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N-2 - USD ($) |  |  | 3 Months Ended
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Jan. 17, 2025 | Jan. 13, 2025 | Dec. 31, 2024 | Sep. 30, 2024 | Jun. 30, 2024 | Mar. 31, 2024 | Dec. 31, 2023 | Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Dec. 31, 2022
Cover [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Entity Central Index Key |  | 0001300391 |  |  |  |  |  |  |  |  |  |
Amendment Flag |  | false |  |  |  |  |  |  |  |  |  |
Entity Inv Company Type |  | N-2 |  |  |  |  |  |  |  |  |  |
Securities Act File Number |  | 333-000000 |  |  |  |  |  |  |  |  |  |
Document Type |  | N-2ASR |  |  |  |  |  |  |  |  |  |
Document Registration Statement |  | true |  |  |  |  |  |  |  |  |  |
Pre-Effective Amendment |  | false |  |  |  |  |  |  |  |  |  |
Post-Effective Amendment |  | false |  |  |  |  |  |  |  |  |  |
Investment Company Act Registration |  | false |  |  |  |  |  |  |  |  |  |
Investment Company Registration Amendment |  | true |  |  |  |  |  |  |  |  |  |
Investment Company Registration Amendment Number |  | 10 |  |  |  |  |  |  |  |  |  |
Entity Registrant Name |  | EATON VANCE ENHANCED EQUITY INCOME FUND |  |  |  |  |  |  |  |  |  |
Entity Address, Address Line One |  | One Post Office Square |  |  |  |  |  |  |  |  |  |
Entity Address, City or Town |  | Boston |  |  |  |  |  |  |  |  |  |
Entity Address, State or Province |  | MA |  |  |  |  |  |  |  |  |  |
Entity Address, Postal Zip Code |  | 02109 |  |  |  |  |  |  |  |  |  |
City Area Code |  | 617 |  |  |  |  |  |  |  |  |  |
Local Phone Number |  | 482-8260 |  |  |  |  |  |  |  |  |  |
Approximate Date of Commencement of Proposed Sale to Public |  | From time to time after the effective date of this Registration Statement. |  |  |  |  |  |  |  |  |  |
Dividend or Interest Reinvestment Plan Only |  | false |  |  |  |  |  |  |  |  |  |
Delayed or Continuous Offering |  | true |  |  |  |  |  |  |  |  |  |
Primary Shelf [Flag] |  | true |  |  |  |  |  |  |  |  |  |
Effective Upon Filing, 462(e) |  | true |  |  |  |  |  |  |  |  |  |
Additional Securities Effective, 413(b) |  | false |  |  |  |  |  |  |  |  |  |
Effective when Declared, Section 8(c) |  | false |  |  |  |  |  |  |  |  |  |
New Effective Date for Previous Filing |  | false |  |  |  |  |  |  |  |  |  |
Additional Securities. 462(b) |  | false |  |  |  |  |  |  |  |  |  |
No Substantive Changes, 462(c) |  | false |  |  |  |  |  |  |  |  |  |
Exhibits Only, 462(d) |  | false |  |  |  |  |  |  |  |  |  |
Registered Closed-End Fund [Flag] |  | true |  |  |  |  |  |  |  |  |  |
Business Development Company [Flag] |  | false |  |  |  |  |  |  |  |  |  |
Interval Fund [Flag] |  | false |  |  |  |  |  |  |  |  |  |
Primary Shelf Qualified [Flag] |  | true |  |  |  |  |  |  |  |  |  |
Entity Well-known Seasoned Issuer |  | Yes |  |  |  |  |  |  |  |  |  |
Entity Emerging Growth Company |  | false |  |  |  |  |  |  |  |  |  |
New CEF or BDC Registrant [Flag] |  | false |  |  |  |  |  |  |  |  |  |
Fee Table [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Shareholder Transaction Expenses [Table Text Block] |  |
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)
(1) | If Common Shares are sold to or through underwriters, the Prospectus Supplement will set forth any applicable sales load.
(2) | Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering.
(3) | 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.
Sales Load [Percent] | [1] | 0.00% |  |  |  |  |  |  |  |  |  |
Dividend Reinvestment and Cash Purchase Fees | [2] | $ 5 |  |  |  |  |  |  |  |  |  |
Other Transaction Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Other Transaction Expenses [Percent] | [3] | 0.00% |  |  |  |  |  |  |  |  |  |
Annual Expenses [Table Text Block] |  |
Annual expenses |  | Percentage of net assets attributable to Common Shares ( 4) |
Investment advisory fee |  |  | 1.00 | % (5)
Other expenses |  |  | 0.10 | %
Total annual Fund operating expenses |  |  | 1.10 | %
(4) | Stated as a percentage of average net assets attributable to Common Shares for the year ended September 30, 2024.
(5) | The advisory fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fees will increase as a percentage of net assets.
Management Fees [Percent] | [4],[5] | 1.00% |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Percent] | [4] | 0.10% |  |  |  |  |  |  |  |  |  |
Total Annual Expenses [Percent] | [4] | 1.10% |  |  |  |  |  |  |  |  |  |
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 1.10% 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
$11 |  | $35 |  | $61 |  | $134
Expense Example, Year 01 |  | $ 11 |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 3 |  | 35 |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 5 |  | 61 |  |  |  |  |  |  |  |  |  |
Expense Example, Years 1 to 10 |  | $ 134 |  |  |  |  |  |  |  |  |  |
Purpose of Fee Table , Note [Text Block] |  | The purpose of the table above is to help you understand all fees and expenses that you, as a holder of Common Shares (“Common Shareholder”), would bear directly or indirectly. |  |  |  |  |  |  |  |  |  |
Basis of Transaction Fees, Note [Text Block] |  | as a percentage of offering price |  |  |  |  |  |  |  |  |  |
Other Transaction Fees, Note [Text Block] |  | Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering. |  |  |  |  |  |  |  |  |  |
Management Fee not based on Net Assets, Note [Text Block] |  | The advisory fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fees will increase as a percentage of net assets. |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Investment Objectives and Practices [Text Block] |  | Investment Objectives, Policies and Risks INVESTMENT OBJECTIVES The Fund’s primary investment objective is to provide current income, with a secondary objective of capital appreciation. The Fund pursues its investment objectives by investing primarily in a portfolio of mid- and large-capitalization common stocks. Under normal market conditions, the Fund seeks to generate current earnings from option premiums by selling covered call options on a substantial portion of its portfolio securities, although on up to 5% of the Fund’s net assets, the Fund may sell the stock underlying a call option prior to purchasing back the call option. Such sales shall occur no more than three days before the option buy back. There can be no assurance that the Fund will achieve its investment objectives. PRIMARY INVESTMENT POLICIES General Composition of the Fund . Under normal market conditions, the Fund invests at least 80% of its total assets in common stocks. For the purposes of the 80% test, total assets is defined as net assets plus any borrowings for investment purposes. Normally, the Fund invests primarily in common stocks of mid- and large-capitalization issuers. The Fund generally invests in common stocks on which exchange traded call options are currently available. The Fund invests primarily in common stocks of U.S. issuers, although the Fund may invest up to 10% of its total assets in securities of foreign issuers, including American Depositary Receipts (‘‘ADRs’’), Global Depositary Receipts (‘‘GDRs’’) and European Depositary Receipts (‘‘EDRs’’). Eaton Vance generally considers mid-capitalization companies to be those companies having market capitalizations within the range of capitalizations for the S&P MidCap 400 ® Index. As of December 31, 2024, the median market capitalization of companies in the S&P MidCap 400 ® Index was approximately $7.0 billion. Market capitalizations of companies within the S&P MidCap 400 ® Growth Index are subject to change. Eaton Vance generally considers large-capitalization companies to be those companies having market capitalizations equal to or greater than the median capitalization of the companies included in the S&P 500 ® . As of December 31, 2024, the median market capitalization of companies in the S&P 500 ® was approximately $37.1 billion. Market capitalizations of companies within the S&P 500 ® Index are subject to change. The Fund’s policy of investing, under normal market circumstances, at least 80% of its total assets in common stocks is not considered to be fundamental by the Fund and can be changed without a vote of the Fund’s shareholders. However, this policy may only be changed by the Fund’s Board of Trustees (the ‘‘Board’’) following the provision of 60 days prior written notice to the Fund’s shareholders. Under normal market conditions, the Fund pursues its primary investment objective principally by employing an options strategy of writing (selling) covered call options on a substantial portion of its portfolio securities, although on up to 5% of the Fund’s net assets, the Fund may sell the stock underlying a call option prior to purchasing back the call option. Such sales shall occur no more than three days before the option buy back. The extent of option writing activity will depend upon market conditions and the Adviser’s ongoing assessment of the attractiveness of writing call options on the Fund’s stock holdings. Writing call options involves a tradeoff between the option premiums received and reduced participation in potential future stock price appreciation. Depending on the Adviser’s evaluation, the Fund may write call options on varying percentages of the Fund’s common stock holdings. The Fund seeks to generate current earnings from option writing premiums and, to a lesser extent, from dividends on stocks held. The Fund may in certain circumstances purchase put options on the S&P 500 ® and other broad-based securities indices deemed suitable for this purpose, and/or on individual stocks held in its portfolio or use other derivative instruments in order to help protect against a decline in the value of its portfolio securities. The premiums paid to acquire any such put options will reduce the amounts available for distribution to Common Shareholders from options activities. The Fund’s investments are normally invested across a broad range of industries and market sectors. The Fund may, however, invest up to any amount less than 25% of its total assets in the securities of issuers in any single industry or group of industries. See ‘‘Risk Considerations – Sector Risk.’’ During unusual market conditions, the Fund 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. Investment Strategy . A team of Eaton Vance investment professionals with extensive experience in equity research and management is responsible for the overall management of the Fund’s investments. The Fund’s investments are actively managed, and securities and other investments may be bought or sold on a daily basis. The Adviser believes that a strategy combining active equity portfolio management with a systematic program of call option writing can provide potentially attractive long-term returns. The Adviser further believes that a strategy of owning common stocks in conjunction with writing call options on a substantial portion of the stocks held should generally provide returns that are superior to simply owning the same stocks under three different stock market scenarios: (1) down-trending equity markets; (2) flat market conditions; and (3) moderately rising equity markets. In the Adviser’s opinion, only in more strongly rising equity markets would the stock-plus-calls strategy generally be expected to underperform the stocks held. For these purposes, the Adviser considers more strongly rising equity market conditions to exist whenever the current annual rate of return for U.S. stocks materially exceeds the long-term historical average of stock market returns. The Adviser considers moderately rising equity market conditions to exist whenever current annual returns on U.S. common stocks are positive, but not materially higher than the long-term historical average of stock market returns. Investment decisions for the Fund will be made primarily on the basis of fundamental research. The portfolio manager utilizes information provided by, and the expertise of, the Adviser’s research staff in making investment decisions. In selecting investments for the Fund, the Adviser considers a variety of issuer characteristics such as sustainable competitive advantage, predictable and dependable cash flows, high quality management teams and solid balance sheets. Many of these considerations are subjective. In addition to its careful research based analysis in selecting investments for the Fund, the Adviser also places a strong emphasis on the ongoing evaluation of portfolio holdings and the appropriate time and circumstances to sell or reduce a holding. In this regard, the Adviser may sell a stock when it believes it is fully valued, the fundamentals of a company deteriorate, a stock’s price falls below its acquisition cost, management fails to execute its strategy or to pursue other more attractive investment opportunities, among other reasons. The Fund writes primarily exchange-listed call options on individual stocks held in the Fund’s portfolio, primarily with shorter maturities (typically one to three months until expiration) and primarily at exercise prices approximately equal to or above the current stock price when written. When an option-writing program is established for a particular stock, options will typically be written on a portion of the total stock position, which may allow for upside potential. If the stock price increases, the Fund will normally look to buy back the call options written and to sell new call options at higher exercise prices (up to the target price determined by the Adviser) as a risk management tool. If the stock price declines, the Fund normally seeks to buy back the call options written or let the calls expire worthless at expiration. The Fund may also write call options with different characteristics and managed differently than described in this paragraph. In addition to the strategy of selling call options, the Fund may invest up to 20% of its total assets in other derivative instruments acquired for hedging, risk management and investment purposes (to gain exposure to securities, securities markets, markets indices and/or currencies consistent with its investment objectives and policies), provided that no more than 10% of the Fund’s total assets may be invested in such derivative instruments acquired for non-hedging purposes. Among other derivative strategies, the Fund may purchase put options on the S&P 500 ® and other broad-based securities indices deemed suitable for this purpose, and/or on individual stocks held in its portfolio in order to help protect against a decline in the value of its portfolio securities. Derivative instruments may be used by the Fund to enhance returns or as a substitute for the purchase or sale of securities. Common Stocks . Under normal market conditions, the Fund will invest at least 80% of its total assets in common stocks. Common stock represents an equity ownership interest in the issuing corporation. Holders of common stock generally have voting rights in the issuer and are entitled to receive common stock dividends when, as and if declared by the corporation’s board of directors. Common stock normally occupies the most subordinated position in an issuer’s capital structure. Returns on common stock investments consist of any dividends received plus the amount of appreciation or depreciation in the value of the stock. The Fund will have substantial exposure to common stocks. Although common stocks have historically generated higher average returns than fixed-income securities over the long term and particularly during periods of high or rising concerns about inflation, common stocks also have experienced significantly more volatility in returns and may not maintain their real value during inflationary periods. An adverse event, such as an unfavorable earnings report, may depress the value of a particular common stock held by the Fund. Also, the prices of common stocks are sensitive to general movements in the stock market and a drop in the stock market may depress the price of common stocks to which the Fund has exposure. Common stock prices fluctuate for many reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant stock market, or when political or economic events affecting the issuers occur. In addition, common stock prices may be sensitive to rising interest rates, as the costs of capital rise and borrowing costs increase. Options—Generally . The Fund’s principal options activity will consist of writing (selling) covered call options on common stocks held, although on up to 5% of the Fund’s net assets, the Fund may sell the stock underlying a call option prior to purchasing back the call option. Such sales shall occur no more than three days before the option buy back. Among other potential options strategies, the Fund may purchase put options on the S&P 500 ® and other broad-based securities indices deemed suitable for this purpose, and/or on individual stocks held in its portfolio to help protect against a decline in the value of its portfolio securities. An option on a security is a contract that gives the holder of the option, in return for a premium, the right to buy from (in the case of a call) or sell to (in the case of a put) the writer of the option the security underlying the option at a specified exercise