversely, fixed-income securities with shorter durations or maturities will be less volatile but may provide lower returns than fixed-income securities with longer durations or maturities. In a rising interest rate environment, the duration of income securities that have the ability to be prepaid or called by the issuer may be extended. In a declining interest rate environment, the proceeds from prepaid or maturing instruments may have to be reinvested at a lower interest rate. The impact of interest rate changes is significantly less for floating-rate instruments that have relatively short periodic rate resets (e.g., ninety days or less). Variable and floating-rate loans and securities generally are less sensitive to interest rate changes, but may decline in value if their interest rates do not rise as much or as quickly as interest rates in general. Conversely, variable and floating-rate loans and securities generally will not increase in value as much as fixed rate debt instruments if interest rates decline. Because the Trust holds variable and floating-rate loans and securities, a decrease in market interest rates will reduce the interest income to be received from such securities. In the event that the Trust has a negative average portfolio duration, the value of the Trust may decline in a declining interest rate environment. Because floating or variable rates on loans only reset periodically, changes in prevailing interest rates may cause some fluctuations in the Trust’s net asset value. Similarly, a sudden and significant increase in market interest rates may cause a decline in the Trust’s net asset value. A material decline in the Trust’s net asset value may impair the Trust’s ability to maintain required levels of asset coverage. Certain countries and regulatory bodies may use negative interest rates as a monetary policy tool to encourage economic growth during periods of deflation. In a negative interest rate environment, debt instruments may trade at negative yields, which means the purchaser of the instrument may receive at maturity less than the total amount invested. |  |  |  |  |  |  |  |  |  |  |  |  |
Issuer Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Issuer Risk. The value of corporate income-producing securities held by the Trust may decline for a number of reasons, which directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. |  |  |  |  |  |  |  |  |  |  |  |  |
LIBOR Transition and Associated Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | LIBOR Transition and Associated Risk. The London Interbank Offered Rate or LIBOR is the average offered rate for various maturities of short-term loans between major international banks who are members of the British Bankers Association. It is used throughout global banking and financial industries to determine interest rates for a variety of financial instruments (such as debt instruments and derivatives) and borrowing arrangements. In July 2017, the Financial Conduct Authority (the “FCA”), the United Kingdom financial regulatory body, announced a desire to phase out the use of LIBOR. The ICE Benchmark Administration Limited, the administrator of LIBOR, ceased publishing certain LIBOR settings on December 31, 2021, and is expected to cease publishing the remaining LIBOR settings on June 30, 2023. Many market participants are in the process of transitioning to the use of alternative reference or benchmark rates. On September 29, 2021 the FCA announced that it will compel the ICE Benchmark Administration Limited (the “IBA”) to publish a subset of non-U.S. LIBOR maturities after December 31, 2021 using a “synthetic” methodology that is not based on panel bank contributions and has indicated that it may also require IBA to publish a subset of U.S. LIBOR maturities after June 30, 2023, using a similar synthetic methodology. However, these synthetic publications are expected to be published for a limited period of time and would be considered non-representative of the underlying market. Although the transition process away from LIBOR has become increasingly well-defined, the impact on certain debt securities, derivatives and other financial instruments that utilize LIBOR remains uncertain. The transition process may involve, among other things, increased volatility or illiquidity in markets for instruments that currently rely on LIBOR. The transition may also result in a change in (i) the value of certain instruments held by the Trust, (ii) the cost of borrowing or the dividend rate for preferred shares, or (iii) the effectiveness of related Trust transactions such as hedges, as applicable. Various financial industry groups are planning for the transition away from LIBOR, but there are obstacles to converting certain longer term securities and transactions to a new benchmark. In June 2017, the Alternative Reference Rates Committee, a group of large U.S. banks working with the Federal Reserve, announced its selection of a new Secured Overnight Financing Rate (“SOFR”), which is intended to be a broad measure of secured overnight U.S. Treasury repo rates, as an appropriate replacement for LIBOR. Bank working groups and regulators in other countries have suggested other alternatives for their markets, including the Sterling Overnight Interbank Average Rate (“SONIA”) in England. Both SOFR and SONIA, as well as certain other proposed replacement rates, are materially different from LIBOR, and changes in the applicable spread for financial instruments transitioning away from LIBOR need to be made to accommodate the differences. Liquid markets for newly-issued instruments that use an alternative reference rate are still developing. Consequently, there may be