MMD MainStay MacKay Defined Term Municipal Opportunities Fund

Note 1–Organization and Business

MainStay MacKay DefinedTerm Municipal Opportunities Fund (the “Fund”) was organized as a Delaware statutory trust on April 20, 2011, pursuant to an agreement and declaration of trust, which was amended and restated on June 4, 2015 (“Declaration of Trust”). The Fund is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as a “diversified”, closed-end management investment company, as those terms are defined in the 1940 Act, as interpreted or modified by regulatory authorities having jurisdiction, from time to time. The Fund first offered Common shares through an initial public offering on June 26, 2012.

Pursuant to the terms of the Declaration of Trust, the Fund will commence the process of liquidation and dissolution at the close of business on December 31, 2024 (the “Termination Date”) unless otherwise extended by a majority of the Board of Trustees (the “Board”) (as discussed in further detail below). During the six-month period preceding the Termination Date or Extended Termination Date (as defined below), the Board may, without shareholder approval unless such approval is required by the 1940 Act, determine to (i) merge or consolidate the Fund so long as the surviving or resulting entity is an open-end registered investment company that is managed by the same investment adviser which serves as the investment adviser to the Fund at that time or is an affiliate of such investment adviser; or (ii) convert the Fund from a closed-end fund into an open-end registered investment company. Upon liquidation and termination of the Fund, shareholders will receive an amount equal to the Fund’s net asset value (“NAV”) at that time, which may be greater or less than the price at which Common shares were issued. The Fund’s investment objectives and policies are not designed to return to investors who purchased Common shares in the initial offering of such shares their initial investment on the Termination Date and such initial investors may receive more or less than their original investment upon termination.

Prior to the commencement of the six-month period preceding the Termination Date, a majority of the Board may extend the Termination Date for a period of not more than two years or such shorter time as may be determined (the “Extended Termination Date”), upon a determination that taking such actions as described in (i) or (ii) above would not, given prevailing market conditions, be in the best interests of the Fund’s shareholders. The Termination Date may be extended an unlimited number of times by the Board prior to the first business day of the sixth month before the next occurring Extended Termination Date.

The Fund’s primary investment objective is to seek current income exempt from regular U.S. Federal income taxes (but which may be includable in taxable income for the purpose of the Federal alternative minimum tax). Total return is a secondary objective.

Note 2–Significant Accounting Policies

The Fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (“FASB”) Accounting Standard Codification Topic 946 Financial Services—Investment Companies. The Fund prepares its financial statements in accordance with generally accepted accounting principles (“GAAP”) in the United States of America and follows the significant accounting policies described below.

(A)  Securities Valuation.  Investments are usually valued as of the close of regular trading on the New York Stock Exchange (the “Exchange”) (usually 4:00 p.m. Eastern time) on each day the Fund is open for business (“valuation date”).

The Board adopted procedures establishing methodologies for the valuation of the Fund’s securities and other assets and delegated the responsibility for valuation determinations under those procedures to the Valuation Committee of the Fund (the “Valuation Committee”). The procedures state that, subject to the oversight of the Board and unless otherwise noted, the responsibility for the day-to-day valuation of portfolio assets (including fair value measurements for the Fund’s assets and liabilities) rests with New York Life Investment Management LLC (“New York Life Investments” or the “Manager”), aided to whatever extent necessary by the Subadvisor (as defined in Note 3(A)). To assess the appropriateness of security valuations, the Manager, the Subadvisor or the Fund’s third-party service provider, who is subject to oversight by the Manager, regularly compares prior day prices, prices on comparable securities and the sale prices to the prior and current day prices and challenges prices with changes exceeding certain tolerance levels with third-party pricing services or broker sources.

The Board authorized the Valuation Committee to appoint a Valuation Subcommittee (the “Subcommittee”) to establish the prices of securities for which market quotations are not readily available or the prices of which are not otherwise readily determinable under the procedures. The Subcommittee meets (in person, via electronic mail or via teleconference) on an as-needed basis. The Valuation Committee meets to ensure that actions taken by the Subcommittee were appropriate.