or ‘‘strike’’ price. The writer of an option on a security has the obligation upon exercise of the option to deliver the underlying security upon payment of the exercise price or to pay the exercise price upon delivery of the underlying security. Certain options, known as ‘‘American style’’ options may be exercised at any time during the term of the option. Other options, known as ‘‘European style’’ options, may be exercised only on the expiration date of the option. Since listed options on individual stocks in the United States are generally American style options, the Adviser believes that substantially all of the single-stock options written or acquired by the Fund will be American style options. Exchange-traded options on stock indices are generally European style options. A call option on a common stock or other security is covered if the Fund owns the security underlying the call or has an absolute and immediate right to acquire that security without additional cash consideration (or, if additional cash consideration is required, cash or other assets determined to be liquid by the Adviser (in accordance with procedures established by the Board) in such amount are segregated by the Fund’s custodian) upon conversion or exchange of other securities held by the Fund. A call option is also covered if the Fund holds a call on the same security as the call written where the exercise price of the call held is (i) equal to or less than the exercise price of the call written, or (ii) greater than the exercise price of the call written, provided the difference is maintained by the Fund in segregated assets determined to be liquid by the Adviser as described above. The Fund may write call options on securities that it owns (so-called covered calls) and also may temporarily hold uncovered call options. With respect to written calls, the Fund may sell the underlying security prior to entering into a closing purchase transaction on up to 5% of its net assets within three days of such transaction. If an option written by the Fund expires unexercised, the Fund realizes on the expiration date a capital gain equal to the premium received by the Fund at the time the option was written. If an option purchased by the Fund expires unexercised, the Fund realizes a capital loss equal to the premium paid. Prior to the earlier of exercise or expiration, an exchange-traded option may be closed out by an offsetting purchase or sale of an option of the same series (type, underlying security, exercise price, and expiration). There can be no assurance, however, that a closing purchase or sale transaction can be effected when the Fund desires. The Fund may sell put or call options it has previously purchased, which could result in a net gain or loss depending on whether the amount realized on the sale is more or less than the premium and other transaction costs paid on the put or call option when purchased. The Fund will realize a capital gain from a closing purchase transaction if the cost of the closing option is less than the premium received from writing the option, or, if it is more, the Fund will realize a capital loss. If the premium received from a closing sale transaction is more than the premium paid to purchase the option, the Fund will realize a capital gain or, if it is less, the Fund will realize a capital loss. In most cases, net gains from the Fund’s option strategy will be short-term capital gains which, for U.S. federal income tax purposes, will constitute net investment company taxable income taxed as ordinary income when distributed to shareholders. See ‘‘Distributions – U.S. Federal Income Tax Matters.’’ The principal factors affecting the market value of an option include supply and demand, interest rates, the current market price of the underlying security in relation to the exercise price of the option, the actual or perceived volatility of the underlying security, and the time remaining until the expiration date. The premium paid for an option purchased by the Fund is an asset of the Fund. The premium received for an option written by the Fund is recorded as an asset and equivalent liability. The Fund then adjusts over time the liability to the market value of the option. The value of an option purchased or written is marked to market daily and is valued at the closing price on the exchange on which it is traded or, if not traded on an exchange or no closing price is available, at the mean between the last bid and asked prices or otherwise at fair value as determined by the Board of the Fund. The transaction costs of buying and selling options consist primarily of commissions (which are imposed in opening, closing, exercise and assignment transactions), but may also include margin and interest costs in particular transactions. The impact of transaction costs on the profitability of a transaction may often be greater for options transactions than for transactions in the underlying securities because these costs are often greater in relation to options premiums than in relation to the prices of underlying securities. Transaction costs may be especially significant in option strategies calling for multiple purchases and sales of options, such as spreads or straddles. Transaction costs may be different for transactions effected in foreign markets than for transactions effected in U.S. markets. Call Options and Covered Call Writing . The Fund follows a principal options strategy known as ‘‘covered call option writing,’’ which is a strategy designed to generate earnings and offset a portion of a market decline in the underlying common stock. The Fund will only write (sell) options on common stocks held in the Fund’s portfolio. It may not sell ‘‘naked’’ call options, i.e ., options representing more shares of the stock than are held in the portfolio. The standard contract size for an exchange-listed single-stock option is 100 shares of the common stock. There are four items needed to identify a particular option contract: (1) the underlying security, (2) the expiration month, (3) the exercise (or strike) price and (4) the type (call or put). For example, 20 ABC Corp. January 40 call options provide the right to purchase 2,000 shares of ABC Corp. common stock on or before January 17, 2025 at $40 per share. A call option whose strike price is above the current price of the underlying stock is called ‘‘out-of-the-money,’’ a call option whose strike price is equal to the current price of the underlying stock is called ‘‘at-the-money’’ and a call option whose strike price is below the current price of the underlying stock is called ‘‘in-the-money.’’ The following is a conceptual example of the returns that may be achieved from a stock-plus-call position, making the following assumptions: ABC common stock trades at $36.36 per share and ABC January 40 call options (10% out-of-the-money) trade at $1.82 per underlying share (5% option premium). This example is not meant to represent the performance of any actual common stock, option contract or the Fund itself. The return over the period until option expiration earned by a holder of ABC stock who writes ABC January 40 call options and maintains the position until expiration will be as follows: (1) if the stock price declines 5%, the option will expire worthless and the holder will have a net return of zero (option premium offsets loss in stock); (2) if the stock price is flat, the option will again expire worthless and the holder will have a net return of 5% (option premium plus no gain or loss on stock); (3) if the stock price rises 10% (to the $40 strike price), the option will again expire with no value and the holder will have a net return of 15% (option premium plus 10% stock return); and (4) if the stock rises 20%, the exercise of the option would limit stock gain to 10% and total net return to 15%. If the stock price at exercise exceeds the strike price, returns from the position are capped at 15%. As demonstrated in the example, writing covered call options on common stocks lowers the variability of potential returns and can enhance returns in three of four stock price performance scenarios (down, flat or moderately up). Only when the stock price at expiration exceeds the sum of the premium received and the option exercise price would the stock-plus-call strategy be expected to provide lower returns than the underlying stock. The amount of downside protection afforded by the strategy in declining stock scenarios is limited, however, to the amount of option premium received. If the stock price declines in an amount greater than the option premium, the Fund will incur a net loss. For conventional listed call options, the option’s expiration date can be up to nine months from the date the call options are first listed for trading. Longer-term call options can have expiration dates up to three years from the date of listing. It is anticipated that many options that are written by the Fund against its stock holdings will be repurchased prior to the option’s expiration date, generating a gain or loss in the options. Options that are not repurchased prior to expiration are subject to exercise by the option holder if the stock price at expiration is above the strike price. Exchange-listed options contracts are originated and standardized by an independent entity called the Options Clearing Corporation (the ‘‘OCC’’). Currently, listed options are available on over 2,300 stocks with new listings added periodically. The Fund will write (sell) call options that are generally issued, guaranteed and cleared by the OCC. Listed call options are traded on the American Stock Exchange, Chicago Board Options Exchange International Securities Exchange, New York Stock Exchange, Pacific Stock Exchange and Philadelphia Stock Exchange. With multiple exercise prices and expiration dates for options on different stocks, the Adviser believes that there exists sufficient opportunities in the options market to meet the needs of the Fund’s investment program. Put Options . Put options are contracts that give the holder of the option, in return for a premium, the right to sell to the writer of the option the security/index underlying the option at a specified exercise price at any time during the term of the option. As discussed above, the Fund may in certain circumstances purchase put options on the S&P 500 ® and other broad-based securities indices deemed suitable for this purpose, and/or on individual stocks held in the portfolio to help protect against a decline in the value of the Fund’s portfolio securities. The premiums paid to acquire put options will reduce amounts available for distribution from the Fund’s options activity. Foreign Securities . The Fund may invest up to 10% of its total assets in securities of issuers located in countries other than the United States. The Fund will not invest in issuers located in emerging market countries. The value of foreign securities is affected by changes in currency rates, foreign tax laws (including withholding or other tax), government policies (in the U.S. or abroad), relations between nations and trading, settlement, custodial and other operational risks. In addition, the costs of investing abroad are generally higher than in the United States, and foreign securities markets may be less liquid, more volatile and less subject to governmental supervision than markets in the United States. Foreign investments also could be affected by other 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. As an alternative to holding foreign-traded securities, the Fund may invest in U.S. dollar-denominated securities of foreign companies that trade on U.S. exchanges or in the U.S. over-the-counter market (including depositary receipts, which evidence ownership in underlying foreign securities).The Fund may invest in ADRs, EDRs and GDRs. ADRs, EDRs and GDRs are certificates evidencing ownership of shares of foreign issuers and are alternatives to purchasing directly the underlying foreign securities in their national markets and currencies. However, they continue to be subject to many of the risks associated with investing directly in foreign securities. These risks include foreign exchange risk as well as the political and economic risks of the underlying issuer’s country. ADRs, EDRs and GDRs may be sponsored or unsponsored. Unsponsored receipts are established without the participation of the issuer. Unsponsored receipts may involve higher expenses, they may not pass-through voting or other shareholder rights, and they may be less liquid. ADDITIONAL INVESTMENT PRACTICES In addition to its primary investment policies, the Fund may engage in the following investment practices to a limited extent. Under normal market conditions, the Fund will invest at least 80% of its total assets in common stocks, including stocks of foreign issuers. The Fund may invest in the aggregate up to 20% of its total assets in all investments described below. Preferred Stocks . Preferred stock, like common stock, represents an equity ownership in an issuer. Generally, preferred stock has a priority of claim over common stock in dividend payments and upon liquidation of the issuer. Unlike common stock, preferred stock does not usually have voting rights. Preferred stock in some instances is convertible into common stock. Although they are equity securities, preferred stocks have certain characteristics of both debt and common stock. They are debt-like in that their promised income is contractually fixed. They are common stock-like in that they do not have rights to precipitate bankruptcy proceedings or collection activities in the event of missed payments. Furthermore, they have many of the key characteristics of equity due to their subordinated position in an issuer’s capital structure and because their quality and value are heavily dependent on the profitability of the issuer rather than on any legal claims to specific assets or cash flows. The Fund will only invest in preferred stocks that are rated investment grade at the time of investment or, if unrated, determined by the Adviser to be of comparable quality. Standard & Poor’s Ratings Group and Fitch Ratings consider securities rated BBB– and above to be investment grade and Moody’s Investors Service, Inc. considers securities rated Baa3 and above to be investment grade. Warrants . The Fund may invest in equity and index warrants of domestic and international issuers. 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. Convertible Securities and Bonds with Warrants Attached . The Fund may invest in preferred stocks and fixed-income obligations that are convertible into common stocks of domestic and foreign issuers, and bonds issued as a unit with warrants. Convertible securities in which the Fund may invest, comprised of both convertible debt and convertible preferred stock, may be converted at either a stated price or at a stated rate into underlying shares of common stock. Because of this feature, convertible securities generally enable an investor to benefit from increases in the market price of the underlying common stock. Convertible securities often provide higher yields than the underlying equity securities, but generally offer lower yields than non-convertible securities of similar quality. The value of convertible securities fluctuates in relation to changes in interest rates like bonds, and, in addition, fluctuates in relation to the underlying common stock. Short Sales . The Fund may sell a security short if it owns at least an equal amount of the security sold short or another security convertible or exchangeable for an equal amount of the security sold short without payment of further compensation (a short sale against-the-box). In a short sale against-the-box, the short seller is exposed to the risk of being forced to deliver stock that it holds to close the position if the borrowed stock is called in by the lender, which would cause gain or loss to be recognized on the delivered stock. The Fund expects normally to close its short sales against-the-box by delivering newly acquired stock. The ability to use short sales against-the-box, certain equity swaps and certain equity collar strategies as a tax-efficient management technique with respect to holdings of appreciated securities is limited to circumstances in which the hedging transaction is closed out not later than thirty days after the end of the Fund’s taxable year in which the transaction was initiated, and the underlying appreciated securities position is held unhedged for at least the next sixty days after the hedging transaction is closed. Not meeting these requirements would trigger the recognition of gain on the underlying appreciated securities position under the U.S. federal tax laws applicable to constructive sales. Temporary Investments . During unusual market conditions, the Fund 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 Fund’s normal investment policies, the Fund may incur transaction costs that would not be incurred if the Fund had remained fully invested in accordance with such normal policies. The Fund’s investment in such temporary investments under unusual market circumstances may not be in furtherance of the Fund’s investment objectives. When-Issued Securities and Forward Commitments . Securities may be purchased on a ‘‘forward commitment’’ or ‘‘when-issued’’ basis (meaning securities are purchased or sold with payment and delivery taking place in the future) in order to secure what is considered to be an advantageous price and yield at the time of entering into the transaction. However, the return on a comparable security when the transaction is consummated may vary from the return 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 occur a month or more before delivery is due. However, no payment or delivery is made until payment is received or delivery is made from the other party to the transaction. Forward commitment or when-issued transactions will not be entered into for the purpose of investment leverage. Illiquid Investments . 