challenges for a Trust to enter into hedging transactions against instruments tied to alternative reference rates until a market for such hedging transactions develops. Additionally, while some existing LIBOR-based instruments may contemplate a scenario where LIBOR is no longer available by providing for an alternative or “fallback” rate-setting methodology, there may be significant uncertainty regarding the effectiveness of any such alternative methodologies to replicate LIBOR. Not all existing LIBOR-based instruments have such fallback provisions, and many that do, do not contemplate the permanent cessation of LIBOR. While it is expected that market participants will amend legacy financial instruments referencing LIBOR to include fallback provisions to alternative reference rates, there remains uncertainty regarding the willingness and ability of parties to add or amend such fallback provisions in legacy instruments maturing after the end of 2021, particularly with respect to legacy cash products. Although there are ongoing efforts among certain government entities and other organizations to address these uncertainties, the ultimate effectiveness of such efforts is not yet known. Any effects of the transition away from LIBOR and the adoption of alternative reference rates, as well as other unforeseen effects, could result in losses to the Trust, and such effects may occur prior to the discontinuation of the remaining LIBOR settings in 2023. Furthermore, the risks associated with the discontinuation of LIBOR and transition to replacement rates may be exacerbated if an orderly transition to an alternative reference rate is not completed in a timely manner. |  |  |  |  |  |  |  |  |  |  |  |  |
Leverage Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Leverage Risk. Certain fund transactions may give rise to leverage. Leverage can result from a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Trust. The Trust is required to segregate liquid assets or otherwise cover the Trust’s obligation created by a transaction that may give rise to leverage. The use of leverage may cause the Trust to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet segregation requirements. Leverage may cause the Trust’s share price to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the value of the Trust’s portfolio securities. The loss on leveraged investments may substantially exceed the initial investment. As discussed above, the Trust currently uses leverage created by issuing APS and borrowings. On June 27, 2001, the Trust issued 2,200 Series A APS and 2,200 Series B APS, with a liquidation preference per share of $25,000 plus accumulated but unpaid dividends. On September 23, 2016, the Trust repurchased 968 Series A APS and 968 Series B APS and on September 14, 2018, the Trust repurchased 480 Series A APS and 480 Series B APS. The Trust has entered into a Revolving Credit and Security Agreement, as amended (the Agreement) with conduit lenders and a bank to borrow up to $50 million ($125 million prior to September 29, 2021). The Trust is required to maintain certain net asset levels during the term of the Agreement. As of June 30, 2022 , the Trust had $26 million in outstanding borrowings under the Agreement , at an interest rate of 1.62 %, in addition to outstanding APS. The Adviser anticipates that the use of leverage (from the issuance of APS and borrowings) may result in higher income to Common Shareholders over time. Leverage creates risks for Common Shareholders, including the likelihood of greater volatility of NAV and market price of the Common Shares and the risk that fluctuations in dividend rates on APS and costs of borrowings may affect the return to Common Shareholders. See also “LIBOR Transition and Associated Risk.” To the extent the income derived from investments purchased with funds received from leverage exceeds the cost of leverage, the Trust’s distributions will be greater than if leverage had not been used. Conversely, if the income from the investments purchased with such funds is not sufficient to cover the cost of leverage, the amount available for distribution to Common Shareholders will be less than if leverage had not been used. In the latter case, Eaton Vance, in its best judgment, may nevertheless determine to maintain the Trust’s leveraged position if it deems such action to be appropriate. While the Trust has preferred shares outstanding, an increase in short-term rates would also result in an increased cost of leverage, which would adversely affect the Trust’s income available for distribution. There can be no assurance that a leveraging strategy will be successful. In addition, under current federal income tax law, the Trust is required to allocate a portion of any net realized capital gains or other taxable income to APS holders. The terms of the Trust’s APS require the Trust to pay to any APS holders additional dividends intended to compensate such holders for taxes payable on any capital gains or other taxable income allocated to such holders. Any such additional dividends will reduce the amount available for distribution to Common Shareholders. As discussed under “Management of the Trust,” the fee paid to Eaton Vance is calculated on the basis of the Trust’s gross assets, including proceeds from the issuance of APS and borrowings, so the fees will be higher when leverage is utilized. In this regard, holders of APS do not bear the investment advisory fee. Rather, Common Shareholders bear the portion of the investment advisory fee attributable to the assets purchased with the proceeds, which means that Common Shareholders effectively bear the entire advisory fee. The APS have been rated Aa3 by