For those securities valued through either a standardized fair valuation methodology or a fair valuation measurement, the Subcommittee deals with such valuation and the Valuation Committee reviews and affirms, if appropriate, the reasonableness of the valuation based on such methodologies and measurements on a regular basis after considering information that is reasonably available and deemed relevant by the Valuation Committee. Any action taken by the Subcommittee with respect to the valuation of a portfolio security or other asset is submitted for review and ratification (if appropriate) to the Valuation Committee and the Board at the next regularly scheduled meeting.

“Fair value” is defined as the price the Fund would reasonably expect to receive upon selling an asset or liability in an orderly transaction to an independent buyer in the principal or most advantageous market for the asset or liability. Fair value measurements are determined within a framework that establishes a three-tier hierarchy that maximizes the use of observable market data and minimizes the use of unobservable inputs to establish a classification of fair value measurements for disclosure purposes. “Inputs” refer broadly to the assumptions that market participants would use in pricing the asset or liability, including assumptions about risk, such as the risk inherent in a particular valuation technique used to measure fair value using a pricing model and/or the risk inherent in the inputs for the valuation technique. Inputs may be observable or unobservable. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Fund. Unobservable inputs reflect the Fund’s own assumptions about the assumptions market participants would use in pricing the asset or liability based on the information available. The inputs or methodology

used for valuing assets or liabilities may not be an indication of the risks associated with investing in those assets or liabilities. The three-tier hierarchy of inputs is summarized below.

The level of an asset or liability within the fair value hierarchy is based on the lowest level of an input, both individually and in the aggregate, that is significant to the fair value measurement. The aggregate value by input level of the Fund’s assets and liabilities as of November 30, 2020, is included at the end of the Portfolio of Investments.

The Fund may use third-party vendor evaluations, whose prices may be derived from one or more of the following standard inputs, among others:

An asset or liability for which market values cannot be measured using the methodologies described above is valued by methods deemed reasonable in good faith by the Valuation Committee, following the procedures established by the Board, to represent fair value. Under these procedures, the Fund generally uses a market-based approach which may use related or comparable assets or liabilities, recent transactions, market multiples, book values, and other relevant information. The Fund may also use an income-based valuation approach in which the anticipated future cash flows of the asset or liability are discounted to calculate fair value. Discounts may also be applied due to the nature and/or duration of any restrictions on the disposition of the asset or liability. Fair value represents a good faith approximation of the value of a security. Fair value determinations involve the consideration of a number of subjective factors, an analysis of applicable facts and circumstances and the exercise of judgment. As a result, it is possible that the fair value for a security determined in good faith in accordance with the Fund’s valuation procedures may differ from valuations for the same security determined by other funds using their own valuation procedures. Although the Fund’s valuation procedures are designed to value a security at the price the Fund may reasonably expect to receive upon the security’s sale in an orderly transaction, there can be no assurance that any fair value determination thereunder would, in fact, approximate the amount that the Fund would actually realize upon the sale of the security or the price at which the security would trade if a reliable market price were readily available. During the six-month period ended November 30, 2020, there were no material changes to the fair value methodologies.

Securities which may be valued in this manner include, but are not limited to: (i) a security for which trading has been halted or suspended; (ii) a debt security that has recently gone into default and for which there is not a current market quotation; (iii) a security of an issuer that has entered into a restructuring; (iv) a security that has been delisted from a national exchange; (v) a security for which the market price is not readily available from a third-party pricing source or, if so provided, does not, in the opinion of the Manager or the Subadvisor, reflect the security’s market value; (vi) a security subject to trading collars for which no or limited trading takes place; and (vii) a security whose principal market has been temporarily closed at a time when, under normal conditions, it would be open. Securities valued in this manner are generally categorized as Level 3 in the hierarchy. No securities held by the Fund as of November 30, 2020, were fair valued in such a manner.