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 Fund to sell the investments and the time when it would be permitted to sell. Thus, the Fund may not be able to obtain as favorable a price as that prevailing at the time of the decision to sell. The Fund 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 Fund’s assets may be invested in investments as to which the Fund, 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 Fund 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 Fund’s net asset value. Other Derivative Instruments . In addition to the strategy of selling call options, the Fund may invest up to 20% of its total assets in derivative instruments (which are instruments that derive their value from another instrument, security or index) acquired for hedging, risk management and investment purposes (to gain exposure to securities, securities markets, markets indices and/or currencies consistent with its investment objectives and policies), provided that no more than 10% of the Fund’s total assets may be invested in such derivative instruments acquired for non-hedging purposes. These strategies may be executed through the use of derivative contracts in the United States or abroad. In the course of pursuing these investment strategies, the Fund may purchase and sell equity and fixed-income indices and other instruments, purchase and sell futures contracts and options thereon, and enter into various transactions such as swaps, caps, floors or collars. In addition, derivatives may also include new techniques, instruments or strategies that are permitted as regulatory changes occur. Derivative instruments may be used by the Fund to enhance returns or as a substitute for the purchase or sale of securities. Swaps . Swap contracts may be purchased or sold to hedge against fluctuations in securities prices, interest rates or market conditions, to mitigate non-payment or default risk, or to gain exposure to particular securities, baskets of securities, indices or currencies. 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 particular security, ‘‘basket’’ of securities or index. The Fund will enter into swaps only on a net basis, i.e ., the two payment streams are netted out, with the Fund receiving or paying, as the case may be, only the net amount of the two payments. If the other party to a swap defaults, the Fund’s risk of loss consists of the net amount of payments that the Fund is contractually entitled to receive. The Fund will not enter into any 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 Fund will have contractual remedies pursuant to the agreements related to the transaction. Swaps are traded in the over-the-counter market. The use of 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 Fund would be unfavorably affected. Total Return Swaps. Total return swaps are contracts in which one party agrees to make payments of the total return from the underlying asset(s), which may include securities, baskets of securities, or securities indices during the specified period, in return for payments equal to a fixed or floating rate of interest or the total return from other underlying asset(s). Interest Rate Swaps. Interest rate swaps involve the exchange by the Fund with another party of their respective commitments to pay or receive interest ( e.g ., an exchange of fixed rate payments for floating rate payments). Futures and Options on Futures . The Fund may purchase and sell various kinds of financial futures contracts and options thereon to seek to hedge against changes in stock prices or interest rates, for other risk management purposes or to gain exposure to certain securities, indices and currencies. Futures contracts may be based on various underlying assets. Such transactions involve a risk of loss or depreciation due to adverse changes in securities prices, which may exceed the Fund’s initial investment in these contracts. The Fund will only purchase or sell futures contracts or related options in compliance with the rules of the Commodity Futures Trading Commission. These transactions involve transaction costs. Sales of futures contracts and related options generally result in realization of short-term or long-term capital gain depending on the period for which the investment is held. To the extent that any futures contract or options on futures contract held by the Fund is a ‘‘section 1256 contract’’ under the Internal Revenue Code of 1986, as amended (the “Code”), the contract will be marked-to-market annually and any gain or loss will be treated as 60% long-term and 40% short-term, regardless of the holding period for such contract. Securities Lending . The Fund may seek to earn income by lending portfolio securities to broker-dealers or other institutional borrowers. 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. Loans will be made only to organizations whose credit quality or claims paying ability is considered by the Adviser to be at least investment grade and when the expected returns, net of administrative expenses and any finders’ fees, justifies the attendant risk. 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 financial condition of the borrower will be monitored by the Adviser on an ongoing basis. The Fund will not lend portfolio securities subject to a written covered call contract. Borrowings . The Fund may borrow money to the extent permitted under the 1940 Act as interpreted, modified or otherwise permitted by the regulatory authority having jurisdiction. Although it does not currently intend to do so, the Fund may in the future from time to time borrow money to add leverage to the portfolio. The Fund may also borrow money for temporary administrative purposes. Reverse Repurchase Agreements . The Fund may enter into reverse repurchase agreements. Under a reverse repurchase agreement, the Fund 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 Fund agrees to repurchase the instrument at an agreed upon time (normally within seven days) and price, which reflects an interest payment. The Fund 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. Income realized on reverse repurchase agreements will be taxable as ordinary income when distributed to shareholders. When the Fund 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 Fund’s assets. As a result, such transactions may increase fluctuations in the market value of the Fund’s assets. While there is a risk that large fluctuations in the market value of the Fund’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. If the Fund 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 Fund’s yield. The SEC recently finalized rules that will require certain reverse repurchase transactions involving U.S. Treasuries to be centrally cleared. Although the impact of these rules on the Fund is difficult to predict, they may reduce the availability or increase the costs of such transactions and may adversely affect the Fund’s performance. Research Process . The Fund’s portfolio management utilizes the information provided by, and the expertise of, the research staff of the 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 Fund’s securities selection process. Portfolio Turnover . The Fund 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 Fund. The portfolio turnover rate(s) for the Fund for the fiscal years ended September 30, 2024 and 2023 were 42% and 63%, 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 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 Fund are trading at a price equal to or above the Fund’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 Fund’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 Fund’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 Fund’s outstanding Common Shares resulting from the Offering may put downward pressure on the market price for the Common Shares of the Fund. 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 Fund’s NAV per Common Share plus the per Common Share amount of commissions. The Fund also issues Common Shares of the Fund 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 Fund. When the Common Shares are trading at a premium, the Fund may also issue Common Shares of the Fund that are sold through transactions effected on the NYSE. The increase in the amount of the Fund’s outstanding Common Shares resulting from that offering may also put downward pressure on the market price for the Common Shares of the Fund. 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 Fund’s per share distribution may decrease (or may consist of return of capital) and the Fund may not participate in market advances to the same extent as if such proceeds were fully invested as planned. Investment and Market Risk . An investment in Common Shares is subject to investment risk, including the possible loss of the entire principal amount invested. An investment in Common Shares represents an indirect investment in the securities owned by the Fund, which are generally traded on a securities exchange or in the over-the-counter markets. The value of these securities, like other market investments, may move up or down, sometimes rapidly and unpredictably. In addition, by writing (selling) call options on the equity securities held in the Fund’s portfolio, the capital appreciation potential of such securities will be limited to the difference between the exercise price of the call options written and the purchase price of the equity security underlying such options. The Common Shares at any point in time may be worth less than the original investment, even after taking into account any reinvestment of distributions. The value of investments held by the Fund may increase or decrease in response to economic, political and financial or other disruptive events (whether real, expected or perceived) in the U.S. and global markets. The frequency and magnitude of such changes in value cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Actions taken by the U.S. Federal Reserve or foreign central banks to stimulate or stabilize economic growth, such as decreases or increases in short-term interest rates, could cause high volatility in markets. 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 high market volatility. No active trading market may exist for certain investments held by the Fund, which may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets. Issuer Risk . The value of securities held by the Fund may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. Equity Risk . At least 80% of the Fund’s total assets are invested in common stocks and therefore a principal risk of investing in the Fund is equity risk. Equity risk is the risk that securities held by the Fund 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. Although common stocks have historically generated higher average returns than fixed-income securities over the long term, common stocks also have experienced significantly more volatility in returns. An adverse event, such as an unfavorable earnings report, may depress the value of equity securities of an issuer held by the Fund; the price of common stock of an issuer may be particularly sensitive to general movements in the stock market; or a drop in the stock market may depress the price of most or all of the common stocks and other equity securities held by the Fund. In addition, common stock of an issuer in the Fund’s portfolio may decline in price if the issuer fails to make anticipated dividend payments because, among other reasons, the issuer of the security experiences a decline in its financial condition. Common equity securities in which the Fund will invest are structurally subordinated to preferred stocks, bonds and other debt instruments in a company’s capital structure, in terms of priority to corporate income, and therefore will be subject to greater dividend risk than preferred stocks or debt instruments of such issuers. Finally, common stock prices may be sensitive to rising interest rates, as the costs of capital rise and borrowing costs increase. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines, the value of Fund shares will also likely decline. Although stock prices can rebound, there is no assurance that values will return to previous levels. Risks Associated with Options on Securities . There are numerous risks associated with transactions in options on securities. A decision as to whether, when and how to use options involves the exercise of skill and judgment, and even a well-conceived transaction may be unsuccessful to some degree because of market behavior or unexpected events. As the writer of a call option, the Fund forgoes, during the option’s life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the option premium received and the exercise price of the call, but has retained the risk of loss, minus the option premium received, should the price of the underlying security decline. The writer of an option has no control over when during the exercise period of the option it may be required to fulfill its obligation as a writer of the option. Once an option writer has received an exercise notice, it cannot effect a closing purchase transaction in order to terminate its obligation under the option and must deliver the underlying security at the exercise price. Thus, the use of options may require the Fund to sell portfolio securities at inopportune times or for prices other than current market values, will limit the amount of appreciation the Fund can realize on an investment, or may cause the Fund to hold a security that it might otherwise sell. The value of options may also be adversely affected if the market for such options becomes less liquid or smaller. There can be no assurance that a liquid market will exist when the Fund seeks to close out an option position either, in the case of a call option written, by buying the option, or, in the case of a purchased put option, by selling the option. Reasons for the absence of a liquid secondary market on an exchange include the following: (i) there may be insufficient trading interest in certain options; (ii) restrictions may be imposed by an exchange on opening transactions or closing transactions or both; (iii) trading halts, suspensions or other restrictions may be imposed with respect to particular classes or series of options; (iv) unusual or unforeseen circumstances may interrupt normal operations on an exchange; (v) the facilities of an exchange or the Options Clearing Corporation (the ‘‘OCC’’) may not at all times be adequate to handle current trading volume; or (vi) one or more exchanges could, for economic or other reasons, decide or be compelled to discontinue the trading of options (or a particular class or series of options) at some future date. If trading were discontinued, the secondary market on that exchange (or in that class or series of options) would cease to exist. However, outstanding options on that exchange that had been issued by the OCC as a result of trades on that exchange would continue to be exercisable in accordance with their terms. The Fund’s ability to terminate over-the-counter options will be more limited than with exchange-traded options and may involve the risk that broker-dealers participating in such transactions will not fulfill their obligations. If the Fund were unable to close out a covered call option that it had written on a security, it would not be able to sell the underlying security unless the option expired without exercise. The hours of trading for options may not conform to the hours during which the underlying securities are traded. To the extent that the options markets close before the markets for the underlying securities, significant price and rate movements can take place in the underlying markets that would not be reflected concurrently in the options markets. Call options are marked to market daily and their value will be affected by changes in the value of and dividend rates of the underlying common stocks, changes in interest rates, changes in the actual or perceived volatility of the stock market and the underlying common stocks and the remaining time to the options’ expiration. Additionally, the exercise price of an option may be adjusted downward before the option’s expiration as a result of the occurrence of certain corporate events affecting the underlying equity security, such as extraordinary dividends, stock splits, merger or other extraordinary distributions or events. A reduction in the exercise price of an option would reduce the Fund’s capital appreciation potential on the underlying