Moody's. The Trust currently intends to seek to maintain this rating or an equivalent credit rating on the APS or any preferred shares it issues. The Rating Agencies which rate the preferred shares and any bank lender in connection with a credit facility or commercial paper program may also impose specific restrictions as a condition to borrowing. Such restrictions may include asset coverage or portfolio composition requirements that are more stringent than those imposed on the Trust by the 1940 Act. These covenants or guidelines do not currently and are not expected to impede Eaton Vance in managing the Trust’s portfolio in accordance with its investment objective and policies and it is not anticipated that they will so impede Eaton Vance in the future. See “Description of Capital Structure - Preferred Shares.” Financial leverage may also be achieved through the purchase of certain derivative instruments. The Trust’s use of derivative instruments exposes the Trust to special risks. See “Investment Objective, Policies and Risks - Additional Investment Practices” and “Investment Objective, Policies, and Risks - Additional Risk Considerations.” |  |  |  |  |  |  |  |  |  |  |  |  |
Liquidity Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Liquidity Risk. The Trust is exposed to liquidity risk when trading volume, lack of a market maker, or legal restrictions impair the Trust’s ability to sell particular investments or close derivative positions at an advantageous market price. Trading opportunities are also more limited for securities and other instruments that are not widely held or are traded in less developed markets. These factors may make it more difficult to sell or buy a security at a favorable price or time. Consequently, the Trust may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Trust’s performance. It also may be more difficult to value less liquid investments. These effects may be exacerbated during times of financial or political stress. In addition, the limited liquidity could affect the market price of the investments, thereby adversely affecting the Trust's net asset value and ability to make dividend distributions. The Trust has no limitation on the amount of its assets which may be invested in illiquid investments. |  |  |  |  |  |  |  |  |  |  |  |  |
Lower Rated Investments Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Lower Rated Investments Risk. Investments rated below investment grade and comparable unrated investments (sometimes referred to as “junk”) have speculative characteristics because of the credit risk associated with their issuers. Changes in economic conditions or other circumstances typically have a greater effect on the ability of issuers of lower rated investments to make principal and interest payments than they do on issuers of higher rated investments. An economic downturn generally leads to a higher non-payment rate, and a lower rated investment may lose significant value before a default occurs. Lower rated investments typically are subject to greater price volatility and illiquidity than higher rated investments. Lower rated investments are considered primarily speculative with respect to the issuer’s capacity to pay interest and repay principal. |  |  |  |  |  |  |  |  |  |  |  |  |
Management Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Management Risk. The Trust is subject to management risk because it is actively managed. Eaton Vance and the individual portfolio managers invest the assets of the Trust as they deem appropriate in implementing the Trust’s investment strategy. Accordingly, the success of the Trust depends upon the investment skills and analytical abilities of Eaton Vance and the individual portfolio managers to develop and effectively implement strategies that achieve the Trust’s investment objective. There is no assurance that Eaton Vance and the individual portfolio managers will be successful in developing and implementing the Trust’s investment strategy. Subjective decisions made by Eaton Vance and the individual portfolio managers may cause the Trust to incur losses or to miss profit opportunities. |  |  |  |  |  |  |  |  |  |  |  |  |
Market Discount Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Market Discount Risk. As with any security, the market value of the Common Shares may increase or decrease from the amount initially paid for the Common Shares. The Trust’s Common Shares have traded both at a premium and at a discount relative to NAV. The shares of closed-end management investment companies frequently trade at a discount from their NAV. This is a risk separate and distinct from the risk that the Trust’s NAV may decrease. |  |  |  |  |  |  |  |  |  |  |  |  |
Market Disruption [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Market Disruption. Global instability, war, geopolitical tensions and terrorist attacks in the United States and around the world have previously resulted, and may in the future result in market volatility and may have long-term effects on the United States and worldwide financial markets and may cause further economic uncertainties in the United States and worldwide. The Trust cannot predict the effects of significant future events on the global economy and securities markets. A similar disruption of the financial markets could impact interest rates, auctions, secondary trading, ratings, credit risk, inflation and other factors relating to the Common Shares. In particular, Non-Investment Grade Bonds and Senior Loans tend to be more volatile than higher rated fixed-income securities so that these events and any actions resulting from them may have a greater impact on the prices and volatility of Non-Investment Grade Bonds and Senior Loans than on higher rated fixed-income securities. |  |  |  |  |  |  |  |  |  |  |  |  |