Municipal debt securities are valued at the evaluated mean prices supplied by a pricing agent or broker selected by the Manager, in consultation with the Subadvisor. Those values reflect broker-dealer supplied prices and electronic data processing techniques, if the evaluated bid or mean prices are deemed by the Manager, in consultation with the Subadvisor, to be representative of market values, at the regular close of trading of the Exchange on each valuation date. Debt securities purchased on a delayed delivery basis are marked to market daily until settlement at the forward settlement date. Municipal debt securities are generally categorized as Level 2 in the hierarchy.

Futures contracts are valued at the last posted settlement price on the market where such futures are primarily traded and are generally categorized as Level 1 in the hierarchy.

Temporary cash investments acquired in excess of 60 days to maturity at the time of purchase are valued using the latest bid prices or using valuations based on a matrix system (which considers such factors as security prices, yields, maturities and ratings), both as furnished by independent pricing services. Temporary cash investments that mature in 60 days or less at the time of purchase (“Short-Term Investments”) are valued using the amortized cost method of valuation, unless the use of such method would be inappropriate. The amortized cost method involves valuing a security at its cost on the date of purchase and thereafter assuming a constant amortization to maturity of the difference between such cost and the value on maturity date. Amortized cost approximates the current fair value of a security. Securities valued using the amortized cost method are not valued using quoted prices in an active market and are generally categorized as Level 2 in the hierarchy.

The information above is not intended to reflect an exhaustive list of the methodologies that may be used to value portfolio investments. The valuation procedures permit the use of a variety of valuation methodologies in connection with valuing portfolio investments. The methodology used for a specific type of investment may vary based on the market data available or other considerations. The methodologies summarized above may not represent the specific means by which portfolio investments are valued on any particular business day.

(B)  Income Taxes.  The Fund’s policy is to comply with the requirements of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), applicable to regulated investment companies and to distribute all of its taxable income to the shareholders of the Fund within the allowable time limits.

The Manager evaluates the Fund’s tax positions to determine if the tax positions taken meet the minimum recognition threshold in connection with accounting for uncertainties in income tax positions taken or expected to be taken for the purposes of measuring and recognizing tax liabilities in the financial statements. Recognition of tax benefits of an uncertain tax position is permitted only to the extent the position is “more likely than not” to be sustained assuming examination by taxing authorities. The Manager analyzed the Fund’s tax positions taken on federal, state and local income tax returns for all open tax years (for up to three tax years), and has concluded that no provisions for federal, state and local income tax are required in the Fund’s financial statements. The Fund’s federal, state and local income tax and federal excise tax returns for tax years for which the applicable statutes of limitations have not expired are subject to examination by the Internal Revenue Service and state and local departments of revenue.

(C)  Dividends and Distributions to Common Shareholders.  Dividends and distributions are recorded on the ex-dividend date. The Fund intends to declare dividends from net investment income, after payment of any dividends on any outstanding Preferred shares, if any, at least monthly and declares and pays distributions from net realized capital gains, if any, at least annually. To the extent that the Fund realizes any capital gains or ordinary taxable income, it will be required to allocate such income between the Common shares and Preferred shares issued by the Fund, in proportion to the total dividends paid to each share class for the year in which the income is realized. Dividends and distributions are determined in accordance with federal income tax regulations and may differ from determinations using GAAP. For information on the Fund’s dividend reinvestment plan, please see page 27.

(D)  Security Transactions and Investment Income.  The Fund records security transactions on the trade date. Realized gains and losses on security transactions are determined using the identified cost method. Interest income is accrued as earned using the effective interest rate method. Discounts and premiums on securities purchased for the Fund are accreted and amortized, respectively, on the effective interest rate method over the life of the respective securities.

The Fund may place a debt security on non-accrual status and reduce related interest income by ceasing current accruals and writing off all or a portion of any interest receivables when the collection of all or a portion of such interest has become doubtful. A debt security is removed from non-accrual status when the issuer resumes interest payments or when collectability of interest is reasonably assured.