security. The number of call options the Fund can write is limited by the number of shares of common stock the Fund holds, and further limited by the fact that listed call options on individual common stocks generally trade in units representing 100 shares of the underlying stock. Furthermore, the Fund’s options transactions will be subject to limitations established by each of the exchanges, boards of trade or other trading facilities on which such options are traded. These limitations govern the maximum number of options in each class which may be written or purchased by a single investor or group of investors acting in concert, regardless of whether the options are written or purchased on the same or different exchanges, boards of trade or other trading facilities or are held or written in one or more accounts or through one or more brokers. Thus, the number of options which the Fund may write or purchase may be affected by options written or purchased by other investment advisory clients of the Adviser. An exchange, board of trade or other trading facility may order the liquidation of positions found to be in excess of these limits, and may impose certain other sanctions. The Fund will not write ‘‘naked’’ or uncovered call options. If the Fund purchases put options for hedging or risk management purposes, the Fund will be subject to the following additional risks. A put option acquired by the Fund and not sold prior to expiration will expire worthless if the price of the stock or index at expiration exceeds the exercise price of the option, thereby causing the Fund to lose its entire investment in the option. If restrictions on exercise were imposed, the Fund might be unable to exercise an option it had purchased. If the Fund were unable to close out an option that it had purchased, it would have to exercise the option in order to realize any profit or the option may expire worthless. Stock market indices on which the Fund may purchase options positions likely will not mirror the Fund’s actual portfolio holdings. The effectiveness of index put options as hedges against declines in the Fund’s stock portfolio will be limited to the extent that the performance of the underlying index does not correlate with that of the Fund’s holdings. See also “Derivatives Risk” below. Risks of Investing in Smaller and Mid-Sized Companies . The Fund may make investments in stocks of companies whose market capitalization is considered middle sized or “mid-cap.” Smaller and mid-sized companies often are newer or less established companies than larger companies. Investments in smaller and mid-sized companies carry additional risks because earnings of these companies tend to be less predictable; they often have limited product lines, markets, distribution channels or financial resources; and the management of such companies may be dependent upon one or a few key people. The market movements of equity securities of smaller and mid-sized companies may be more abrupt or erratic than the market movements of equity securities of larger, more established companies or the stock market in general. Historically, smaller and mid-sized companies have sometimes gone through extended periods when they did not perform as well as larger companies. In addition, equity securities of smaller and mid-sized companies generally are less liquid than those of larger companies. This means that the Fund could have greater difficulty selling such securities at the time and price that the Fund would like. Risks of Growth Stock Investing . The Fund invests substantially in stocks with ‘‘growth’’ characteristics. Growth stocks can react differently to issuer, political, market, and economic developments than the market as a whole and other types of stocks. Growth stocks tend to be more expensive relative to their earnings or assets compared to other types of stocks. As a result, growth stocks tend to be sensitive to changes in their earnings and more volatile than other types of stocks. Benchmark Reference Rates Risk. Many debt securities, derivatives, and other financial instruments utilize benchmark or reference rates for variable interest rate calculations, including the Euro Interbank Offer Rate, Sterling Overnight Index Average Rate, and the Secured Overnight Financing Rate (each a “Reference Rate”). Instruments in which the Fund invests may pay interest at floating rates based on such Reference Rates or may be subject to interest caps or floors based on such Reference Rates. The Fund and issuers of instruments in which the Fund invests may also obtain financing at floating rates based on such Reference Rates. The elimination of a Reference Rate or any other changes to or reforms of the determination or supervision of Reference Rates could have an adverse impact on the market for, or value of, any instruments or payments linked to those Reference Rates. For example, some Reference Rates, as well as other types of rates and indices, are described as “benchmarks” and have been the subject of ongoing national and international regulatory reform, including under the European Union regulation on indices used as benchmarks in financial instruments and financial contracts. As a result, the manner of administration of benchmarks has changed and may further change in the future, with the result that relevant benchmarks may perform differently than in the past, the use of benchmarks that are not compliant with the new standards by certain supervised entities may be restricted, and certain benchmarks may be eliminated entirely. Such changes could cause increased market volatility and disruptions in liquidity for instruments that rely on or are impacted by such benchmarks. Additionally, there could be other consequences which cannot be predicted . Foreign Investment Risk . The value of foreign securities is affected by changes in currency rates, foreign tax laws (including withholding or other tax), government policies (in the U.S. or abroad), relations between nations and trading, settlement, custodial and other operational risks. In addition, the costs of investing abroad are generally higher than in the United States, and foreign securities markets may be less liquid, more volatile and less subject to governmental supervision than markets in the United States. Foreign investments also could be affected by other 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. As an alternative to holding foreign-traded securities, the Fund may invest in U.S. dollar-denominated securities of foreign companies that trade on U.S. exchanges or in the U.S. over-the-counter market (including depositary receipts, which evidence ownership in underlying foreign securities). Since the Fund may invest in securities denominated or quoted in currencies other than the U.S. dollar, 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 or other tax), governmental administration of economic or monetary policies (in the U.S. 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. Because foreign companies are not subject to uniform accounting, auditing and financial reporting standards, practices and requirements comparable to those applicable to U.S. companies, there may be less publicly available information about a foreign company than about a domestic company. Volume and liquidity in most foreign debt markets are less than in the United States and securities of some foreign companies are less liquid and more volatile than securities of comparable U.S. companies. There is generally less government supervision and regulation of securities exchanges, broker-dealers and listed companies than in the United States. Mail service between the United States and foreign countries may be slower or less reliable than within the United States, thus increasing the risk of delayed settlements of portfolio transactions for, or loss of certificates of, portfolio securities. Payment for securities before delivery may be required. In addition, with respect to certain foreign countries, there is the possibility of expropriation or confiscatory taxation, political or social instability, or diplomatic developments, which could affect investments in those countries. Moreover, individual foreign economies may differ favorably or unfavorably from the U.S. economy in such respects as growth of gross national product, rate of inflation, capital reinvestment, resource self-sufficiency and balance of payments position. Foreign securities markets, while growing in volume and sophistication, are generally not as developed as those in the United States, and securities of some foreign issuers (particularly those located in developing countries) may be less liquid and more volatile than securities of comparable U.S. companies. 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 regarding the economic relationship between the UK and the EU. Market uncertainty remains 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. If one or more additional countries leave the EU or the EU dissolves, the world’s securities markets likely will be significantly disrupted. Emerging Markets Investment Risk. Investment markets within emerging market countries are typically smaller, less liquid, less developed and more volatile than those in more developed markets like the United States, and may be focused in certain sectors. Emerging market securities often involve greater risks than developed market securities. The information available about an emerging market issuer may be less reliable than for comparable issuers in more developed capital markets. 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. Interest Rate Risk . The level of premiums from call options writing and the amounts available for distribution from the Fund’s options activity may decrease in declining interest rate environments. Any preferred stocks paying fixed dividend rates in which the Fund invests, will likely change in value as market interest rates change. When interest rates rise, the market value of such securities generally will fall. To the extent that the Fund invests in preferred stocks, the net asset value and price of the Common Shares may decline if market interest rates rise. During periods of declining interest rates, an issuer of preferred stock may exercise its option to redeem securities prior to maturity, forcing the Fund to reinvest in lower yielding securities. This is known as call risk. During periods of rising interest rates, the average life of certain types of securities may be extended because of slower than expected payments. This may lock in a below market yield, increase the security’s duration, and reduce the value of the security. This is known as extension risk. The value of the Fund’s common stock investments may also be influenced by changes in interest rates. Sector Risk . The Fund may invest a significant portion of its assets in securities of issuers in any single industry or sector of the economy (a broad based economic segment that may include many distinct industries) if companies in that industry or sector meet the Fund’s investment criteria. If the Fund is focused in an industry or sector, it may present more risks than if it were broadly diversified over numerous industries or sectors of the economy. This may make the Fund more susceptible to adverse economic, political, or regulatory occurrences affecting these sectors. As the percentage of the Fund’s assets invested in a particular sector increases, so does the potential for fluctuation in the net asset value of Common Shares. The Fund may not invest 25% or more of its total assets in the securities of issuers in any single industry or group of industries. Derivatives Risk . In addition to writing call options, the risks of which are described above, the Fund may invest up to 20% of its total assets in other derivative investments acquired for hedging, risk management and investment purposes. Derivative transactions including options on securities and securities indices and other transactions in which the Fund may engage (such as futures contracts and options thereon, swaps and short sales) may subject the Fund to increased risk of principal loss due to unexpected movements in stock prices, changes in stock volatility levels and interest rates, and imperfect correlations between the Fund’s securities holdings and indices upon which derivative transactions are based. The Fund also will be subject to credit risk with respect to the counterparties to any over-the-counter derivatives contracts purchased by the Fund. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery under the derivative contract in a bankruptcy or other reorganization proceeding. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances. 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, such regulations require many derivatives to be margined and/or cleared and traded on an exchange, expand entity registration requirements, impose business conduct requirements on counterparties, and impose other regulatory requirements that impact derivatives markets. The SEC adopted Rule 18f 4 under the 1940 Act, which applies to the Fund’s use of derivative investments and certain financing transactions. Among other things, Rule 18f 4 requires certain funds that invest in derivative instruments beyond a specified limited amount (generally greater than 10% of the Fund’s net assets) to apply a value-at-risk based limit to their use of certain derivative instruments and financing transactions and to adopt and implement a derivatives risk management program. To the extent the Fund uses derivative instruments (excluding certain currency and interest rate hedging transactions) in a limited amount (generally up to 10% of the Fund’s net assets), it will not be subject to the full requirements of Rule 18f 4. In addition, to the extent that the Fund enters into reverse repurchase agreements or similar financing transactions, the Fund may elect to either treat all of its reverse repurchase agreements or similar financing transactions as derivatives transactions for purposes of Rule 18f 4 or comply (with respect to reverse repurchase agreements or similar financing transactions) with the asset coverage requirements under Section 18 of the 1940 Act. The implementation of these requirements or 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 Fund engages in derivative transactions. The Adviser cannot predict the effects of any these regulations or any new governmental regulations that may be implemented, and there can be no assurance that any such government regulations will not adversely affect the Fund’s performance or ability to achieve its investment objectives. Liquidity Risk . The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund 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 Fund’s performance. These effects may be exacerbated during times of financial or political stress. The financial markets in general have in recent years experienced periods of extreme secondary market supply and demand imbalance, resulting in a loss of liquidity during which market prices were suddenly and substantially below traditional measures of intrinsic value. During such periods, some securities could be sold only at arbitrary prices and with substantial losses. Periods of such market dislocation may occur again at any time. Inflation Risk . Inflation risk is the risk that the purchasing power 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. Market Discount Risk . The shares of closed-end management investment companies often trade at a discount from their net asset value, and the Fund’s Common Shares may likewise trade at a discount from net asset value. The trading price of the Fund’s Common Shares may be less than the public offering price. The returns earned by Common Shareholders who purchased their Common Shares in this offering and sell their Common Shares below net asset value will be reduced. Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions and there is no guarantee that such decisions will produce the desired results or expected returns. General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objectives. It is possible to lose money by investing in the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Financial Leverage Risk . Although the Fund has no current intention to do so, the Fund is authorized to utilize leverage through the issuance of preferred shares and/or borrowings, including the issuance of debt securities. In the event that the Fund determines in the future to utilize investment leverage, there can be no assurance that such a leveraging strategy will be successful during any period in which it is employed. Leverage creates risks for Common Shareholders, including the likelihood of greater volatility of net asset value and market price of the Common Shares and the risk that fluctuations in distribution rates on any preferred shares or fluctuations in borrowing costs may affect the return to Common Shareholders. To the extent the income derived from securities purchased with proceeds received from leverage exceeds the cost of leverage, the Fund’s distributions will be greater than if leverage had not been used. Conversely, if the income from the securities purchased with such proceeds 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 Fund’s leveraged position if it deems such action to be appropriate. The costs of an offering of preferred shares and/or a borrowing program would be borne by Common Shareholders and consequently would result in a reduction of the net asset value of Common Shares. In addition, the fee paid to Eaton Vance will be calculated on the basis of the Fund’s average daily gross assets, including proceeds from the issuance of preferred shares and/or borrowings, so the fees will be higher when leverage is utilized. In this regard, holders of preferred shares 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 of the preferred shares offering. Management Risk . The Fund is subject to management risk because it is actively managed. Eaton Vance and the individual portfolio managers invest the assets of the Fund as they deem appropriate in implementing the Fund’s investment strategy. Accordingly, the success of the Fund 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 Fund’s investment objective. There is no assurance that Eaton Vance and the individual portfolio managers will be successful in developing and implementing the Fund’s investment strategy. Subjective decisions made by Eaton Vance and the individual portfolio managers may cause the Fund to incur losses or to miss profit opportunities. Cybersecurity Risk. With the increased use of technologies by Fund service providers to conduct business, such as the Internet, the Fund is susceptible to operational, information security and related risks. The Fund relies on communications technology, systems, and networks to engage with clients, employees, accounts, shareholders, and service providers, and a cyber incident may inhibit the Fund’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. 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 Fund, such as trading and NAV calculation, 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 Fund’s ability to plan for or respond to a cyber attack. Similar types of cybersecurity risks also are present for issuers of securities in which the Fund invests, which could have material adverse consequences for those issuers and result in a decline in the market price of their securities. Furthermore, as a result of cyber attacks, technological disruptions, malfunctions or failures, an exchange or market may close or suspend trading in specific securities or the entire market, which could prevent the Fund from, among other things, buying or selling the Fund or accurately pricing its securities. Like other funds and business enterprises, the Fund 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 Fund or its service providers. The Fund uses third party service providers who are also heavily dependent on computers and technology for their operations. Cybersecurity failures by or breaches of the Fund’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 Fund invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Fund, impede Fund trading, interfere with the Fund’s ability to calculate its NAV, limit a shareholder’s ability to purchase or redeem shares of the Fund 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 Fund’s 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 Fund cannot control the cybersecurity plans and systems put in place by service providers to the Fund and issuers in which the Fund invests. The Fund and its shareholders could be negatively impacted as a result. Focused Investment Risk. To the extent the Fund has substantial investments in a relatively small number of securities or issuers, or a particular market, industry, group of industries, currency, country, region, group of countries, asset class, or sector, the Fund’s net asset value may be more volatile and the Fund will be subject to greater risk than a fund that invests in a more diverse investment portfolio. Similarly, to the extent the Fund holds investments with closely correlated market prices, it will be subject to greater risk than a fund with investments that are not as closely correlated. Changes in the value of a single security or issuer or the impact of a single economic, political, or regulatory occurrence may have a greater adverse impact on the Fund’s net asset value. A fund that invests in the securities of a small number of issuers has greater exposure to adverse developments affecting those issuers and a resulting decline in the market price of those issuers’ securities as compared to a fund that invests in the securities of a larger number of issuers. Companies that share common characteristics are often subject to similar business risks and regulatory burdens and often react similarly to specific economic, market, political or other developments. Similarly, funds having a significant portion of their assets in investments tied economically to a particular geographic region, country, or market (e.g., emerging markets) or to sectors within a region, country, or market have more exposure to regional and country economic risks than do funds whose investments are more geographically diverse. The political and economic prospects of one country or group of countries within the same geographic region may affect other countries in that region, and a recession, debt crisis or decline in the value of the currency of one country can spread to other countries. Furthermore, companies in a particular geographic region or country are vulnerable to events affecting other companies in that region or country because they often share common characteristics, are exposed to similar business risks and regulatory burdens, and react similarly to specific economic, market, political, or other developments. Information Technology Sector Risk. If the Fund concentrates investments in the information technology sector, the value of Fund shares may be particularly impacted by events that adversely affect the information technology sector, such as rapid changes in technology product cycles, competition for the services of qualified personnel and government regulation. The products of information technology companies may face product obsolescence due to rapid technological developments and frequent new product introduction and unpredictable changes in growth rates. Companies in the information technology sector also can be heavily dependent on patent protection and the expiration of patents may adversely affect the profitability of these companies. As a result, the value of shares may fluctuate more than that of a fund that does not concentrate in companies in the technology sector. Recent Market Conditions. Both U.S. and international markets have experienced significant volatility in recent months and years. As a result of such volatility, investment returns may fluctuate significantly. National economies are substantially interconnected, as are global financial markets, which creates the possibility that conditions in one country or region might adversely impact issuers in a different country or region. However, the interconnectedness of economies and/or markets may be diminishing, which may impact such economies and markets in ways that cannot be foreseen at this time. The U.S. government and the U.S. Federal Reserve, as well as certain foreign governments and central banks, have from time to time taken steps to support financial markets. The U.S. government and the U.S. Federal Reserve may, conversely, reduce market support activities, including by taking action intended to increase certain interest rates. This and other government intervention may not work as intended, particularly if the efforts are perceived by investors as being unlikely to achieve the desired results. Changes in government activities in this regard, such as changes in interest rate policy, can negatively affect financial markets generally, increase market volatility and reduce the value and liquidity of securities in which the Fund invests. Some countries, including the United States, have adopted more protectionist trade policies. Slowing global economic growth, the rise in protectionist trade policies, changes to some major international trade agreements, risks associated with the trade agreement between the UK and EU, and the risks associated with trade negotiations between the United States and China, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, the current strength of the U.S. dollar may decrease foreign demand for U.S. assets, which could have a negative impact on certain issuers and/or industries. Regulators in the United States have proposed and adopted a number of changes to regulations involving the markets and issuers, some of which apply to the Fund. The full effect of various newly adopted regulations is not currently known. Additionally, it is not currently known whether any of the proposed regulations will be adopted. However, due to the scope of regulations being proposed and adopted, certain of these changes to regulation could limit the Fund’s ability to pursue its investment strategies or make certain investments, may make it more costly for it to operate, or adversely impact performance. Tensions, war, or open conflict between nations, such as between Russia and Ukraine, in the Middle East, or in eastern Asia could affect the economies of many nations, including the United States. The duration of ongoing hostilities and any sanctions and related events cannot be predicted. Those events present material uncertainty and risk with respect to markets globally and the performance of the Fund and its investments or operations could be negatively impacted. There is widespread concern about the potential effects of global climate change on property and security values. Certain issuers, industries and regions may be adversely affected by the impact of climate change in ways that cannot be foreseen. The impact of legislation, regulation and international accords related to climate change may negatively impact certain issuers and/or industries. Market Disruption . Global instability, war, geopolitical tensions and terrorist attacks in the United States and around the world have previously resulted, and may continue to 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 Fund 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. Financials Sector Risk. To the extent the Fund invests a substantial portion of its assets in the financials sector, factors that have an adverse impact on this sector may have a disproportionate impact on the Fund’s performance. The financials sector can be affected by global and local economic conditions, such as the levels and liquidity of the global and local financial and asset markets, the absolute and relative level and volatility of interest rates and equity prices, investor sentiment, inflation, and the availability and cost of credit. Companies in the financials sector may be subject to extensive government regulations that affect the scope of their activities, the prices they can charge for products and services, and the amount of capital they must maintain. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operations and profitability of the financials sector. Global economies and financial markets are becoming increasingly. Anti-Takeover Provisions . The Fund’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 making it more difficult to acquire control of the Fund or to change the composition of its Board. See “Description of Capital Structure—Certain Provisions of the Organizational Documents—Anti-Takeover Provisions in the Organizational Documents.” |  |  |  |  |  |  |  |  |  |
Share Price [Table Text Block] |  | 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 Fund’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 |
12/31/2024 |  |  | $21.98 |  |  |  | $19.62 |  |  |  | $21.11 |  |  |  | $20.13 |  |  |  | 4.12 | % |  |  | (2.53 | )%
9/30/2024 |  |  | $20.23 |  |  |  | $17.76 |  |  |  | $20.26 |  |  |  | $18.39 |  |  |  | (0.15 | )% |  |  | (3.43 | )%
6/30/2024 |  |  | $19.47 |  |  |  | $17.44 |  |  |  | $19.71 |  |  |  | $18.05 |  |  |  | (1.22 | )% |  |  | (3.38 | )%
3/31/2024 |  |  | $18.88 |  |  |  | $16.05 |  |  |  | $18.77 |  |  |  | $16.85 |  |  |  | 0.59 | % |  |  | (4.75 | )%
12/31/2023 |  |  | $16.58 |  |  |  | $14.39 |  |  |  | $17.13 |  |  |  | $15.22 |  |  |  | (3.21 | )% |  |  | (5.45 | )%
9/30/2023 |  |  | $16.86 |  |  |  | $15.82 |  |  |  | $16.74 |  |  |  | $15.80 |  |  |  | 0.72 | % |  |  | 0.13 | %
6/30/2023 |  |  | $16.49 |  |  |  | $15.06 |  |  |  | $16.56 |  |  |  | $15.51 |  |  |  | (0.42 | )% |  |  | (2.90 | )%
3/31/2023 |  |  | $16.71 |  |  |  | $14.70 |  |  |  | $15.87 |  |  |  | $14.79 |  |  |  | 5.29 | % |  |  | (0.61 | )%
12/31/2022 |  |  | $16.89 |  |  |  | $14.36 |  |  |  | $15.85 |  |  |  | $14.46 |  |  |  | 6.56 | % |  |  | (0.69 | )%
Lowest Price or Bid |  |  |  | $ 19.62 | $ 17.76 | $ 17.44 | $ 16.05 | $ 14.39 | $ 15.82 | $ 15.06 | $ 14.7 | $ 14.36
Highest Price or Bid |  |  |  | 21.98 | 20.23 | 19.47 | 18.88 | 16.58 | 16.86 | 16.49 | 16.71 | 16.89
Lowest Price or Bid, NAV |  |  |  | 20.13 | 18.39 | 18.05 | 16.85 | 15.22 | 15.8 | 15.51 | 14.79 | 14.46
Highest Price or Bid, NAV |  |  |  | $ 21.11 | $ 20.26 | $ 19.71 | $ 18.77 | $ 17.13 | $ 16.74 | $ 16.56 | $ 15.87 | $ 15.85
Highest Price or Bid, Premium (Discount) to NAV [Percent] |  |  |  | 4.12% | (0.15%) | (1.22%) | 0.59% | (3.21%) | 0.72% | (0.42%) | 5.29% | 6.56%
Lowest Price or Bid, Premium (Discount) to NAV [Percent] |  |  |  | (2.53%) | (3.43%) | (3.38%) | (4.75%) | (5.45%) | 0.13% | (2.90%) | (0.61%) | (0.69%)
Share Price |  |  | $ 20.34 |  |  |  |  |  |  |  |  |
NAV Per Share |  |  | $ 20.13 |  |  |  |  |  |  |  |  |
Latest Premium (Discount) to NAV [Percent] |  |  | 1.04% |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock [Table Text Block] |  | Description of Capital Structure The Fund is an unincorporated business trust established under the laws of the Commonwealth of Massachusetts by the Declaration of Trust dated and filed with the Secretary of the Commonwealth on August 10, 2004. 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 Fund 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 Fund to issue an unlimited number of full and fractional Common Shares. Each Common Share represents an equal proportionate interest in the assets of the Fund with each other Common Share in the Fund. 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 Fund 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 Fund 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 Fund, after paying or adequately providing for the payment of all liabilities of the Fund and the liquidation preference with respect to any outstanding preferred shares, and upon receipt of such releases, indemnities and refunding agreements as they deem necessary for their protection, the Board may distribute the remaining assets of the Fund among the Common Shareholders. The Declaration of Trust provides that Common Shareholders are not liable for any liabilities of the Fund and permits inclusion of a clause to that effect in every agreement entered into by the Fund and, in coordination with the Fund’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 Fund’s Organizational Documents described in the foregoing sentence make the likelihood of such personal liability remote. If there are any borrowings or preferred shares outstanding, the Fund may not be permitted to declare any cash distribution on its Common Shares, unless at the time of such declaration, (i) all accrued distributions on preferred shares or accrued interest on borrowings have been paid and (ii) the value of the Fund’s total assets (determined after deducting the amount of such distribution), less all liabilities and indebtedness of the Fund 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. In addition to the requirements of the 1940 Act, the Fund may be required to comply with other asset coverage requirements as a condition of the Fund obtaining a rating of preferred shares from a nationally recognized statistical rating agency (a “Rating Agency”). These requirements may include an asset coverage test more stringent than under the 1940 Act. This limitation on the Fund’s ability to make distributions on its Common Shares could in certain circumstances impair the ability of the Fund to maintain its qualification for taxation as a RIC for U.S. federal income tax purposes. If the Fund were in the future to issue preferred shares or borrow money, it would intend, 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 distributions to the holders of the preferred shares in certain circumstances in connection with any potential impairment of the Fund’s status as a RIC. See “U.S. Federal Income Tax Matters.” Depending on the timing of any such redemption or repayment, the Fund may be required to pay a premium in addition to the liquidation preference of the preferred shares to the holders thereof. The Fund 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 Fund generally will not issue Common Share certificates. However, upon written request to the Fund’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. REPURCHASE OF COMMON SHARES AND OTHER DISCOUNT MEASURES Because shares of closed-end management investment companies frequently trade at a discount to their net asset values, the Board has determined that from time-to-time it may be in the interest of Common Shareholders for the Fund to take corrective actions to reduce trading discounts in the Common Shares. 