Market Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Market Risk. The value of investments held by the Trust may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include such events as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest . These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Trust. The frequency and magnitude of resulting changes in the value of the Trust‘s investments cannot be predicted. Certain securities and other investments held by the Trust may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to higher market volatility. No active trading market may exist for certain investments held by the Trust, which may impair the ability of the Trust to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets. |  |  |  |  |  |  |  |  |  |  |  |  |
Money Market Instrument Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Money Market Instrument Risk. Money market instruments may be adversely affected by market and economic events, such as a sharp rise in prevailing short-term interest rates; adverse developments in the banking industry, which issues or guarantees many money market instruments; adverse economic, political or other developments affecting issuers of money market instruments; changes in the credit quality of issuers; and default by a counterparty. |  |  |  |  |  |  |  |  |  |  |  |  |
Non-Investment Grade Bonds Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Non-Investment Grade Bonds Risk. The Trust’s investments in Non-Investment Grade Bonds, commonly referred to as “junk bonds,” are predominantly speculative because of the credit risk of their issuers. While offering a greater potential opportunity for capital appreciation and higher yields, Non-Investment Grade Bonds typically entail greater potential price volatility and may be less liquid than higher-rated securities. Issuers of Non-Investment Grade Bonds are more likely to default on their payments of interest and principal owed to the Trust, and such defaults will reduce the Trust’s net asset value and income distributions. The prices of these lower rated obligations are more sensitive to negative developments than higher rated securities. Adverse business conditions, such as a decline in the issuer’s revenues or an economic downturn, generally lead to a higher non-payment rate. In addition, a security may lose significant value before a default occurs as the market adjusts to expected higher non-payment rates. |  |  |  |  |  |  |  |  |  |  |  |  |
Pooled Investment Vehicles Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Pooled Investment Vehicles Risk. Pooled investment vehicles are open- and closed-end investment companies and exchange-traded funds (“ETFs”). Pooled investment vehicles are subject to the risks of investing in the underlying securities or other investments. Shares of closed-end investment companies and ETFs may trade at a premium or discount to net asset value and are subject to secondary market trading risks. In addition, the Trust will bear a pro rata portion of the operating expenses of a pooled investment vehicle in which it invests. |  |  |  |  |  |  |  |  |  |  |  |  |
Prepayment Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Prepayment Risk. During periods of declining interest rates or for other purposes, Borrowers may exercise their option to prepay principal earlier than scheduled. For fixed-income securities, such payments often occur during periods of declining interest rates, forcing the Trust to reinvest in lower yielding securities. This is known as call or prepayment risk. Non-Investment Grade Bonds frequently have call features that allow the issuer to redeem the security at dates prior to its stated maturity at a specified price (typically greater than par) only if certain prescribed conditions are met (“call protection”). An issuer may redeem a Non-Investment Grade Bond if, for example, the issuer can refinance the debt at a lower cost due to declining interest rates or an improvement in the credit standing of the issuer. Senior Loans typically have no such call protection. For premium bonds (bonds acquired at prices that exceed their par or principal value) purchased by the Trust, prepayment risk may be enhanced. |  |  |  |  |  |  |  |  |  |  |  |  |
Recent Market Conditions [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Recent Market Conditions. An outbreak of respiratory disease caused by a novel coronavirus was first detected in China in late 2019 and subsequently spread internationally. This coronavirus has resulted in closing borders, enhanced health screenings, changes to healthcare service preparation and delivery, quarantines, cancellations, disruptions to supply chains and customer activity, as well as general concern and uncertainty. The impact of this coronavirus has resulted in a substantial economic downturn, which may continue for an extended period of time. Health crises caused by outbreaks of disease, such as the coronavirus outbreak, may exacerbate other pre-existing political, social and economic risks and disrupt normal market conditions and operations. The impact of this outbreak has negatively affected the worldwide economy, as well as the economies of individual countries and industries, and could continue to affect the market in significant and unforeseen ways. Other epidemics and pandemics that may arise in the future may have similar effects. For example, a global pandemic or other widespread health crisis could cause substantial market volatility and exchange trading suspensions and closures. In addition, the