(E)  Expenses.  Expenses of the Fund are recorded on the date the expenses are incurred. The expenses borne by the Fund, including those of related parties to the Fund, are shown in the Statement of Operations. Certain expenses of the Fund are allocated in proportion to other funds within the MainStay Group of Funds.

(F)  Use of Estimates.  In preparing financial statements in conformity with GAAP, the Manager makes estimates and assumptions that affect the reported amounts and disclosures in the financial statements. Actual results could differ from those estimates.

(G)  Futures Contracts.  A futures contract is an agreement to purchase or sell a specified quantity of an underlying instrument at a specified future date and price, or to make or receive a cash payment

based on the value of a financial instrument (e.g., foreign currency, interest rate, security or securities index). The Fund is subject to risks such as market price risk and/or interest rate risk in the normal course of investing in these contracts. Upon entering into a futures contract, the Fund is required to pledge to the broker or futures commission merchant an amount of cash and/or U.S. government securities equal to a certain percentage of the collateral amount, known as the “initial margin.” During the period the futures contract is open, changes in the value of the contract are recognized as unrealized appreciation or depreciation by marking to market such contract on a daily basis to reflect the market value of the contract at the end of each day’s trading. The Fund agrees to receive from or pay to the broker or futures commission merchant an amount of cash equal to the daily fluctuation in the value of the contract. Such receipts or payments are known as “variation margin.” When the futures contract is closed, the Fund records a realized gain or loss equal to the difference between the proceeds from (or cost of) the closing transaction and the Fund’s basis in the contract.

The use of futures contracts involves, to varying degrees, elements of market risk in excess of the amount recognized in the Statement of Assets and Liabilities. The contract or notional amounts and variation margin reflect the extent of the Fund’s involvement in open futures positions. There are several risks associated with the use of futures contracts as hedging techniques. There can be no assurance that a liquid market will exist at the time when the Fund seeks to close out a futures contract. If no liquid market exists, the Fund would remain obligated to meet margin requirements until the position is closed. Futures contracts may involve a small initial investment relative to the risk assumed, which could result in losses greater than if the Fund did not invest in futures contracts. Futures contracts may be more volatile than direct investments in the instrument underlying the futures and may not correlate to the underlying instrument, causing a given hedge not to achieve its objectives. The Fund’s activities in futures contracts have minimal counterparty risk as they are conducted through regulated exchanges that guarantee the futures against default by the counterparty. In the event of a bankruptcy or insolvency of a futures commission merchant that holds margin on behalf of the Fund, the Fund may not be entitled to the return of the entire margin owed to the Fund, potentially resulting in a loss. The Fund may invest in futures contracts to seek enhanced returns or to reduce the risk of loss by hedging certain of its holdings. The Fund’s investment in futures contracts and other derivatives may increase the volatility of the Fund’s NAV and may result in a loss to the Fund. As of November 30, 2020, there were no open futures contracts held by the Fund.

(H)  Tender Option Bonds.  The Fund may leverage its assets through the use of proceeds received from tender option bond (“TOB”) transactions. In a TOB transaction, a tender option bond trust (a “TOB Issuer”) is typically established, which forms a special purpose trust into which the Fund, or an agent on behalf of the Fund, transfers municipal bonds or other municipal securities (“Underlying Securities”). A TOB Issuer typically issues two classes of beneficial interests: short-term floating rate notes (“TOB Floaters”) with a fixed principal amount representing a senior interest in the Underlying Securities, and which are sold to third party investors, and residual interest municipal tender option bonds (“TOB Residuals”) representing a subordinate interest in the Underlying Securities, and which are generally issued to the Fund. The

interest rate on the TOB Floaters resets periodically, usually weekly, to a prevailing market rate, and holders of the TOB Floaters are granted the option to tender their TOB Floaters back to the TOB Issuer for repurchase at their principal amount plus accrued interest thereon periodically, usually daily or weekly. The Fund may invest in both TOB Floaters and TOB Residuals. The Fund may not invest more than 5% of its Managed Assets (as defined in Note 3(A)) in any single TOB Issuer. The Fund may invest in both TOB Floaters and TOB Residuals issued by the same TOB Issuer.