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 net asset value of the Common Shares, the liquidity of the assets of the Fund, the effect on the Fund’s expenses, whether such transactions would impair the Fund’s status as a RIC or result in a failure to comply with applicable asset coverage requirements, general economic conditions and such other events or conditions that may have a material effect on the Fund’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 Common Shares trading at a price equal to or approximating their net asset value. In recognition of the possibility that the Common Shares might trade at a discount to net asset value 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. The Board of Trustees initially approved a share repurchase program for the Fund on August 6, 2012. Pursuant to the reauthorization of the share repurchase program by the Board of Trustees in March 2019, the Fund 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 Fund to purchase a specific amount of shares. Results of the share repurchase program are disclosed in the Fund’s annual and semiannual reports to shareholders. PREFERRED SHARES The Fund has no current intention of issuing any shares other than the Common Shares. However, the Declaration of Trust authorizes the issuance of an unlimited number of shares of beneficial interest with preference rights (the “preferred shares”) in one or more series, with rights as determined by the Board, by action of the Board without the approval of the Common Shareholders. Under the requirements of the 1940 Act, the Fund 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 Fund, less all liabilities 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 Fund, if any, plus the aggregate liquidation preference of the preferred shares. If the Fund seeks a rating for preferred shares, asset coverage requirements in addition to those set forth in the 1940 Act may be imposed. The liquidation value of any preferred shares would be expected to equal their aggregate original purchase price plus 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 any preferred shares, including their distribution rate, voting rights, liquidation preference and redemption provisions, will be determined by the Board (subject to applicable law and the Fund’s Declaration of Trust) if and when it authorizes preferred shares. The Fund 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 Fund to lengthen such intervals. At times, the distribution rate on any preferred shares may exceed the Fund’s return after expenses on the investment of proceeds from the preferred shares and the Fund’s leverage structure, resulting in a lower rate of return to Common Shareholders than if the Fund were not so structured. In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Fund, the terms of any preferred shares may entitle the holders of preferred shares to receive a preferential liquidating distribution (expected to equal the original purchase price per share plus redemption premium, if any, together with accrued and unpaid dividends, whether or not earned or declared and on a cumulative basis) before any distribution of assets is made to Common Shareholders. 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 Fund. Holders of preferred shares, voting as a class, would be entitled to elect two of the Fund’s Trustees if any preferred shares are issued. 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 Fund. Under the 1940 Act, if at any time dividends on the preferred shares are unpaid in an amount equal to two full years’ dividends thereon, the holders of all outstanding preferred shares, voting as a class, will be allowed to elect a majority of the Board until all distributions in arrears have been paid or declared and set apart for payment. In addition, if required by a Rating Agency rating the preferred shares or if the Board determines it to be in the best interests of the Common Shareholders, issuance of the preferred shares may result in more restrictive provisions than required under the 1940 Act. In this regard, holders of preferred shares may be entitled to elect a majority of the 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 Fund. All such actions must be consistent with (i) the obligations of the Fund with respect to the holders of preferred shares (which obligations arise primarily from the contractual terms of the preferred shares, as specified in the Declaration of Trust and By-laws of the Fund) and (ii) the fiduciary duties owed to the Fund, which include the duties of loyalty and care. In the event of any future issuance of preferred shares, the Fund likely would seek a credit rating for such preferred shares from a Rating Agency. In such event, as long as preferred shares are outstanding, the composition of its portfolio will reflect guidelines established by such Rating Agency. Based on previous guidelines established by Rating Agencies for the securities of other issuers, the Fund anticipates that the guidelines with respect to any preferred shares would establish a set of tests for portfolio composition and asset coverage that supplement (and in some cases are more restrictive than) the applicable requirements under the 1940 Act. Although no assurance can be given as to the nature or extent of the guidelines that may be imposed in connection with obtaining a rating of any preferred shares, the Fund anticipates that such guidelines would include asset coverage requirements that are more restrictive than those under the 1940 Act, restrictions on certain portfolio investments and investment practices and certain mandatory redemption requirements relating to any preferred shares. No assurance can be given that the guidelines actually imposed with respect to any preferred shares by a Rating Agency would be more or less restrictive than those described in this Prospectus. |  |  |  |  |  |  |  |  |  |
Outstanding Securities [Table Text Block] |  | The following table provides information about our outstanding Common Shares as of January 13, 2025:
Title of Class |  | Amount Authorized |  | Amount Held by the Fund for its Account |  | Amount Outstanding
Common Shares |  | Unlimited |  | 0 |  | 40,775,628
Investment and Market Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Investment and Market Risk . An investment in Common Shares is subject to investment risk, including the possible loss of the entire principal amount invested. An investment in Common Shares represents an indirect investment in the securities owned by the Fund, which are generally traded on a securities exchange or in the over-the-counter markets. The value of these securities, like other market investments, may move up or down, sometimes rapidly and unpredictably. In addition, by writing (selling) call options on the equity securities held in the Fund’s portfolio, the capital appreciation potential of such securities will be limited to the difference between the exercise price of the call options written and the purchase price of the equity security underlying such options. The Common Shares at any point in time may be worth less than the original investment, even after taking into account any reinvestment of distributions. The value of investments held by the Fund may increase or decrease in response to economic, political and financial or other disruptive events (whether real, expected or perceived) in the U.S. and global markets. The frequency and magnitude of such changes in value cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Actions taken by the U.S. Federal Reserve or foreign central banks to stimulate or stabilize economic growth, such as decreases or increases in short-term interest rates, could cause high volatility in markets. 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 high market volatility. No active trading market may exist for certain investments held by the Fund, which may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets. |  |  |  |  |  |  |  |  |  |
Issuer Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Issuer Risk . The value of securities held by the Fund may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer’s goods and services. |  |  |  |  |  |  |  |  |  |
Equity Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Equity Risk . At least 80% of the Fund’s total assets are invested in common stocks and therefore a principal risk of investing in the Fund is equity risk. Equity risk is the risk that securities held by the Fund 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. Although common stocks have historically generated higher average returns than fixed-income securities over the long term, common stocks also have experienced significantly more volatility in returns. An adverse event, such as an unfavorable earnings report, may depress the value of equity securities of an issuer held by the Fund; the price of common stock of an issuer may be particularly sensitive to general movements in the stock market; or a drop in the stock market may depress the price of most or all of the common stocks and other equity securities held by the Fund. In addition, common stock of an issuer in the Fund’s portfolio may decline in price if the issuer fails to make anticipated dividend payments because, among other reasons, the issuer of the security experiences a decline in its financial condition. Common equity securities in which the Fund will invest are structurally subordinated to preferred stocks, bonds and other debt instruments in a company’s capital structure, in terms of priority to corporate income, and therefore will be subject to greater dividend risk than preferred stocks or debt instruments of such issuers. Finally, common stock prices may be sensitive to rising interest rates, as the costs of capital rise and borrowing costs increase. Market conditions may affect certain types of stocks to a greater extent than other types of stocks. If the stock market declines, the value of Fund shares will also likely decline. Although stock prices can rebound, there is no assurance that values will return to previous levels. |  |  |  |  |  |  |  |  |  |
Risks of Investing in Smaller and Mid Sized Companies [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Risks of Investing in Smaller and Mid-Sized Companies . The Fund may make investments in stocks of companies whose market capitalization is considered middle sized or “mid-cap.” Smaller and mid-sized companies often are newer or less established companies than larger companies. Investments in smaller and mid-sized companies carry additional risks because earnings of these companies tend to be less predictable; they often have limited product lines, markets, distribution channels or financial resources; and the management of such companies may be dependent upon one or a few key people. The market movements of equity securities of smaller and mid-sized companies may be more abrupt or erratic than the market movements of equity securities of larger, more established companies or the stock market in general. Historically, smaller and mid-sized companies have sometimes gone through extended periods when they did not perform as well as larger companies. In addition, equity securities of smaller and mid-sized companies generally are less liquid than those of larger companies. This means that the Fund could have greater difficulty selling such securities at the time and price that the Fund would like. |  |  |  |  |  |  |  |  |  |
Risks of Growth Stock Investing [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Risks of Growth Stock Investing . The Fund invests substantially in stocks with ‘‘growth’’ characteristics. Growth stocks can react differently to issuer, political, market, and economic developments than the market as a whole and other types of stocks. Growth stocks tend to be more expensive relative to their earnings or assets compared to other types of stocks. As a result, growth stocks tend to be sensitive to changes in their earnings and more volatile than other types of stocks. |  |  |  |  |  |  |  |  |  |
Foreign Investment Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Foreign Investment Risk . The value of foreign securities is affected by changes in currency rates, foreign tax laws (including withholding or other tax), government policies (in the U.S. or abroad), relations between nations and trading, settlement, custodial and other operational risks. In addition, the costs of investing abroad are generally higher than in the United States, and foreign securities markets may be less liquid, more volatile and less subject to governmental supervision than markets in the United States. Foreign investments also could be affected by other 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. As an alternative to holding foreign-traded securities, the Fund may invest in U.S. dollar-denominated securities of foreign companies that trade on U.S. exchanges or in the U.S. over-the-counter market (including depositary receipts, which evidence ownership in underlying foreign securities). Since the Fund may invest in securities denominated or quoted in currencies other than the U.S. dollar, 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 or other tax), governmental administration of economic or monetary policies (in the U.S. 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. Because foreign companies are not subject to uniform accounting, auditing and financial reporting standards, practices and requirements comparable to those applicable to U.S. companies, there may be less publicly available information about a foreign company than about a domestic company. Volume and liquidity in most foreign debt markets are less than in the United States and securities of some foreign companies are less liquid and more volatile than securities of comparable U.S. companies. There is generally less government supervision and regulation of securities exchanges, broker-dealers and listed companies than in the United States. Mail service between the United States and foreign countries may be slower or less reliable than within the United States, thus increasing the risk of delayed settlements of portfolio transactions for, or loss of certificates of, portfolio securities. Payment for securities before delivery may be required. In addition, with respect to certain foreign countries, there is the possibility of expropriation or confiscatory taxation, political or social instability, or diplomatic developments, which could affect investments in those countries. Moreover, individual foreign economies may differ favorably or unfavorably from the U.S. economy in such respects as growth of gross national product, rate of inflation, capital reinvestment, resource self-sufficiency and balance of payments position. Foreign securities markets, while growing in volume and sophistication, are generally not as developed as those in the United States, and securities of some foreign issuers (particularly those located in developing countries) may be less liquid and more volatile than securities of comparable U.S. companies. 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 regarding the economic relationship between the UK and the EU. Market uncertainty remains 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. If one or more additional countries leave the EU or the EU dissolves, the world’s securities markets likely will be significantly disrupted. |  |  |  |  |  |  |  |  |  |
Emerging Markets Investment Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Emerging Markets Investment Risk. Investment markets within emerging market countries are typically smaller, less liquid, less developed and more volatile than those in more developed markets like the United States, and may be focused in certain sectors. Emerging market securities often involve greater risks than developed market securities. The information available about an emerging market issuer may be less reliable than for comparable issuers in more developed capital markets. |  |  |  |  |  |  |  |  |  |
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. |  |  |  |  |  |  |  |  |  |
Sector Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Sector Risk . The Fund may invest a significant portion of its assets in securities of issuers in any single industry or sector of the economy (a broad based economic segment that may include many distinct industries) if companies in that industry or sector meet the Fund’s investment criteria. If the Fund is focused in an industry or sector, it may present more risks than if it were broadly diversified over numerous industries or sectors of the economy. This may make the Fund more susceptible to adverse economic, political, or regulatory occurrences affecting these sectors. As the percentage of the Fund’s assets invested in a particular sector increases, so does the potential for fluctuation in the net asset value of Common Shares. The Fund may not invest 25% or more of its total assets in the securities of issuers in any single industry or group of industries. |  |  |  |  |  |  |  |  |  |
Derivatives Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Derivatives Risk . In addition to writing call options, the risks of which are described above, the Fund may invest up to 20% of its total assets in other derivative investments acquired for hedging, risk management and investment purposes. Derivative transactions including options on securities and securities indices and other transactions in which the Fund may engage (such as futures contracts and options thereon, swaps and short sales) may subject the Fund to increased risk of principal loss due to unexpected movements in stock prices, changes in stock volatility levels and interest rates, and imperfect correlations between the Fund’s securities holdings and indices upon which derivative transactions are based. The Fund also will be subject to credit risk with respect to the counterparties to any over-the-counter derivatives contracts purchased by the Fund. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery under the derivative contract in a bankruptcy or other reorganization proceeding. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances. 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, such regulations require many derivatives to be margined and/or cleared and traded on an exchange, expand entity registration requirements, impose business conduct requirements on counterparties, and impose other regulatory requirements that impact derivatives markets. The SEC adopted Rule 18f 4 under the 1940 Act, which applies to the Fund’s use of derivative investments and certain financing transactions. Among other things, Rule 18f 4 requires certain funds that invest in derivative instruments beyond a specified limited amount (generally greater than 10% of the Fund’s net assets) to apply a value-at-risk based limit to their use of certain derivative instruments and financing transactions and to adopt and implement a derivatives risk management program. To the extent the Fund uses derivative instruments (excluding certain currency and interest rate hedging transactions) in a limited amount (generally up to 10% of the Fund’s net assets), it will not be subject to the full requirements of Rule 18f 4. In addition, to the extent that the Fund enters into reverse repurchase agreements or similar financing transactions, the Fund may elect to either treat all of its reverse repurchase agreements or similar financing transactions as derivatives transactions for purposes of Rule 18f 4 or comply (with respect to reverse repurchase agreements or similar financing transactions) with the asset coverage requirements under Section 18 of the 1940 Act. The implementation of these requirements or 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 Fund engages in derivative transactions. The Adviser cannot predict the effects of any these regulations or any new governmental regulations that may be implemented, and there can be no assurance that any such government regulations will not adversely affect the Fund’s performance or ability to achieve its investment objectives. |  |  |  |  |  |  |  |  |  |
Liquidity Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Liquidity Risk . The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund 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 Fund’s performance. These effects may be exacerbated during times of financial or political stress. The financial markets in general have in recent years experienced periods of extreme secondary market supply and demand imbalance, resulting in a loss of liquidity during which market prices were suddenly and substantially below traditional measures of intrinsic value. During such periods, some securities could be sold only at arbitrary prices and with substantial losses. Periods of such market dislocation may occur again at any time. |  |  |  |  |  |  |  |  |  |
Inflation Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Inflation Risk . Inflation risk is the risk that the purchasing power 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. |  |  |  |  |  |  |  |  |  |
Market Discount Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Market Discount Risk . The shares of closed-end management investment companies often trade at a discount from their net asset value, and the Fund’s Common Shares may likewise trade at a discount from net asset value. The trading price of the Fund’s Common Shares may be less than the public offering price. The returns earned by Common Shareholders who purchased their Common Shares in this offering and sell their Common Shares below net asset value will be reduced. |  |  |  |  |  |  |  |  |  |
Risks Associated with Active Management [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions and there is no guarantee that such decisions will produce the desired results or expected returns. |  |  |  |  |  |  |  |  |  |
Recent Market Conditions [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Recent Market Conditions. Both U.S. and international markets have experienced significant volatility in recent months and years. As a result of such volatility, investment returns may fluctuate significantly. National economies are substantially interconnected, as are global financial markets, which creates the possibility that conditions in one country or region might adversely impact issuers in a different country or region. However, the interconnectedness of economies and/or markets may be diminishing, which may impact such economies and markets in ways that cannot be foreseen at this time. The U.S. government and the U.S. Federal Reserve, as well as certain foreign governments and central banks, have from time to time taken steps to support financial markets. The U.S. government and the U.S. Federal Reserve may, conversely, reduce market support activities, including by taking action intended to increase certain interest rates. This and other government intervention may not work as intended, particularly if the efforts are perceived by investors as being unlikely to achieve the desired results. Changes in government activities in this regard, such as changes in interest rate policy, can negatively affect financial markets generally, increase market volatility and reduce the value and liquidity of securities in which the Fund invests. Some countries, including the United States, have adopted more protectionist trade policies. Slowing global economic growth, the rise in protectionist trade policies, changes to some major international trade agreements, risks associated with the trade agreement between the UK and EU, and the risks associated with trade negotiations between the United States and China, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, the current strength of the U.S. dollar may decrease foreign demand for U.S. assets, which could have a negative impact on certain issuers and/or industries. Regulators in the United States have proposed and adopted a number of changes to regulations involving the markets and issuers, some of which apply to the Fund. The full effect of various newly adopted regulations is not currently known. Additionally, it is not currently known whether any of the proposed regulations will be adopted. However, due to the scope of regulations being proposed and adopted, certain of these changes to regulation could limit the Fund’s ability to pursue its investment strategies or make certain investments, may make it more costly for it to operate, or adversely impact performance. Tensions, war, or open conflict between nations, such as between Russia and Ukraine, in the Middle East, or in eastern Asia could affect the economies of many nations, including the United States. The duration of ongoing hostilities and any sanctions and related events cannot be predicted. Those events present material uncertainty and risk with respect to markets globally and the performance of the Fund and its investments or operations could be negatively impacted. There is widespread concern about the potential effects of global climate change on property and security values. Certain issuers, industries and regions may be adversely affected by the impact of climate change in ways that cannot be foreseen. The impact of legislation, regulation and international accords related to climate change may negatively impact certain issuers and/or industries. |  |  |  |  |  |  |  |  |  |
Cybersecurity Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Cybersecurity Risk. With the increased use of technologies by Fund service providers to conduct business, such as the Internet, the Fund is susceptible to operational, information security and related risks. The Fund relies on communications technology, systems, and networks to engage with clients, employees, accounts, shareholders, and service providers, and a cyber incident may inhibit the Fund’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. 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 Fund, such as trading and NAV calculation, 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 Fund’s ability to plan for or respond to a cyber attack. Similar types of cybersecurity risks also are present for issuers of securities in which the Fund invests, which could have material adverse consequences for those issuers and result in a decline in the market price of their securities. Furthermore, as a result of cyber attacks, technological disruptions, malfunctions or failures, an exchange or market may close or suspend trading in specific securities or the entire market, which could prevent the Fund from, among other things, buying or selling the Fund or accurately pricing its securities. Like other funds and business enterprises, the Fund 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 Fund or its service providers. The Fund uses third party service providers who are also heavily dependent on computers and technology for their operations. Cybersecurity failures by or breaches of the Fund’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 Fund invests, may disrupt and otherwise adversely affect their business operations. This may result in financial losses to the Fund, impede Fund trading, interfere with the Fund’s ability to calculate its NAV, limit a shareholder’s ability to purchase or redeem shares of the Fund 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 Fund’s 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 Fund cannot control the cybersecurity plans and systems put in place by service providers to the Fund and issuers in which the Fund invests. The Fund and its shareholders could be negatively impacted as a result. |  |  |  |  |  |  |  |  |  |
Anti Takeover Provisions [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Anti-Takeover Provisions . The Fund’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 making it more difficult to acquire control of the Fund or to change the composition of its Board. See “Description of Capital Structure—Certain Provisions of the Organizational Documents—Anti-Takeover Provisions in the Organizational Documents.” |  |  |  |  |  |  |  |  |  |
General Fund Investing Risks [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objectives. It is possible to lose money by investing in the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. |  |  |  |  |  |  |  |  |  |
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 Fund are trading at a price equal to or above the Fund’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 Fund’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 Fund’s NAV may decrease. |  |  |  |  |  |  |  |  |  |
Risks Associated with Options on Securities [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Risks Associated with Options on Securities . There are numerous risks associated with transactions in options on securities. A decision as to whether, when and how to use options involves the exercise of skill and judgment, and even a well-conceived transaction may be unsuccessful to some degree because of market behavior or unexpected events. As the writer of a call option, the Fund forgoes, during the option’s life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the option premium received and the exercise price of the call, but has retained the risk of loss, minus the option premium received, should the price of the underlying security decline. The writer of an option has no control over when during the exercise period of the option it may be required to fulfill its obligation as a writer of the option. Once an option writer has received an exercise notice, it cannot effect a closing purchase transaction in order to terminate its obligation under the option and must deliver the underlying security at the exercise price. Thus, the use of options may require the Fund to sell portfolio securities at inopportune times or for prices other than current market values, will limit the amount of appreciation the Fund can realize on an investment, or may cause the Fund to hold a security that it might otherwise sell. The value of options may also be adversely affected if the market for such options becomes less liquid or smaller. There can be no assurance that a liquid market will exist when the Fund seeks to close out an option position either, in the case of a call option written, by buying the option, or, in the case of a purchased put option, by selling the option. Reasons for the absence of a liquid secondary market on an exchange include the following: (i) there may be insufficient trading interest in certain options; (ii) restrictions may be imposed by an exchange on opening transactions or closing transactions or both; (iii) trading halts, suspensions or other restrictions may be imposed with respect to particular classes or series of options; (iv) unusual or unforeseen circumstances may interrupt normal operations on an exchange; (v) the facilities of an exchange or the Options Clearing Corporation (the ‘‘OCC’’) may not at all times be adequate to handle current trading volume; or (vi) one or more exchanges could, for economic or other reasons, decide or be compelled to discontinue the trading of options (or a particular class or series of options) at some future date. If trading were discontinued, the secondary market on that exchange (or in that class or series of options) would cease to exist. However, outstanding options on that exchange that had been issued by the OCC as a result of trades on that exchange would continue to be exercisable in accordance with their terms. The Fund’s ability to terminate over-the-counter options will be more limited than with exchange-traded options and may involve the risk that broker-dealers participating in such transactions will not fulfill their obligations. If the Fund were unable to close out a covered call option that it had written on a security, it would not be able to sell the underlying security unless the option expired without exercise. The hours of trading for options may not conform to the hours during which the underlying securities are traded. To the extent that the options markets close before the markets for the underlying securities, significant price and rate movements can take place in the underlying markets that would not be reflected concurrently in the options markets. Call options are marked to market daily and their value will be affected by changes in the value of and dividend rates of the underlying common stocks, changes in interest rates, changes in the actual or perceived volatility of the stock market and the underlying common stocks and the remaining time to the options’ expiration. Additionally, the exercise price of an option may be adjusted downward before the option’s expiration as a result of the occurrence of certain corporate events affecting the underlying equity security, such as extraordinary dividends, stock splits, merger or other extraordinary distributions or events. A reduction in the exercise price of an option would reduce the Fund’s capital appreciation potential on the underlying security. The number of call options the Fund can write is limited by the number of shares of common stock the Fund holds, and further limited by the fact that listed call options on individual common stocks generally trade in units representing 100 shares of the underlying stock. Furthermore, the Fund’s options transactions will be subject to limitations established by each of the exchanges, boards of trade or other trading facilities on which such options are traded. These limitations govern the maximum number of options in each class which may be written or purchased by a single investor or group of investors acting in concert, regardless of whether the options are written or purchased on the same or different exchanges, boards of trade or other trading facilities or are held or written in one or more accounts or through one or more brokers. Thus, the number of options which the Fund may write or purchase may be affected by options written or purchased by other investment advisory clients of the Adviser. An exchange, board of trade or other trading facility may order the liquidation of positions found to be in excess of these limits, and may impose certain other sanctions. The Fund will not write ‘‘naked’’ or uncovered call options. If the Fund purchases put options for hedging or risk management purposes, the Fund will be subject to the following additional risks. A put option acquired by the Fund and not sold prior to expiration will expire worthless if the price of the stock or index at expiration exceeds the exercise price of the option, thereby causing the Fund to lose its entire investment in the option. If restrictions on exercise were imposed, the Fund might be unable to exercise an option it had purchased. If the Fund were unable to close out an option that it had purchased, it would have to exercise the option in order to realize any profit or the option may expire worthless. Stock market indices on which the Fund may purchase options positions likely will not mirror the Fund’s actual portfolio holdings. The effectiveness of index put options as hedges against declines in the Fund’s stock portfolio will be limited to the extent that the performance of the underlying index does not correlate with that of the Fund’s holdings. See also “Derivatives Risk” below. |  |  |  |  |  |  |  |  |  |
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 Fund’s outstanding Common Shares resulting from the Offering may put downward pressure on the market price for the Common Shares of the Fund. 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 Fund’s NAV per Common Share plus the per Common Share amount of commissions. The Fund also issues Common Shares of the Fund 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 Fund. When the Common Shares are trading at a premium, the Fund may also issue Common Shares of the Fund that are sold through transactions effected on the NYSE. The increase in the amount of the Fund’s outstanding Common Shares resulting from that offering may also put downward pressure on the market price for the Common Shares of the Fund. 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 Fund’s per share distribution may decrease (or may consist of return of capital) and the Fund may not participate in market advances to the same extent as if such proceeds were fully invested as planned. |  |  |  |  |  |  |  |  |  |
Benchmark Reference Rates Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Benchmark Reference Rates Risk. Many debt securities, derivatives, and other financial instruments utilize benchmark or reference rates for variable interest rate calculations, including the Euro Interbank Offer Rate, Sterling Overnight Index Average Rate, and the Secured Overnight Financing Rate (each a “Reference Rate”). Instruments in which the Fund invests may pay interest at floating rates based on such Reference Rates or may be subject to interest caps or floors based on such Reference Rates. The Fund and issuers of instruments in which the Fund invests may also obtain financing at floating rates based on such Reference Rates. The elimination of a Reference Rate or any other changes to or reforms of the determination or supervision of Reference Rates could have an adverse impact on the market for, or value of, any instruments or payments linked to those Reference Rates. For example, some Reference Rates, as well as other types of rates and indices, are described as “benchmarks” and have been the subject of ongoing national and international regulatory reform, including under the European Union regulation on indices used as benchmarks in financial instruments and financial contracts. As a result, the manner of administration of benchmarks has changed and may further change in the future, with the result that relevant benchmarks may perform differently than in the past, the use of benchmarks that are not compliant with the new standards by certain supervised entities may be restricted, and certain benchmarks may be eliminated entirely. Such changes could cause increased market volatility and disruptions in liquidity for instruments that rely on or are impacted by such benchmarks. Additionally, there could be other consequences which cannot be predicted . |  |  |  |  |  |  |  |  |  |
Financial Leverage Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Financial Leverage Risk . Although the Fund has no current intention to do so, the Fund is authorized to utilize leverage through the issuance of preferred shares and/or borrowings, including the issuance of debt securities. In the event that the Fund determines in the future to utilize investment leverage, there can be no assurance that such a leveraging strategy will be successful during any period in which it is employed. Leverage creates risks for Common Shareholders, including the likelihood of greater volatility of net asset value and market price of the Common Shares and the risk that fluctuations in distribution rates on any preferred shares or fluctuations in borrowing costs may affect the return to Common Shareholders. To the extent the income derived from securities purchased with proceeds received from leverage exceeds the cost of leverage, the Fund’s distributions will be greater than if leverage had not been used. Conversely, if the income from the securities purchased with such proceeds 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 Fund’s leveraged position if it deems such action to be appropriate. The costs of an offering of preferred shares and/or a borrowing program would be borne by Common Shareholders and consequently would result in a reduction of the net asset value of Common Shares. In addition, the fee paid to Eaton Vance will be calculated on the basis of the Fund’s average daily gross assets, including proceeds from the issuance of preferred shares and/or borrowings, so the fees will be higher when leverage is utilized. In this regard, holders of preferred shares 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 of the preferred shares offering. |  |  |  |  |  |  |  |  |  |
Management Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Management Risk . The Fund is subject to management risk because it is actively managed. Eaton Vance and the individual portfolio managers invest the assets of the Fund as they deem appropriate in implementing the Fund’s investment strategy. Accordingly, the success of the Fund 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 Fund’s investment objective. There is no assurance that Eaton Vance and the individual portfolio managers will be successful in developing and implementing the Fund’s investment strategy. Subjective decisions made by Eaton Vance and the individual portfolio managers may cause the Fund to incur losses or to miss profit opportunities. |  |  |  |  |  |  |  |  |  |
Focused Investment Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Focused Investment Risk. To the extent the Fund has substantial investments in a relatively small number of securities or issuers, or a particular market, industry, group of industries, currency, country, region, group of countries, asset class, or sector, the Fund’s net asset value may be more volatile and the Fund will be subject to greater risk than a fund that invests in a more diverse investment portfolio. Similarly, to the extent the Fund holds investments with closely correlated market prices, it will be subject to greater risk than a fund with investments that are not as closely correlated. Changes in the value of a single security or issuer or the impact of a single economic, political, or regulatory occurrence may have a greater adverse impact on the Fund’s net asset value. A fund that invests in the securities of a small number of issuers has greater exposure to adverse developments affecting those issuers and a resulting decline in the market price of those issuers’ securities as compared to a fund that invests in the securities of a larger number of issuers. Companies that share common characteristics are often subject to similar business risks and regulatory burdens and often react similarly to specific economic, market, political or other developments. Similarly, funds having a significant portion of their assets in investments tied economically to a particular geographic region, country, or market (e.g., emerging markets) or to sectors within a region, country, or market have more exposure to regional and country economic risks than do funds whose investments are more geographically diverse. The political and economic prospects of one country or group of countries within the same geographic region may affect other countries in that region, and a recession, debt crisis or decline in the value of the currency of one country can spread to other countries. Furthermore, companies in a particular geographic region or country are vulnerable to events affecting other companies in that region or country because they often share common characteristics, are exposed to similar business risks and regulatory burdens, and react similarly to specific economic, market, political, or other developments. |  |  |  |  |  |  |  |  |  |
Information Technology Sector Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Information Technology Sector Risk. If the Fund concentrates investments in the information technology sector, the value of Fund shares may be particularly impacted by events that adversely affect the information technology sector, such as rapid changes in technology product cycles, competition for the services of qualified personnel and government regulation. The products of information technology companies may face product obsolescence due to rapid technological developments and frequent new product introduction and unpredictable changes in growth rates. Companies in the information technology sector also can be heavily dependent on patent protection and the expiration of patents may adversely affect the profitability of these companies. As a result, the value of shares may fluctuate more than that of a fund that does not concentrate in companies in the technology sector. |  |  |  |  |  |  |  |  |  |
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 continue to 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 Fund 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. |  |  |  |  |  |  |  |  |  |
Financials Sector Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Financials Sector Risk. To the extent the Fund invests a substantial portion of its assets in the financials sector, factors that have an adverse impact on this sector may have a disproportionate impact on the Fund’s performance. The financials sector can be affected by global and local economic conditions, such as the levels and liquidity of the global and local financial and asset markets, the absolute and relative level and volatility of interest rates and equity prices, investor sentiment, inflation, and the availability and cost of credit. Companies in the financials sector may be subject to extensive government regulations that affect the scope of their activities, the prices they can charge for products and services, and the amount of capital they must maintain. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operations and profitability of the financials sector. Global economies and financial markets are becoming increasingly. |  |  |  |  |  |  |  |  |  |
Interest Rate Risk [Member] |  |  |  |  |  |  |  |  |  |  |  |
General Description of Registrant [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Risk [Text Block] |  | Interest Rate Risk . The level of premiums from call options writing and the amounts available for distribution from the Fund’s options activity may decrease in declining interest rate environments. Any preferred stocks paying fixed dividend rates in which the Fund invests, will likely change in value as market interest rates change. When interest rates rise, the market value of such securities generally will fall. To the extent that the Fund invests in preferred stocks, the net asset value and price of the Common Shares may decline if market interest rates rise. During periods of declining interest rates, an issuer of preferred stock may exercise its option to redeem securities prior to maturity, forcing the Fund to reinvest in lower yielding securities. This is known as call risk. During periods of rising interest rates, the average life of certain types of securities may be extended because of slower than expected payments. This may lock in a below market yield, increase the security’s duration, and reduce the value of the security. This is known as extension risk. The value of the Fund’s common stock investments may also be influenced by changes in interest rates. |  |  |  |  |  |  |  |  |  |
Business Contact [Member] |  |  |  |  |  |  |  |  |  |  |  |
Cover [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Entity Address, Address Line One |  | One Post Office Square |  |  |  |  |  |  |  |  |  |
Entity Address, City or Town |  | Boston |  |  |  |  |  |  |  |  |  |
Entity Address, State or Province |  | MA |  |  |  |  |  |  |  |  |  |
Entity Address, Postal Zip Code |  | 02109 |  |  |  |  |  |  |  |  |  |
Contact Personnel Name |  | Deidre E. Walsh |  |  |  |  |  |  |  |  |  |
Common Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |
Other Annual Expenses [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Basis of Transaction Fees, Note [Text Block] |  | Percentage of net assets attributable to Common Shares |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Security Title [Text Block] |  | COMMON SHARES |  |  |  |  |  |  |  |  |  |
Security Preemptive and Other Rights [Text Block] |  | The Common Shares have no preemptive rights. |  |  |  |  |  |  |  |  |  |
Outstanding Security, Title [Text Block] |  |  | Common Shares |  |  |  |  |  |  |  |  |
Outstanding Security, Held [Shares] |  |  | 0 |  |  |  |  |  |  |  |  |
Outstanding Security, Not Held [Shares] |  |  | 40,775,628 |  |  |  |  |  |  |  |  |
Preferred Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Security Title [Text Block] |  | PREFERRED SHARES |  |  |  |  |  |  |  |  |  |
Security Voting Rights [Text Block] |  | Holders of preferred shares, voting as a class, would be entitled to elect two of the Fund’s Trustees if any preferred shares are issued. 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 Fund. |  |  |  |  |  |  |  |  |  |
Security Liquidation Rights [Text Block] |  | In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Fund, the terms of any preferred shares may entitle the holders of preferred shares to receive a preferential liquidating distribution (expected to equal the original purchase price per share plus redemption premium, if any, together with accrued and unpaid dividends, whether or not earned or declared and on a cumulative basis) before any distribution of assets is made to Common Shareholders. |  |  |  |  |  |  |  |  |  |
Security Obligations of Ownership [Text Block] |  | the obligations of the Fund with respect to the holders of preferred shares (which obligations arise primarily from the contractual terms of the preferred shares, as specified in the Declaration of Trust and By-laws of the Fund) and (ii) the fiduciary duties owed to the Fund, which include the duties of loyalty and care. |  |  |  |  |  |  |  |  |  |
Preferred Stock Restrictions, Other [Text Block] |  | Although no assurance can be given as to the nature or extent of the guidelines that may be imposed in connection with obtaining a rating of any preferred shares, the Fund anticipates that such guidelines would include asset coverage requirements that are more restrictive than those under the 1940 Act, restrictions on certain portfolio investments and investment practices and certain mandatory redemption requirements relating to any preferred shares. |  |  |  |  |  |  |  |  |  |
Rights Subject to Other than Majority Vote [Text Block] |  | Under the 1940 Act, if at any time dividends on the preferred shares are unpaid in an amount equal to two full years’ dividends thereon, the holders of all outstanding preferred shares, voting as a class, will be allowed to elect a majority of the Board until all distributions in arrears have been paid or declared and set apart for payment. |  |  |  |  |  |  |  |  |  |
[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] | Eaton Vance Management (“EVM”) will pay the expenses of the offering (other than the applicable commissions); therefore, offering expenses are not included in the Summary of Fund Expenses. Offering expenses generally include, but are not limited to, the preparation, review and filing with the SEC of the Fund’s registration statement (including its current Prospectus Supplement, the accompanying Prospectus and Statement of Additional Information (“SAI”)), the preparation, review and filing of any associated marketing or similar materials, costs associated with the printing, mailing or other distribution of its current Prospectus Supplement, the accompanying Prospectus, SAI and/or marketing materials, associated filing fees, stock exchange listing fees, and legal and auditing fees associated with the offering.
[4] | Stated as a percentage of average net assets attributable to Common Shares for the year ended September 30, 2024.
[5] | The advisory fee paid by the Fund to EVM is based on the average daily gross assets of the Fund, including all assets attributable to any form of investment leverage that the Fund may utilize. Accordingly, if the Fund were to utilize investment leverage in the future, the investment adviser fees will increase as a percentage of net assets.

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