increasing interconnectedness of markets around the world may result in many markets being affected by events or conditions in a single country or region or events affecting a single or small number of issuers. The coronavirus outbreak and public and private sector responses thereto have led to large portions of the populations of many countries working from home for indefinite periods of time, temporary or permanent layoffs, disruptions in supply chains, and lack of availability of certain goods. The impact of such responses could adversely affect the information technology and operational systems upon which the Trust and the Trust’s service providers rely, and could otherwise disrupt the ability of the employees of the Trust’s service providers to perform critical tasks relating to the Trust. Any such impact could adversely affect the Trust’s performance, or the performance of the securities in which the Trust invests and may lead to losses on your investment in the Trust. |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Regulatory Risk. To the extent that legislation or state or federal regulators that regulate certain financial institutions impose additional requirements or restrictions with respect to the ability of such institutions to make loans, particularly in connection with highly leveraged transactions, the availability of Senior Loans for investment may be adversely affected. Further, such legislation or regulation could depress the market value of Senior Loans. |  |  |  |  |  |  |  |  |  |  |  |  |
Reinvestment Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Reinvestment Risk. Income from the Trust’s portfolio will decline if and when the Trust invests the proceeds from matured, traded or called debt obligations into lower yielding instruments. |  |  |  |  |  |  |  |  |  |  |  |  |
Secondary Market for the Common Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Secondary Market for the Common Shares. The issuance of Common Shares through the Offering may have an adverse effect on the secondary market for the Common Shares. The increase in the amount of the Trust’s outstanding Common Shares resulting from the Offering may put downward pressure on the market price for the Common Shares of the Trust. Common Shares will not be issued pursuant to the Offering at any time when Common Shares are trading at a price lower than a price equal to the Trust’s NAV per Common Share plus the per Common Share amount of commissions. The Trust also issues Common Shares of the Trust through its dividend reinvestment plan. See “Dividend Reinvestment Plan.” Common Shares may be issued under the plan at a discount to the market price for such Common Shares, which may put downward pressure on the market price for Common Shares of the Trust. When the Common Shares are trading at a premium, the Trust may also issue Common Shares of the Trust that are sold through transactions effected on the NYSE. The increase in the amount of the Trust’s outstanding Common Shares resulting from that offering may also put downward pressure on the market price for the Common Shares of the Trust. The voting power of current shareholders will be diluted to the extent that such shareholders do not purchase shares in any future Common Share offerings or do not purchase sufficient shares to maintain their percentage interest. In addition, if the Adviser is unable to invest the proceeds of such offering as intended, the Trust’s per share distribution may decrease (or may consist of return of capital) and the Trust may not participate in market advances to the same extent as if such proceeds were fully invested as planned. |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Loans Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Senior Loans Risk. The risks associated with Senior Loans are similar to the risks of Non-Investment Grade Bonds (discussed below), although Senior Loans are typically senior and secured in contrast to Non-Investment Grade Bonds, which are often subordinated and unsecured. Senior Loans’ higher standing has historically resulted in generally higher recoveries in the event of a corporate reorganization or other restructuring. In addition, because their interest rates are adjusted for changes in short-term interest rates, Senior Loans generally have less interest rate risk than Non-Investment Grade Bonds, which are typically fixed rate. The Trust’s investments in Senior Loans are typically below investment grade and are considered speculative because of the credit risk of their issuers. Such companies are more likely to default on their payments of interest and principal owed to the Trust, and such defaults could reduce the Trust’s net asset value and income distributions. An economic downturn generally leads to a higher non-payment rate, and a debt obligation may lose significant value before a default occurs. Moreover, any specific collateral used to secure a loan may decline in value or lose all its value or become illiquid, which would adversely affect the loan’s value. “Junior Loans” are secured and unsecured subordinated loans, second lien loans and subordinate bridge loans. Senior Loans and Junior Loans are referred to together herein as “loans.” Loans and other debt securities are also subject to the risk of price declines and to increases in prevailing interest rates, although floating-rate debt instruments are less exposed to this risk than fixed-rate debt instruments. Interest rate changes may also increase prepayments of debt obligations and require the Trust to invest assets at lower yields. Loans are traded in a private, unregulated inter-dealer or inter-bank resale market and are generally subject to contractual restrictions that must be satisfied before a loan can be bought or sold. These restrictions may impede the Trust’s ability to buy or sell loans (thus affecting their liquidity) and may negatively impact the transaction price. See also “Market Risk” above. It also may take longer than seven days for transactions in loans to settle. The types of covenants included in loan agreements generally vary depending on market conditions, the creditworthiness of the issuer, the nature of the collateral securing the loan and possibly other factors. Loans with fewer covenants that restrict activities of the borrower may provide the borrower with more flexibility to take actions that may be detrimental to the loan holders and provide fewer investor protections in the event of such actions or if covenants are breached. The Trust may experience relatively greater realized or unrealized losses or delays and expense in enforcing its rights with respect to loans with fewer restrictive covenants. Loans to entities located outside of the U.S. may have substantially different lender protections and covenants as compared to loans to U.S. entities and may involve greater risks. The Trust may have difficulties and incur expense enforcing its rights with respect to non-U.S. loans and such loans could be subject to bankruptcy laws that are materially different than in the U.S. Loans may be structured such that they are not securities under securities law, and in the event of fraud or misrepresentation by a borrower, lenders may not have the protection of the anti-fraud provisions of the federal securities laws. Loans are also subject to risks associated with other types of income investments, including credit risk and risks of lower rated investments. |  |  |  |  |  |  |  |  |  |  |  |  |
U.S. Government Securities Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | U.S. Government Securities Risk. Although certain U.S. Government-sponsored agencies (such as the Federal Home Loan Mortgage Corporation and the Federal National Mortgage Association) may be chartered or sponsored by acts of Congress, their securities are neither issued nor guaranteed by the U.S. Treasury. U.S. Treasury securities generally have a lower return than other obligations because of their higher credit quality and market liquidity. |  |  |  |  |  |  |  |  |  |  |  |  |
Business Contact [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cover [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Address Line One |  | Two International Place |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, City or Town |  | Boston |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, State or Province |  | MA |  |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Postal Zip Code |  | 02110 |  |  |  |  |  |  |  |  |  |  |  |  |
Contact Personnel Name |  | Deidre E. Walsh |  |  |  |  |  |  |  |  |  |  |  |  |
Common Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Lowest Price or Bid |  |  |  | $ 6.21 | $ 6.64 | $ 6.88 | $ 6.94 | $ 6.87 | $ 6.76 | $ 6.44 | $ 6.2 | $ 5.42 | $ 4.8 | $ 6.98 | $ 7
Highest Price or Bid |  |  |  | 6.8 | 6.94 | 6.97 | 6.99 | 6.9 | 6.91 | 6.77 | 6.53 | 6.36 | 7.07 | 7.01 | 7.04
Lowest Price or Bid, NAV |  |  |  | 5.37 | 6.07 | 6.56 | 6.63 | 6.61 | 6.33 | 5.8 | 5.29 | 4.48 | 3.84 | 6.09 | 6.03
Highest Price or Bid, NAV |  |  |  | $ 6.44 | $ 7 | $ 7.2 | $ 7.12 | $ 6.8 | $ 6.7 | $ 6.43 | $ 6.01 | $ 5.57 | $ 6.58 | $ 6.41 | $ 6.32
Highest Price or Bid, Premium (Discount) to NAV [Percent] |  |  |  | (5.29%) | 0.86% | 3.30% | 1.86% | (1.45%) | (3.04%) | (5.02%) | (7.96%) | (12.42%) | (6.93%) | (8.56%) | (10.23%)
Lowest Price or Bid, Premium (Discount) to NAV [Percent] |  |  |  | (13.53%) | (8.58%) | (4.65%) | (4.42%) | (3.78%) | (6.36%) | (9.94%) | (14.68%) | (17.34%) | (20.00%) | (12.75%) | (13.86%)
[1] | If Common Shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load.
[2] | You will be charged a $5.00 service charge and pay brokerage charges if you direct the plan agent to sell your Common Shares held in a dividend reinvestment account.
[3] | The Adviser will pay the expenses of the Offering (other than the applicable commissions); therefore, Offering expenses are not included in the Summary of Trust Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Trust’s registration statement (including this Prospectus and the SAI), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of this Prospectus, the SAI and/or marketing materials, associated filing fees, NYSE listing fees, and legal and auditing fees associated with the Offering.
[4] | As of June 30, 2022, the Trust’s outstanding borrowings of 15.31% and APS of 22.14% represented approximately 37.45% leverage.
[5] | Stated as a percentage of average net assets attributable to Common Shares for the year ended June 30, 2022.
[6] | The investment adviser fee paid by the Trust to the Adviser is based on the average weekly gross assets of the Trust, including all assets attributable to any form of investment leverage that the Trust may utilize. Accordingly, if the Trust were to increase investment leverage in the future, the investment adviser fee will increase as a percentage of net assets. Pursuant to the investment advisory agreement, the investment adviser fee was computed at an annual rate of 0.73% of the Trust’s average weekly gross assets through April 30, 2022 and beginning May 1, 2022, at 0.72% of the Trust’s average weekly gross assets, and is payable monthly. The annual investment adviser fee rate shall be reduced to the following as of the stated date: May 1, 2023: 0.71%, May 1, 2024: 0.70%, May 1, 2025: 0.69% and May 1, 2026: 0.55%.

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