Typically, a fund serves as the sponsor of the TOB issuer (“Fund-sponsored TOB”). Under this structure, a fund establishes, structures and “sponsors” the TOB Issuer in which it holds TOB Residuals. The Fund uses this or a similar structure for any TOB in which it invests. In connection with Fund-sponsored TOBs, the fund sponsoring the Fund-sponsored TOB (“Fund Sponsor”) may contract with a third-party to perform some or all of the Fund Sponsor’s duties as sponsor. Regardless of whether the Fund Sponsor delegates any of its sponsorship duties to a third party, the Fund Sponsor’s expanded role under the Fund-sponsored TOB structure may increase the Fund Sponsor’s operational and regulatory risk. If the third-party is unable to perform its obligations as an administrative agent, the Fund Sponsor itself would be subject to such obligations or would need to secure a replacement agent. The obligations that the Fund Sponsor may be required to undertake could include reporting and recordkeeping obligations under the Internal Revenue Code and federal securities laws and contractual obligations with other TOB service providers. The Fund may serve as a Fund Sponsor to a Fund-sponsored TOB. If the Fund serves as a Fund Sponsor, it would be subject to the obligations discussed above and the risks attendant to such obligations.

Under the Fund-sponsored TOB structure, the TOB Issuer receives Underlying Securities from the Fund through (or as) the Fund Sponsor and then issues TOB Floaters to third party investors and TOB Residuals to the Fund. The Fund is paid the cash (less transaction expenses, which are borne by the Fund) received by the TOB Issuer from the sale of TOB Floaters and typically will invest the cash in additional municipal bonds or other investments permitted by its investment policies. TOB Floaters may have first priority on the cash flow from the securities held by the TOB Issuer and are enhanced with a liquidity support arrangement from a bank or an affiliate of the sponsor (the “liquidity provider”), which allows holders to tender their position back to the TOB Issuer at par (plus accrued interest). The Fund, in addition to receiving cash from the sale of TOB Floaters, also receives TOB Residuals. TOB Residuals provide the Fund with the right to (1) cause the holders of TOB Floaters to tender their notes to the TOB Issuer at par (plus accrued interest), and (2) acquire the Underlying Securities from the TOB Issuer. In addition, all voting rights and decisions to be made with respect to any other rights relating to the Underlying Securities deposited in the TOB Issuer are passed through to the Fund, as the holder of TOB Residuals. Such a transaction, in effect, creates exposure for the Fund to the entire return of the Underlying Securities deposited in the TOB Issuer, with a net cash investment by the Fund that is less than the value of the Underlying Securities deposited in the TOB Issuer. This multiplies the positive or negative impact of the Underlying Securities’ return within the Fund (thereby creating leverage). Income received from TOB Residuals will vary inversely with the short-term rate paid to holders of TOB Floaters and in most circumstances, TOB Residuals represent substantially all of

the Underlying Securities’ downside investment risk and also benefits disproportionately from any potential appreciation of the Underlying Securities’ value. The amount of such increase or decrease is a function, in part, of the amount of TOB Floaters sold by the TOB Issuer of these securities relative to the amount of TOB Residuals that it sells. The greater the amount of TOB Floaters sold relative to TOB Residuals, the more volatile the income paid on TOB Residuals will be. The price of TOB Residuals will be more volatile than that of the Underlying Securities because the interest rate is dependent on not only the fixed coupon rate of the Underlying Securities, but also on the short-term interest rate paid on TOB Floaters.

For TOB Floaters, generally, the interest rate earned will be based upon the market rates for municipal securities with maturities or remarketing provisions that are comparable in duration to the periodic interval of the tender option, which may vary from weekly, to monthly, to extended periods of one year or multiple years. Since the option feature has a shorter term than the final maturity or first call date of the Underlying Securities deposited in the TOB Issuer, the Fund, if it is the holder of the TOB Floaters, relies upon the terms of the agreement with the financial institution furnishing the option as well as the credit strength of that institution. As further assurance of liquidity, the terms of the TOB Issuer provide for a liquidation of the Underlying Security deposited in the TOB Issuer and the application of the proceeds to pay off the TOB Floaters.

The TOB Issuer may be terminated without the consent of the Fund upon the occurrence of certain events, such as the bankruptcy or default of the issuer of the Underlying Securities deposited in the TOB Issuer, a substantial downgrade in the credit quality of the issuer of the securities deposited in the TOB Issuer, the inability of the TOB Issuer to obtain liquidity support for the TOB Floaters, a substantial decline in the market value of the Underlying Securities deposited in the TOB Issuer, or the inability of the sponsor to remarket any TOB Floaters tendered to it by holders of the TOB Floaters. In such an event, the TOB Floaters would be redeemed by the TOB Issuer at par (plus accrued interest) out of the proceeds from a sale of the Underlying Securities deposited in the TOB Issuer. If this happens, the Fund would be entitled to the assets of the TOB Issuer, if any, that remain after the TOB Floaters have been redeemed at par (plus accrued interest). If there are insufficient proceeds from the sale of these Underlying Securities to redeem all of the TOB Floaters at par (plus accrued interest), the liquidity provider or holders of the TOB Floaters would bear the losses on those securities and there would be no recourse to the Fund’s assets (unless the Fund held a recourse TOB Residual).

To the extent that the remarketing agent and/or the liquidity provider is a banking entity, the TOB may face heightened liquidity risks due to restrictions applicable to banking entities under the Volcker Rule. The Volcker Rule generally prohibits banking entities from engaging in proprietary trading or from acquiring or retaining an ownership interest in, or sponsoring, a hedge fund or private equity fund (a “Covered Fund”). TOB Issuers are often structured as a Covered Fund, and therefore, a banking entity that is a remarketing agent would not be able to repurchase tendered TOB Floaters for its own account upon a failed remarketing. In the event of a failed remarketing, a banking entity serving as liquidity provider may loan the necessary funds to the TOB Issuer to purchase the tendered TOB Floaters. The TOB Issuer, not the Fund Sponsor or the Fund, would be the borrower and the loan from the

liquidity provider will be secured by the purchased TOB Floaters now held by the TOB Issuer. However, the Fund Sponsor and the Fund would bear the risk of loss with respect to any liquidity shortfall to the extent it entered into a reimbursement agreement with the liquidity provider. If a TOB Issuer in which the Fund invests experiences adverse events in connection with a failed remarketing of TOB Floaters or a liquidity shortfall, the Fund would experience a loss.

For financial reporting purposes, Underlying Securities that are deposited into a TOB Issuer are treated as investments of the Fund, and are presented in the Fund’s Portfolio of Investments. Outstanding TOB Floaters issued by a TOB Issuer are presented as a liability at their face value as “Payable for Floating Rate Note Obligations” in the Fund’s Statement of Assets and Liabilities. The face value of the TOB Floaters approximates their fair value of the floating rate notes. Interest income from the Underlying Securities are recorded by the Fund on an accrual basis. Interest expense incurred on the TOB Floaters and other expenses related to remarketing, administration and trustee services to a TOB Issuer are recognized as a component of “Interest expense and fees” in the Statement of Operations.

At November 30, 2020, the aggregate value of the Underlying Securities transferred to the TOB Issuer and the related liability for TOB Floaters were as follows:

During the six-month period ended November 30, 2020, the Fund’s average TOB Floaters outstanding and the daily weighted average interest rate, including fees, were as follows: