As filed with the Securities and Exchange Commission on February 10, 2021

Securities Act File No. 333-            

Investment Company Act File No. 811-22426

U.S. SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

BlackRock Taxable Municipal Bond Trust

(Exact Name of Registrant as Specified In Charter)

100 Bellevue Parkway

Wilmington, Delaware 19809

(Address of Principal Executive Offices)

Registrant’s Telephone Number, including Area Code: (800) 882-0052

John M. Perlowski, President

BlackRock Taxable Municipal Bond Trust

55 East 52nd Street

New York, New York 10055

(Name and Address of Agent For Service)

Copies of information to:

Margery K. Neale, Esq.

Elliot J. Gluck, Esq.

Willkie Farr & Gallagher LLP

787 Seventh Avenue

New York, New York 10019

Approximate Date of Commencement of Proposed Public Offering: From time to time after the effective date of this Registration Statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, check the following box  ☐

If any securities being registered on this Form will be offered on a delayed or continuous basis in reliance on Rule 415 under the Securities Act of 1933 (“Securities Act”), other than securities offered in connection with a dividend reinvestment plan, check the following box  ☒

If this Form is a registration statement pursuant to General Instruction A.2 or a post-effective amendment thereto, check the following box  ☒

If this Form is a registration statement pursuant to General Instruction B or a post-effective amendment thereto that will become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box  ☒

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction B to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box  ☐

It is proposed that this filing will become effective (check appropriate box):

If appropriate, check the following box:

Check each box that appropriately characterizes the Registrant:

BASE PROSPECTUS

$533,000,000

BlackRock Taxable Municipal Bond Trust

Shares of Beneficial Interest

Rights to Purchase Shares of Beneficial Interest

BlackRock Taxable Municipal Bond Trust (the “Trust,” “we,” “us” or “our”) is a diversified, closed-end management investment company. The Trust’s primary investment objective is to seek high current income, with a secondary objective of capital appreciation.

We may offer, from time to time, in one or more offerings, our common shares of beneficial interest, par value $.001 per share (“common shares”), or subscription rights to purchase our common shares. Common shares may be offered at prices and on terms to be set forth in one or more supplements to this Prospectus (each, a “Prospectus Supplement”). You should read this Prospectus and the applicable Prospectus Supplement carefully before you invest in our common shares.

Our common shares may be offered directly to one or more purchasers, including existing shareholders in a rights offering, through agents designated from time to time by us, or to or through underwriters or dealers. The Prospectus Supplement relating to the offering will identify any agents or underwriters involved in the sale of our common shares, and will set forth any applicable purchase price, fee, commission or discount arrangement between us and our agents or underwriters, or among our underwriters, or the basis upon which such amount may be calculated. The Prospectus Supplement relating to any offering of rights will set forth the number of common shares issuable upon the exercise of each right (or number of rights) and the other terms of such rights offering. We may not sell any of our common shares through agents, underwriters or dealers without delivery of a Prospectus Supplement describing the method and terms of the particular offering of our common shares.

Our common shares are listed on the New York Stock Exchange (“NYSE”) under the symbol “BBN.” The last reported sale price of our common shares, as reported by the NYSE on February 9, 2021 was $26.65 per common share. The net asset value of our common shares at the close of business on February 9, 2021 was $25.35 per common share. Rights issued by the Trust may also be listed on a securities exchange.

Investing in the Trust’s common shares involves certain risks that are described in the “Risks” section beginning on page 24 of this Prospectus. Certain of these risks are summarized in “Prospectus Summary—Special Risk Considerations” beginning on page 4.

Shares of closed-end management investment companies frequently trade at a discount to their net asset value. The Trust’s common shares have traded at a discount to net asset value, including during recent periods. If the Trust’s common shares trade at a discount to its net asset value, the risk of loss may increase for purchasers in a public offering.

Neither the Securities and Exchange Commission (“SEC”) nor any state securities commission has approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

This Prospectus, together with any Prospectus Supplement, sets forth concisely the information about the Trust that a prospective investor should know before investing. You should read this Prospectus and applicable Prospectus Supplement, which contain important information, before deciding whether to invest in the common shares. You should retain the Prospectus and Prospectus Supplement for future reference. A Statement of Additional Information

(“SAI”), dated February 10, 2021, containing additional information about the Trust, has been filed with the SEC and, as amended from time to time, is incorporated by reference in its entirety into this Prospectus. You may call (800) 882-0052, visit the Trust’s website (http://www.blackrock.com) or write to the Trust to obtain, free of charge, copies of the SAI and the Trust’s semi-annual and annual reports, as well as to obtain other information about the Trust or to make shareholder inquiries. The SAI, as well as the Trust’s semi-annual and annual reports, are also available for free on the SEC’s website (http://www.sec.gov). You may also e-mail requests for these documents to publicinfo@sec.gov. Information contained in, or that can be accessed through, the Trust’s website is not part of this Prospectus.

You should not construe the contents of this Prospectus as legal, tax or financial advice. You should consult with your own professional advisors as to the legal, tax, financial or other matters relevant to the suitability of an investment in the Trust.

The Trust’s common shares do not represent a deposit or an obligation of, and are not guaranteed or endorsed by, any bank or other insured depository institution, and are not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.

Prospectus dated February 10, 2021

Beginning on January 1, 2021, as permitted by regulations adopted by the SEC, paper copies of the Trust’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call Computershare at 1-800-699-1236 to request that you continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC or its affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

TABLE OF CONTENTS

You should rely only on the information contained in, or incorporated by reference into, this Prospectus and any related Prospectus Supplement in making your investment decisions. The Trust has not authorized any person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. The Trust is not making an offer to sell the common shares in any jurisdiction where the offer or sale is not permitted. You should assume that the information in this Prospectus and any Prospectus Supplement is accurate only as of the dates on their covers. The Trust’s business, financial condition and prospects may have changed since the date of its description in this Prospectus or the date of its description in any Prospectus Supplement.

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The following example illustrates the expenses (including the sales load of $10.00 and offering costs of $0.20) that you would pay on a $1,000 investment in common shares, assuming (i) total net annual expenses of 1.97% of net assets attributable to common shares, and (ii) a 5% annual return:

The example should not be considered a representation of future expenses. The example assumes that the estimated “Other expenses” set forth in the Estimated Annual Expenses table are accurate and that all dividends and distributions are reinvested at NAV. Actual expenses may be greater or less than those assumed. Moreover, the Trust’s actual rate of return may be greater or less than the hypothetical 5% return shown in the example.

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FINANCIAL HIGHLIGHTS

The financial highlights table is intended to help you understand the Trust’s financial performance for the periods presented. Certain information reflects financial results for a single Trust Share. The information for the fiscal years ended July 31, 2020, 2019, 2018, 2017 and 2016, which has been audited by Deloitte & Touche LLP, independent registered public accounting firm for the Trust. The report of Deloitte & Touche LLP is included in the Trust’s July 31, 2020 annual report, is incorporated by reference into the SAI and can be obtained by shareholders. The Trust’s financial statements are included in the Trust’s annual report and are incorporated by reference into the SAI.

(For a share outstanding throughout each period)

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USE OF PROCEEDS

The net proceeds from the issuance of common shares hereunder will be invested in accordance with the Trust’s investment objectives and policies as stated below. We currently anticipate that we will be able to invest all of the net proceeds in accordance with our investment objectives and policies within approximately three months from the date on which the proceeds from an offering are received by the Trust. Pending such investment, it is anticipated that the proceeds will be invested in short-term investment grade securities or in high quality, short-term money market instruments.

THE TRUST

The Trust is a diversified, closed-end management investment company registered under the Investment Company Act. The Trust was formed as a Delaware statutory trust on June 7, 2010 pursuant to an Agreement and Declaration of Trust governed by the laws of the State of Delaware and the Certificate of Trust filed with the Secretary of State of the State of Delaware. The Trust was known as “BlackRock Build America Bond Trust” prior to August 10, 2015. The Trust’s principal office is located at 100 Bellevue Parkway, Wilmington, Delaware 19809, and its telephone number is (800) 882-0052.

The Trust commenced operations on August 27, 2010, upon the initiation of an initial public offering of 50,750,00 of its common shares. The proceeds of such offering were approximately $967.295 million after the payment of organizational and offering expenses. The Trust’s common shares are traded on the NYSE under the symbol “BBN.”

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DESCRIPTION OF SHARES

Common Shares

The Trust is a statutory trust formed under the laws of Delaware and governed by an Amended and Restated Agreement and Declaration of Trust dated as of July 16, 2010 (the “Agreement and Declaration of Trust”). The Trust is authorized to issue an unlimited number of common shares of beneficial interest, par value $0.001 per share. Each common share has one vote and, when issued and paid for in accordance with the terms of this offering, will be fully paid and, under the Delaware Statutory Trust Act, the purchasers of the common shares will have no obligation to make further payments for the purchase of the common shares or contributions to the Trust solely by reason of their ownership of the common shares, except that the Trustees shall have the power to cause shareholders to pay certain expenses of the Trust by setting off charges due from shareholders from declared but unpaid dividends or distributions owed the shareholders and/or by reducing the number of common shares owned by each respective shareholder. If and whenever preferred shares are outstanding, the holders of common shares will not be entitled to receive any distributions from the Trust unless all accrued dividends on preferred shares have been paid, unless asset coverage (as defined in the Investment Company Act) with respect to preferred shares would be at least 200% after giving effect to the distributions and unless certain other requirements imposed by any rating agencies rating the preferred shares have been met. See “Description of Shares—Preferred Shares” in the SAI. All common shares are equal as to dividends, assets and voting privileges and have no conversion, preemptive or other subscription rights. The Trust will send annual and semi-annual reports, including financial statements, to all holders of its shares.

Unlike open-end funds, closed-end funds like the Trust do not continuously offer shares and do not provide daily redemptions. Rather, if a shareholder determines to buy additional common shares or sell shares already held, the shareholder may do so by trading through a broker on the NYSE or otherwise. Shares of closed-end investment companies frequently trade on an exchange at prices lower than NAV. Shares of closed-end investment companies like the Trust have during some periods traded at prices higher than NAV and during other periods have traded at prices lower than NAV. Because the market value of the common shares may be influenced by such factors as dividend levels (which are in turn affected by expenses), call protection on its portfolio securities, dividend stability, portfolio credit quality, the Trust’s NAV, relative demand for and supply of such shares in the market, general market and economic conditions and other factors beyond the control of the Trust, the Trust cannot assure you that common shares will trade at a price equal to or higher than NAV in the future. The common shares are designed primarily for long-term investors and you should not purchase the common shares if you intend to sell them soon after purchase. See “Repurchase of Common Shares” below and “Repurchase of Common Shares” in the SAI.

The Trust’s outstanding common shares are, and when issued, the common shares offered by this Prospectus will be, publicly held and listed and traded on the NYSE under the symbol “BBN.” The Trust determines its NAV on a daily basis. The following table sets forth, for the quarters indicated, the highest and lowest daily closing prices on the NYSE per common share, and the NAV per common share and the premium to or discount from NAV, on the date of each of the high and low market prices. The table also sets forth the number of common shares traded on the NYSE during the respective quarters.

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As of February 9, 2021, the NAV per common share of the Trust was $25.35 and the market price per common share was $26.65, representing a premium to NAV of 5.13%. Common shares of the Trust have historically traded at both a premium and discount to NAV.

As of February 9, 2021, the Trust has outstanding 57,217,439 common shares.

Preferred Shares

The Agreement and Declaration of Trust provides that the Board may authorize and issue preferred shares, with rights as determined by the Board, by action of the Board without the approval of the holders of the common shares. Holders of common shares have no preemptive right to purchase any preferred shares that might be issued. The Trust does not currently intend to issue preferred shares. Under the Investment Company Act, the Trust is not permitted to issue preferred shares unless immediately after such issuance the value of the Trust’s total assets is at least 200% of the liquidation value of the outstanding preferred shares (i.e., the liquidation value may not exceed 50% of the Trust’s total assets). In addition, the Trust is not permitted to declare any cash dividend or other distribution on its common shares unless, at the time of such declaration, the value of the Trust’s total assets is at least 200% of such liquidation value. If the Trust issues preferred shares, it may be subject to restrictions imposed by the guidelines of one or more rating agencies that may issue ratings for preferred shares issued by the Trust. These guidelines may impose asset coverage or portfolio composition requirements that are more stringent than those imposed on the Trust by the Investment Company Act. It is not anticipated that these covenants or guidelines would impede the Advisor from managing the Trust’s portfolio in accordance with the Trust’s investment objectives and policies. Please see “Description of Capital Stock” in the SAI for more information.

THE TRUST’S INVESTMENTS

Investment Objectives and Policies

Please refer to the section of the Trust’s most recent annual report on Form N-CSR entitled “Trust Investment Objectives, Policies and Risks—Investment Objectives and Policies”, which is incorporated by reference herein, for a discussion of the Trust’s investment objectives and policies.

Description of Municipal Securities

Set forth below is a detailed description of the municipal securities in which the Trust invests. Information with respect to ratings assigned to tax-exempt obligations that the Trust may purchase is set forth in “Appendix A—Ratings of Investments” in the SAI. Obligations are included within the term municipal securities if the interest paid thereon is excluded from gross income for federal income tax purposes in the opinion of bond counsel to the issuer.

Municipal securities include debt obligations issued to obtain funds for various public purposes, including the construction of a wide range of public facilities, refunding of outstanding obligations and obtaining funds for general operating expenses and loans to other public institutions and facilities. In addition, certain types of PABs are issued by or on behalf of public authorities to finance various privately owned or operated facilities, including among other

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things, airports, public ports, mass commuting facilities, multi-family housing projects, as well as facilities for water supply, gas, electricity, sewage or solid waste disposal and other specialized facilities. Other types of PABs, the proceeds of which are used for the construction, equipment or improvement of privately operated industrial or commercial facilities, may constitute municipal securities. The interest on municipal securities may bear a fixed rate or be payable at a variable or floating rate. The two principal classifications of municipal securities are “general obligation” bonds and “revenue” bonds, which latter category includes PABs and, for bonds issued on or before August 15, 1986, industrial development bonds. Municipal securities typically are issued to finance public projects, such as roads or public buildings, to pay general operating expenses or to refinance outstanding debt. Municipal securities may also be issued for private activities, such as housing, medical and educational facility construction, or for privately owned industrial development and pollution control projects. General obligation bonds are backed by the full faith and credit, or taxing authority, of the issuer and may be repaid from any revenue source. Revenue bonds may be repaid only from the revenues of a specific facility or source. Municipal securities may be issued on a long-term basis to provide permanent financing. The repayment of such debt may be secured generally by a pledge of the full faith and credit taxing power of the issuer, a limited or special tax, or any other revenue source, including project revenues, which may include tolls, fees and other user charges, lease payments and mortgage payments. Municipal securities may also be issued to finance projects on a short-term interim basis, anticipating repayment with the proceeds of the later issuance of long-term debt.

The municipal securities in which the Trust invests pay interest or income that, in the opinion of bond counsel to the issuer, is exempt from regular Federal income tax. The Advisor does not conduct its own analysis of the tax status of the interest paid by municipal securities held by the Trust, but will rely on the opinion of counsel to the issuer of each such instrument. The Trust may also invest in municipal securities issued by United States Territories (such as Puerto Rico or Guam) that are exempt from regular Federal income tax. In addition to the types of municipal securities described in this Prospectus, the Trust may invest in other securities that pay interest or income that is, or make other distributions that are, exempt from regular Federal income tax and/or state and local personal taxes, regardless of the technical structure of the issuer of the instrument. The Trust treats all of such tax-exempt securities as municipal securities.

The yields on municipal securities are dependent on a variety of factors, including prevailing interest rates and the condition of the general money market and the municipal security market, the size of a particular offering, the maturity of the obligation and the rating of the issue. The market value of municipal securities will vary with changes in interest rate levels and as a result of changing evaluations of the ability of bond issuers to meet interest and principal payments.

The Trust has not established any limit on the percentage of its portfolio that may be invested in PABs. The Trust may not be a suitable investment for investors who are already subject to the federal alternative minimum tax or who would become subject to the federal alternative minimum tax as a result of an investment in the Trust’s common shares.

General Obligation Bonds. General obligation bonds are typically secured by the issuer’s pledge of its faith, credit and taxing power for the repayment of principal and the payment of interest. The taxing power of any governmental entity may be limited, however, by provisions of its state constitution or laws, and an entity’s creditworthiness will depend on many factors, including potential erosion of its tax base due to population declines, natural disasters, declines in the state’s industrial base or inability to attract new industries, economic limits on the ability to tax without eroding the tax base, state legislative proposals or voter initiatives to limit ad valorem real property taxes and the extent to which the entity relies on federal or state aid, access to capital markets or other factors beyond the state’s or entity’s control. Accordingly, the capacity of the issuer of a general obligation bond as to the timely payment of interest and the repayment of principal when due is affected by the issuer’s maintenance of its tax base.

Revenue Bonds. Revenue or special obligation bonds are typically payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise tax or other specific revenue sources such as payments from the user of the facility being financed. Accordingly, the timely payment of interest and the repayment of principal in accordance with the terms of the revenue or special obligation bond is a function of the economic viability of such facility or such revenue source. Revenue bonds issued by state or local agencies to finance the development of low-income, multi-family housing involve special risks in addition to those associated with municipal securities generally, including that the underlying properties may not generate sufficient

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income to pay expenses and interest costs. Such bonds are generally non-recourse against the property owner, may be junior to the rights of others with an interest in the properties, may pay interest that changes based in part on the financial performance of the property, may be prepayable without penalty and may be used to finance the construction of housing developments which, until completed and rented, do not generate income to pay interest. Increases in interest rates payable on senior obligations may make it more difficult for issuers to meet payment obligations on subordinated bonds.

Municipal Notes. Municipal notes are shorter term municipal debt obligations. They may provide interim financing in anticipation of tax collection, bond sales or revenue receipts. If there is a shortfall in the anticipated proceeds, repayment on the note may be delayed or the note may not be fully repaid, and the Trust may lose money.

Municipal Commercial Paper. Municipal commercial paper is generally unsecured and issued to meet short-term financing needs. The lack of security presents some risk of loss to the Trust since, in the event of an issuer’s bankruptcy, unsecured creditors are repaid only after the secured creditors out of the assets, if any, that remain.

PABs. The Trust may purchase municipal securities classified as PABs. Interest received on certain PABs is treated as an item of “tax preference” for purposes of the federal alternative minimum tax and may impact the overall tax liability of certain investors in the Trust. PABs, formerly referred to as industrial development bonds, are issued by, or on behalf of, states, municipalities or public authorities to obtain funds to provide privately operated housing facilities, airport, mass transit or port facilities, sewage disposal, solid waste disposal or hazardous waste treatment or disposal facilities and certain local facilities for water supply, gas or electricity. Other types of PABs, the proceeds of which are used for the construction, equipment, repair or improvement of privately operated industrial or commercial facilities, may constitute municipal securities, although the federal tax laws may place substantial limitations on the size of such issues. Such bonds are secured primarily by revenues derived from loan repayments or lease payments due from the entity which may or may not be guaranteed by a parent company or otherwise secured. PABs generally are not secured by a pledge of the taxing power of the issuer of such bonds. Therefore, an investor should be aware that repayment of such bonds generally depends on the revenues of a private entity and be aware of the risks that such an investment may entail. The continued ability of an entity to generate sufficient revenues for the payment of principal and interest on such bonds will be affected by many factors including the size of the entity, capital structure, demand for its products or services, competition, general economic conditions, government regulation and the entity’s dependence on revenues for the operation of the particular facility being financed.

Moral Obligation Bonds. Municipal securities may also include “moral obligation” bonds, which are normally issued by special purpose public authorities. If an issuer of moral obligation bonds is unable to meet its obligations, the repayment of such bonds becomes a moral commitment but not a legal obligation of the state or municipality in question.

Municipal Lease Obligations. Also included within the general category of municipal securities are certificates of participation (“COPs”) issued by government authorities or entities to finance the acquisition or construction of equipment, land and/or facilities. COPs represent participations in a lease, an installment purchase contract or a conditional sales contract (hereinafter collectively called “lease obligations”) relating to such equipment, land or facilities. Municipal leases, like other municipal debt obligations, are subject to the risk of non-payment. Although lease obligations do not constitute general obligations of the issuer for which the issuer’s unlimited taxing power is pledged, a lease obligation is frequently backed by the issuer’s covenant to budget for, appropriate and make the payments due under the lease obligation. However, certain lease obligations contain “non-appropriation” clauses which provide that the issuer has no obligation to make lease or installment purchase payments in future years unless money is appropriated for such purpose on a yearly basis. Although “non-appropriation” lease obligations are secured by the leased property, disposition of the property in the event of foreclosure might prove difficult and the value of the property may be insufficient to issue lease obligations. Certain investments in lease obligations may be illiquid.

The ability of issuers of municipal leases to make timely lease payments may be adversely impacted in general economic downturns and as relative governmental cost burdens are allocated and reallocated among federal, state and local governmental units. Such non-payment would result in a reduction of income to the Trust, and could result

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in a reduction in the value of the municipal lease experiencing non-payment and a potential decrease in the NAV of the Trust. Issuers of municipal lease obligations might seek protection under the bankruptcy laws. In the event of bankruptcy of such an issuer, the Trust could experience delays and limitations with respect to the collection of principal and interest on such municipal leases and the Trust may not, in all circumstances, be able to collect all principal and interest to which it is entitled. To enforce its rights in the event of a default in lease payments, the Trust might take possession of and manage the assets securing the issuer’s obligations on such securities, which may increase the Trust’s operating expenses and adversely affect the NAV of the Trust. When the lease contains a non-appropriation clause, however, the failure to pay would not be a default and the Trust would not have the right to take possession of the assets. Any income derived from the Trust’s ownership or operation of such assets may not be tax-exempt or may fail to generate qualifying income for purposes of the income tests applicable to regulated investment companies. In addition, the Trust’s intention to qualify as a regulated investment company under the Code may limit the extent to which the Trust may exercise its rights by taking possession of such assets, because as a regulated investment company the Trust is subject to certain limitations on its investments and on the nature of its income.

Zero-Coupon Bonds. Municipal securities may include zero-coupon bonds. Zero-coupon bonds are securities that are sold at a discount to par value and do not pay interest during the life of the security. The discount approximates the total amount of interest the security will accrue and compound over the period until maturity at a rate of interest reflecting the market rate of the security at the time of issuance. Upon maturity, the holder of a zero-coupon bond is entitled to receive the par value of the security.

While interest payments are not made on such securities, holders of such securities are deemed to have received income (“phantom income”) annually, notwithstanding that cash may not be received currently. The effect of owning instruments that do not make current interest payments is that a fixed yield is earned not only on the original investment but also, in effect, on all discount accretion during the life of the obligations. This implicit reinvestment of earnings at a fixed rate eliminates the risk of being unable to invest distributions at a rate as high as the implicit yield on the zero-coupon bond, but at the same time eliminates the holder’s ability to reinvest at higher rates in the future. For this reason, some of these securities may be subject to substantially greater price fluctuations during periods of changing market interest rates than are comparable securities that pay interest currently. Longer term zero-coupon bonds are more exposed to interest rate risk than shorter term zero-coupon bonds. These investments benefit the issuer by mitigating its need for cash to meet debt service, but also require a higher rate of return to attract investors who are willing to defer receipt of cash.

The Trust accrues income with respect to these securities for U.S. federal income tax and accounting purposes prior to the receipt of cash payments. Zero-coupon bonds may be subject to greater fluctuation in value and less liquidity in the event of adverse market conditions than comparably rated securities that pay cash interest at regular intervals.

Further, to maintain its qualification for pass-through treatment under the federal tax laws, the Trust is required to distribute income to its shareholders and, consequently, may have to dispose of other, more liquid portfolio securities under disadvantageous circumstances or may have to leverage itself by borrowing in order to generate the cash to satisfy these distributions. The required distributions may result in an increase in the Trust’s exposure to zero-coupon bonds.

In addition to the above-described risks, there are certain other risks related to investing in zero-coupon bonds. During a period of severe market conditions, the market for such securities may become even less liquid. In addition, as these securities do not pay cash interest, the Trust’s investment exposure to these securities and their risks, including credit risk, will increase during the time these securities are held in the Trust’s portfolio.

Pre-Refunded Municipal Securities. The principal of, and interest on, pre-refunded municipal securities are no longer paid from the original revenue source for the securities. Instead, the source of such payments is typically an escrow fund consisting of U.S. Government securities. The assets in the escrow fund are derived from the proceeds of refunding bonds issued by the same issuer as the pre-refunded municipal securities. Issuers of municipal securities use this advance refunding technique to obtain more favorable terms with respect to securities that are not yet subject to call or redemption by the issuer. For example, advance refunding enables an issuer to refinance debt at lower market interest rates, restructure debt to improve cash flow or eliminate restrictive covenants in the indenture or other governing instrument for the pre-refunded municipal securities.

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However, except for a change in the revenue source from which principal and interest payments are made, the pre-refunded municipal securities remain outstanding on their original terms until they mature or are redeemed by the issuer.

Special Taxing Districts. Special taxing districts are organized to plan and finance infrastructure developments to induce residential, commercial and industrial growth and redevelopment. The bond financing methods such as tax increment finance, tax assessment, special services district and Mello-Roos bonds (a type of municipal security established by the Mello-Roos Community Facilities Act of 1982), are generally payable solely from taxes or other revenues attributable to the specific projects financed by the bonds without recourse to the credit or taxing power of related or overlapping municipalities. They often are exposed to real estate development-related risks and can have more taxpayer concentration risk than general tax-supported bonds, such as general obligation bonds. Further, the fees, special taxes, or tax allocations and other revenues that are established to secure such financings are generally limited as to the rate or amount that may be levied or assessed and are not subject to increase pursuant to rate covenants or municipal or corporate guarantees. The bonds could default if development failed to progress as anticipated or if larger taxpayers failed to pay the assessments, fees and taxes as provided in the financing plans of the districts.

Indexed and Inverse Floating Rate Securities. The Trust may invest in municipal securities (and Non-Municipal Tax-Exempt Securities) that yield a return based on a particular index of value or interest rates. For example, the Trust may invest in municipal securities that pay interest based on an index of municipal security interest rates. The principal amount payable upon maturity of certain municipal securities also may be based on the value of the index. To the extent the Trust invests in these types of municipal securities, the Trust’s return on such municipal securities will be subject to risk with respect to the value of the particular index. Interest and principal payable on the municipal securities may also be based on relative changes among particular indices. Also, the Trust may invest in so-called “inverse floating rate bonds” or “residual interest bonds” on which the interest rates vary inversely with a short-term floating rate (which may be reset periodically by a Dutch auction, a remarketing agent, or by reference to a short-term tax-exempt interest rate index). The Trust may purchase synthetically created inverse floating rate bonds evidenced by custodial or trust receipts. Generally, income on inverse floating rate bonds will decrease when short-term interest rates increase, and will increase when short-term interest rates decrease. Such securities have the effect of providing a degree of investment leverage, since they may increase or decrease in value in response to changes, as an illustration, in market interest rates at a rate which is a multiple (typically two) of the rate at which fixed rate long-term tax-exempt securities increase or decrease in response to such changes. As a result, the market values of such securities will generally be more volatile than the market values of fixed rate tax-exempt securities. To seek to limit the volatility of these securities, the Trust may purchase inverse floating rate bonds with shorter-term maturities or limitations on the extent to which the interest rate may vary. Certain investments in such obligations may be illiquid. See “The Trust’s Investments—Leverage—Tender Option Bond Transactions.”

When-Issued Securities, Delayed Delivery Securities and Forward Commitments. The Trust may purchase or sell securities that it is entitled to receive on a when-issued basis. The Trust may also purchase or sell securities on a delayed delivery basis. The Trust may also purchase or sell securities through a forward commitment. These transactions involve the purchase or sale of securities by the Trust at an established price with payment and delivery taking place in the future. The purchase will be recorded on the date the Trust enters into the commitment and the value of the securities will thereafter be reflected in the Trust’s NAV. The Trust has not established any limit on the percentage of its assets that may be committed in connection with these transactions. At the time the Trust enters into a transaction on a when-issued basis, it will segregate or designate on its books and records cash or liquid assets with a value not less than the value of the when-issued securities.

There can be no assurance that a security purchased on a when-issued basis will be issued or that a security purchased or sold through a forward commitment will be delivered. A default by a counterparty may result in the Trust missing the opportunity of obtaining a price considered to be advantageous. The value of securities in these transactions on the delivery date may be more or less than the Trust’s purchase price. The Trust may bear the risk of a decline in the value of the security in these transactions and may not benefit from an appreciation in the value of the security during the commitment period.

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If deemed advisable as a matter of investment strategy, the Trust may dispose of or renegotiate a commitment after it has been entered into, and may sell securities it has committed to purchase before those securities are delivered to the Trust on the settlement date. In these cases the Trust may realize a taxable capital gain or loss.

When the Trust engages in when-issued, delayed delivery or forward commitment transactions, it relies on the other party to consummate the trade. Failure of such party to do so may result in the Trust’s incurring a loss or missing an opportunity to obtain a price considered to be advantageous.

The market value of the securities underlying a commitment to purchase securities, and any subsequent fluctuations in their market value, is taken into account when determining the market value of the Trust starting on the day the Trust agrees to purchase the securities. The Trust does not earn interest on the securities it has committed to purchase until they are paid for and delivered on the settlement date.

Yields. Yields on municipal securities are dependent on a variety of factors, including the general condition of the money market and of the municipal security market, the size of a particular offering, the financial condition of the issuer, the maturity of the obligation and the rating of the issue. The ability of the Trust to achieve its investment objective is also dependent on the continuing ability of the issuers of the securities in which the Trust invests to meet their obligations for the payment of interest and principal when due. There are variations in the risks involved in holding municipal securities, both within a particular classification and between classifications, depending on numerous factors. Furthermore, the rights of owners of municipal securities and the obligations of the issuer of such municipal securities may be subject to applicable bankruptcy, insolvency and similar laws and court decisions affecting the rights of creditors generally and to general equitable principles, which may limit the enforcement of certain remedies.

“High Yield” or “Junk” Bonds. The Trust may invest up to 20% of its Managed Assets in securities rated below investment grade such as those rated Ba or below by Moody’s and BB or below by S&P or Fitch or in unrated securities determined by the Advisor to be of comparable quality. Information with respect to ratings assigned to tax-exempt obligations that the Trust may purchase is set forth in “Appendix A—Ratings of Investments” in the SAI. Municipal securities of below investment grade quality (“Ba/BB” or below) are commonly known as “junk bonds.” Securities rated below investment grade are judged to have speculative characteristics with respect to their interest and principal payments. Such securities may face major ongoing uncertainties or exposure to adverse business, financial or economic conditions which could lead to inadequate capacity to meet timely interest and principal payments.

Strategic Transactions

The Trust may engage in various strategic transactions for hedging and risk management purposes or to enhance total return (“Strategic Transactions”). Strategic Transactions involve the use of derivative instruments. Such instruments may include, but are not limited to, financial futures contracts, swap contracts (including, but not limited to, credit default swaps), options on financial futures, options on swap contracts and other derivative instruments. If the Trust engages in Strategic Transactions for hedging and risk management purposes, it primarily intends to use strategies that include swaps (including interest rate swaps), financial futures contracts, options on financial futures or options based either on an index of long-term securities or on taxable debt securities whose prices, in the opinion of the Advisor, correlate with the prices of the Trust’s investments. If the Trust engages in Strategic Transactions to enhance total return, it primarily intends to use the same strategies as discussed above for hedging and risk management purposes and, in addition, to engage in credit derivative transactions, including credit default swaps. There is no assurance that these derivative strategies will be available at any time or that the Advisor will determine to use them for hedging or risk management purposes or to enhance total return or, if used, that the strategies will be successful.

There is no particular strategy that requires use of one technique rather than another as the decision to use any particular strategy or instrument is a function of market conditions and the composition of the portfolio. The ability of the Trust to use Strategic Transactions successfully will depend on the Advisor’s ability to predict pertinent market movements as well as sufficient correlation among the instruments, which cannot be assured. Strategic Transactions subject the Trust to the risk that, if the Advisor incorrectly forecasts market values, interest rates or other applicable factors, the Trust’s performance could suffer. Certain of these Strategic Transactions, such as

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investments in inverse floating rate securities and credit default swaps, may provide investment leverage to the Trust’s portfolio. The Trust is not required to use derivatives or other portfolio strategies to seek to hedge its portfolio and may choose not to do so.

The use of Strategic Transactions may result in losses greater than if they had not been used, may require the Trust to sell or purchase portfolio securities at inopportune times or for prices other than current market values, may limit the amount of appreciation the Trust can realize on an investment or may cause the Trust to hold a security that it might otherwise sell. Furthermore, the Trust may only engage in Strategic Transactions from time to time and may not necessarily be engaging in hedging activities when movements in interest rates occur.

Inasmuch as any obligations of the Trust that arise from the use of Strategic Transactions will be covered by segregated or earmarked liquid assets or offsetting transactions, the Trust and the Advisor believe such obligations do not constitute senior securities and, accordingly, will not treat such transactions as being subject to its borrowing restrictions. Additionally, segregated or earmarked liquid assets, amounts paid by the Trust as premiums and cash or other assets held in margin accounts with respect to Strategic Transactions are not otherwise available to the Trust for investment purposes.

Certain federal income tax requirements may restrict or affect the ability of the Trust to engage in Strategic Transactions. In addition, the use of certain Strategic Transactions may give rise to taxable income and have certain other consequences.

Put and Call Options on Securities and Indices. The Trust may purchase and sell put and call options on securities and indices. A put option gives the purchaser of the option the right to sell and the writer the obligation to buy the underlying security at the exercise price during the option period. The Trust may also purchase and sell options on bond indices (“index options”). Index options are similar to options on securities except that, rather than taking or making delivery of securities underlying the option at a specified price upon exercise, an index option gives the holder the right to receive cash upon exercise of the option if the level of the bond index upon which the option is based is greater, in the case of a call, or less, in the case of a put, than the exercise price of the option. The purchase of a put option on a debt security could protect the Trust’s holdings in a security or a number of securities against a substantial decline in the market value. A call option gives the purchaser of the option the right to buy and the seller the obligation to sell the underlying security or index at the exercise price during the option period or for a specified period prior to a fixed date. The purchase of a call option on a security could protect the Trust against an increase in the price of a security that it intended to purchase in the future.

Writing Covered Call Options. The Trust is authorized to write (i.e., sell) covered call options with respect to municipal securities it owns, thereby giving the holder of the option the right to buy the underlying security covered by the option from the Trust at the stated exercise price until the option expires. The Trust writes only covered call options, which means that so long as the Trust is obligated as the writer of a call option, it will own the underlying securities subject to the option.

The Trust receives a premium from writing a call option, which increases the Trust’s return on the underlying security in the event the option expires unexercised or is closed out at a profit. By writing a call, the Trust limits its opportunity to profit from an increase in the market value of the underlying security above the exercise price of the option for as long as the Trust’s obligation as a writer continues. Covered call options serve as a partial hedge against a decline in the price of the underlying security. The Trust may engage in closing transactions in order to terminate outstanding options that it has written.

Additional Information About Options. The Trust’s ability to close out its position as a purchaser or seller of an exchange-listed put or call option is dependent upon the existence of a liquid secondary market on option exchanges. Among the possible reasons for the absence of a liquid secondary market on an exchange are: (i) insufficient trading interest in certain options; (ii) restrictions on transactions imposed by an exchange; (iii) trading halts, suspensions or other restrictions imposed with respect to particular classes or series of options or underlying securities; (iv) interruption of the normal operations on an exchange; (v) inadequacy of the facilities of an exchange or OCC to handle current trading volume; or (vi) a decision by one or more exchanges to discontinue the trading of options (or a particular class or series of options), in which event the secondary market on that exchange (or in that class or series of options) would cease to exist, although outstanding options on that exchange that had been listed by the

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OCC as a result of trades on that exchange would generally continue to be exercisable in accordance with their terms. OTC options are purchased from or sold to dealers, financial institutions or other counterparties which have entered into direct agreements with the Trust. With OTC options, such variables as expiration date, exercise price and premium will be agreed upon between the Trust and the counterparty, without the intermediation of a third party such as the OCC. If the counterparty fails to make or take delivery of the securities underlying an option it has written, or otherwise settle the transaction in accordance with the terms of that option as written, the Trust would lose the premium paid for the option as well as any anticipated benefit of the transaction. OTC options and assets used to cover OTC options written by the Trust are considered by the staff of the Securities and Exchange Commission (the “SEC”) to be illiquid. The illiquidity of such options or assets may prevent a successful sale of such options or assets, result in a delay of sale, or reduce the amount of proceeds that might otherwise be realized.

The Trust may engage in options and futures transactions on exchanges and options in the over-the-counter markets. The Trust will only enter into OTC options with counterparties the Advisor believes to be creditworthy at the time they enter into such transactions.

The hours of trading for options on debt securities may not conform to the hours during which the underlying securities are traded. To the extent that the option markets close before the markets for the underlying securities, significant price and rate movements can take place in the underlying markets that cannot be reflected in the option markets.

Financial Futures Transactions and Options. The Trust is authorized to purchase and sell certain exchange traded financial futures contracts (“financial futures contracts”) in order to hedge its investments against declines in value, and to hedge against increases in the cost of securities it intends to purchase or to seek to enhance the Trust’s return. However, any transactions involving financial futures or options (including puts and calls associated therewith) will be in accordance with the Trust’s investment policies and limitations. A financial futures contract obligates the seller of a contract to deliver and the purchaser of a contract to take delivery of the type of financial instrument covered by the contract, or in the case of index-based futures contracts to make and accept a cash settlement, at a specific future time for a specified price. To hedge its portfolio, the Trust may take an investment position in a futures contract which will move in the opposite direction from the portfolio position being hedged. A sale of financial futures contracts may provide a hedge against a decline in the value of portfolio securities because such depreciation may be offset, in whole or in part, by an increase in the value of the position in the financial futures contracts. A purchase of financial futures contracts may provide a hedge against an increase in the cost of securities intended to be purchased because such appreciation may be offset, in whole or in part, by an increase in the value of the position in the futures contracts.

Distributions, if any, of net long-term capital gains from certain transactions in futures or options are taxable at long-term capital gains rates for U.S. federal income tax purposes.

Futures Contracts. A futures contract is an agreement between two parties to buy and sell a security or, in the case of an index-based futures contract, to make and accept a cash settlement for a set price on a future date. A majority of transactions in futures contracts, however, do not result in the actual delivery of the underlying instrument or cash settlement, but are settled through liquidation, i.e., by entering into an offsetting transaction. Futures contracts have been designed by boards of trade which have been designated “contracts markets” by the CFTC.

The purchase or sale of a futures contract differs from the purchase or sale of a security in that no price or premium is paid or received. Instead, an amount of cash or securities acceptable to the broker and the relevant contract market, which varies, but is generally about 5% of the contract amount, must be deposited with the broker. This amount is known as “initial margin” and represents a “good faith” deposit assuring the performance of both the purchaser and seller under the futures contract. Subsequent payments to and from the broker, called “variation margin,” are required to be made on a daily basis as the price of the futures contract fluctuates making the long and short positions in the futures contract more or less valuable, a process known as “marking to the market.” At any time prior to the settlement date of the futures contract, the position may be closed out by taking an opposite position that will operate to terminate the position in the futures contract. A final determination of variation margin is then made, additional cash is required to be paid to or released by the broker and the purchaser realizes a loss or gain. In addition, a nominal commission is paid on each completed sale transaction.

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The Trust may also purchase and sell financial futures contracts on U.S. Government securities as a hedge against adverse changes in interest rates as described below. With respect to U.S. Government securities, currently there are financial futures contracts based on long-term U.S. Treasury bonds, U.S. Treasury notes, Government National Mortgage Association (“GNMA”) Certificates and three-month U.S. Treasury bills. The Trust may purchase and write call and put options on futures contracts on U.S. Government securities and purchase and sell municipal security index futures contracts in connection with its hedging strategies.

The Trust also may engage in other futures contracts transactions such as futures contracts on other municipal bond indices that may become available if the Advisor should determine that there is normally a sufficient correlation between the prices of such futures contracts and the municipal securities in which the Trust invests to make such hedging appropriate.

Futures Strategies. The Trust may sell a financial futures contract (i.e., assume a short position) in anticipation of a decline in the value of its investments resulting from an increase in interest rates or otherwise. The risk of decline could be reduced without employing futures as a hedge by selling investments and either reinvesting the proceeds in securities with shorter maturities or by holding assets in cash. This strategy, however, entails increased transaction costs in the form of dealer spreads and typically would reduce the average yield of the Trust’s portfolio securities as a result of the shortening of maturities. The sale of futures contracts provides an alternative means of hedging against declines in the value of its investments. As such values decline, the value of the Trust’s positions in the futures contracts will tend to increase, thus offsetting all or a portion of the depreciation in the market value of the Trust’s investments that are being hedged. While the Trust will incur commission expenses in selling and closing out futures positions, commissions on futures transactions are typically lower than transaction costs incurred in the purchase and sale of the Trust’s investments being hedged. In addition, the ability of the Trust to trade in the standardized contracts available in the futures markets may offer a more effective defensive position than a program to reduce the average maturity of the portfolio securities due to the unique and varied credit and technical characteristics of the instruments available to the Trust. Employing futures as a hedge also may permit the Trust to assume a defensive posture without reducing the yield on its investments beyond any amounts required to engage in futures trading.

When the Trust intends to purchase a security, the Trust may purchase futures contracts as a hedge against any increase in the cost of such security resulting from a decrease in interest rates or otherwise, that may occur before such purchase can be effected. Subject to the degree of correlation between such securities and the futures contracts, subsequent increases in the cost of such securities should be reflected in the value of the futures held by the Trust. As such purchases are made, an equivalent amount of futures contracts will be closed out. Due to changing market conditions and interest rate forecasts, however, a futures position may be terminated without a corresponding purchase of portfolio securities.

Call Options on Futures Contracts. The Trust may also purchase and sell exchange traded call and put options on financial futures contracts. The purchase of a call option on a futures contract is analogous to the purchase of a call option on an individual security. Depending on the pricing of the option compared to either the futures contract upon which it is based or the price of the underlying securities, it may or may not be less risky than ownership of the futures contract or underlying securities. Like the purchase of a futures contract, the Trust may purchase a call option on a futures contract to hedge against a market advance when the Trust is not fully invested.

The writing of a call option on a futures contract constitutes a partial hedge against declining prices of the securities which are deliverable upon exercise of the futures contract. If the futures price at expiration is below the exercise price, the Trust will retain the full amount of the option premium, which provides a partial hedge against any decline that may have occurred in the Trust’s portfolio holdings.

Put Options on Futures Contracts. The purchase of a put option on a futures contract is analogous to the purchase of a protective put option on portfolio securities. The Trust may purchase a put option on a futures contract to hedge the Trust’s portfolio against the risk of rising interest rates.

The writing of a put option on a futures contract constitutes a partial hedge against increasing prices of the securities which are deliverable upon exercise of the futures contract. If the futures price at expiration is higher than the

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exercise price, the Trust will retain the full amount of the option premium, which provides a partial hedge against any increase in the price of securities which the Trust intends to purchase.

The writer of an option on a futures contract is required to deposit initial and variation margin pursuant to requirements similar to those applicable to futures contracts. Premiums received from the writing of an option will be included in initial margin. The writing of an option on a futures contract involves risks similar to those relating to futures contracts.

The CFTC subjects advisers to registered investment companies to regulation by the CFTC if a fund that is advised by the investment adviser either (i) invests, directly or indirectly, more than a prescribed level of its liquidation value in CFTC-regulated futures, options and swaps (“CFTC Derivatives”), or (ii) markets itself as providing investment exposure to such instruments. To the extent the Trust uses CFTC Derivatives, it intends to do so below such prescribed levels and will not market itself as a “commodity pool” or a vehicle for trading such instruments. Accordingly, the Advisor has claimed an exclusion from the definition of the term “commodity pool operator” under the Commodity Exchange Act (“CEA”) pursuant to Rule 4.5 under the CEA. The Advisor is not, therefore, subject to registration or regulation as a “commodity pool operator” under the CEA in respect of the Trust.

Counterparty Credit Standards. To the extent that the Trust engages in principal transactions, including, but not limited to, OTC options, forward currency transactions, swap transactions, repurchase and reverse repurchase agreements and the purchase and sale of bonds and other fixed-income securities, it must rely on the creditworthiness of its counterparties under such transactions. In certain instances, the credit risk of a counterparty is increased by the lack of a central clearing house for certain transactions, including certain swap contracts. In the event of the insolvency of a counterparty, the Trust may not be able to recover its assets, in full or at all, during the insolvency process. Counterparties to investments may have no obligation to make markets in such investments and may have the ability to apply essentially discretionary margin and credit requirements. Similarly, the Trust will be subject to the risk of bankruptcy of, or the inability or refusal to perform with respect to such investments by, the counterparties with which it deals. The Advisor will seek to minimize the Trust’s exposure to counterparty risk by entering into such transactions with counterparties the Advisor believes to be creditworthy at the time it enters into the transaction. Certain option transactions and Strategic Transactions may require the Trust to provide collateral to secure its performance obligations under a contract, which would also entail counterparty credit risk.

LEVERAGE

The Trust intends to use leverage to seek to achieve its investment objectives. The Trust may use leverage by investing in derivative instruments with leverage embedded in them, such as reverse repurchase agreements and TOBs Residuals. The Trust may use combined economic leverage of up to 100% of its net assets (50% of its Managed Assets), all or a portion of which may be effected through the use of reverse repurchase agreements or TOBs Residuals. The Trust may also, but does not currently intend to, use leverage by borrowing funds from banks or other financial institutions, by issuing preferred shares or by any other means permitted under the Investment Company Act. The Trust is permitted to borrow money or issue debt securities in an amount up to 33 1/3% of its Managed Assets (50% of its net assets), and issue preferred shares in an amount up to 50% of its Managed Assets (100% of its net assets).

The use of leverage, including investments in reverse repurchase agreements and TOBs Residuals, can create risks. When leverage is employed, the NAV and market price of the common shares and the yield to holders of common shares will be more volatile than if leverage were not used. Changes in the value of the Trust’s portfolio, including securities bought with the proceeds of leverage, will be borne entirely by the holders of common shares. If there is a net decrease or increase in the value of the Trust’s investment portfolio, leverage will decrease or increase, as the case may be, the NAV per common share to a greater extent than if the Trust did not utilize leverage. A reduction in the Trust’s NAV may cause a reduction in the market price of its shares. During periods in which the Trust is using leverage, the fees paid to the Advisor for advisory and sub-advisory services will be higher than if the Trust did not use leverage, because the fees paid will be calculated on the basis of the Trust’s Managed Assets, which includes the proceeds from leverage. The Trust’s leveraging strategy may not be successful.

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Certain types of borrowings by the Trust may result in the Trust being subject to covenants in credit agreements relating to asset coverage and portfolio composition requirements. The Trust may be subject to certain restrictions on investments imposed by one or more lenders or by guidelines of one or more rating agencies, which may issue ratings for any short-term debt securities or preferred shares issued by the Trust. These guidelines may impose asset coverage or portfolio composition requirements that are more stringent than those imposed by the Investment Company Act. The Advisor does not believe that these covenants or guidelines will impede it from managing the Trust’s portfolio in accordance with its investment objectives and policies if the Trust were to utilize leverage. To the extent permitted, the Board of Trustees of the Trust may modify the Trust’s borrowing policies, including the purposes of borrowings, and the length of time that the Trust may hold portfolio securities purchased with borrowed money. The rights of any lenders to the Trust to receive payments of interest or repayments of principal may be senior to those of the shareholders.

Under the Investment Company Act, the Trust is not permitted to borrow for any purposes if, immediately after such borrowing, the Trust would have an asset coverage ratio (as defined in the Investment Company Act) of less than 300% with respect to indebtedness or less than 200% with respect to preferred stock. The Investment Company Act also provides that the Trust may not declare distributions, or purchase its stock (including through tender offers), if immediately after doing so it will have an asset coverage ratio of less than 300% or 200%, as applicable. Under the Investment Company Act, certain short-term borrowings (such as for cash management purposes) are not subject to these limitations if (i) repaid within 60 days, (ii) not extended or renewed, and (iii) which are not in excess of 5% of the total assets of a Trust.

The use of TOBs Residuals will require the Trust to earmark or segregate liquid assets in an amount equal to any TOBs Floaters, plus any accrued but unpaid interest due on the TOBs Floaters, issued by TOBs Issuers sponsored on behalf of the Trust that are not owned by the Trust. The use of a reverse repurchase agreement will require the Trust to earmark or segregate liquid assets in an amount equal to the Trust’s repurchase obligation under the reverse repurchase agreement. The Trust will not earmark or segregate assets transferred to a TOBs Issuer or a reverse repurchase agreement counterparty. The Trust reserves the right to modify its asset segregation policies in the future to the extent that such changes are in accordance with applicable regulations or interpretations.

Effects of Leverage

Assuming that leverage will represent approximately 32.70% of the Trust’s Managed Assets and that the Trust will bear expenses relating to that leverage at an average annual rate of 1.89%, the income generated by the Trust’s portfolio (net of estimated expenses) must exceed 0.62% in order to cover the expenses specifically related to the Trust’s use of leverage. Of course, these numbers are merely estimates used for illustration. Actual leverage expenses will vary frequently and may be significantly higher or lower than the rate estimated above.

The following table is furnished in response to requirements of the SEC. It is designed to illustrate the effect of leverage on common share total return, assuming investment portfolio total returns (comprised of income and changes in the value of investments held in the Trust’s portfolio) of (10)%, (5)%, 0%, 5% and 10%. These assumed investment portfolio returns are hypothetical figures and are not necessarily indicative of the investment portfolio returns experienced or expected to be experienced by the Trust. The table further reflects the use of leverage representing 32.7% of the Trust’s Managed Assets and an assumed annual cost of leverage of 1.89%.

Common share total return is composed of two elements: the common share dividends paid by the Trust (the amount of which is largely determined by the net investment income of the Trust after paying for any leverage used by the Trust) and gains or losses on the value of the securities the Trust owns. As required by SEC rules, the table assumes that the Trust is more likely to suffer capital losses than to enjoy capital appreciation. For example, to assume a total return of 0% the Trust must assume that the interest it receives on its investments is entirely offset by losses in the value of those securities.

Reverse Repurchase Agreements

Borrowings may be made by the Trust through reverse repurchase agreements under which the Trust sells portfolio securities to financial institutions, such as banks and broker-dealers, and agrees to repurchase them at an agreed upon date and price. Such agreements are considered to be borrowings under the Investment Company Act. The Trust may utilize reverse repurchase agreements when it is anticipated that the interest income to be earned from the investment of the proceeds of the transaction is greater than the interest expense of the transaction.

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Tender Option Bond Transactions

The Trust currently leverages its assets through the use of TOB Residuals, which are derivative interests in municipal bonds. The TOB Residuals in which the Trust will invest pay interest or income that, in the opinion of counsel to the issuer of such TOB Residuals, is exempt from regular U.S. federal income tax. No independent investigation will be made to confirm the tax-exempt status of the interest or income paid by TOB Residuals held by the Trust. Although volatile, TOB Residuals typically offer the potential for yields exceeding the yields available on fixed rate municipal bonds with comparable credit quality.

TOB Residuals represent beneficial interests in a TOB Trust formed for the purpose of holding municipal bonds contributed by one or more funds. A TOB Trust typically issues two classes of beneficial interests: TOB Floaters, which are sold to third party investors, and TOB Residuals, which are generally issued to the fund(s) that transferred municipal bonds to the TOB Trust. The Trust may invest in both TOB Floaters and TOB Residuals. TOB Floaters may have first priority on the cash flow from the municipal bonds held by the TOB Trust and are enhanced with a liquidity support arrangement from a third party TOBs Liquidity Provider (defined below) which allows holders to tender their position at par (plus accrued interest). The Trust, as a holder of TOB Residuals, is paid the residual cash flow from the TOB Trust. The Trust contributes municipal bonds to the TOB Trust and is paid the cash received by the TOB Trust from the sale of the TOB Floaters, less certain transaction costs, and typically will invest the cash to purchase additional municipal bonds or other investments permitted by its investment policies. If the Trust ever purchases all or a portion of the TOB Floaters sold by the TOB Trust, it may surrender those TOB Floaters together with a proportionate amount of TOB Residuals to the TOB Trust in exchange for a proportionate amount of the municipal bonds owned by the TOB Trust.

Other BlackRock-advised Funds (as defined below) may contribute municipal bonds to a TOB Trust into which the Trust has contributed municipal bonds. If multiple BlackRock-advised Funds participate in the same TOB Trust, the economic rights and obligations under the TOB Residual will generally be shared among the funds ratably in proportion to their participation in the TOB Trust.

The municipal bonds transferred to a TOB Trust typically are high grade municipal bonds. In certain cases, when municipal bonds transferred are lower grade municipal bonds, the TOB Trust transaction includes a credit enhancement feature that provides for the timely payment of principal and interest on the bonds to the TOB Trust by a credit enhancement provider. The TOB Trust would be responsible for the payment of the credit enhancement fee and the Trust, as a TOB Residual holder, would be responsible for reimbursement of any payments of principal and interest made by the credit enhancement provider.

The TOB Residuals held by the Trust generally provide the Trust with the right to cause the holders of a proportional share of the TOB Floaters to tender their notes to the TOB Trust at par plus accrued interest. Thereafter, the Trust may withdraw a corresponding share of the municipal bonds from the TOB Trust. As a result, a tender option bond transaction, in effect, creates exposure for the Trust to the entire return of the municipal bonds in the TOB Trust, with a net cash investment by the Trust that is less than the value of the municipal bonds in the TOB Trust. This multiplies the positive or negative impact of the municipal bonds’ return within the Trust (thereby creating leverage). The leverage within a TOB Trust depends on the value of the municipal bonds deposited in the TOB Trust relative to the value of the TOB Floaters it issues.

The Trust may invest in highly leveraged TOB Residuals. A TOB Residual generally is considered highly leveraged if the principal amount of the TOB Floaters issued by the related TOB Trust exceeds 75% of the principal amount of the municipal bonds owned by the TOB Trust.

The leverage attributable to the Trust’s use of TOB Residuals may be “called away” on relatively short notice and therefore may be less permanent than more traditional forms of leverage. The TOB Trust may be collapsed without the consent of the Trust upon the occurrence of termination events, as defined in the TOB Trust agreements. Upon the occurrence of a termination event, a TOB Trust would be liquidated with the proceeds applied first to any accrued fees owed to the trustee of the TOB Trust, the remarketing agent of the TOB Floaters and the TOBs Liquidity Provider. Upon certain termination events, the holders of the TOB Floaters would be paid before the TOB Residual holders (i.e., the Trust) whereas in other termination events, the holders of TOB Floaters and the TOB Residual holders would be paid pro rata.

TOB Trusts are typically supported by a liquidity facility provided by a TOBs Liquidity Provider that allows the holders of the TOB Floaters to tender their TOB Floaters in exchange for payment of par plus accrued interest on any business day (subject to the non-occurrence of a termination event). The tendered TOB Floaters are remarketed

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by a remarketing agent. In the event of a failed remarketing, the TOB Trust may draw upon a loan from the TOBs Liquidity Provider to purchase the tendered TOB Floaters. Any loans made by the TOBs Liquidity Provider will be secured by the purchased TOB Floaters held by the TOB Trust and will be subject to an increased interest rate based on number of days the loan is outstanding.

The Trust may invest in a TOB Trust on either a non-recourse or recourse basis. When the Trust invests in TOB Trusts on a non-recourse basis, and the TOBs Liquidity Provider is required to make a payment under the liquidity facility, the TOBs Liquidity Provider will typically liquidate all or a portion of the municipal bonds held in the TOB Trust and then fund the balance, if any, of the Liquidation Shortfall. If the Trust invests in a TOB Trust on a recourse basis, it will typically enter into a reimbursement agreement with the TOBs Liquidity Provider pursuant to which the Trust is required to reimburse the TOBs Liquidity Provider the amount of any Liquidation Shortfall. As a result, if the Trust invests in a recourse TOB Trust, the Trust will bear the risk of loss with respect to any Liquidation Shortfall. If multiple BlackRock-advised Funds participate in any such TOB Trust, these losses will be shared ratably, in proportion to their participation in the TOB Trust.

Under accounting rules, Municipal Bonds of the Trust that are deposited into a TOB Trust are investments of the Trust and are presented on the Trust’s Schedule of Investments and outstanding TOB Floaters issued by a TOB Trust are presented as liabilities in the Trust’s Statement of Assets and Liabilities. Interest income from the underlying Municipal Bonds is recorded by the Trust on an accrual basis. Interest expense incurred on the TOB Floaters and other expenses related to remarketing, administration, trustee and other services to a TOB Trust are reported as expenses of the Trust. In addition, under accounting rules, loans made to a TOB Trust sponsored by the Trust may be presented as loans of the Trust in the Trust’s financial statements even if there is no recourse to the Trust’s assets.

For TOB Floaters, generally, the interest rate earned will be based upon the market rates for municipal bonds with maturities or remarketing provisions that are comparable in duration to the periodic interval of the tender option. Since the tender option feature has a shorter term than the final maturity or first call date of the underlying municipal bonds deposited in the TOB Trust, the holder of the TOB Floaters relies upon the terms of the agreement with the financial institution furnishing the liquidity facility as well as the credit strength of that institution. The perceived reliability and creditworthiness, of many major financial institutions, some of which sponsor and/or provide liquidity support to TOB Trusts increases the risk associated with TOB Floaters. This in turn may reduce the desirability of TOB Floaters as investments, which could impair the viability or availability of TOB Trusts.

The use of TOB Residuals will require the Trust to earmark or segregate liquid assets in an amount equal to any TOB Floaters, plus any accrued but unpaid interest due on the TOB Floaters, issued by TOB Trusts sponsored by, or on behalf of, the Trust that are not owned by the Trust. The use of TOB Residuals may also require the Trust to earmark or segregate liquid assets in an amount equal to loans provided by the TOBs Liquidity Provider to the TOB Trust to purchase tendered TOB Floaters. The Trust reserves the right to modify its asset segregation policies in the future to the extent that such changes are in accordance with applicable regulations or interpretations. Future regulatory requirements or SEC guidance may necessitate more onerous contractual or regulatory requirements, which may increase the costs or reduce the degree of potential economic benefits of TOB Trust transactions or limit the Trust’s ability to enter into or manage TOB Trust transactions.

Credit Facility

The Trust may borrow through a credit facility. If the Trust enters into a credit facility, the Trust may be required to prepay outstanding amounts or incur a penalty rate of interest upon the occurrence of certain events of default. The

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Trust would also likely have to indemnify the lenders under the credit facility against liabilities they may incur in connection therewith. In addition, the Trust expects that any credit facility would contain covenants that, among other things, likely would limit the Trust’s ability to pay distributions in certain circumstances, incur additional debt, change certain of its investment policies and engage in certain transactions, including mergers and consolidations, and require asset coverage ratios in addition to those required by the Investment Company Act. The Trust may be required to pledge its assets and to maintain a portion of its assets in cash or high-grade securities as a reserve against interest or principal payments and expenses. The Trust expects that any credit facility would have customary covenant, negative covenant and default provisions. There can be no assurance that the Trust will enter into an agreement for a credit facility or one on terms and conditions representative of the foregoing, or that additional material terms will not apply. In addition, if entered into, a credit facility may in the future be replaced or refinanced by one or more credit facilities having substantially different terms or by the issuance of preferred shares.

Preferred Shares

The Trust is permitted to leverage its portfolio by issuing preferred shares. Under the Investment Company Act, the Trust is not permitted to issue preferred shares if, immediately after such issuance, the liquidation value of the Trust’s outstanding preferred shares exceeds 50% of its assets (including the proceeds from the issuance) less liabilities other than borrowings (i.e., the value of the Trust’s assets must be at least 200% of the liquidation value of its outstanding preferred shares). In addition, the Trust would not be permitted to declare any cash dividend or other distribution on its common shares unless, at the time of such declaration, the value of the Trust’s assets less liabilities other than borrowings is at least 200% of such liquidation value.

The Trust expects that preferred shares, if issued, will pay adjustable rate dividends based on shorter-term interest rates, which would be redetermined periodically by a fixed spread or remarketing process, subject to a maximum rate which would increase over time in the event of an extended period of unsuccessful remarketing. The adjustment period for preferred share dividends could be as short as one day or as long as a year or more. Preferred shares, if issued, could include a liquidity feature that allows holders of preferred shares to have their shares purchased by a liquidity provider in the event that sell orders have not been matched with purchase orders and successfully settled in a remarketing. The Trust expects that it would pay a fee to the provider of this liquidity feature, which would be borne by common shareholders of the Trust. The terms of such liquidity feature could require the Trust to redeem preferred shares still owned by the liquidity provider following a certain period of continuous, unsuccessful remarketing, which may adversely impact the Trust.

If preferred shares are issued, the Trust may, to the extent possible, purchase or redeem preferred shares from time to time to the extent necessary in order to maintain asset coverage of any preferred shares of at least 200%. In addition, as a condition to obtaining ratings on the preferred shares, the terms of any preferred shares issued are expected to include asset coverage maintenance provisions which will require the redemption of the preferred shares in the event of non-compliance by the Trust and may also prohibit dividends and other distributions on the common shares in such circumstances. In order to meet redemption requirements, the Trust may have to liquidate portfolio securities. Such liquidations and redemptions would cause the Trust to incur related transaction costs and could result in capital losses to the Trust. Prohibitions on dividends and other distributions on the common shares could impair the Trust’s ability to qualify as a RIC under the Code. If the Trust has preferred shares outstanding, two of the Directors will be elected by the holders of preferred shares voting separately as a class. The remaining Directors will be elected by holders of common shares and preferred shares voting together as a single class. In the event the Trust failed to pay dividends on preferred shares for two years, holders of preferred shares would be entitled to elect a majority of the Directors.

If the Trust issues preferred shares, the Trust expects that it will be subject to certain restrictions imposed by guidelines of one or more rating agencies that may issue ratings for preferred shares issued by the Trust. These guidelines are expected to impose asset coverage or portfolio composition requirements that are more stringent than those imposed on the Trust by the Investment Company Act. It is not anticipated that these covenants or guidelines would impede the Advisor from managing the Trust’s portfolio in accordance with the Trust’s investment objective and policies.

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Derivatives

The Trust may enter into derivative transactions that have economic leverage embedded in them. Derivative transactions that the Trust may enter into and the risks associated with them are described elsewhere in this Prospectus and are also referred to as “Strategic Transactions.” The Trust cannot assure you that investments in derivative transactions that have economic leverage embedded in them will result in a higher return on its common shares.

To the extent the terms of such transactions obligate the Trust to make payments, the Trust may earmark or segregate cash or liquid assets in an amount at least equal to the current value of the amount then payable by the Trust under the terms of such transactions or otherwise cover such transactions in accordance with applicable interpretations of the staff of the SEC. If the current value of the amount then payable by the Trust under the terms of such transactions is represented by the notional amounts of such investments, the Trust would segregate or earmark cash or liquid assets having a market value at least equal to such notional amounts, and if the current value of the amount then payable by the Trust under the terms of such transactions is represented by the market value of the Trust’s current obligations, the Trust would segregate or earmark cash or liquid assets having a market value at least equal to such current obligations. To the extent the terms of such transactions obligate the Trust to deliver particular securities to extinguish the Trust’s obligations under such transactions the Trust may “cover” its obligations under such transactions by either (i) owning the securities or collateral underlying such transactions or (ii) having an absolute and immediate right to acquire such securities or collateral without additional cash consideration (or, if additional cash consideration is required, having earmarked or segregated an appropriate amount of cash or liquid assets). Such earmarking, segregation or cover is intended to provide the Trust with available assets to satisfy its obligations under such transactions. As a result of such earmarking, segregation or cover, the Trust’s obligations under such transactions will not be considered senior securities representing indebtedness for purposes of the Investment Company Act, or considered borrowings subject to the Trust’s limitations on borrowings discussed above, but may create leverage for the Trust. To the extent that the Trust’s obligations under such transactions are not so earmarked, segregated or covered, such obligations may be considered “senior securities representing indebtedness” under the Investment Company Act and therefore subject to the 300% asset coverage requirement.

These earmarking, segregation or cover requirements can result in the Trust maintaining securities positions it would otherwise liquidate, segregating or earmarking assets at a time when it might be disadvantageous to do so or otherwise restrict portfolio management.

On October 28, 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies (“Rule 18f-4”). The Trust will be required to implement and comply with Rule 18f-4 by August 19, 2022. Once implemented, Rule 18f-4 will impose limits on the amount of derivatives a fund can enter into, eliminate the asset segregation framework currently used by funds to comply with Section 18 of the Investment Company Act, treat derivatives as senior securities and require funds whose use of derivatives is more than a limited specified exposure amount to establish and maintain a comprehensive derivatives risk management program and appoint a derivatives risk manager.

Temporary Borrowings

The Trust may also borrow money as a temporary measure for extraordinary or emergency purposes, including the payment of dividends and the settlement of securities transactions which otherwise might require untimely dispositions of Trust securities.

RISKS

The NAV and market price of, and dividends paid on, the common shares will fluctuate with and be affected by, among other things, the risks of investing in the Trust.

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General Risks

Please refer to the section of the Trust’s most recent annual report on Form N-CSR entitled “Trust Investment Objectives, Policies and Risks—Risk Factors”, which is incorporated by reference herein, for a discussion of the general risks of investing in the Trust.

Other Risks

Risk Associated with Recent Market Events

Stresses associated with the 2008 financial crisis in the United States and global economies peaked approximately a decade ago, but periods of unusually high volatility in the financial markets and restrictive credit conditions, sometimes limited to a particular sector or a geography, continue to recur. Some countries, including the United States, have adopted and/or are considering the adoption of more protectionist trade policies, a move away from the tighter financial industry regulations that followed the financial crisis, and/or substantially reducing corporate taxes. The exact shape of these policies is still being considered, but the equity and debt markets may react strongly to expectations of change, which could increase volatility, especially if the market’s expectations are not borne out. A rise in protectionist trade policies, and the possibility of changes to some international trade agreements, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, geopolitical and other risks, including environmental and public health, may add to instability in world economies and markets generally. Economies and financial markets throughout the world are becoming increasingly interconnected. As a result, whether or not the Trust invests in securities of issuers located in or with significant exposure to countries experiencing economic, political and/or financial difficulties, the value and liquidity of the Trust’s investments may be negatively affected by such events.

An outbreak of respiratory disease caused by a novel coronavirus was first detected in China in December 2019 and has now developed into a global pandemic. The pandemic has resulted in closing borders, enhanced health screenings, healthcare service preparation and delivery, quarantines, cancellations, disruptions to supply chains and customer activity, as well as general concern and uncertainty. The impact of this pandemic, and other pandemics and epidemics that may arise in the future, could affect the economies of many nations, individual companies and the markets in general in ways that cannot necessarily be foreseen at the present time. In addition, the impact of infectious diseases in developing or emerging market countries may be greater due to less established health care systems. Health crises caused by the novel coronavirus pandemic may exacerbate other pre-existing political, social and economic risks in certain countries. The impact of the pandemic may last for an extended period of time.

LIBOR Risk

The Trust may be exposed to financial instruments that are tied to the London Interbank Offered Rate (“LIBOR”) to determine payment obligations, financing terms, hedging strategies or investment value. The Trust’s investments may pay interest at floating rates based on LIBOR or may be subject to interest caps or floors based on LIBOR. The Trust may also obtain financing at floating rates based on LIBOR. Derivative instruments utilized by the Trust may also reference LIBOR.

In 2017, the head of the United Kingdom’s Financial Conduct Authority announced a desire to phase out the use of LIBOR by the end of 2021, and it is expected that LIBOR will cease to be published after that time. The Trust may have investments linked to other interbank offered rates, such as the Euro Overnight Index Average (“EONIA”), which may also cease to be published. Various financial industry groups have begun planning for the transition away from LIBOR, but there are challenges to converting certain securities and transactions to a new reference rate (e.g., the Secured Overnight Financing Rate (“SOFR”), which is intended to replace the U.S. dollar LIBOR).

Neither the effect of the LIBOR transition process nor its ultimate success can yet be known. The transition process might lead to increased volatility and illiquidity in markets for, and reduce the effectiveness of new hedges placed against, instruments whose terms currently include LIBOR. While some existing LIBOR-based instruments may contemplate a scenario where LIBOR is no longer available by providing for an alternative rate-setting methodology, there may be significant uncertainty regarding the effectiveness of any such alternative methodologies to replicate LIBOR. Not all existing LIBOR-based instruments may have alternative rate-setting provisions and there remains uncertainty regarding the willingness and ability of issuers to add alternative rate-setting provisions in

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certain existing instruments. In addition, a liquid market for newly issued instruments that use a reference rate other than LIBOR still may be developing. There may also be challenges for the Trust to enter into hedging transactions against such newly issued instruments until a market for such hedging transactions develops. All of the aforementioned may adversely affect the Trust’s performance or NAV.

Market Disruption and Geopolitical Risk

The occurrence of events similar to those in recent years, such as the aftermath of the war in Iraq, instability in Afghanistan, Pakistan, Egypt, Libya, Syria, Russia, Ukraine and the Middle East, new and ongoing epidemics and pandemics of infectious diseases and other global health events, natural/environmental disasters, terrorist attacks in the United States and around the world, social and political discord, debt crises (such as the Greek crisis), sovereign debt downgrades, increasingly strained relations between the United States and a number of foreign countries, including traditional allies, such as certain European countries, and historical adversaries, such as North Korea, Iran, China and Russia, and the international community generally, new and continued political unrest in various countries, such as Venezuela and Spain, the exit or potential exit of one or more countries from the EU or the EMU, and continued changes in the balance of political power among and within the branches of the U.S. government, among others, may result in market volatility, may have long term effects on the U.S. and worldwide financial markets, and may cause further economic uncertainties in the United States and worldwide. The coronavirus pandemic has led to illiquidity and volatility in the municipal bond markets and may lead to downgrades in the credit quality of certain municipal issuers.

China and the United States have each recently imposed tariffs on the other country’s products. These actions may trigger a significant reduction in international trade, the oversupply of certain manufactured goods, substantial price reductions of goods and possible failure of individual companies and/or large segments of China’s export industry, which could have a negative impact on the Trust’s performance. U.S. companies that source material and goods from China and those that make large amounts of sales in China would be particularly vulnerable to an escalation of trade tensions. Uncertainty regarding the outcome of the trade tensions and the potential for a trade war could cause the U.S. dollar to decline against safe haven currencies, such as the Japanese yen and the Euro. Events such as these and their consequences are difficult to predict and it is unclear whether further tariffs may be imposed or other escalating actions may be taken in the future.

The decision made in the British referendum of June 23, 2016 to leave the EU, an event widely referred to as “Brexit,” has led to volatility in the financial markets of the United Kingdom (“UK”) and more broadly across Europe and may also lead to weakening in consumer, corporate and financial confidence in such markets. Pursuant to an agreement between the UK and the EU, the UK left the EU on January 31, 2020. The UK and EU have reached an agreement effective January 1, 2021 on the terms of their future trading relationship relating principally to the trading of goods; however, negotiations are ongoing for matters not covered by the agreement, such as the trade of financial services. The longer term economic, legal, political and social framework to be put in place between the UK and the EU remains unclear at this stage and ongoing political and economic uncertainty and periods of exacerbated volatility in both the UK and in wider European markets may continue for some time. In particular, the decision made in the British referendum may lead to a call for similar referendums in other European jurisdictions which may cause increased economic volatility in the European and global markets. This uncertainty may have an adverse effect on the economy generally and on the ability of the Trust and its investments to execute their respective strategies and to receive attractive returns. In particular, currency volatility may mean that the returns of the Trust and its investments are adversely affected by market movements and may make it more difficult, or more expensive, if the Trust elects to execute currency hedges. Potential decline in the value of the British Pound and/or the Euro against other currencies, along with the potential downgrading of the UK’s sovereign credit rating, may also have an impact on the performance of portfolio companies or investments located in the UK or Europe. In light of the above, no definitive assessment can currently be made regarding the impact that Brexit will have on the Trust, its investments or its organization more generally.

The occurrence of any of these above events could have a significant adverse impact on the value and risk profile of the Trust’s portfolio. The Trust does not know how long the securities markets may be affected by similar events and cannot predict the effects of similar events in the future on the U.S. economy and securities markets. There can be no assurance that similar events and other market disruptions will not have other material and adverse implications.

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Regulation and Government Intervention Risk

The U.S. Government and the Federal Reserve, as well as certain foreign governments, recently have taken unprecedented actions designed to support certain financial institutions and segments of the financial markets that experienced extreme volatility, such as implementing stimulus packages, providing liquidity in fixed income, commercial paper and other markets and providing tax breaks, among other actions. The reduction or withdrawal of Federal Reserve or other U.S. or non-U.S. governmental support could negatively affect financial markets generally and reduce the value and liquidity of certain securities. Additionally, with the cessation of certain market support activities, the Trust may face a heightened level of interest rate risk as a result of a rise or increased volatility in interest rates.

Federal, state, and other governments, their regulatory agencies or self-regulatory organizations may take actions that affect the regulation of the issuers in which the Trust invests. Legislation or regulation may also change the way in which the Trust is regulated. Such legislation or regulation could limit or preclude the Trust’s ability to achieve its investment objective.

In the aftermath of the global financial crisis, there appears to be a renewed popular, political and judicial focus on finance related consumer protection. Financial institution practices are also subject to greater scrutiny and criticism generally. In the case of transactions between financial institutions and the general public, there may be a greater tendency toward strict interpretation of terms and legal rights in favor of the consuming public, particularly where there is a real or perceived disparity in risk allocation and/or where consumers are perceived as not having had an opportunity to exercise informed consent to the transaction. In the event of conflicting interests between retail investors holding common shares of a closed-end investment company such as the Trust and a large financial institution, a court may similarly seek to strictly interpret terms and legal rights in favor of retail investors.

The Trust may be affected by governmental action in ways that are not foreseeable, and there is a possibility that such actions could have a significant adverse effect on the Trust and its ability to achieve its investment objective.

Regulation as a “Commodity Pool”

The CFTC subjects advisers to registered investment companies to regulation by the CFTC if a fund that is advised by the investment adviser either (i) invests, directly or indirectly, more than a prescribed level of its liquidation value in CFTC-regulated futures, options and swaps (“CFTC Derivatives”), or (ii) markets itself as providing investment exposure to such instruments. To the extent the Trust uses CFTC Derivatives, it intends to do so below such prescribed levels and will not market itself as a “commodity pool” or a vehicle for trading such instruments. Accordingly, the Advisor has claimed an exclusion from the definition of the term “commodity pool operator” under the Commodity Exchange Act (“CEA”) pursuant to Rule 4.5 under the CEA. The Advisor is not, therefore, subject to registration or regulation as a “commodity pool operator” under the CEA in respect of the Trust.

Failures of Futures Commission Merchants and Clearing Organizations Risk

The Trust is required to deposit funds to margin open positions in cleared derivative instruments (both futures and swaps) with a clearing broker registered as a “futures commission merchant” (“FCM”). The CEA requires an FCM to segregate all funds received from customers with respect to any orders for the purchase or sale of U.S. domestic futures contracts and cleared swaps from the FCM’s proprietary assets. Similarly, the CEA requires each FCM to hold in a separate secure account all funds received from customers with respect to any orders for the purchase or sale of foreign futures contracts and segregate any such funds from the funds received with respect to domestic futures contracts. However, all funds and other property received by an FCM from its customers are held by an FCM on a commingled basis in an omnibus account and amounts in excess of assets posted to the clearing organization may be invested by an FCM in certain instruments permitted under the applicable regulation. There is a risk that assets deposited by the Trust with any FCM as margin for futures contracts or commodity options may, in certain circumstances, be used to satisfy losses of other clients of the Trust’s FCM. In addition, the assets of the Trust posted as margin against both swaps and futures contracts may not be fully protected in the event of the FCM’s bankruptcy.

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Legal, Tax and Regulatory Risks

Legal, tax and regulatory changes could occur that may have material adverse effects on the Trust. For example, the regulatory and tax environment for derivative instruments in which the Trust may participate is evolving, and such changes in the regulation or taxation of derivative instruments may have material adverse effects on the value of derivative instruments held by the Trust and the ability of the Trust to pursue its investment strategies.

To qualify for the favorable U.S. federal income tax treatment generally accorded to RICs, the Trust must, among other things, derive in each taxable year at least 90% of its gross income from certain prescribed sources and distribute for each taxable year at least 90% of its “investment company taxable income” (generally, ordinary income plus the excess, if any, of net short-term capital gain over net long-term capital loss). If for any taxable year the Trust does not qualify as a RIC, all of its taxable income for that year (including its net capital gain) would be subject to tax at regular corporate rates without any deduction for distributions to shareholders, and such distributions would be taxable as ordinary dividends to the extent of the Trust’s current and accumulated earnings and profits.

The Biden presidential administration has called for significant changes to U.S. fiscal, tax, trade, healthcare, immigration, foreign, and government regulatory policy. In this regard, there is significant uncertainty with respect to legislation, regulation and government policy at the federal level, as well as the state and local levels. Recent events have created a climate of heightened uncertainty and introduced new and difficult-to-quantify macroeconomic and political risks with potentially far-reaching implications. There has been a corresponding meaningful increase in the uncertainty surrounding interest rates, inflation, foreign exchange rates, trade volumes and fiscal and monetary policy. To the extent the U.S. Congress or the current presidential administration implements changes to U.S. policy, those changes may impact, among other things, the U.S. and global economy, international trade and relations, unemployment, immigration, corporate taxes, healthcare, the U.S. regulatory environment, inflation and other areas. Although the Trust cannot predict the impact, if any, of these changes to the Trust’s business, they could adversely affect the Trust’s business, financial condition, operating results and cash flows. Until the Trust knows what policy changes are made and how those changes impact the Trust’s business and the business of the Trust’s competitors over the long term, the Trust will not know if, overall, the Trust will benefit from them or be negatively affected by them.

The rules dealing with U.S. federal income taxation are constantly under review by persons involved in the legislative process and by the Internal Revenue Service and the U.S. Treasury Department. Revisions in U.S. federal tax laws and interpretations of these laws could adversely affect the tax consequences of your investment.

Investment Company Act Regulations

The Trust is a registered closed-end management investment company and as such is subject to regulations under the Investment Company Act. Generally speaking, any contract or provision thereof that is made, or where performance involves a violation of the Investment Company Act or any rule or regulation thereunder is unenforceable by either party unless a court finds otherwise.

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Legislation Risk

At any time after the date of this Prospectus, legislation may be enacted that could negatively affect the assets of the Trust. Legislation or regulation may change the way in which the Trust itself is regulated. The Advisor cannot predict the effects of any new governmental regulation that may be implemented and there can be no assurance that any new governmental regulation will not adversely affect the Trust’s ability to achieve its investment objective.

Potential Conflicts of Interest of the Advisor and Others

The investment activities of BlackRock, Inc. (previously defined as “BlackRock”), the ultimate parent company of the Advisor, and its Affiliates, and their respective directors, officers or employees, in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Trust and its shareholders. BlackRock and its Affiliates provide investment management services to other funds and discretionary managed accounts that may follow investment programs similar to that of the Trust. Subject to the requirements of the Investment Company Act, BlackRock and its Affiliates intend to engage in such activities and may receive compensation from third parties for their services. Neither BlackRock nor any Affiliate is under any obligation to share any investment opportunity, idea or strategy with the Trust. As a result, an Affiliate may compete with the Trust for appropriate investment opportunities. The results of the Trust’s investment activities, therefore, may differ from those of an Affiliate and of other accounts managed by BlackRock or an Affiliate, and it is possible that the Trust could sustain losses during periods in which one or more Affiliates and other accounts achieve profits on their trading for proprietary or other accounts. BlackRock has adopted policies and procedures designed to address potential conflicts of interests. For additional information about potential conflicts of interest and the way in which BlackRock addresses such conflicts, please see “Conflicts of Interest” and “Management of the Trust—Portfolio Management—Potential Material Conflicts of Interest” in the SAI.

Defensive Investing Risk

For defensive purposes, the Trust may allocate assets into cash or short-term fixed-income securities without limitation. In doing so, the Trust may succeed in avoiding losses but may otherwise fail to achieve its investment objective. Further, the value of short-term fixed-income securities may be affected by changing interest rates and by changes in credit ratings of the investments. If the Trust holds cash uninvested it will be subject to the credit risk of the depository institution holding the cash.

Decision-Making Authority Risk

Investors have no authority to make decisions or to exercise business discretion on behalf of the Trust, except as set forth in the Trust’s governing documents. The authority for all such decisions is generally delegated to the Board, which in turn, has delegated the day-to-day management of the Trust’s investment activities to the Advisor, subject to oversight by the Board.

Management Risk

The Trust is subject to management risk because it is an actively managed investment portfolio. The Advisor and the individual portfolio managers will apply investment techniques and risk analyses in making investment decisions for the Trust, but there can be no guarantee that these will produce the desired results. The Trust may be subject to a relatively high level of management risk because the Trust may invest in derivative instruments, which may be highly specialized instruments that require investment techniques and risk analyses different from those associated with equities and bonds.

Valuation Risk

The Trust is subject to valuation risk, which is the risk that one or more of the securities in which the Trust invests are valued at prices that the Trust is unable to obtain upon sale due to factors such as incomplete data, market instability or human error. The Advisor may use an independent pricing service or prices provided by dealers to value securities at their market value. Because the secondary markets for certain investments may be limited, such

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investments may be difficult to value. See “Net Asset Value.” When market quotations are not available, the Advisor may price such investments pursuant to a number of methodologies, such as computer-based analytical modeling or individual security evaluations. These methodologies generate approximations of market values, and there may be significant professional disagreement about the best methodology for a particular type of financial instrument or different methodologies that might be used under different circumstances. In the absence of an actual market transaction, reliance on such methodologies is essential, but may introduce significant variances in the ultimate valuation of the Trust’s investments. Technological issues and/or errors by pricing services or other third-party service providers may also impact the Trust’s ability to value it investments and the calculation of the Trust’s NAV.

When market quotations are not readily available or are deemed to be inaccurate or unreliable, the Trust values its investments at fair value as determined in good faith pursuant to policies and procedures approved by the Board. Fair value is defined as the amount for which assets could be sold in an orderly disposition over a reasonable period of time, taking into account the nature of the asset. Fair value pricing may require determinations that are inherently subjective and inexact about the value of a security or other asset. As a result, there can be no assurance that fair value priced assets will not result in future adjustments to the prices of securities or other assets, or that fair value pricing will reflect a price that the Trust is able to obtain upon sale, and it is possible that the fair value determined for a security or other asset will be materially different from quoted or published prices, from the prices used by others for the same security or other asset and/or from the value that actually could be or is realized upon the sale of that security or other asset. For example, the Trust’s NAV could be adversely affected if the Trust’s determinations regarding the fair value of the Trust’s investments were materially higher than the values that the Trust ultimately realizes upon the disposal of such investments. Where market quotations are not readily available, valuation may require more research than for more liquid investments. In addition, elements of judgment may play a greater role in valuation in such cases than for investments with a more active secondary market because there is less reliable objective data available.

Because of overall size, duration and maturities of positions held by the Trust, the value at which its investments can be liquidated may differ, sometimes significantly, from the interim valuations obtained by the Trust. In addition, the timing of liquidations may also affect the values obtained on liquidation. Securities held by the Trust may routinely trade with bid-offer spreads that may be significant. There can be no guarantee that the Trust’s investments could ultimately be realized at the Trust’s valuation of such investments. In addition, the Trust’s compliance with the asset diversification tests applicable to regulated investment companies depends on the fair market values of the Trust’s assets, and, accordingly, a challenge to the valuations ascribed by the Trust could affect its ability to comply with those tests or require it to pay penalty taxes in order to cure a violation thereof.

The Trust’s NAV per share is a critical component in several operational matters including computation of advisory and services fees and determination of the price at which a tender offer will be made. Consequently, variance in the valuation of the Trust’s investments will impact, positively or negatively, the fees and expenses shareholders will pay.

Reliance on the Advisor Risk

The Trust is dependent upon services and resources provided by the Advisor, and therefore the Advisor’s parent, BlackRock. The Advisor is not required to devote its full time to the business of the Trust and there is no guarantee or requirement that any investment professional or other employee of the Advisor will allocate a substantial portion of his or her time to the Trust. The loss of one or more individuals involved with the Advisor could have a material adverse effect on the performance or the continued operation of the Trust. For additional information on the Advisor and BlackRock, see “Management of the Trust—Investment Advisor.”

Reliance on Service Providers Risk

The Trust must rely upon the performance of service providers to perform certain functions, which may include functions that are integral to the Trust’s operations and financial performance. Failure by any service provider to carry out its obligations to the Trust in accordance with the terms of its appointment, to exercise due care and skill or to perform its obligations to the Trust at all as a result of insolvency, bankruptcy or other causes could have a material adverse effect on the Trust’s performance and returns to shareholders. The termination of the Trust’s

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relationship with any service provider, or any delay in appointing a replacement for such service provider, could materially disrupt the business of the Trust and could have a material adverse effect on the Trust’s performance and returns to shareholders.

Information Technology Systems Risk

The Trust is dependent on the Advisor for certain management services as well as back-office functions. The Advisor depends on information technology systems in order to assess investment opportunities, strategies and markets and to monitor and control risks for the Trust. It is possible that a failure of some kind which causes disruptions to these information technology systems could materially limit the Advisor’s ability to adequately assess and adjust investments, formulate strategies and provide adequate risk control. Any such information technology-related difficulty could harm the performance of the Trust. Further, failure of the back-office functions of the Advisor to process trades in a timely fashion could prejudice the investment performance of the Trust.

Cyber Security Risk

With the increased use of technologies such as the Internet to conduct business, the Trust is susceptible to operational, information security and related risks. 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 (i.e., efforts to make network services unavailable to intended users). Cyber security failures by or breaches of the Advisor and other service providers (including, but not limited to, fund accountants, custodians, transfer agents and administrators), and the issuers of securities in which the Trust invests, have the ability to cause disruptions and impact business operations, potentially resulting in financial losses, interference with the Trust’s ability to calculate its NAV, impediments to trading, the inability of shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, or additional compliance costs. In addition, substantial costs may be incurred in order to prevent any cyber incidents in the future. While the Trust has established business continuity plans in the event of, and risk management systems to prevent, such cyber-attacks, there are inherent limitations in such plans and systems including the possibility that certain risks have not been identified. Furthermore, the Trust cannot control the cyber security plans and systems put in place by service providers to the Trust and issuers in which the Trust invests. As a result, the Trust or its shareholders could be negatively impacted.

Misconduct of Employees and of Service Providers Risk

Misconduct or misrepresentations by employees of the Advisor or the Trust’s service providers could cause significant losses to the Trust. Employee misconduct may include binding the Trust to transactions that exceed authorized limits or present unacceptable risks and unauthorized trading activities, concealing unsuccessful trading activities (which, in any case, may result in unknown and unmanaged risks or losses) or making misrepresentations regarding any of the foregoing. Losses could also result from actions by the Trust’s service providers, including, without limitation, failing to recognize trades and misappropriating assets. In addition, employees and service providers may improperly use or disclose confidential information, which could result in litigation or serious financial harm, including limiting the Trust’s business prospects or future marketing activities. Despite the Advisor’s due diligence efforts, misconduct and intentional misrepresentations may be undetected or not fully comprehended, thereby potentially undermining the Advisor’s due diligence efforts. As a result, no assurances can be given that the due diligence performed by the Advisor will identify or prevent any such misconduct.

Special Risks for Holders of Rights

There is a risk that performance of the Trust may result in the common shares purchasable upon exercise of the rights being less attractive to investors at the conclusion of the subscription period. This may reduce or eliminate the value of the rights. Investors who receive rights may find that there is no market to sell rights they do not wish to exercise. If investors exercise only a portion of the rights, common shares may trade at less favorable prices than larger offerings for similar securities.

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Portfolio Turnover Risk

The Trust’s annual portfolio turnover rate may vary greatly from year to year, as well as within a given year. Portfolio turnover rate is not considered a limiting factor in the execution of investment decisions for the Trust. A higher portfolio turnover rate results in correspondingly greater brokerage commissions and other transactional expenses that are borne by the Trust. High portfolio turnover may result in an increased realization of net short-term capital gains by the Trust which, when distributed to common shareholders, will be taxable as ordinary income. Additionally, in a declining market, portfolio turnover may create realized capital losses.

Anti-Takeover Provisions Risk

The Trust’s Agreement and Declaration of Trust and Bylaws include provisions that could limit the ability of other entities or persons to acquire control of the Trust or convert the Trust to open-end status or to change the composition of the Board. Such provisions could limit the ability of shareholders to sell their shares at a premium over prevailing market prices by discouraging a third party from seeking to obtain control of the Trust. See “Certain Provisions in the Agreement and Declaration of Trust and Bylaws.”

HOW THE TRUST MANAGES RISK

Investment Limitations

The Trust has adopted certain investment limitations designed to limit investment risk. Some of these limitations are fundamental and thus may not be changed without the approval of the holders of a majority of the outstanding common shares. See “Investment Objectives and Policies—Investment Restrictions” in the SAI.

The restrictions and other limitations set forth throughout this Prospectus and in the SAI apply only at the time of purchase of securities and will not be considered violated unless an excess or deficiency occurs or exists immediately after and as a result of the acquisition of securities.

Management of Investment Portfolio and Capital Structure to Limit Leverage Risk

The Trust may take certain actions if short-term interest rates increase or market conditions otherwise change (or the Trust anticipates such an increase or change) and any leverage the Trust may have outstanding begins (or is expected) to adversely affect common shareholders. In order to attempt to offset such a negative impact of any outstanding leverage on common shareholders, the Trust may shorten the average maturity of its investment portfolio (by investing in short-term securities) or may reduce any indebtedness that it may have incurred. The success of any such attempt to limit leverage risk depends on the Advisor’s ability to accurately predict interest rate or other market changes. Because of the difficulty of making such predictions, the Trust may never attempt to manage its capital structure in the manner described in this paragraph.

If market conditions suggest that employing leverage, or employing additional leverage if the Trust already has outstanding leverage, would be beneficial, the Trust may enter into one or more credit facilities, increase any existing credit facilities, sell preferred shares or engage in additional leverage transactions, subject to the restrictions of the Investment Company Act.

Strategic Transactions

The Trust may use certain Strategic Transactions designed to limit the risk of price fluctuations of securities and to preserve capital. These Strategic Transactions include using swaps, financial futures contracts, options on financial futures or options based on either an index of long-term securities, or on securities whose prices, in the opinion of the Advisor, correlate with the prices of the Trust’s investments. There can be no assurance that Strategic Transactions will be used or used effectively to limit risk, and Strategic Transactions may be subject to their own risks.

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MANAGEMENT OF THE TRUST

Trustees and Officers

The Board is responsible for the overall management of the Trust, including supervision of the duties performed by the Advisor. There are ten Trustees. A majority of the Trustees are Independent Trustees of the Trust. The name and business address of the Trustees and officers of the Trust and their principal occupations and other affiliations during the past five years are set forth under “Management of the Trust” in the SAI.

Investment Advisor

The Advisor is responsible for the management of the Trust’s portfolio and provides the necessary personnel, facilities, equipment and certain other services necessary to the operation of the Trust. The Advisor, located at 100 Bellevue Parkway, Wilmington, Delaware 19809, is a wholly-owned subsidiary of BlackRock.

BlackRock is one of the world’s largest publicly-traded investment management firms. As of December 31, 2020, BlackRock’s assets under management were approximately $8.676 trillion. BlackRock has over 30 years of experience managing closed-end products and, as of December 31, 2020, advised a registered closed-end family of 67 exchange-listed active funds with approximately $54.5 billion in assets.

BlackRock is independent in ownership and governance, with no single majority shareholder and a majority of independent directors.

Investment Philosophy

BlackRock’s investment decision-making process for the municipal security sector is subject to the same discipline, oversight and investment philosophy that the firm applies to other sectors of the fixed-income market.

BlackRock uses a relative value strategy that evaluates the trade-off between risk and return to seek to achieve the Trust’s investment objective. This strategy is combined with disciplined risk control techniques and applied in sector, sub-sector and individual security selection decisions. BlackRock’s extensive personnel and technology resources are the key drivers of the investment philosophy.

Portfolio Managers

The members of the portfolio management team who are primarily responsible for the day-to-day management of the Trust’s portfolio are as follows:

Peter Hayes, Managing Director of BlackRock, Inc., is Chief Investment Officer and Head of the Municipal Bond Group within the Portfolio Management Group (“PMG”) as well as Global Head of the Financial Institutions Group Investments Business. He is a member of the PMG Executive Committee and BlackRock’s Global Operating Committee. He also leads the Municipal Bond Operating Committee responsible for Portfolio Management, Credit Research, Trading and Strategy. Mr. Hayes’ service with BlackRock, Inc. dates back to 1987, including his years with Merrill Lynch Investment Managers (“MLIM”), which merged with BlackRock in 2006. At MLIM, he was head of the short term tax-exempt trading desk, and managed the CMA Tax-Exempt Fund and other short term municipal bond portfolios. Prior to joining MLIM, Mr. Hayes was a trader for Shawmut Bank. Mr. Hayes earned a BA degree in economics from the College of the Holy Cross.

Theodore R. Jaeckel, Jr., Managing Director of BlackRock, Inc., is Co-Head of the Municipal Funds team within the Municipal Fixed Income business within PMG. He is also a member of BlackRock’s Municipal Bond Operating Committee, which oversees all municipal bond portfolio management, research and trading activities. Mr. Jaeckel’s service with the BlackRock, Inc. dates back to 1991, including his years with MLIM. At MLIM, he was a portfolio manager for municipal bond alternative and high yield strategies. Prior to joining MLIM, Mr. Jaeckel was a municipal bond trader with Chemical Bank. Mr. Jaeckel earned a BA degree in history from Hamilton College in 1981.

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Michael A. Kalinoski, CFA, Director of BlackRock, Inc., is a portfolio manager on the Municipal Mutual Fund Desk within BlackRock’s Municipal Fixed Income business within PMG. Mr. Kalinoski’s service with BlackRock, Inc. dates back to 1999, including his years with MLIM. At MLIM, he was a member of the tax-exempt fixed income team responsible for managing a number of national and state funds. Prior to joining MLIM in 1999, Mr. Kalinoski was a municipal trader with Strong Capital Management. Mr. Kalinoski earned a BS degree in accounting from Marquette University in 1992.

Christian Romaglino, CFA, Director of BlackRock, Inc., is a portfolio manager for the Municipal Fixed Income business within PMG. Prior to joining BlackRock, Inc. in 2017, Mr. Romaglino was a portfolio manager at Brown Brothers Harriman focusing on a diverse set of institutional mandates and high net worth separately managed accounts. Mr. Romaglino also held various trading and portfolio construction positions at Brown Brothers Harriman across several taxable fixed income sectors prior to 2010 when he transitioned to Municipals. Mr. Romaglino earned a BS degree in Industrial Engineering from Lehigh University.

The SAI provides additional information about each portfolio manager’s compensation, other accounts managed by the portfolio management team and the ownership of the Trust’s securities by each portfolio manager.

Investment Management Agreement

Pursuant to an investment management agreement between the Advisor and the Trust (the “Investment Management Agreement”), the Trust has agreed to pay the Advisor a monthly management fee at an annual rate equal to 0.55% of the average daily value of the Trust’s Managed Assets. “Managed Assets” means the total assets of the Trust (including any assets attributable to money borrowed for investment purposes) minus the sum of the Trust’s accrued liabilities (other than money borrowed for investment purposes).

A discussion regarding the basis for the approval of the Investment Management Agreement by the Board is available in the Trust’s annual report to shareholders for the fiscal year ended July 31, 2020.

Except as otherwise described in this Prospectus, the Trust pays, in addition to the fees paid to the Advisor, all other costs and expenses of its operations, including compensation of its Trustees (other than those affiliated with the Advisor), custodian, leveraging expenses, transfer and dividend disbursing agent expenses, legal fees, rating agency fees, listing fees and expenses, expenses of independent auditors, expenses of repurchasing shares, expenses of preparing, printing and distributing shareholder reports, notices, proxy statements and reports to governmental agencies and taxes, if any.

The Trust and the Advisor have entered into the Fee Waiver Agreement, pursuant to which the Advisor has contractually agreed to waive the management fee with respect to any portion of the Trust’s assets attributable to investments in any equity and fixed-income mutual funds and ETFs managed by the Advisor or its affiliates that have a contractual fee, through June 30, 2022. In addition, effective December 1, 2019, pursuant to the Fee Waiver Agreement, the Advisor has contractually agreed to waive its management fees by the amount of investment advisory fees the Trust pays to the Advisor indirectly through its investment in money market funds advised by the Advisor or its affiliates, through June 30, 2022. The Fee Waiver Agreement may be continued from year to year thereafter, provided that such continuance is specifically approved by the Advisor and the Trust (including by a majority of the Trust’s Independent Trustees). Neither the Advisor nor the Trust is obligated to extend the Fee Waiver Agreement. The Fee Waiver Agreement may be terminated at any time, without the payment of any penalty, only by the Trust (upon the vote of a majority of the Independent Trustees or a majority of the outstanding voting securities of the Trust), upon 90 days’ written notice by the Trust to the Advisor.

Administration and Accounting Services

State Street Bank and Trust Company provides certain administration and accounting services to the Trust pursuant to an Administration and Trust Accounting Services Agreement (the “Administration Agreement”). Pursuant to the Administration Agreement, State Street Bank and Trust Company provides the Trust with, among other things, customary fund accounting services, including computing the Trust’s NAV and maintaining books, records and

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other documents relating to the Trust’s financial and portfolio transactions, and customary fund administration services, including assisting the Trust with regulatory filings, tax compliance and other oversight activities. For these and other services it provides to the Trust, State Street Bank and Trust Company is paid a monthly fee from the Trust at an annual rate ranging from 0.0075% to 0.015% of the Trust’s Managed Assets, along with an annual fixed fee ranging from $3,000 to $10,000 for the services it provides to the Trust.

Custodian and Transfer Agent

The custodian of the assets of the Trust is State Street Bank and Trust Company, whose principal business address is One Lincoln Street, Boston, Massachusetts 02111. The custodian is responsible for, among other things, receipt of and disbursement of funds from the Trust’s accounts, establishment of segregated accounts as necessary, and transfer, exchange and delivery of Trust portfolio securities.

Computershare Trust Company, N.A., whose principal business address is 150 Royall Street, Canton, Massachusetts 02021, serves as the Trust’s transfer agent with respect to the common shares.

Independent Registered Public Accounting Firm

Deloitte & Touche LLP, whose principal business address is 200 Berkeley Street, Boston, MA 02116, is the independent registered public accounting firm of the Trust and is expected to render an opinion annually on the financial statements of the Trust.

NET ASSET VALUE

The NAV of the Trust’s common shares will be computed based upon the value of the Trust’s portfolio securities and other assets. NAV per common share will be determined as of the close of the regular trading session on the NYSE on each business day on which the NYSE is open for trading. The Trust calculates NAV per common share by subtracting the Trust’s liabilities (including accrued expenses, dividends payable and any borrowings of the Trust), and the liquidation value of any outstanding preferred shares of the Trust from the Trust’s total assets (the value of the securities the Trust holds plus cash or other assets, including interest accrued but not yet received) and dividing the result by the total number of common shares of the Trust outstanding.

Valuation of securities held by the Trust is as follows:

Fixed-Income Investments. Fixed-income securities for which market quotations are readily available are generally valued using such securities’ current market value. The Trust values fixed-income portfolio securities and non-exchange traded derivatives using the last available bid prices or current market quotations provided by dealers or prices (including evaluated prices) supplied by the Trust’s approved independent third-party pricing services, each in accordance with valuation procedures approved by the Board. The pricing services may use matrix pricing or valuation models that utilize certain inputs and assumptions to derive values, including transaction data (e.g., recent representative bids and offers), credit quality information, perceived market movements, news, and other relevant information and by other methods, which may include consideration of: yields or prices of securities of comparable quality, coupon, maturity and type; indications as to values from dealers; general market conditions; and other factors and assumptions. Pricing services generally value fixed-income securities assuming orderly transactions of an institutional round lot size, but the Trust may hold or transact in such securities in smaller, odd lot sizes. Odd lots often trade at lower prices than institutional round lots. The amortized cost method of valuation may be used with respect to debt obligations with sixty days or less remaining to maturity unless the Advisor determines such method does not represent fair value. Loan participation notes are generally valued at the mean of the last available bid prices from one or more brokers or dealers as obtained from independent third-party pricing services. Certain fixed-income investments including asset-backed and mortgage-related securities may be valued based on valuation models that consider the estimated cash flows of each tranche of the entity, establish a benchmark yield and develop an estimated tranche specific spread to the benchmark yield based on the unique attributes of the tranche.

Options, Futures, Swaps and Other Derivatives. Exchange-traded equity options for which market quotations are readily available are valued at the mean of the last bid and ask prices as quoted on the Exchange or the board of

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trade on which such options are traded. In the event that there is no mean price available for an exchange traded equity option held by the Trust on a day on which the Trust values such option, the last bid (long positions) or ask (short positions) price, if available, will be used as the value of such option. If no bid or ask price is available on a day on which the Trust values such option, the prior day’s price will be used, unless the Advisor determines that such prior day’s price no longer reflects the fair value of the option in which case such option will be treated as a fair value asset. OTC derivatives may be valued using a mathematical model which may incorporate a number of market data factors. Financial futures contracts and options thereon, which are traded on exchanges, are valued at their last sale price or settle price as of the close of such exchanges. Swap agreements and other derivatives are generally valued daily based upon quotations from market makers or by a pricing service in accordance with the valuation procedures approved by the Board.

Equity Investments. Equity securities traded on a recognized securities exchange (e.g., NYSE), separate trading boards of a securities exchange or through a market system that provides contemporaneous transaction pricing information (an “Exchange”) are valued via independent pricing services generally at the Exchange closing price or if an Exchange closing price is not available, the last traded price on that Exchange prior to the time as of which the assets or liabilities are valued; however, under certain circumstances other means of determining current market value may be used. If an equity security is traded on more than one Exchange, the current market value of the security where it is primarily traded generally will be used. In the event that there are no sales involving an equity security held by the Trust on a day on which the Trust values such security, the last bid (long positions) or ask (short positions) price, if available, will be used as the value of such security. If the Trust holds both long and short positions in the same security, the last bid price will be applied to securities held long and the last ask price will be applied to securities sold short. If no bid or ask price is available on a day on which the Trust values such security, the prior day’s price will be used, unless the Advisor determines that such prior day’s price no longer reflects the fair value of the security, in which case such asset would be treated as a fair value asset.

Underlying Trusts. Shares of underlying open-end funds are valued at NAV. Shares of underlying exchange-traded closed-end funds or other exchange-traded funds will be valued at their most recent closing price.

General Valuation Information. In determining the market value of portfolio investments, the Trust may employ independent third party pricing services, which may use, without limitation, a matrix or formula method that takes into consideration market indexes, matrices, yield curves and other specific adjustments. This may result in the securities being valued at a price different from the price that would have been determined had the matrix or formula method not been used. All cash, receivables and current payables are carried on the Trust’s books at their face value. The price the Trust could receive upon the sale of any particular portfolio investment may differ from the Trust’s valuation of the investment, particularly for securities that trade in thin or volatile markets or that are valued using a fair valuation methodology or a price provided by an independent pricing service. As a result, the price received upon the sale of an investment may be less than the value ascribed by the Trust, and the Trust could realize a greater than expected loss or lesser than expected gain upon the sale of the investment. The Trust’s ability to value its investment may also be impacted by technological issues and/or errors by pricing services or other third party service providers.

Prices obtained from independent third party pricing services, broker-dealers or market makers to value the Trust’s securities and other assets and liabilities are based on information available at the time the Trust values its assets and liabilities. In the event that a pricing service quotation is revised or updated subsequent to the day on which the Trust valued such security, the revised pricing service quotation generally will be applied prospectively. Such determination shall be made considering pertinent facts and circumstances surrounding such revision.

In the event that application of the methods of valuation discussed above result in a price for a security which is deemed not to be representative of the fair market value of such security, the security will be valued by, under the direction of or in accordance with a method specified by the Board as reflecting fair value. All other assets and liabilities (including securities for which market quotations are not readily available) held by the Trust (including restricted securities) are valued at fair value as determined in good faith by the Board or by the Advisor (its delegate). Any assets and liabilities which are denominated in a foreign currency are translated into U.S. dollars at the prevailing rates of exchange.

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Certain of the securities acquired by the Trust may be traded on foreign exchanges or OTC markets on days on which the Trust’s NAV is not calculated and common shares are not traded. In such cases, the NAV of the Trust’s common shares may be significantly affected on days when investors can neither purchase nor sell shares of the Trust.

Fair Value. When market quotations are not readily available or are believed by the Advisor to be unreliable, the Trust’s investments are valued at fair value (“Fair Value Assets”). Fair Value Assets are valued by the Advisor in accordance with procedures approved by the Board. The Advisor may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its complete lack of trading, if the Advisor believes a market quotation from a broker-dealer or other source is unreliable (e.g., where it varies significantly from a recent trade, or no longer reflects the fair value of the security or other asset or liability subsequent to the most recent market quotation), where the security or other asset or liability is only thinly traded or due to the occurrence of a significant event subsequent to the most recent market quotation. For this purpose, a “significant event” is deemed to occur if the Advisor determines, in its business judgment prior to or at the time of pricing the Trust’s assets or liabilities, that it is likely that the event will cause a material change to the last exchange closing price or closing market price of one or more assets or liabilities held by the Trust. On any date the NYSE is open and the primary exchange on which a foreign asset or liability is traded is closed, such asset or liability will be valued using the prior day’s price, provided that the Advisor is not aware of any significant event or other information that would cause such price to no longer reflect the fair value of the asset or liability, in which case such asset or liability would be treated as a Fair Value Asset. For certain foreign securities, a third-party vendor supplies evaluated, systematic fair value pricing based upon the movement of a proprietary multi-factor model after the relevant foreign markets have closed. This systematic fair value pricing methodology is designed to correlate the prices of foreign securities following the close of the local markets to the price that might have prevailed as of the Trust’s pricing time.

The Advisor, with input from the BlackRock Portfolio Management Group, will submit its recommendations regarding the valuation and/or valuation methodologies for Fair Value Assets to BlackRock’s Valuation Committee. The BlackRock Valuation Committee may accept, modify or reject any recommendations. In addition, the Trust’s accounting agent periodically endeavors to confirm the prices it receives from all third party pricing services, index providers and broker-dealers, and, with the assistance of the Advisor, to regularly evaluate the values assigned to the securities and other assets and liabilities of the Trust. The pricing of all Fair Value Assets is subsequently reported to the Board or a Committee thereof.

When determining the price for a Fair Value Asset, the BlackRock Valuation Committee shall seek to determine the price that the Trust might reasonably expect to receive from the current sale of that asset or liability in an arm’s-length transaction. The price generally may not be determined based on what the Trust might reasonably expect to receive for selling an asset or liability at a later time or if it holds the asset or liability to maturity. Fair value determinations shall be based upon all available factors that the BlackRock Valuation Committee deems relevant at the time of the determination, and may be based on analytical values determined by the Advisor using proprietary or third party valuation models.

Fair value represents a good faith approximation of the value of an asset or liability. The fair value of one or more assets or liabilities may not, in retrospect, be the price at which those assets or liabilities could have been sold during the period in which the particular fair values were used in determining the Trust’s NAV. As a result, the Trust’s sale or repurchase of its shares at NAV, at a time when a holding or holdings are valued at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

The Trust’s annual audited financial statements, which are prepared in accordance with accounting principles generally accepted in the United States of America (“US GAAP”), follow the requirements for valuation set forth in Financial Accounting Standards Board Accounting Standards Codification Topic 820, “Fair Value Measurements and Disclosures” (“ASC 820”), which defines and establishes a framework for measuring fair value under US GAAP and expands financial statement disclosure requirements relating to fair value measurements.

Generally, ASC 820 and other accounting rules applicable to investment companies and various assets in which they invest are evolving. Such changes may adversely affect the Trust. For example, the evolution of rules governing the

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determination of the fair market value of assets or liabilities to the extent such rules become more stringent would tend to increase the cost and/or reduce the availability of third-party determinations of fair market value.

DISTRIBUTIONS

The Trust intends to make regular monthly cash distributions of all or a portion of its net investment income to holders of the Trust’s common shares. Net capital gains, if any, will be distributed at least annually to holders of the Trust’s common shares. The Trust’s net investment income consists of all interest income accrued on portfolio assets less all expenses of the Trust. The Trust is required to allocate net capital gains and other taxable income, if any, received by the Trust among its shareholders on a pro rata basis in the year for which such capital gains and other income is realized.

The tax treatment and characterization of the Trust’s distributions may vary significantly from time to time because of the varied nature of the Trust’s investments. The ultimate tax characterization of the Trust’s distributions made in a fiscal year cannot finally be determined until after the end of that fiscal year. As a result, there is a possibility that the Trust may make total distributions during a fiscal year in an amount that exceeds the Trust’s earnings and profits for U.S. federal income tax purposes. In such situations, the amount by which the Trust’s total distributions exceed earnings and profits would generally be treated as a return of capital reducing the amount of a shareholder’s tax basis in such shareholder’s shares, with any amounts exceeding such basis treated as gain from the sale of shares.

Various factors will affect the level of the Trust’s net investment income, such as its asset mix, its level of retained earnings, the amount of leverage utilized by the Trust and the effects thereof and the movement of interest rates for municipal bonds. To permit the Trust to maintain more stable monthly distributions and to the extent consistent with the distribution requirements imposed on regulated investment companies by the Code, the Trust may from time to time distribute less than the entire amount earned in a particular period. The income would be available to supplement future distributions. As a result, the distributions paid by the Trust for any particular month may be more or less than the amount actually earned by the Trust during that month. Undistributed earnings will increase the Trust’s NAV and, correspondingly, distributions from undistributed earnings and from capital, if any, will reduce the Trust’s NAV.

Shareholders will automatically have all dividends and distributions reinvested in common shares of the Trust in accordance with the Trust’s dividend reinvestment plan, unless an election is made to receive cash by contacting the Reinvestment Plan Agent (as defined herein), at (800) 699-1236. See “Dividend Reinvestment Plan.”

DIVIDEND REINVESTMENT PLAN

Unless the registered owner of common shares elects to receive cash by contacting Computershare Trust Company, N.A. (the “Reinvestment Plan Agent”), all dividends or other distributions (together, a “dividend”) declared for your common shares of the Trust will be automatically reinvested by the Reinvestment Plan Agent, as agent for shareholders in administering the Trust’s dividend reinvestment plan (the “Reinvestment Plan”), in additional common shares of the Trust. Shareholders who elect not to participate in the Reinvestment Plan will receive all dividends in cash paid by check mailed directly to the shareholder of record (or, if the common shares are held in street or other nominee name, then to such nominee) by the Reinvestment Plan Agent. You may elect not to participate in the Reinvestment Plan and to receive all dividends in cash by contacting the Reinvestment Plan Agent at the address set forth below. Participation in the Reinvestment Plan is completely voluntary and may be terminated or resumed at any time without penalty by written notice if received and processed by the Reinvestment Plan Agent prior to the dividend record date. Additionally, the Reinvestment Plan Agent seeks to process notices received after the record date but prior to the payable date and such notices often will become effective by the payable date. Where late notices are not processed by the applicable payable date, such termination or resumption will be effective with respect to any subsequently declared dividend.

Some brokers may automatically elect to receive cash on your behalf and may re-invest that cash in additional common shares of the Trust for you. If you wish for all dividends declared on your common shares of the Trust to be automatically reinvested pursuant to the Reinvestment Plan, please contact your broker.

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The Reinvestment Plan Agent will open an account for each common shareholder under the Reinvestment Plan in the same name in which such common shareholder’s common shares are registered. Whenever the Trust declares a dividend payable in cash, non-participants in the Reinvestment Plan will receive cash and participants in the Reinvestment Plan will receive the equivalent in common shares. The common shares will be acquired by the Reinvestment Plan Agent for the participants’ accounts, depending upon the circumstances described below, either (i) through receipt of additional unissued but authorized common shares from the Trust (“newly issued common shares”) or (ii) by purchase of outstanding common shares on the open market (“open-market purchases”). If, on the dividend payment date, the NAV is equal to or less than the market price per share plus estimated brokerage commissions (such condition often referred to as a “market premium”), the Reinvestment Plan Agent will invest the dividend amount in newly issued common shares on behalf of the participants. The number of newly issued common shares to be credited to each participant’s account will be determined by dividing the dollar amount of the dividend by the NAV on the dividend payment date. However, if the NAV is less than 95% of the market price on the dividend payment date, the dollar amount of the dividend will be divided by 95% of the market price on the dividend payment date. If, on the dividend payment date, the NAV is greater than the market price per share plus estimated brokerage commissions (such condition often referred to as a “market discount”), the Reinvestment Plan Agent will invest the dividend amount in common shares acquired on behalf of the participants in open-market purchases. In the event of a market discount on the dividend payment date, the Reinvestment Plan Agent will have until the last business day before the next date on which the common shares trade on an “ex-dividend” basis or 30 days after the dividend payment date, whichever is sooner, to invest the dividend amount in common shares acquired in open-market purchases. It is contemplated that the Trust will pay monthly income dividends. If, before the Reinvestment Plan Agent has completed its open-market purchases, the market price per common share exceeds the NAV per common share, the average per common share purchase price paid by the Reinvestment Plan Agent may exceed the NAV of the common shares, resulting in the acquisition of fewer common shares than if the dividend had been paid in newly issued common shares on the dividend payment date. Because of the foregoing difficulty with respect to open-market purchases, the Reinvestment Plan provides that if the Reinvestment Plan Agent is unable to invest the full dividend amount in open-market purchases, or if the market discount shifts to a market premium during the purchase period, the Reinvestment Plan Agent may cease making open-market purchases and may invest any uninvested portion in newly issued shares. Investments in newly issued shares made in this manner would be made pursuant to the same process described above and the date of issue for such newly issued shares will substitute for the dividend payment date.

The Reinvestment Plan Agent maintains all shareholders’ accounts in the Reinvestment Plan and furnishes written confirmation of all transactions in the accounts, including information needed by shareholders for tax records. Common shares in the account of each Reinvestment Plan participant will be held by the Reinvestment Plan Agent on behalf of the Reinvestment Plan participant, and each shareholder proxy will include those shares purchased or received pursuant to the Reinvestment Plan.

In the case of shareholders such as banks, brokers or nominees, which hold shares for others who are the beneficial owners, the Reinvestment Plan Agent will administer the Reinvestment Plan on the basis of the number of common shares certified from time to time by the record shareholder’s name and held for the account of beneficial owners who participate in the Reinvestment Plan.

The Reinvestment Plan Agent’s fees for the handling of the reinvestment of dividends will be paid by the Trust. However, each participant will pay a $0.02 per share fee incurred in connection with open-market purchases, which will be deducted from the value of the dividend. The automatic reinvestment of dividends will not relieve participants of any U.S. federal, state or local income tax that may be payable (or required to be withheld) on such dividends. See “Tax Matters.”

Participants that request a sale of shares through the Reinvestment Plan Agent are subject to a $2.50 sales fee and a $0.15 per share fee. Per share fees include any applicable brokerage commissions the Reinvestment Plan Agent is required to pay.

The Trust reserves the right to amend or terminate the Reinvestment Plan. There is no direct service charge to participants with regard to purchases in the Reinvestment Plan; however, the Trust reserves the right to amend the Reinvestment Plan to include a service charge payable by the participants. Notice of amendments to the Reinvestment Plan will be sent to participants.

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All correspondence concerning the Reinvestment Plan should be directed to the Reinvestment Plan Agent, through the internet at http://www.computershare.com/blackrock, or in writing to Computershare, P.O. Box 505000, Louisville, KY 40233, Telephone: (800) 699-1236. Overnight correspondence should be directed to the Reinvestment Plan Agent at Computershare, 462 South 4th Street, Suite 1600, Louisville, KY 40202.

RIGHTS OFFERINGS

The Trust may in the future, and at its discretion, choose to make offerings of rights to its shareholders to purchase common shares. Rights may be issued independently or together with any other offered security and may or may not be transferable by the person purchasing or receiving the rights. In connection with a rights offering to shareholders, we would distribute certificates or other documentation (i.e., rights cards distributed in lieu of certificates) evidencing the rights and a Prospectus Supplement to our shareholders as of the record date that we set for determining the shareholders eligible to receive rights in such rights offering. Any such future rights offering will be made in accordance with the Investment Company Act. Under the laws of Delaware, the Board is authorized to approve rights offerings without obtaining shareholder approval.

The staff of the SEC has interpreted the Investment Company Act as not requiring shareholder approval of a transferable rights offering to purchase common shares at a price below the then current NAV so long as certain conditions are met, including: (i) a good faith determination by a fund’s board that such offering would result in a net benefit to existing shareholders; (ii) the offering fully protects shareholders’ preemptive rights and does not discriminate among shareholders (except for the possible effect of not offering fractional rights); (iii) management uses its best efforts to ensure an adequate trading market in the rights for use by shareholders who do not exercise such rights; and (iv) the ratio of a transferable rights offering does not exceed one new share for each three rights held.

The applicable Prospectus Supplement would describe the following terms of the rights in respect of which this Prospectus is being delivered:

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A certain number of rights would entitle the holder of the right(s) to purchase for cash such number of common shares at such exercise price as in each case is set forth in, or be determinable as set forth in, the Prospectus Supplement relating to the rights offered thereby. Rights would be exercisable at any time up to the close of business on the expiration date for such rights set forth in the Prospectus Supplement. After the close of business on the expiration date, all unexercised rights would become void. Upon expiration of the rights offering and the receipt of payment and the rights certificate or other appropriate documentation properly executed and completed and duly executed at the corporate trust office of the rights agent, or any other office indicated in the Prospectus Supplement, the common shares purchased as a result of such exercise will be issued as soon as practicable. To the extent permissible under applicable law, we may determine to offer any unsubscribed offered securities directly to persons other than shareholders, to or through agents, underwriters or dealers or through a combination of such methods, as set forth in the applicable Prospectus Supplement.

TAX MATTERS

The following discussion is a brief summary of certain U.S. federal income tax considerations affecting the Trust and the purchase, ownership and disposition of the Trust’s common shares. A more detailed discussion of the tax rules applicable to the Trust and its common shareholders can be found in the SAI that is incorporated by reference into this Prospectus. Except as otherwise noted, this discussion assumes you are a taxable U.S. holder (as defined below) and that you hold your common shares as capital assets for U.S. federal income tax purposes (generally, assets held for investment). This discussion is based upon current provisions of the Code, the regulations promulgated thereunder and judicial and administrative authorities, all of which are subject to change or differing interpretations by the courts or the Internal Revenue Service, possibly with retroactive effect. No attempt is made to present a detailed explanation of all U.S. federal tax concerns affecting the Trust and its common shareholders. The Trust has not sought and will not seek any ruling from the Internal Revenue Service regarding any matters discussed herein. No assurance can be given that the Internal Revenue Service would not assert, or that a court would not sustain, a position contrary to those set forth below. This summary does not discuss any aspects of non-U.S., state or local tax. The discussion set forth herein does not constitute tax advice and potential investors are urged to consult their own tax advisers to determine the specific U.S. federal, state, local and foreign tax consequences to them of investing in the Trust.

In addition, no attempt is made to address tax considerations applicable to an investor with a special tax status, such as without limitation, a financial institution, REIT, insurance company, regulated investment company, individual retirement account, other tax-exempt organization, dealer in securities or currencies, person holding shares of the Trust as part of a hedging, integrated, conversion or straddle transaction, trader in securities that has elected the mark-to-market method of accounting for its securities, U.S. holder (as defined below) whose functional currency is not the U.S. dollar, investor with “applicable financial statements” within the meaning of Section 451(b) of the Code, or non-U.S. investor. Furthermore, this discussion does not reflect possible application of the alternative minimum tax.

A U.S. holder is a beneficial owner that is for U.S. federal income tax purposes:

Taxation of the Trust

The Trust has elected to be treated as a RIC under Subchapter M of the Code. In order to qualify as a RIC, the Trust must, among other things, satisfy certain requirements relating to the sources of its income, diversification of its assets, and distribution of its income to its shareholders. First, the Trust must derive at least 90% of its annual gross

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income from dividends, interest, payments with respect to securities loans, gains from the sale or other disposition of stock or securities or foreign currencies, or other income (including but not limited to gains from options, futures and forward contracts) derived with respect to its business of investing in such stock, securities or currencies, or net income derived from interests in “qualified publicly traded partnerships” (as defined in the Code) (the “90% gross income test”). Second, the Trust must diversify its holdings so that, at the close of each quarter of its taxable year, (i) at least 50% of the value of its total assets consists of cash, cash items, U.S. Government securities, securities of other RICs and other securities, with such other securities limited in respect of any one issuer to an amount not greater in value than 5% of the value of the Trust’s total assets and to not more than 10% of the outstanding voting securities of such issuer, and (ii) not more than 25% of the market value of the total assets is invested in the securities (other than U.S. Government securities and securities of other RICs) of any one issuer, any two or more issuers controlled by the Trust and engaged in the same, similar or related trades or businesses, or any one or more “qualified publicly traded partnerships.”

As long as the Trust qualifies as a RIC, the Trust will generally not be subject to corporate-level U.S. federal income tax on income and gains that it distributes each taxable year to its shareholders, provided that in such taxable year it distributes at least 90% of the sum of (i) its net tax-exempt interest income, if any, and (ii) its “investment company taxable income” (which includes, among other items, dividends, taxable interest, taxable original issue discount and market discount income, income from securities lending, net short-term capital gain in excess of net long-term capital loss, and any other taxable income other than “net capital gain” (as defined below) and is reduced by deductible expenses) determined without regard to the deduction for dividends paid. The Trust may retain for investment its net capital gain (which consists of the excess of its net long-term capital gain over its net short-term capital loss). However, if the Trust retains any net capital gain or any investment company taxable income, it will be subject to tax at regular corporate rates on the amount retained.

The Code imposes a 4% nondeductible excise tax on the Trust to the extent the Trust does not distribute by the end of any calendar year at least the sum of (i) 98% of its ordinary income (not taking into account any capital gain or loss) for the calendar year and (ii) 98.2% of its capital gain in excess of its capital loss (adjusted for certain ordinary losses) for a one-year period generally ending on October 31 of the calendar year (unless an election is made to use the Trust’s fiscal year). In addition, the minimum amounts that must be distributed in any year to avoid the excise tax will be increased or decreased to reflect any under-distribution or over-distribution, as the case may be, from the previous year. For purposes of the excise tax, the Trust will be deemed to have distributed any income on which it paid U.S. federal income tax. While the Trust intends to distribute any income and capital gain in the manner necessary to minimize imposition of the 4% nondeductible excise tax, there can be no assurance that sufficient amounts of the Trust’s taxable income and capital gain will be distributed to entirely avoid the imposition of the excise tax. In that event, the Trust will be liable for the excise tax only on the amount by which it does not meet the foregoing distribution requirement.

If in any taxable year the Trust should fail to qualify under Subchapter M of the Code for tax treatment as a RIC, the Trust would incur a regular corporate U.S. federal income tax upon all of its taxable income for that year, and all distributions to its shareholders (including distributions of net capital gain) would be taxable to shareholders as ordinary dividend income for U.S. federal income tax purposes to the extent of the Trust’s earnings and profits. Provided that certain holding period and other requirements were met, such dividends would be eligible (i) to be treated as qualified dividend income in the case of shareholders taxed as individuals and (ii) for the dividends received deduction in the case of corporate shareholders. In addition, to qualify again to be taxed as a RIC in a subsequent year, the Trust would be required to distribute to shareholders its earnings and profits attributable to non-RIC years. In addition, if the Trust failed to qualify as a RIC for a period greater than two taxable years, then, in order to qualify as a RIC in a subsequent year, the Trust would be required to elect to recognize and pay tax on any net built-in gain (the excess of aggregate gain, including items of income, over aggregate loss that would have been realized if the Trust had been liquidated) or, alternatively, be subject to taxation on such built-in gain recognized for a period of five years.

The remainder of this discussion assumes that the Trust qualifies for taxation as a RIC.

The Trust’s Investments. Certain of the Trust’s investment practices are subject to special and complex U.S. federal income tax provisions (including mark-to-market, constructive sale, straddle, wash sale, short sale and other rules) that may, among other things, (i) disallow, suspend or otherwise limit the allowance of certain losses or deductions,

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(ii) convert lower taxed long-term capital gains or qualified dividend income into higher taxed short-term capital gains or ordinary income, (iii) convert ordinary loss or a deduction into capital loss (the deductibility of which is more limited), (iv) cause the Trust to recognize income or gain without a corresponding receipt of cash, (v) adversely affect the time as to when a purchase or sale of stock or securities is deemed to occur, (vi) adversely alter the characterization of certain complex financial transactions and (vii) produce income that will not be “qualified” income for purposes of the 90% annual gross income requirement described above. These U.S. federal income tax provisions could therefore affect the amount, timing and character of distributions to common shareholders. The Trust intends to monitor its transactions and may make certain tax elections and may be required to dispose of securities to mitigate the effect of these provisions and prevent disqualification of the Trust as a RIC. Additionally, the Trust may be required to limit its activities in derivative instruments in order to enable it to maintain its RIC status.

The Trust may invest a portion of its net assets in below investment grade securities. Investments in these types of securities may present special tax issues for the Trust. U.S. federal income tax rules are not entirely clear about issues such as when the Trust may cease to accrue interest, original issue discount or market discount, when and to what extent deductions may be taken for bad debts or worthless securities, how payments received on obligations in default should be allocated between principal and income and whether modifications or exchanges of debt obligations in a bankruptcy or workout context are taxable. These and other issues could affect the Trust’s ability to distribute sufficient income to preserve its status as a RIC or to avoid the imposition of U.S. federal income or excise tax.

Certain debt securities acquired by the Trust may be treated as debt securities that were originally issued at a discount. Generally, the amount of the original issue discount is treated as interest income and is included in taxable income (and required to be distributed by the Trust in order to qualify as a RIC and avoid U.S. federal income tax or the 4% excise tax on undistributed income) over the term of the security, even though payment of that amount is not received until a later time, usually when the debt security matures.

If the Trust purchases a debt security on a secondary market at a price lower than its adjusted issue price, the excess of the adjusted issue price over the purchase price is “market discount.” Unless the Trust makes an election to accrue market discount on a current basis, generally, any gain realized on the disposition of, and any partial payment of principal on, a debt security having market discount is treated as ordinary income to the extent the gain, or principal payment, does not exceed the “accrued market discount” on the debt security. Market discount generally accrues in equal daily installments. If the Trust ultimately collects less on the debt instrument than its purchase price plus the market discount previously included in income, the Trust may not be able to benefit from any offsetting loss deductions.

The Trust may invest in preferred securities or other securities the U.S. federal income tax treatment of which may not be clear or may be subject to recharacterization by the Internal Revenue Service. To the extent the tax treatment of such securities or the income from such securities differs from the tax treatment expected by the Trust, it could affect the timing or character of income recognized by the Trust, potentially requiring the Trust to purchase or sell securities, or otherwise change its portfolio, in order to comply with the tax rules applicable to RICs under the Code.

Gain or loss on the sale of securities by the Trust will generally be long-term capital gain or loss if the securities have been held by the Trust for more than one year. Gain or loss on the sale of securities held for one year or less will be short-term capital gain or loss.

Because the Trust may invest in foreign securities, its income from such securities may be subject to non-U.S. taxes.

Foreign currency gain or loss on foreign currency exchange contracts, non-U.S. dollar-denominated securities contracts, and non-U.S. dollar-denominated futures contracts, options and forward contracts that are not section 1256 contracts (as defined below) generally will be treated as ordinary income and loss.

Income from options on individual securities written by the Trust will generally not be recognized by the Trust for tax purposes until an option is exercised, lapses or is subject to a “closing transaction” (as defined by applicable regulations) pursuant to which the Trust’s obligations with respect to the option are otherwise terminated. If the option lapses without exercise, the premiums received by the Trust from the writing of such options will generally

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be characterized as short-term capital gain. If the Trust enters into a closing transaction, the difference between the premiums received and the amount paid by the Trust to close out its position will generally be treated as short-term capital gain or loss. If an option written by the Trust is exercised, thereby requiring the Trust to sell the underlying security, the premium will increase the amount realized upon the sale of the security, and the character of any gain on such sale of the underlying security as short-term or long-term capital gain will depend on the holding period of the Trust in the underlying security. Because the Trust will not have control over the exercise of the options it writes, such exercises or other required sales of the underlying securities may cause the Trust to realize gains or losses at inopportune times.

Index options that qualify as “section 1256 contracts” will generally be “marked-to-market” for U.S. federal income tax purposes. As a result, the Trust will generally recognize gain or loss on the last day of each taxable year equal to the difference between the value of the option on that date and the adjusted basis of the option. The adjusted basis of the option will consequently be increased by such gain or decreased by such loss. Any gain or loss with respect to options on indices and sectors that qualify as “section 1256 contracts” will be treated as short-term capital gain or loss to the extent of 40% of such gain or loss and long-term capital gain or loss to the extent of 60% of such gain or loss. Because the mark-to-market rules may cause the Trust to recognize gain in advance of the receipt of cash, the Trust may be required to dispose of investments in order to meet its distribution requirements. “Mark-to-market” losses may be suspended or otherwise limited if such losses are part of a straddle or similar transaction.

Taxation of Common Shareholders

Trust distributions of its tax-exempt interest on municipal securities, if properly reported by the Trust to its shareholders (“exempt-interest dividends”), will generally be exempt from regular federal income tax. In order for the Trust to pay exempt-interest dividends, at least 50% of the value of the Trust’s total assets must consist of tax-exempt obligations on a quarterly basis. If the Trust does not meet this requirement, it would not be able to pay tax-exempt dividends, and your distributions attributable to interest received by the Trust from any source (including distributions of tax-exempt interest income) would be taxable as ordinary income to the extent of the Trust’s earnings and profits.

The Trust will either distribute or retain for reinvestment all or part of its net capital gain. If any such gain is retained, the Trust will be subject to a corporate income tax on such retained amount. In that event, the Trust expects to report the retained amount as undistributed capital gain in a notice to its common shareholders, each of whom, if subject to U.S. federal income tax on long-term capital gains, (i) will be required to include in income for U.S. federal income tax purposes as long-term capital gain its share of such undistributed amounts, (ii) will be entitled to credit its proportionate share of the tax paid by the Trust against its U.S. federal income tax liability and to claim refunds to the extent that the credit exceeds such liability and (iii) will increase its basis in its common shares by the amount of undistributed capital gains included in the shareholder’s income less the tax deemed paid by the shareholder under clause (ii).

Distributions paid to you by the Trust from its net capital gain, if any, that the Trust properly reports as capital gain dividends (“capital gain dividends”) are taxable as long-term capital gains, regardless of how long you have held your common shares. All other dividends paid to you by the Trust (including dividends from net short-term capital gains) from its current or accumulated earnings and profits, other than exempt-interest dividends (“ordinary income dividends”) are generally subject to tax as ordinary income. Provided that certain holding period and other requirements are met, ordinary income dividends (if properly reported by the Trust) may qualify (i) for the dividends received deduction in the case of corporate shareholders to the extent that the Trust’s income consists of dividend income from U.S. corporations, and (ii) in the case of individual shareholders, as “qualified dividend income” eligible to be taxed at long-term capital gains rates to the extent that the Trust receives qualified dividend income. Qualified dividend income is, in general, dividend income from taxable domestic corporations and certain qualified foreign corporations (e.g., generally, foreign corporations incorporated in a possession of the United States or in certain countries with a qualifying comprehensive tax treaty with the United States, or whose stock with respect to which such dividend is paid is readily tradable on an established securities market in the United States). There can be no assurance as to what portion, if any, of the Trust’s distributions will constitute qualified dividend income or be eligible for the dividends received deduction.

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Any distributions you receive that are in excess of the Trust’s current and accumulated earnings and profits will be treated as a return of capital to the extent of your adjusted tax basis in your common shares, and thereafter as capital gain from the sale of common shares. The amount of any Trust distribution that is treated as a return of capital will reduce your adjusted tax basis in your common shares, thereby increasing your potential gain or reducing your potential loss on any subsequent sale or other disposition of your common shares.

Common shareholders may be entitled to offset their capital gain dividends with capital losses. The Code contains a number of statutory provisions affecting when capital losses may be offset against capital gain, and limiting the use of losses from certain investments and activities. Accordingly, common shareholders that have capital losses are urged to consult their tax advisers.

Dividends and other taxable distributions are taxable to you even though they are reinvested in additional common shares of the Trust. Dividends and other distributions paid by the Trust are generally treated under the Code as received by you at the time the dividend or distribution is made. If, however, the Trust pays you a dividend in January that was declared in the previous October, November or December to common shareholders of record on a specified date in one of such months, then such dividend will be treated for U.S. federal income tax purposes as being paid by the Trust and received by you on December 31 of the year in which the dividend was declared. In addition, certain other distributions made after the close of the Trust’s taxable year may be “spilled back” and treated as paid by the Trust (except for purposes of the 4% nondeductible excise tax) during such taxable year. In such case, you will be treated as having received such dividends in the taxable year in which the distributions were actually made.

Interest on certain “private activity bonds” is an item of tax preference subject to the alternative minimum tax on individuals. The Trust may invest a portion of its assets in municipal bonds subject to this provision so that a portion of its exempt-interest dividends is an item of tax preference to the extent such dividends represent interest received from these private activity bonds. Accordingly, investment in the Trust could cause a holder of common shares to be subject to, or result in an increased liability under, the alternative minimum tax.

Exempt-interest dividends are included in determining what portion, if any, of a person’s Social Security and railroad retirement benefits will be includable in gross income subject to federal income tax.

The price of common shares purchased at any time may reflect the amount of a forthcoming distribution. Those purchasing common shares just prior to the record date of a distribution will receive a distribution which will be taxable to them even though it represents, economically, a return of invested capital.

The Trust will send you information after the end of each year setting forth the amount and tax status of any distributions paid to you by the Trust.

The sale or other disposition of common shares will generally result in capital gain or loss to you and will be long-term capital gain or loss if you have held such common shares for more than one year at the time of sale. Any loss upon the sale or other disposition of common shares held for six months or less will be treated as long-term capital loss to the extent of any capital gain dividends received (including amounts credited as an undistributed capital gain dividend) by you with respect to such common shares. Any loss you recognize on a sale or other disposition of common shares will be disallowed if you acquire other common shares (whether through the automatic reinvestment of dividends or otherwise) within a 61-day period beginning 30 days before and ending 30 days after your sale or exchange of the common shares. In such case, your tax basis in the common shares acquired will be adjusted to reflect the disallowed loss.

If the Trust liquidates, shareholders generally will realize capital gain or loss upon such liquidation in an amount equal to the difference between the amount of cash or other property received by the shareholder (including any property deemed received by reason of its being placed in a liquidating trust) and the shareholder’s adjusted tax basis in its common shares. Any such gain or loss will be long-term if the shareholder is treated as having a holding period in the Trust shares of greater than one year, and otherwise will be short-term.

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Current U.S. federal income tax law taxes both long-term and short-term capital gain of corporations at the rates applicable to ordinary income. For non-corporate taxpayers, short-term capital gain is currently taxed at rates applicable to ordinary income while long-term capital gain generally is taxed at a reduced maximum rate. The deductibility of capital losses is subject to limitations under the Code.

Certain U.S. holders who are individuals, estates or trusts and whose income exceeds certain thresholds will be required to pay a 3.8% Medicare tax on all or a portion of their “net investment income,” which includes dividends received from the Trust and capital gains from the sale or other disposition of the Trust’s common shares.

A common shareholder that is a nonresident alien individual or a foreign corporation (a “foreign investor”) generally will be subject to U.S. federal withholding tax at the rate of 30% (or possibly a lower rate provided by an applicable tax treaty) on ordinary income dividends (except as discussed below). In general, U.S. federal withholding tax and U.S. federal income tax will not apply to any gain or income realized by a foreign investor in respect of any distribution of exempt-interest dividends or net capital gain (including amounts credited as an undistributed capital gain dividend) or upon the sale or other disposition of common shares of the Trust. Different tax consequences may result if the foreign investor is engaged in a trade or business in the United States or, in the case of an individual, is present in the United States for 183 days or more during a taxable year and certain other conditions are met. Foreign investors should consult their tax advisers regarding the tax consequences of investing in the Trust’s common shares.

Ordinary income dividends properly reported by a RIC are generally exempt from U.S. federal withholding tax where they (i) are paid in respect of the RIC’s “qualified net interest income” (generally, its U.S.-source interest income, other than certain contingent interest and interest from obligations of a corporation or partnership in which the RIC is at least a 10% shareholder, reduced by expenses that are allocable to such income) or (ii) are paid in respect of the RIC’s “qualified short-term capital gains” (generally, the excess of the RIC’s net short-term capital gain over its long-term capital loss for such taxable year). Depending on its circumstances, the Trust may report all, some or none of its potentially eligible dividends as such qualified net interest income or as qualified short-term capital gains, and/or treat such dividends, in whole or in part, as ineligible for this exemption from withholding. In order to qualify for this exemption from withholding, a foreign investor needs to comply with applicable certification requirements relating to its non-U.S. status (including, in general, furnishing an IRS Form W-8BEN, W-8BEN-E or substitute Form). In the case of common shares held through an intermediary, the intermediary may have withheld tax even if the Trust reported the payment as qualified net interest income or qualified short-term capital gain. Foreign investors should contact their intermediaries with respect to the application of these rules to their accounts. There can be no assurance as to what portion of the Trust’s distributions would qualify for favorable treatment as qualified net interest income or qualified short-term capital gains.

In addition, withholding at a rate of 30% will apply to dividends paid in respect of common shares of the Trust held by or through certain foreign financial institutions (including investment funds), unless such institution enters into an agreement with the Treasury to report, on an annual basis, information with respect to shares in, and accounts maintained by, the institution to the extent such shares or accounts are held by certain U.S. persons and by certain non-U.S. entities that are wholly or partially owned by U.S. persons and to withhold on certain payments. Accordingly, the entity through which common shares of the Trust are held will affect the determination of whether such withholding is required. Similarly, dividends paid in respect of common shares of the Trust held by an investor that is a non-financial foreign entity that does not qualify under certain exemptions will be subject to withholding at a rate of 30%, unless such entity either (i) certifies that such entity does not have any “substantial United States owners” or (ii) provides certain information regarding the entity’s “substantial United States owners,” which the Trust or applicable withholding agent will in turn provide to the Secretary of the Treasury. An intergovernmental agreement between the United States and an applicable foreign country, or future Treasury regulations or other guidance, may modify these requirements. The Trust will not pay any additional amounts to common shareholders in respect of any amounts withheld. Foreign investors are encouraged to consult with their tax advisers regarding the possible implications of these rules on their investment in the Trust’s common shares.

U.S. federal backup withholding tax may be required on dividends, distributions and sale proceeds payable to certain non-exempt common shareholders who fail to supply their correct taxpayer identification number (in the case of individuals, generally, their social security number) or to make required certifications, or who are otherwise subject to backup withholding. Backup withholding is not an additional tax and any amount withheld may be refunded or

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credited against your U.S. federal income tax liability, if any, provided that you timely furnish the required information to the Internal Revenue Service.

Ordinary income dividends, capital gain dividends, and gain from the sale or other disposition of common shares of the Trust also may be subject to state, local, and/or foreign taxes. Common shareholders are urged to consult their own tax advisers regarding specific questions about U.S. federal, state, local or foreign tax consequences to them of investing in the Trust.

The foregoing is a general and abbreviated summary of certain provisions of the Code and the Treasury regulations currently in effect as they directly govern the taxation of the Trust and its common shareholders. These provisions are subject to change by legislative or administrative action, and any such change may be retroactive. A more detailed discussion of the tax rules applicable to the Trust and its common shareholders can be found in the SAI that is incorporated by reference into this Prospectus. Common shareholders are urged to consult their tax advisers regarding specific questions as to U.S. federal, state, local and foreign income or other taxes.

Please refer to the SAI for more detailed information. You are urged to consult your tax adviser.

TAXATION OF HOLDERS OF RIGHTS

The value of a right will not be includible in the income of a common shareholder at the time the right is issued.

The basis of a right issued to a common shareholder will be zero, and the basis of the share with respect to which the subscription right was issued (the old share) will remain unchanged, unless either (a) the fair market value of the right on the date of distribution is at least 15% of the fair market value of the old share, or (b) such shareholder affirmatively elects (in the manner set out in Treasury regulations under the Code) to allocate to the subscription right a portion of the basis of the old share. If either (a) or (b) applies, then except as described below such shareholder must allocate basis between the old share and the right in proportion to their fair market values on the date of distribution.

The basis of a right purchased in the market will generally be its purchase price.

The holding period of a right issued to a common shareholder will include the holding period of the old share. No gain or loss will be recognized by a common shareholder upon the exercise of a right.

No loss will be recognized by a common shareholder if a right distributed to such common shareholder expires unexercised because the basis of the old share may be allocated to a right only if the right is exercised. If a right that has been purchased in the market expires unexercised, there will be a recognized loss equal to the basis of the right.

Any gain or loss on the sale of a right will be a capital gain or loss if the right is held as a capital asset (which in the case of rights issued to common shareholders will depend on whether the old share of beneficial interest is held as a capital asset), and will be a long-term capital gain or loss if the holding period is deemed to exceed one year.

CERTAIN PROVISIONS IN THE AGREEMENT AND DECLARATION OF TRUST AND BYLAWS

The Agreement and Declaration of Trust includes provisions that could have the effect of limiting the ability of other entities or persons to acquire control of the Trust or to change the composition of the Board. This could have the effect of depriving shareholders of an opportunity to sell their shares at a premium over prevailing market prices by discouraging a third party from seeking to obtain control over the Trust. Such attempts could have the effect of increasing the expenses of the Trust and disrupting the normal operation of the Trust. The Board is divided into three classes. At each annual meeting of shareholders or special meeting in lieu thereof the term of only one class of Trustees expires and only the Trustees in that one class stand for re-election. Trustees standing for election at an annual meeting of shareholders or special meeting in lieu thereof are elected to a three-year term. This provision could delay for up to two years the replacement of a majority of the Board. A Trustee may be removed from office for cause only, and only by the action of a majority of the remaining Trustees followed by a vote of the holders of at least 75% of the shares then entitled to vote for the election of the respective Trustee.

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In addition, the Trust’s Agreement and Declaration of Trust requires the favorable vote of a majority of the Board followed by the favorable vote of the holders of at least 75% of the outstanding shares of each affected class or series of the Trust, voting separately as a class or series, to approve, adopt or authorize certain transactions with 5% or greater holders of a class or series of shares and their associates, unless the transaction has been approved by at least 80% of the Trustees, in which case “a majority of the outstanding voting securities” (as defined in the Investment Company Act) of the Trust shall be required. These voting requirements are in addition to any regulatory relief required from the SEC with respect to such transaction. For purposes of these provisions, a 5% or greater holder of a class or series of shares (a “Principal Shareholder”) refers to any person who, whether directly or indirectly and whether alone or together with its affiliates and associates, beneficially owns 5% or more of the outstanding shares of all outstanding classes or series of shares of beneficial interest of the Trust.

The 5% holder transactions subject to these special approval requirements are:

To convert the Trust to an open-end investment company, the Trust’s Agreement and Declaration of Trust requires the favorable vote of a majority of the Board followed by the favorable vote of the holders of at least 75% of the outstanding shares of each affected class or series of shares of the Trust, voting separately as a class or series, unless such conversion has been approved by at least 80% of the Trustees, in which case “a majority of the outstanding voting securities” (as defined in the Investment Company Act) of the Trust shall be required. The foregoing vote would satisfy a separate requirement in the Investment Company Act that any conversion of the Trust to an open-end investment company be approved by the shareholders. If approved in the foregoing manner, we anticipate conversion of the Trust to an open-end investment company might not occur until 90 days after the shareholders’ meeting at which such conversion was approved and would also require at least 10 days’ prior notice to all shareholders. Conversion of the Trust to an open-end investment company would require the redemption of any outstanding preferred shares, which could eliminate or alter the leveraged capital structure of the Trust with respect to the common shares. Following any such conversion, it is also possible that certain of the Trust’s investment policies and strategies would have to be modified to assure sufficient portfolio liquidity, including in order to comply with Rule 22e-4 under the Investment Company Act. In the event of conversion, the common shares would cease to be listed on the NYSE or other national securities exchanges or market systems. Shareholders of an open-end investment company may require the company to redeem their shares at any time, except in certain circumstances as authorized by or under the Investment Company Act, at their NAV, less such redemption charge, if any, as might be in effect at the time of a redemption. The Trust expects to pay all such redemption requests in cash, but reserves the right to pay redemption requests in a combination of cash or securities. If such partial payment in securities were made, investors may incur brokerage costs in converting such securities to cash. If the Trust were converted to an open-end fund, it is likely that new shares would be sold at NAV plus a sales load. The Board believes, however, that the closed-end structure is desirable in light of the Trust’s investment objectives and policies. Therefore, you should assume that it is not likely that the Board would vote to convert the Trust to an open-end fund.

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For the purposes of calculating “a majority of the outstanding voting securities” under the Trust’s Agreement and Declaration of Trust, each class and series of the Trust shall vote together as a single class, except to the extent required by the Investment Company Act or the Trust’s Agreement and Declaration of Trust with respect to any class or series of shares. If a separate vote is required, the applicable proportion of shares of the class or series, voting as a separate class or series, also will be required.

The Board has determined that provisions with respect to the Board and the shareholder voting requirements described above, which voting requirements are greater than the minimum requirements under Delaware law or the Investment Company Act, are in the best interests of shareholders generally. Reference should be made to the Agreement and Declaration of Trust on file with the SEC for the full text of these provisions.

The Trust’s Bylaws generally require that advance notice be given to the Trust in the event a shareholder desires to nominate a person for election to the Board or to transact any other business at an annual meeting of shareholders. Notice of any such nomination or business must be delivered to or received at the principal executive offices of the Trust not less than 120 calendar days nor more than 150 calendar days prior to the anniversary date of the prior year’s annual meeting (subject to certain exceptions). Any notice by a shareholder must be accompanied by certain information as provided in the Bylaws. Reference should be made to the Bylaws on file with the SEC for the full text of these provisions.

CLOSED-END FUND STRUCTURE

The Trust is a diversified, closed-end management investment company (commonly referred to as a closed-end fund). Closed-end funds differ from open-end funds (which are generally referred to as mutual funds) in that closed-end funds generally list their shares for trading on a stock exchange and do not redeem their shares at the request of the shareholder. This means that if you wish to sell your shares of a closed-end fund you must trade them on the stock exchange like any other stock at the prevailing market price at that time. In a mutual fund, if the shareholder wishes to sell shares of the fund, the mutual fund will redeem or buy back the shares at NAV. Also, mutual funds generally offer new shares on a continuous basis to new investors and closed-end funds generally do not. The continuous inflows and outflows of assets in a mutual fund can make it difficult to manage the fund’s investments. By comparison, closed-end funds are generally able to stay more fully invested in securities that are consistent with their investment objectives and also have greater flexibility to make certain types of investments and to use certain investment strategies, such as financial leverage and investments in illiquid securities.

Shares of closed-end funds frequently trade at a discount to their NAV. Because of this possibility and the recognition that any such discount may not be in the interest of shareholders, the Board might consider from time to time engaging in open-market repurchases, tender offers for shares or other programs intended to reduce the discount. We cannot guarantee or assure, however, that the Board will decide to engage in any of these actions. Nor is there any guarantee or assurance that such actions, if undertaken, would result in the shares trading at a price equal or close to the NAV. See “Repurchase of Common Shares” below and “Repurchase of Common Shares” in the SAI. The Board might also consider converting the Trust to an open-end mutual fund, which would also require a vote of the shareholders of the Trust.

REPURCHASE OF COMMON SHARES

Shares of closed-end investment companies often trade at a discount to their NAVs and the Trust’s common shares may also trade at a discount to their NAV, although it is possible that they may trade at a premium above NAV. The market price of the Trust’s common shares will be determined by such factors as relative demand for and supply of such common shares in the market, the Trust’s NAV, general market and economic conditions and other factors beyond the control of the Trust. See “Net Asset Value” and “Description of Capital Stock—Common Shares.” Although the Trust’s common shareholders will not have the right to redeem their common shares, the Trust may take action to repurchase common shares in the open market or make tender offers for its common shares. This may have the effect of reducing any market discount from NAV.

There is no assurance that, if action is undertaken to repurchase or tender for common shares, such action will result in the common shares’ trading at a price which approximates their NAV. Although share repurchases and tender offers could have a favorable effect on the market price of the Trust’s common shares, you should be aware that the

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acquisition of common shares by the Trust will decrease the capital of the Trust and, therefore, may have the effect of increasing the Trust’s expense ratio and decreasing the asset coverage with respect to any borrowings or preferred shares outstanding. Any share repurchases or tender offers will be made in accordance with the requirements of the Exchange Act, the Investment Company Act and the principal stock exchange on which the common shares are traded. For additional information, see “Repurchase of Common Shares” in the SAI.

PLAN OF DISTRIBUTION

We may sell common shares, including to existing shareholders in a rights offering, through underwriters or dealers, directly to one or more purchasers (including existing shareholders in a rights offering), through agents, to or through underwriters or dealers, or through a combination of any such methods of sale. The applicable Prospectus Supplement will identify any underwriter or agent involved in the offer and sale of our common shares, any sales loads, discounts, commissions, fees or other compensation paid to any underwriter, dealer or agent, the offering price, net proceeds and use of proceeds and the terms of any sale. In the case of a rights offering, the applicable Prospectus Supplement will set forth the number of our common shares issuable upon the exercise of each right and the other terms of such rights offering.

The distribution of our common shares may be effected from time to time in one or more transactions at a fixed price or prices, which may be changed, at prevailing market prices at the time of sale, at prices related to such prevailing market prices, or at negotiated prices. Sales of our common shares may be made in transactions that are deemed to be “at the market” as defined in Rule 415 under the Securities Act, including sales made directly on the NYSE or sales made to or through a market maker other than on an exchange.

We may sell our common shares directly to, and solicit offers from, institutional investors or others who may be deemed to be underwriters as defined in the Securities Act for any resales of the securities. In this case, no underwriters or agents would be involved. We may use electronic media, including the Internet, to sell offered securities directly.

In connection with the sale of our common shares, underwriters or agents may receive compensation from us in the form of discounts, concessions or commissions. Underwriters may sell our common shares to or through dealers, and such dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for whom they may act as agents. Underwriters, dealers and agents that participate in the distribution of our common shares may be deemed to be underwriters under the Securities Act, and any discounts and commissions they receive from us and any profit realized by them on the resale of our common shares may be deemed to be underwriting discounts and commissions under the Securities Act. Any such underwriter or agent will be identified and any such compensation received from us will be described in the applicable Prospectus Supplement. The maximum amount of compensation to be received by any Financial Industry Regulatory Authority member or independent broker-dealer will not exceed eight percent for the sale of any securities being offered pursuant to Rule 415 under the Securities Act. We will not pay any compensation to any underwriter or agent in the form of warrants, options, consulting or structuring fees or similar arrangements. In connection with any rights offering to existing shareholders, we may enter into a standby underwriting arrangement with one or more underwriters pursuant to which the underwriter(s) will purchase common shares remaining unsubscribed after the rights offering.

If a Prospectus Supplement so indicates, we may grant the underwriters an option to purchase additional common shares at the public offering price, less the underwriting discounts and commissions, within 45 days from the date of the Prospectus Supplement, to cover any over-allotments.

Under agreements into which we may enter, underwriters, dealers and agents who participate in the distribution of our common shares may be entitled to indemnification by us against certain liabilities, including liabilities under the Securities Act. Underwriters, dealers and agents may engage in transactions with us, or perform services for us, in the ordinary course of business.

If so indicated in the applicable Prospectus Supplement, we will ourselves, or will authorize underwriters or other persons acting as our agents to solicit offers by certain institutions to purchase our common shares from us pursuant to contracts providing for payment and delivery on a future date. Institutions with which such contacts may be made

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include commercial and savings banks, insurance companies, pension funds, investment companies, educational and charitable institutions and others, but in all cases such institutions must be approved by us. The obligation of any purchaser under any such contract will be subject to the condition that the purchase of the common shares shall not at the time of delivery be prohibited under the laws of the jurisdiction to which such purchaser is subject. The underwriters and such other agents will not have any responsibility in respect of the validity or performance of such contracts. Such contracts will be subject only to those conditions set forth in the Prospectus Supplement, and the Prospectus Supplement will set forth the commission payable for solicitation of such contracts.

To the extent permitted under the Investment Company Act and the rules and regulations promulgated thereunder, the underwriters may from time to time act as brokers or dealers and receive fees in connection with the execution of our portfolio transactions after the underwriters have ceased to be underwriters and, subject to certain restrictions, each may act as a broker while it is an underwriter.

A Prospectus and accompanying Prospectus Supplement in electronic form may be made available on the websites maintained by underwriters. The underwriters may agree to allocate a number of securities for sale to their online brokerage account holders. Such allocations of securities for Internet distributions will be made on the same basis as other allocations. In addition, securities may be sold by the underwriters to securities dealers who resell securities to online brokerage account holders.

In order to comply with the securities laws of certain states, if applicable, our common shares offered hereby will be sold in such jurisdictions only through registered or licensed brokers or dealers.

INCORPORATION BY REFERENCE

This Prospectus is part of a registration statement that we have filed with the SEC. We are allowed to “incorporate by reference” the information that we file with the SEC, which means that we can disclose important information to you by referring you to those documents. We incorporate by reference into this Prospectus the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including any filings on or after the date of this Prospectus from the date of filing (excluding any information furnished, rather than filed), until we have sold all of the offered securities to which this Prospectus and any accompanying prospectus supplement relates or the offering is otherwise terminated. The information incorporated by reference is an important part of this Prospectus. Any statement in a document incorporated by reference into this Prospectus will be deemed to be automatically modified or superseded to the extent a statement contained in (1) this Prospectus or (2) any other subsequently filed document that is incorporated by reference into this Prospectus modifies or supersedes such statement. The documents incorporated by reference herein include:

The Trust will provide without charge to each person, including any beneficial owner, to whom this Prospectus is delivered, upon written or oral request, a copy of any and all of the documents that have been or may be incorporated by reference in this Prospectus or the accompanying prospectus supplement. You should direct requests for documents by calling:

Client Services Desk

(800) 882-0052

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The Trust makes available this Prospectus, SAI and the Trust’s annual and semi-annual reports, free of charge, at http://www.blackrock.com. You may also obtain this Prospectus, the SAI, other documents incorporated by reference and other information the Trust files electronically, including reports and proxy statements, on the SEC website (http://www.sec.gov) or with the payment of a duplication fee, by electronic request at publicinfo@sec.gov. Information contained in, or that can be accessed through, the Trust’s website is not incorporated by reference into this Prospectus and should not be considered to be part of this Prospectus or the accompanying prospectus supplement.

PRIVACY PRINCIPLES OF THE TRUST

The Trust is committed to maintaining the privacy of shareholders and to safeguarding their non-public personal information. The following information is provided to help you understand what personal information the Trust collects, how we protect that information, and why in certain cases we may share such information with select other parties.

The Trust does not receive any non-public personal information relating to its shareholders who purchase shares through their broker-dealers. In the case of shareholders who are record holders of the Trust, the Trust receives personal non-public information on account applications or other forms. With respect to these shareholders, the Trust also has access to specific information regarding their transactions in the Trust.

The Trust does not disclose any non-public personal information about its shareholders or former shareholders to anyone, except as permitted by law or as is necessary in order to service our shareholders’ accounts (for example, to a transfer agent).

The Trust restricts access to non-public personal information about its shareholders to BlackRock employees with a legitimate business need for the information. The Trust maintains physical, electronic and procedural safeguards designed to protect the non-public personal information of our shareholders.

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$533,000,000

BLACKROCK TAXABLE MUNICIPAL BOND TRUST

Common Shares of Beneficial Interest

Rights to Purchase Common Shares of Beneficial Interest

PROSPECTUS

February 10, 2021

The information in this Prospectus Supplement is not complete and may be changed. BlackRock Taxable Municipal Bond Trust may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This Prospectus Supplement is not an offer to sell these securities and is not soliciting offers to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED [●], 2021

PROSPECTUS SUPPLEMENT

(To Prospectus dated February 10, 2021)

Filed Pursuant to Rule 424(b)([•])

Registration Statement No. 333-[•]

BLACKROCK TAXABLE MUNICIPAL

BOND TRUST

Up to [●] Common Shares of Beneficial Interest

BlackRock Taxable Municipal Bond Trust (the “Trust,” “we,” “us” or “our”) is offering for sale [●] of our common shares of beneficial interest (“common shares”). Our common shares are listed on the New York Stock Exchange (“NYSE”) under the symbol “BBN.” As of the close of business on [●], 2021, the last reported net asset value per share of our common shares was $[●] and the last reported sales price per share of our common shares on the NYSE was $[●].

The Trust is a diversified, closed-end management investment company registered under the Investment Company Act of 1940, as amended (the “Investment Company Act”). The Trust’s primary investment objective is to seek high current income, with a secondary objective of capital appreciation. The Trust’s investment adviser is BlackRock Advisors, LLC (the “Advisor”).

Sales of our common shares, if any, under this Prospectus Supplement and the accompanying Prospectus may be made in negotiated transactions or transactions that are deemed to be “at the market” as defined in Rule 415 under the Securities Act of 1933, as amended (the “Securities Act”), including sales made directly on the NYSE or sales made to or through a market maker other than on an exchange.

Investing in the Trust’s common shares involves certain risks that are described in the “Risks” section beginning on page 24 of the accompanying Prospectus.

NEITHER THE SEC NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED THESE SECURITIES OR DETERMINED IF THIS PROSPECTUS SUPPLEMENT IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

[●], 2021

This Prospectus Supplement, together with the accompanying Prospectus, sets forth concisely the information about the Trust that a prospective investor should know before investing. You should read this Prospectus Supplement and the accompanying Prospectus, which contain important information, before deciding whether to invest in the common shares. You should retain the accompanying Prospectus and this Prospectus Supplement for future reference. A Statement of Additional Information (“SAI”), dated February 10, 2021, containing additional information about the Trust, has been filed with the Securities and Exchange Commission (“SEC”) and, as amended from time to time, is incorporated by reference in its entirety into this Prospectus Supplement and the accompanying Prospectus. This Prospectus Supplement, the accompanying Prospectus and the SAI are part of a “shelf” registration statement filed with the SEC. This Prospectus Supplement describes the specific details regarding this offering, including the method of distribution. If information in this Prospectus Supplement is inconsistent with the accompanying Prospectus or the SAI, you should rely on this Prospectus Supplement. You may call (800) 882-0052, visit the Trust’s website (http://www.blackrock.com) or write to the Trust to obtain, free of charge, copies of the SAI and the Trust’s semi-annual and annual reports, as well as to obtain other information about the Trust or to make shareholder inquiries. The SAI, as well as the Trust’s semi-annual and annual reports, are also available for free on the SEC’s website (http://www.sec.gov). You may also e-mail requests for these documents to publicinfo@sec.gov. Information contained in, or that can be accessed through, the Trust’s website is not part of this Prospectus Supplement or the accompanying Prospectus.

You should not construe the contents of this Prospectus Supplement and the accompanying Prospectus as legal, tax or financial advice. You should consult with your own professional advisors as to the legal, tax, financial or other matters relevant to the suitability of an investment in the Trust.

The Trust’s common shares do not represent a deposit or an obligation of, and are not guaranteed or endorsed by, any bank or other insured depository institution, and are not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.

Beginning on January 1, 2021, as permitted by regulations adopted by the SEC, paper copies of the Trust’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call Computershare at 1-800-699-1236 to request that you continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC or its affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

S-2

You should rely only on the information contained or incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. Neither the Trust nor the underwriters have authorized anyone to provide you with different information. The Trust is not making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained in this Prospectus Supplement and the accompanying Prospectus is accurate as of any date other than the date of this Prospectus Supplement and the accompanying Prospectus, respectively. Our business, financial condition, results of operations and prospects may have changed since those dates. In this Prospectus Supplement and in the accompanying Prospectus, unless otherwise indicated, “Trust,” “us,” “our” and “we” refer to BlackRock Taxable Municipal Bond Trust, a Delaware statutory trust.

TABLE OF CONTENTS

Prospectus Supplement

TABLE OF CONTENTS

Prospectus

S-3

CAUTIONARY NOTICE REGARDING FORWARD-LOOKING STATEMENTS

This Prospectus Supplement, the accompanying Prospectus and the SAI contain “forward-looking statements.” Forward-looking statements can be identified by the words “may,” “will,” “intend,” “expect,” “estimate,” “continue,” “plan,” “anticipate,” and similar terms and the negative of such terms. Such forward-looking statements may be contained in this Prospectus Supplement as well as in the accompanying Prospectus. By their nature, all forward-looking statements involve risks and uncertainties, and actual results could differ materially from those contemplated by the forward-looking statements. Several factors that could materially affect our actual results are the performance of the portfolio of securities we hold, the price at which our shares will trade in the public markets and other factors discussed in our periodic filings with the SEC.

Although we believe that the expectations expressed in our forward-looking statements are reasonable, actual results could differ materially from those projected or assumed in our forward-looking statements. Our future financial condition and results of operations, as well as any forward-looking statements, are subject to change and are subject to inherent risks and uncertainties, such as those disclosed in the “Risks” section of the accompanying Prospectus. All forward-looking statements contained or incorporated by reference in this Prospectus Supplement or the accompanying Prospectus are made as of the date of this Prospectus Supplement or the accompanying Prospectus, as the case may be. Except for our ongoing obligations under the federal securities laws, we do not intend, and we undertake no obligation, to update any forward-looking statement. The forward-looking statements contained in this Prospectus Supplement, the accompanying Prospectus and the SAI are excluded from the safe harbor protection provided by Section 27A of the Securities Act.

Currently known risk factors that could cause actual results to differ materially from our expectations include, but are not limited to, the factors described in the “Risks” section of the accompanying Prospectus. We urge you to review carefully those sections for a more detailed discussion of the risks of an investment in our common shares.

S-4

PROSPECTUS SUPPLEMENT SUMMARY

The following summary is qualified in its entirety by reference to the more detailed information included elsewhere in this Prospectus Supplement and in the accompanying Prospectus and in the SAI.

The Trust

The Trust is a diversified, closed-end management investment company. The Trust’s primary investment objective is to seek high current income, with a secondary objective of capital appreciation. There can be no assurance that the Trust’s investment objectives will be achieved or that the Trust’s investment program will be successful. The Trust’s common shares are listed for trading on the NYSE under the symbol “BBN.”

Investment Advisor

BlackRock Advisors, LLC (previously defined as the “Advisor”) is the Trust’s investment adviser. The Advisor receives an annual fee, payable monthly, in an amount equal to 0.55% of the average daily value of the Trust’s Managed Assets. “Managed Assets” means the total assets of the Trust (including any assets attributable to money borrowed for investment purposes) minus the sum of the Trust’s accrued liabilities (other than money borrowed for investment purposes).

The Offering

[The provisions of the Investment Company Act generally require that the public offering price of common shares (less any underwriting commissions and discounts) must equal or exceed the net asset value per share of a company’s common shares (calculated within 48 hours of pricing).

Sales of our common shares, if any, under this Prospectus Supplement and the accompanying Prospectus may be made in negotiated transactions or transactions that are deemed to be “at the market” as defined in Rule 415 under the Securities Act, including sales made directly on the NYSE or sales made to or through a market maker other than on an exchange.]

Use of Proceeds

We currently anticipate that we will be able to invest all of the net proceeds of any sales of common shares pursuant to this Prospectus Supplement in accordance with our investment objectives and policies as described in the accompanying Prospectus under “The Trust’s Investments” within approximately three months of the receipt of such proceeds. Pending such investment, it is anticipated that the proceeds will be invested in short-term investment grade securities or in high quality, short-term money market instruments. Depending on market conditions and operations, a portion of the cash held by the Trust, including any proceeds raised from the offering, may be used to pay distributions in accordance with the Trust’s distribution policy and may be a return of capital.

S-5

Example

The following example illustrates the expenses (including the sales load of $[●] and offering costs of $[●]) that you would pay on a $1,000 investment in common shares, assuming (i) total net annual expenses of [●]% of net assets attributable to common shares and (ii) a 5% annual return:

The example should not be considered a representation of future expenses. The example assumes that the estimated “Other expenses” set forth in the Estimated Annual Expenses table are accurate and that all dividends and distributions are reinvested at net asset value. Actual expenses may be greater or less than those assumed. Moreover, the Trust’s actual rate of return may be greater or less than the hypothetical 5% return shown in the example.

USE OF PROCEEDS

We estimate the total net proceeds of the offering to be $[●], based on the public offering price of $[●] per share and after deducting underwriting discounts and commissions and estimated offering expenses payable by us.

The net proceeds from the issuance of common shares hereunder will be invested in accordance with the Trust’s investment objectives and policies as set forth in this Prospectus Supplement and the accompanying Prospectus. We currently anticipate that we will be able to invest all of the net proceeds in accordance with our investment objectives and policies within approximately three months of the receipt of such proceeds. Pending such investment, it is anticipated that the proceeds will be invested in short-term investment grade securities or in high quality, short-term money market instruments. Depending on market conditions and operations, a portion of the cash held by the Trust, including any proceeds raised from the offering, may be used to pay distributions in accordance with the

S-6

Trust’s distribution policy and may be a return of capital. A return of capital is a return to investors of a portion of their original investment in the Trust. In general terms, a return of capital would involve a situation in which a Trust distribution (or a portion thereof) represents a return of a portion of a shareholder’s investment in the Trust, rather than making a distribution that is funded from the Trust’s earned income or other profits. Although return of capital distributions may not be currently taxable, such distributions would decrease the basis of a shareholder’s shares, and therefore, may increase a shareholder’s tax liability for capital gains upon a sale of shares, even if sold at a loss to the shareholder’s original investments.

CAPITALIZATION

The following table sets forth the unaudited capitalization of the Trust as of [●], 2021 and its adjusted capitalization assuming the common shares available in the offering discussed in this Prospectus Supplement had been issued.

[To be provided.]

PLAN OF DISTRIBUTION

[To be provided.]

LEGAL MATTERS

Certain legal matters in connection with the common shares will be passed upon for the Trust by Willkie Farr & Gallagher LLP, New York, New York, counsel to the Trust. Willkie Farr & Gallagher LLP may rely as to certain matters of Delaware law on the opinion of Morris, Nichols, Arsht & Tunnell LLP, Wilmington, Delaware. [Certain legal matters will be passed on by [●] as special counsel to the Underwriters in connection with the offering.]

ADDITIONAL INFORMATION

This Prospectus Supplement and the accompanying Prospectus constitute part of a Registration Statement filed by the Trust with the SEC under the Securities Act and the Investment Company Act. This Prospectus Supplement and the accompanying Prospectus omit certain of the information contained in the Registration Statement, and reference is hereby made to the Registration Statement and related exhibits for further information with respect to the Trust and the common shares offered hereby. Any statements contained herein concerning the provisions of any document are not necessarily complete, and, in each instance, reference is made to the copy of such document filed as an exhibit to the Registration Statement or otherwise filed with the SEC. Each such statement is qualified in its entirety by such reference. The complete Registration Statement may be obtained from the SEC upon payment of the fee prescribed by its rules and regulations or free of charge through the SEC’s website (http://www.sec.gov).

S-7

BLACKROCK TAXABLE MUNICIPAL BOND TRUST

[●] Common Shares of Beneficial Interest

PROSPECTUS SUPPLEMENT

[●], 2021

Until [            ], 2021 (25 days after the date of this Prospectus Supplement), all dealers that buy, sell or trade the common shares, whether or not participating in this offering, may be required to deliver a prospectus. This is in addition to the dealers’ obligation to deliver a prospectus when acting as underwriters.

The information in this Prospectus Supplement is not complete and may be changed. BlackRock Taxable Municipal Bond Trust may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This Prospectus Supplement is not an offer to sell these securities and is not soliciting offers to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED [●], 2021

PROSPECTUS SUPPLEMENT

(To Prospectus dated February 10, 2021)

Filed Pursuant to Rule 424

Registration Statement No. 333-[•]

BLACKROCK TAXABLE MUNICIPAL

BOND TRUST

[●] Rights for [●] Shares of Beneficial Interest

Subscription Rights to Acquire Shares of Beneficial Interest

BlackRock Taxable Municipal Bond Trust (the “Trust,” “we,” “us” or “our”) is issuing subscription rights (the “Rights”) to our common shareholders (the “Common Shareholders”) to purchase additional common shares of beneficial interest (each, a “Common Share” and collectively, the “Common Shares”).

The Trust is a diversified, closed-end management investment company registered under the Investment Company Act of 1940, as amended. The Trust’s primary investment objective is to seek high current income, with a secondary objective of capital appreciation. The Trust’s investment adviser is BlackRock Advisors, LLC (the “Advisor”).

The Common Shares are listed on the New York Stock Exchange (“NYSE”) under the symbol “BBN.” Common Shareholders of record on [●], 2021 (the “Record Date”) will receive [●] Right for each Common Share held. These Rights are transferable and will allow the holders thereof to purchase additional Common Shares. The Rights will be listed for trading on the [●] under the symbol “[●]” during the course of the Rights offering.

On [●], 2021 (the last trading date prior to the Common Shares trading ex-Rights), the last reported net asset value per share of the Common Shares was $[●] and the last reported sales price per share of Common Shares on the NYSE was $[●].

This Prospectus Supplement, together with the accompanying Prospectus, sets forth concisely the information about the Trust that a prospective investor should know before investing. You should read this Prospectus Supplement and the accompanying Prospectus, which contain important information, before deciding whether to invest in the Common Shares. You should retain the accompanying Prospectus and this Prospectus Supplement for future reference. A Statement of Additional Information (“SAI”), dated February 10, 2021, containing additional information about the Trust, has been filed with the Securities and Exchange Commission (“SEC”) and, as amended from time to time, is incorporated by reference in its entirety into this Prospectus Supplement and the accompanying Prospectus. This Prospectus Supplement, the accompanying Prospectus and the SAI are part of a “shelf” registration statement filed with the SEC. This Prospectus Supplement describes the specific details regarding this offering, including the method of distribution. If information in this Prospectus Supplement is inconsistent with the accompanying Prospectus or the SAI, you should rely on this Prospectus Supplement. You may call (800) 882-0052, visit the Trust’s website (http://www.blackrock.com) or write to the Trust to obtain, free of charge, copies of the SAI and the Trust’s semi-annual and annual reports, as well as to obtain other information about the Trust or to make shareholder inquiries. The SAI, as well as the Trust’s semi-annual and annual reports, are also available for free on the SEC’s website (http://www.sec.gov). You may also e-mail requests for these documents to publicinfo@sec.gov. Information contained in, or that can be accessed through, the Trust’s website is not part of this Prospectus

Supplement or the accompanying Prospectus. Common Shareholders please call toll-free at [●] (banks and brokers please call [●]) or please send written requests to [●].

Investing in Common Shares through Rights involves certain risks that are described in the “Special Characteristics and Risks of the Rights Offering” section of this Prospectus Supplement.

The Common Shares are expected to be ready for delivery in book-entry form through the [insert depository name] on or about [●], 2019[, unless extended. If the offering is extended, the Common Shares are expected to be ready for delivery in book-entry form through the [●] on or about [●], 2021.]

You should not construe the contents of this Prospectus Supplement and the accompanying Prospectus as legal, tax or financial advice. You should consult with your own professional advisors as to the legal, tax, financial or other matters relevant to the suitability of an investment in the Trust.

The Trust’s Common Shares do not represent a deposit or an obligation of, and are not guaranteed or endorsed by, any bank or other insured depository institution, and are not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.

Beginning on January 1, 2021, as permitted by regulations adopted by the SEC, paper copies of the Trust’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

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You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call Computershare at 1-800-699-1236 to request that you continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC or its affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

The date of this Prospectus Supplement is [●], 2021.

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You should rely only on the information contained or incorporated by reference in this Prospectus Supplement and the accompanying Prospectus. The Trust has not authorized anyone to provide you with different information. The Trust is not making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained in this Prospectus Supplement and the accompanying Prospectus is accurate as of any date other than the date of this Prospectus Supplement and the accompanying Prospectus, respectively. This Prospectus Supplement will be amended to reflect material changes to the information contained herein and will be delivered to shareholders. Our business, financial condition, results of operations and prospects may have changed since those dates. In this Prospectus Supplement and in the accompanying Prospectus, unless otherwise indicated, “Trust,” “us,” “our” and “we” refer to BlackRock Taxable Municipal Bond Trust, a Delaware statutory trust.

TABLE OF CONTENTS

TABLE OF CONTENTS

Prospectus

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CAUTIONARY NOTICE REGARDING FORWARD-LOOKING STATEMENTS

This Prospectus Supplement, the accompanying Prospectus and the SAI contain “forward-looking statements.” Forward-looking statements can be identified by the words “may,” “will,” “intend,” “expect,” “estimate,” “continue,” “plan,” “anticipate,” and similar terms and the negative of such terms. Such forward-looking statements may be contained in this Prospectus Supplement as well as in the accompanying Prospectus and in the SAI. By their nature, all forward-looking statements involve risks and uncertainties, and actual results could differ materially from those contemplated by the forward-looking statements. Several factors that could materially affect our actual results are the performance of the portfolio of securities we hold, the price at which our shares will trade in the public markets and other factors discussed in our periodic filings with the SEC.

Although we believe that the expectations expressed in our forward-looking statements are reasonable, actual results could differ materially from those projected or assumed in our forward-looking statements. Our future financial condition and results of operations, as well as any forward-looking statements, are subject to change and are subject to inherent risks and uncertainties, such as those disclosed in the “Risks” section of the accompanying Prospectus and “Special Characteristics and Risks of the Rights Offering” in this Prospectus Supplement. All forward-looking statements contained or incorporated by reference in this Prospectus Supplement or the accompanying Prospectus, or in the SAI, are made as of the date of this Prospectus Supplement or the accompanying Prospectus or SAI, as the case may be. Except for our ongoing obligations under the federal securities laws, we do not intend, and we undertake no obligation, to update any forward-looking statement. The forward-looking statements contained in this Prospectus Supplement, the accompanying Prospectus and the SAI are excluded from the safe harbor protection provided by Section 27A of the Securities Act of 1933, as amended (the “Securities Act”).

Currently known risk factors that could cause actual results to differ materially from our expectations include, but are not limited to, the factors described in the “Risks” section of the accompanying Prospectus as well as in the “Special Characteristics and Risks of the Rights Offering” section of this Prospectus Supplement. We urge you to review carefully those sections for a more detailed discussion of the risks of an investment in the Common Shares.

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DESCRIPTION OF THE RIGHTS OFFERING

Terms of the Rights Offering

The Trust is issuing to Record Date Shareholders Rights to subscribe for Common Shares of the Trust. Each Record Date Shareholder is being issued one transferable Right for each Common Share owned on the Record Date. The Rights entitle the holder to acquire, at a subscription price per Common Share (the “Subscription Price”) determined based upon a formula equal to [●]% of the average of the last reported sales price of the Trust’s Common Shares on the NYSE on the Expiration Date (as defined below) and each of the [four] preceding trading days (the “Formula Price”), [●] new Common Share for each [●] Rights held. If, however, the Formula Price is less than [●]% of the NAV per Common Share of the Trust’s Common Shares at the close of trading on the NYSE on the Expiration Date, then the Subscription Price will be [●]% of the Trust’s NAV per Common Share at the close of trading on the NYSE on that day. The estimated Subscription Price to the public of $[●] is based upon [●]% of the last reported sales price of the Trust’s Common Shares on the NYSE on [●], 2021. Fractional shares will not be issued upon the exercise of the Rights. Accordingly, Common Shares may be purchased only pursuant to the exercise of Rights in integral multiples of [●]. The number of Rights to be issued to a Record Date Shareholder will be rounded up to the nearest number of Rights evenly divisible by [●]. In the case of Common Shares held of record by Cede & Co. (“Cede”), as nominee for the Depository Trust Company (“DTC”)], or any other depository or nominee, the number of Rights issued to Cede or such other depository or nominee will be adjusted to permit rounding up (to the nearest number of Rights evenly divisible by [●]) of the Rights to be received by beneficial owners for whom it is the holder of record only if [insert nominee name] or such other depository or nominee provides to the Trust on or before the close of business on [●], 2021 written representation of the number of Rights required for such rounding. Rights may be exercised at any time during the period (the “Subscription Period”) which commences on [●], 2021, and ends at [5:00 PM Eastern Time] on [●], 2021 (the “Expiration Date”), unless otherwise extended. Shares of the Trust, as a closed-end fund, can trade at a discount to NAV. Upon exercise of the Rights offering, Trust shares are expected to be issued at a price below NAV per Common Share. The right to acquire one Common Share for each [●] Rights held during the Subscription Period (or any extension of the Subscription Period) at the Subscription Price will be referred to in the remainder of this Prospectus Supplement as the “Rights offering.” Rights will expire

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on the Expiration Date and thereafter may not be exercised. Any Common Shares issued as a result of the Rights offering will not be Record Date shares for the Trust’s monthly distribution to be paid on [●], 2019 and will not be entitled to receive such distribution.

The Trust has entered into a dealer manager agreement with [●] (the “Dealer Manager”) that allows the Dealer Manager to take actions to seek to facilitate the trading market for Rights and the placement of Common Shares pursuant to the exercise of Rights. Those actions are expected to involve the Dealer Manager purchasing and exercising Rights during the Subscription Period at prices determined at the time of such exercise, which are expected to vary from the Subscription Price. See “Plan of Distribution” for additional information.

Rights may be evidenced by subscription certificates or may be uncertificated and evidenced by other appropriate documentation (i.e., a rights card distributed to registered shareholders in lieu of a subscription certificate) (“Subscription Certificates”). The number of Rights issued to each holder will be stated on the Subscription Certificate delivered to the holder. The method by which Rights may be exercised and Common Shares paid for is set forth below in “Method of Exercise of Rights,” “Payment for Shares” and “Plan of Distribution.” A holder of Rights will have no right to rescind a purchase after [●] (the “Rights Agent”) has received payment. See “Payment for Shares” below. It is anticipated that the Common Shares issued pursuant to an exercise of Rights will be listed on the [●].

[Holders of Rights [who are Record Date Shareholders] are entitled to subscribe for additional Common Shares at the same Subscription Price pursuant to the over-subscription privilege, subject to certain limitations, allotment and the right of the Board to eliminate the primary over-subscription privilege [or secondary] over-subscription privilege. See “Over-Subscription Privilege” below.]

For purposes of determining the maximum number of Common Shares that may be acquired pursuant to the Rights offering, broker-dealers, trust companies, banks or others whose shares are held of record by Cede or by any other depository or nominee will be deemed to be the holders of the Rights that are held by Cede or such other depository or nominee on their behalf.

The Rights are transferable until the completion of the Subscription Period and will be admitted for trading on the [●] under the symbol “[●].” Assuming a market exists for the Rights, the Rights may be purchased and sold through usual brokerage channels and also sold through the Rights Agent. Although no assurance can be given that a market for the Rights will develop, trading in the Rights on the [●] is expected to begin two Business Days prior to the Record Date and may be conducted until the close of trading on the last [●] trading day prior to the Expiration Date. Trading of the Rights on the [●] is expected to be conducted on a when-issued basis until and including the date on which the Subscription Certificates are mailed to Record Date Shareholders of record and thereafter is expected to be conducted on a regular way basis until and including the last [●] trading day prior to the Expiration Date. The method by which Rights may be transferred is set forth below under “Method of Transferring Rights.” The Common Shares are expected to begin trading ex-Rights one Business Day prior to the Record Date as determined and announced by the [●]. The Rights offering may be terminated or extended by the Trust at any time for any reason before the Expiration Date. If the Trust terminates the Rights offering, the Trust will issue a press release announcing such termination and will direct the Rights Agent to return, without interest, all subscription proceeds received to such shareholders who had elected to purchase Common Shares.

Nominees who hold the Trust’s Common Shares for the account of others, such as banks, broker-dealers, trustees or depositories for securities, should notify the respective beneficial owners of such shares as soon as possible to ascertain such beneficial owners’ intentions and to obtain instructions with respect to the Rights. If the beneficial owner so instructs, the nominee should complete the Subscription Certificate and submit it to the Rights Agent with proper payment. In addition, beneficial owners of the Common Shares or Rights held through such a nominee should contact the nominee and request the nominee to effect transactions in accordance with such beneficial owner’s instructions.

[Participants in the Trust’s Dividend Reinvestment Plan (the “Plan”) will be issued Rights in respect of the Common Shares held in their accounts in the Plan. Participants wishing to exercise these Rights must exercise the Rights in accordance with the procedures set forth in “Method of Exercise of Rights” and “Payment for Shares.”]

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Conditions of the Rights Offering

The Rights offering is being made in accordance with the Investment Company Act of 1940, as amended (the “Investment Company Act”) without shareholder approval. The staff of the SEC has interpreted the Investment Company Act as not requiring shareholder approval of a transferable rights offering to purchase common shares at a price below the then current NAV so long as certain conditions are met, including: (i) a good faith determination by a fund’s board that such offering would result in a net benefit to existing shareholders; (ii) the offering fully protects shareholders’ preemptive rights and does not discriminate among shareholders (except for the possible effect of not offering fractional rights); (iii) management uses its best efforts to ensure an adequate trading market in the rights for use by shareholders who do not exercise such rights; and (iv) the ratio of a transferable rights offering does not exceed one new share for each three rights held.

[Over-Subscription Privilege

The Board has the right in its absolute discretion to eliminate the over-subscription privilege with respect to primary over-subscription shares and secondary over-subscription shares if it considers it to be in the best interest of the Trust to do so. The Board may make that determination at any time, without prior notice to Rights holders or others, up to and including the fifth day following the Expiration Date. If the primary over-subscription privilege is not eliminated, it will operate as set forth below.

Rights holders [who are Record Date Shareholders and who fully exercise their Rights] are entitled to subscribe for additional Common Shares at the same Subscription Price pursuant to the over-subscription privilege, subject to certain limitations and subject to allotment.

[Record Date Shareholders who fully exercise all Rights initially issued to them] are entitled to buy those Common Shares, referred to as “primary over-subscription shares,” that were not purchased by other holders of Rights at the same Subscription Price. If enough primary over-subscription shares are available, all such requests will be honored in full. If the requests for primary over-subscription shares exceed the primary over-subscription shares available, the available primary over-subscription shares will be allocated pro rata among those fully exercising [Record Date Shareholders] who over-subscribe based on the number of Rights originally issued to them by the Trust. Common Shares acquired pursuant to the over-subscription privilege are subject to allotment.

[In addition, the Trust, in its sole discretion, may determine to issue additional Common Shares at the same Subscription Price in an amount of up to [    ]% of the shares issued pursuant to the primary subscription, referred to as “secondary over-subscription shares.” Should the Trust determine to issue some or all of the secondary over-subscription shares, they will be allocated only among Record Date Shareholders who submitted over-subscription

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requests. Secondary over-subscription shares will be allocated pro rata among those fully exercising Record Date Shareholders who over-subscribe based on the number of Rights originally issued to them by the Trust. Rights acquired in the secondary market may not participate in the over-subscription privilege.]

Record Date Shareholders who are fully exercising their Rights during the Subscription Period should indicate, on the Subscription Certificate that they submit with respect to the exercise of the Rights issued to them, how many Common Shares they are willing to acquire pursuant to the over-subscription privilege. Rights acquired in the secondary market may not participate in the over-subscription privilege.

To the extent sufficient Common Shares are not available to fulfill all over-subscription requests, unsubscribed Common Shares (the “Excess Shares”) will be allocated pro rata among those Record Date Shareholders who over-subscribe based on the number of Rights issued to them by the Trust. The allocation process may involve a series of allocations in order to assure that the total number of Common Shares available for over-subscriptions is distributed on a pro rata basis.

The formula to be used in allocating the Excess Shares is as follows:

Banks, broker-dealers, trustees and other nominee holders of Rights will be required to certify to the Rights Agent, before any over-subscription privilege may be exercised with respect to any particular beneficial owner, as to the aggregate number of Rights exercised during the Subscription Period and the number of Common Shares subscribed for pursuant to the over-subscription privilege by such beneficial owner and that such beneficial owner’s subscription was exercised in full. Nominee holder over-subscription forms and beneficial owner certification forms will be distributed to banks, broker-dealers, trustees and other nominee holders of Rights with the Subscription Certificates. [Nominees should also notify holders purchasing Rights in the secondary market that such Rights may not participate in the over-subscription privilege.]

The Trust will not otherwise offer or sell any Common Shares that are not subscribed for pursuant to the primary subscription, the primary over-subscription privilege or the secondary over-subscription privilege pursuant to the Rights offering.]

Sales by Rights Agent

Holders of Rights who are unable or do not wish to exercise any or all of their Rights may instruct the Rights Agent to sell any unexercised Rights. The Subscription Certificates representing the Rights to be sold by the Rights Agent must be received prior to [5:00 PM, Eastern Time], on [●], 2021, five Business Days prior to the Expiration Date (or, if the Subscription Period is extended, prior to [5:00 PM, Eastern Time], on the fifth Business Day prior to the extended Expiration Date). Upon the timely receipt of the appropriate instructions to sell Rights, the Rights Agent will use its best efforts to complete the sale and will remit the proceeds of sale, net of any commissions, to the holders. The Rights Agent will also attempt to sell any Rights attributable to shareholders of record whose addresses are outside the United States, or who have an APO or FPO address. The selling Rights holder will pay all brokerage commissions incurred by the Rights Agent. These sales may be effected by the Rights Agent. The Rights Agent will automatically attempt to sell any unexercised Rights that remain unclaimed as a result of Subscription Certificates being returned by the postal authorities as undeliverable as of the [●] Business Day prior to the Expiration Date. The Rights Agent will attempt to sell such Rights, including by first offering such Rights to the Dealer Manager for purchase by the Dealer Manager at the then-current market price on the [●]. The Rights Agent will offer Rights to the Dealer Manager before attempting to sell them on the [●], which may affect the market price for Rights on the [●] and reduce the number of Rights available for purchase on the [●], thereby reducing the ability of new investors to participate in the offering. These sales will be made net of commissions, taxes and any other expenses paid on behalf of the nonclaiming holders of Rights. Proceeds from those sales will be held by Computershare Trust Company, N.A. in its capacity as the Trust’s transfer agent, for the account of the nonclaiming holder of Rights until the proceeds are either claimed or escheated. There can be no assurance that the Rights Agent will be able to

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complete the sale of any of these Rights and neither the Trust nor the Rights Agent has guaranteed any minimum sales price for the Rights. All of these Rights will be sold at the market price, if any, through an exchange or market trading the Rights. If the Rights can be sold, sales of the Rights will be deemed to have been effected at the weighted average price received by the Rights Agent on the day such Rights are sold, less any applicable brokerage commissions, taxes and other expenses.

[Dealer Manager

[●] (previously defined as the “Dealer Manager”), a registered broker-dealer, may also act on behalf of its clients to purchase or sell Rights in the open market and may receive commissions from its clients for such services. Holders of Rights attempting to sell any unexercised Rights in the open market through a broker-dealer other than the Dealer Manager may be charged a different commission and should consider the commissions and fees charged by the broker-dealer prior to selling their Rights on the open market. The Dealer Manager is not expected to purchase Rights as principal for its own account in order to seek to facilitate the trading market for Rights or otherwise. See “Plan of Distribution” for additional information.]

Sale of Rights

The Rights are transferable and will be admitted for trading on the [●] under the symbol “[●].” Although no assurance can be given that a market for the Rights will develop, trading in the Rights on the [●] is expected to begin two Business Days prior to the Record Date and may be conducted until the close of trading on the last [●] trading day prior to the Expiration Date.

The value of the Rights, if any, will be reflected by the market price. Rights may be sold by individual holders or may be submitted to the Rights Agent for sale. Any Rights submitted to the Rights Agent for sale must be received by the Rights Agent prior to [5:00 PM, Eastern Time], on [●], 2021, five Business Days prior to the Expiration Date (or, if the Subscription Period is extended, prior to [5:00 PM, Eastern Time], on the [●] Business Day prior to the extended Expiration Date).

[Rights that are sold will not confer any right to acquire any Common Shares in any primary over-subscription privilege or secondary over-subscription privilege, if any, and any Record Date Shareholder who sells any Rights will not be eligible to participate in the primary over-subscription privilege or secondary over-subscription privilege, if any.]

Trading of the Rights on the [●] will be conducted on a when-issued basis until and including the date on which the Subscription Certificates are mailed to Record Date Shareholders of record and thereafter will be conducted on a regular-way basis until and including the last [●] trading day prior to the Expiration Date. The Common Shares are expected to begin trading ex-Rights one Business Day prior to the Record Date.

Shareholders are urged to obtain a recent trading price for the Rights on the [●] from their broker, bank, financial advisor or the financial press.

Method of Transferring Rights

The Rights evidenced by a single Subscription Certificate may be transferred in whole by endorsing the Subscription Certificate for transfer in accordance with the accompanying instructions. A portion of the Rights evidenced by a single Subscription Certificate (but not fractional Rights) may be transferred by delivering to the Rights Agent a Subscription Certificate properly endorsed for transfer, with instructions to register the portion of the Rights evidenced thereby in the name of the transferee (and to issue a new Subscription Certificate to the transferee evidencing the transferred Rights). In this event, a new Subscription Certificate evidencing the balance of the Rights will be issued to the Rights holder or, if the Rights holder so instructs, to an additional transferee.

Holders wishing to transfer all or a portion of their Rights (but not fractional Rights) should promptly transfer such Rights to ensure that: (i) the transfer instructions will be received and processed by the Rights Agent, (ii) a new Subscription Certificate will be issued and transmitted to the transferee or transferees with respect to transferred

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Rights, and to the holder with respect to retained Rights, if any, and (iii) the Rights evidenced by the new Subscription Certificates may be exercised or sold by the recipients thereof prior to the Expiration Date. Neither the Trust nor the Rights Agent shall have any liability to a transferee or holder of Rights if Subscription Certificates are not received in time for exercise or sale prior to the Expiration Date.

Except for the fees charged by the Rights Agent (which will be paid by the Trust as described below), all commissions, fees and other expenses (including brokerage commissions and transfer taxes) incurred in connection with the purchase, sale, transfer or exercise of Rights will be for the account of the holder of the Rights, and none of these commissions, fees or expenses will be borne by the Trust or the Rights Agent.

The Trust anticipates that the Rights will be eligible for transfer through, and that the exercise of the Rights may be effected through, the facilities of [insert depository] (Rights exercised through [insert depository] are referred to as “[insert depository] Exercised Rights”).

Rights Agent

The Rights Agent is [●]. The Rights Agent will receive from the Trust an amount estimated to be $[●], comprised of the fee for its services and the reimbursement for certain expenses related to the Rights offering. The shareholders of the Trust will indirectly pay such amount.

Information Agent

INQUIRIES BY ALL HOLDERS OF RIGHTS SHOULD BE DIRECTED TO: THE INFORMATION AGENT, [●]; HOLDERS PLEASE CALL TOLL-FREE AT [●]; BANKS AND BROKERS PLEASE CALL [●].

Method of Exercise of Rights

Rights may be exercised by completing and signing the Subscription Certificate and mailing it in the envelope provided, or otherwise delivering the completed and signed Subscription Certificate to the Rights Agent, together with payment for the Common Shares as described below under “Payment for Shares.” Rights may also be exercised through the broker of a holder of Rights, who may charge the holder of Rights a servicing fee in connection with such exercise. See “Plan of Distribution” for additional information regarding the purchase and exercise of Rights by the Dealer Manager.

Completed Subscription Certificates and payment must be received by the Rights Agent prior to [5:00 PM Eastern Time], on the Expiration Date (unless payment is effected by means of a notice of guaranteed delivery as described below under “Payment for Shares”). Your broker, bank, trust company or other intermediary may impose a deadline for exercising Rights earlier than [5:00 PM, Eastern Time], on the Expiration Date. The Subscription Certificate and payment should be delivered to the Rights Agent at the following address:

If By Mail:

BlackRock Taxable Municipal Bond Trust

[●]

If By Overnight Courier:

BlackRock Taxable Municipal Bond Trust

[●]

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Payment for Shares

Holders of Rights who acquire Common Shares in the Rights offering may choose between the following methods of payment:

A PAYMENT PURSUANT TO THIS METHOD MUST BE IN UNITED STATES DOLLARS BY CHECK (WHICH MUST INCLUDE THE NAME OF THE SHAREHOLDER ON THE CHECK) DRAWN ON A BANK LOCATED IN THE CONTINENTAL UNITED STATES, MUST BE PAYABLE TO BLACKROCK TAXABLE MUNICIPAL BOND TRUST AND MUST ACCOMPANY AN EXECUTED SUBSCRIPTION CERTIFICATE TO BE ACCEPTED.

The method and timing of payment for Common Shares acquired by the Dealer Manager through the exercise of Rights is described under “Plan of Distribution.”

If a holder of Rights who acquires Common Shares pursuant to the Rights offering does not make payment of all amounts due, the Trust reserves the right to take any or all of the following actions: (i) find other purchasers for such subscribed-for and unpaid-for Common Shares; (ii) apply any payment actually received by it toward the purchase of the greatest whole number of Common Shares which could be acquired by such holder upon exercise of the Rights or any over-subscription privilege; (iii) sell all or a portion of the Common Shares purchased by the holder, in the open market, and apply the proceeds to the amounts owed; and (iv) exercise any and all other rights or remedies to which it may be entitled, including, without limitation, the right to set off against payments actually received by it with respect to such subscribed Common Shares and to enforce the relevant guarantee of payment.

Any payment required from a holder of Rights must be received by the Rights Agent prior to [5:00 PM Eastern Time] on the Expiration Date. Issuance and delivery of the Common Shares purchased are subject to collection of checks.

Within [●] Business Days following the Expiration Date (the “Confirmation Date”), a confirmation will be sent by the Rights Agent to each holder of Rights (or, if the Common Shares are held by [insert nominee name] or any other depository or nominee, to [insert nominee name] or such other depository or nominee), showing (i) the number of Common Shares acquired pursuant to the subscription, (ii) the number of Common Shares, if any, acquired pursuant to the over-subscription privilege, and (iii) the per share and total purchase price for the Common Shares. Any payment required from a holder of Rights must be received by the Rights Agent on or prior to the Expiration Date. Any excess payment to be refunded by the Trust to a holder of Rights, or to be paid to a holder of Rights as a result of sales of Rights on its behalf by the Rights Agent, will be mailed by the Rights Agent to the holder within [●] Business Days after the Expiration Date.

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A holder of Rights will have no right to rescind a purchase after the Rights Agent has received payment either by means of a notice of guaranteed delivery or a check, which must include the name of the shareholder on the check.

Upon acceptance of a subscription, all funds received by the Rights Agent shall be held by the Rights Agent as agent for the Trust and deposited in one or more bank accounts. Such funds may be invested by the Rights Agent in: bank accounts, short-term certificates of deposit, bank repurchase agreements, and disbursement accounts with commercial banks meeting certain standards. The Rights Agent may receive interest, dividends or other earnings in connection with such deposits or investments.

Holders, such as broker-dealers, trustees or depositories for securities, who hold Common Shares for the account of others, should notify the respective beneficial owners of the Common Shares as soon as possible to ascertain such beneficial owners’ intentions and to obtain instructions with respect to the Rights. If the beneficial owner so instructs, the record holder of the Rights should complete Subscription Certificates and submit them to the Rights Agent with the proper payment. In addition, beneficial owners of Common Shares or Rights held through such a holder should contact the holder and request that the holder effect transactions in accordance with the beneficial owner’s instructions. [Banks, broker-dealers, trustees and other nominee holders that hold Common Shares of the Trust for the accounts of others are advised to notify those persons that purchase Rights in the secondary market that such Rights may not participate in any over-subscription privilege offered.]

THE INSTRUCTIONS ACCOMPANYING THE SUBSCRIPTION CERTIFICATES SHOULD BE READ CAREFULLY AND FOLLOWED IN DETAIL. DO NOT SEND SUBSCRIPTION CERTIFICATES TO THE TRUST.

THE METHOD OF DELIVERY OF SUBSCRIPTION CERTIFICATES AND PAYMENT OF THE SUBSCRIPTION PRICE TO THE RIGHTS AGENT WILL BE AT THE ELECTION AND RISK OF THE RIGHTS HOLDERS, BUT IF SENT BY MAIL IT IS RECOMMENDED THAT THE CERTIFICATES AND PAYMENTS BE SENT BY REGISTERED MAIL, PROPERLY INSURED, WITH RETURN RECEIPT REQUESTED, AND THAT A SUFFICIENT NUMBER OF DAYS BE ALLOWED TO ENSURE DELIVERY TO THE RIGHTS AGENT AND CLEARANCE OF PAYMENT PRIOR TO [5:00 PM EASTERN TIME], ON THE EXPIRATION DATE. BECAUSE UNCERTIFIED PERSONAL CHECKS MAY TAKE AT LEAST FIVE BUSINESS DAYS TO CLEAR, YOU ARE STRONGLY URGED TO PAY, OR ARRANGE FOR PAYMENT, BY MEANS OF A CERTIFIED OR CASHIER’S CHECK, WHICH MUST INCLUDE THE NAME OF THE SHAREHOLDER ON THE CHECK.

All questions concerning the timeliness, validity, form and eligibility of any exercise of Rights will be determined by the Trust, whose determinations will be final and binding. The Trust in its sole discretion may waive any defect or irregularity, or permit a defect or irregularity to be corrected within such time as it may determine, or reject the purported exercise of any Right. Subscriptions will not be deemed to have been received or accepted until all irregularities have been waived or cured within such time as the Trust determines in its sole discretion. Neither the Trust nor the Rights Agent will be under any duty to give notification of any defect or irregularity in connection with the submission of Subscription Certificates or incur any liability for failure to give such notification.

Foreign Restrictions

Subscription Certificates will only be mailed to Record Date Shareholders of record whose addresses are within the United States (other than an APO or FPO address). Because the Rights offering will not be registered in any jurisdiction other than the United States, the Rights Agent will attempt to sell all of the Rights issued to shareholders of record outside of these jurisdictions and remit the net proceeds, if any, to such shareholders of record. If the Rights can be sold, sales of these Rights will be deemed to have been effected at the weighted average price received by the Rights Agent on the day the Rights are sold, less any applicable brokerage commissions, taxes and other expenses.

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Notice of Net Asset Value Decline

The Trust has, pursuant to the SEC’s regulatory requirements, undertaken to suspend the Rights offering until the Trust amends this Prospectus Supplement if, after [●], 2021 (the date of this Prospectus Supplement), the Trust’s NAV declines more than 10% from the Trust’s NAV as of that date. In that event, the Expiration Date will be extended and the Trust will notify Record Date Shareholders of record of any such decline and permit Rights holders to cancel their exercise of Rights.

Employee Benefit Plan and IRA Considerations

[Holders of Rights that are employee benefit plans subject to limitations imposed by the Internal Revenue Code of 1986, as amended (the “Code”), such as employee plans subject to the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), Keogh Plans and Individual Retirement Accounts (“IRA”) (each a “Benefit Plan” and collectively, “Benefit Plans”), should be aware that the use of additional contributions of cash outside of the Benefit Plan to exercise Rights may be treated as additional contributions to the Benefit Plan. When taken together with contributions previously made, such deemed additional contributions may be in excess of tax limitations and subject the Rights holder to excise taxes for excess or nondeductible contributions. In the case of Benefit Plans qualified under Section 401(a) of the Code, additional contributions could cause the maximum contribution limitations of Section 415 of the Code or other qualification rules to be violated. Benefit Plans contemplating making additional contributions to exercise Rights should consult with their legal and tax counsel prior to making such contributions.

Benefit Plans and other tax exempt entities, including governmental plans, should also be aware that if they borrow to finance their exercise of Rights, they may become subject to the tax on unrelated business taxable income (“UBTI”) under Section 511 of the Code. If any portion of an IRA is used as security for a loan, the portion so used may also be treated as distributed to the IRA depositor.

A Benefit Plan may also be subject to laws, such as ERISA, that impose certain requirements on the Benefit Plan and on those persons who are fiduciaries with respect to the Benefit Plans (the “Benefit Plan Fiduciary”). Such requirements may include prudence and diversification requirements and require that investments be made in accordance with the documents governing the Benefit Plan. The exercise of Rights by a Benefit Plan Fiduciary for a Benefit Plan should be considered in light of such fiduciary requirements.

In addition, ERISA and the Code prohibit certain transactions involving the assets of a Benefit Plan and certain persons (referred to as “parties in interest” for purposes of ERISA and “disqualified persons” for purposes of the Code) having certain relationships to such Benefit Plans, unless a statutory or administrative exemption is applicable to the transaction. A party in interest or disqualified person who engages in a nonexempt prohibited transaction may be subject to excise taxes and other penalties and liabilities under ERISA and the Code (or with respect to certain Benefit Plans, such as IRAs, a prohibited transaction may cause the Benefit Plan to lose its tax-exempt status). In this regard, the U.S. Department of Labor has issued prohibited transaction class exemptions (“PTCEs”) that may apply to the exercise of the Rights and holding of the Common Shares. These class exemptions include, without limitation, PTCE 84-14 respecting transactions determined by independent qualified professional asset managers, PTCE 90-1 respecting insurance company pooled separate accounts, PTCE 91-38 respecting bank collective investment funds, PTCE 95-60 respecting life insurance company general accounts and PTCE 96-23 respecting transactions determined by in-house asset managers, PTCE 84-24 governing purchases of shares in investment companies) and PTCE 75-1 respecting sales of securities. In addition, Section 408(b)(17) of ERISA and Section 4975(d)(20) of the Code each provides a limited exemption, commonly referred to as the “service provider exemption,” from the prohibited transaction provisions of ERISA and Section 4975 of the Code for certain transactions between a Benefit Plan and a person that is a party in interest and/or a disqualified person (other than a fiduciary or an affiliate that, directly or indirectly, has or exercises any discretionary authority or control or renders any investment advice with respect to the assets of any Benefit Plan involved in the transaction) solely by reason of providing services to the Benefit Plan or by relationship to a service provider, provided that the Benefit Plan receives no less, nor pays no more, than adequate consideration. There can be no assurance that all of the conditions of any such exemptions or any other exemption will be satisfied at the time that the Rights are exercised, or thereafter while the Common Shares are held, if the facts relied upon for using a prohibited transaction exemption change.

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By its exercise of the Rights, each Benefit Plan will be deemed to have represented and warranted that (i) neither the exercise of the Rights, nor the investment in Common Shares pursuant to such exercise, will result in a non-exempt prohibited transaction under ERISA or Section 4975 of the Code, or any substantially similar law, and (ii) neither the Advisor, the Dealer Manager, the Trust or any of their affiliates is or will be a Benefit Plan Fiduciary with respect to the Benefit Plan’s exercise of the Rights or its investment in Common Shares, for purposes of ERISA and Section 4975 of the Code, or any applicable substantially similar law.

Due to the complexity of these rules and the penalties for noncompliance, fiduciaries of Benefit Plans, including the Benefit Plan Fiduciary, should consult with their legal and tax counsel regarding the consequences of their exercise of Rights under ERISA, the Code and other similar laws.]

SUMMARY OF TRUST EXPENSES

The following table and example are intended to assist you in understanding the various costs and expenses directly or indirectly associated with investing in our Common Shares as a percentage of net assets attributable to Common Shares. Amounts are for the current fiscal year after giving effect to anticipated net proceeds of the Rights offering, assuming that we incur the estimated offering expenses.

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The purpose of the table above and the examples below is to help you understand all fees and expenses that you, as a holder of Common Shares, would bear directly or indirectly.

Example

The following example illustrates the expenses (including the sales load of $[●] and offering costs of $[●]) that you would pay on a $1,000 investment in common shares, assuming (i) total net annual expenses of [●]% of net assets attributable to common shares, and (ii) a 5% annual return:

USE OF PROCEEDS

The Trust estimates the net proceeds of the Rights offering to be approximately $[●], based on the estimated Subscription Price per Common Share of $[●] ([●]% of the last reported sales price of the Trust’s Common Shares on the NYSE on [●], 2021), assuming all new Common Shares offered are sold and that the expenses related to the Rights offering estimated at approximately $[●] are paid.

The net proceeds from the Rights offering hereunder will be invested in accordance with the Trust’s investment objectives and policies as set forth in this Prospectus Supplement and the accompanying Prospectus. We currently anticipate that we will be able to invest all of the net proceeds in accordance with our investment objectives and policies within approximately three months of the receipt of such proceeds. Pending such investment, it is anticipated that the proceeds will be invested in short-term investment grade securities or in high quality, short-term money market instruments. Depending on market conditions and operations, a portion of the cash held by the Trust, including any proceeds raised from the offering, may be used to pay distributions in accordance with the Trust’s distribution policy and may be a return of capital. A return of capital is a return to investors of a portion of their original investment in the Trust. In general terms, a return of capital would involve a situation in which a Trust distribution (or a portion thereof) represents a return of a portion of a shareholder’s investment in the Trust, rather than making a distribution that is funded from the Trust’s earned income or other profits. Although return of capital distributions may not be currently taxable, such distributions would decrease the basis of a shareholder’s shares, and therefore, may increase a shareholder’s tax liability for capital gains upon a sale of shares, even if sold at a loss to the shareholder’s original investments.

CAPITALIZATION

The following table sets forth the unaudited capitalization of the Trust as of [●], 2021 and its adjusted capitalization assuming the Common Shares available in the Rights offering discussed in this Prospectus Supplement had been issued.

[To be provided.]

SPECIAL CHARACTERISTICS AND RISKS OF THE RIGHTS OFFERING

Risk is inherent in all investing. Therefore, before investing in the Common Shares you should consider the risks associated with such an investment carefully. See “Risks” in the Prospectus. The following summarizes some of the matters that you should consider before investing in the Trust through the Rights offering:

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Dilution. Record Date Shareholders who do not fully exercise their Rights will, at the completion of the Rights offering, own a smaller proportional interest in the Trust than owned prior to the Rights offering. The completion of the Rights offering will result in immediate voting dilution for such shareholders. Further, both the sales load and the expenses associated with the Rights offering will immediately reduce the NAV of each outstanding Common Share. In addition, if the Subscription Price is less than the NAV per Common Share as of the Expiration Date, the completion of this Rights offering will result in an immediate dilution of the NAV per Common Share for all existing Common Shareholders (i.e., will cause the NAV per Common Share to decrease). It is anticipated that existing Common Shareholders will experience immediate dilution even if they fully exercise their Rights. Such dilution is not currently determinable because it is not known how many Common Shares will be subscribed for, what the NAV per Common Share or market price of the Common Shares will be on the Expiration Date or what the Subscription Price per Common Share will be. If the Subscription Price is substantially less than the current NAV per Common Share, this dilution could be substantial. The Trust will pay expenses associated with the Rights offering, estimated at approximately $[●]. In addition, the Trust has agreed to pay a dealer manager fee (sales load) equal to [●]% of the Subscription Price per Common Share issued pursuant to the exercise of Rights (including pursuant to the Over-Subscription Privilege). The Trust, not investors, pays the sales load, which is ultimately borne by all Common Shareholders. All of the costs of the Rights offering will be borne by the Trust’s Common Shareholders. See “Table of Fees and Expenses” in this Prospectus Supplement and “Summary of Trust Expenses” in the accompanying Prospectus for more information.

If you do not exercise all of your Rights, you may own a smaller proportional interest in the Trust when the Rights offering is over. In addition, you will experience an immediate dilution of the aggregate NAV per Common Share if you do not participate in the Rights offering and will experience a reduction in the NAV per Common Share whether or not you exercise your Rights, if the Subscription Price is below the Trust’s NAV per Common Share on the Expiration Date, because:

On the other hand, if the Subscription Price is above the Trust’s NAV per Common Share on the Expiration Date, you may experience an immediate accretion of the aggregate NAV per share of your Common Shares even if you do not exercise your Rights and an immediate increase in the NAV per Common Share whether or not you participate in the Rights offering, because:

[Furthermore, if you do not participate in the secondary over-subscription, if it is available, your percentage ownership will also be diluted.] The Trust cannot state precisely the amount of any dilution because it is not known at this time what the NAV per Common Share will be on the Expiration Date or what proportion of the Rights will be exercised. The impact of the Rights offering on NAV per Common Share is shown by the following examples, assuming the Rights offering is fully subscribed and a $[●] Subscription Price:

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If you do not wish to exercise your Rights, you should consider selling them as set forth in this Prospectus Supplement. Any cash you receive from selling your Rights may serve as partial compensation for any possible dilution of your interest in the Trust. The Trust cannot give assurance, however, that a market for the Rights will develop or that the Rights will have any marketable value.

[The Trust’s largest shareholders could increase their percentage ownership in the Trust through the exercise of the primary subscription and over-subscription privilege.]

Risks of Investing in Rights. Shares of closed-end funds such as the Trust frequently trade at a discount to NAV. If the Formula Price is less than [●]% of NAV on the Expiration Date, then the Subscription Price will likely be greater than the market price of a Common Share on that date. In addition, the Formula Price, even if above [●]% of NAV, may be still above the market price of a Common Share on the Expiration Date. If either event occurs, the Rights will have no value, and a person who exercises Rights will experience an immediate loss of value.

Leverage. Leverage creates a greater risk of loss, as well as a potential for more gain, for the Common Shares than if leverage were not used. Following the completion of the Rights offering, the Trust’s amount of leverage outstanding will decrease. The leverage of the Trust as of [●], 2021 was approximately [●]% of the Trust’s Managed Assets. After the completion of the Rights offering, the amount of leverage outstanding is expected to decrease to approximately [●]% of the Trust’s Managed Assets. The use of leverage for investment purposes creates opportunities for greater total returns but at the same time increases risk. When leverage is employed, the NAV and market price of the Common Shares and the yield to holders of Common Shares may be more volatile. Any investment income or gains earned with respect to the amounts borrowed in excess of the interest due on the borrowing will augment the Trust’s income. Conversely, if the investment performance with respect to the amounts borrowed fails to cover the interest on such borrowings, the value of the Trust’s Common Shares may decrease more quickly than would otherwise be the case, and distributions on the Common Shares could be reduced or eliminated. Interest payments and fees incurred in connection with such borrowings will reduce the amount of net income available for distribution to holders of the Common Shares.

Because the fee paid to the Advisor is calculated on the basis of the Trust’s Managed Assets, which include the proceeds of leverage, the dollar amount of the management fee paid by the Trust to the Advisor will be higher (and the Advisor will be benefited to that extent) when leverage is used. The Advisor will use leverage only if it believes such action would result in a net benefit to the Trust’s shareholders after taking into account the higher fees and expenses associated with leverage (including higher management fees).

The Trust’s leveraging strategy may not be successful.

Increase in Share Price Volatility; Decrease in Share Price. The Rights offering may result in an increase in trading of the Common Shares, which may increase volatility in the market price of the Common Shares. The Rights

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offering may result in an increase in the number of shareholders wishing to sell their Common Shares, which would exert downward price pressure on the price of Common Shares.

Under-Subscription. It is possible that the Rights offering will not be fully subscribed. Under-subscription of the Rights offering would have an impact on the net proceeds of the Rights offering and whether the Trust achieves any benefits.

TAXATION

The following is a general summary of the U.S. federal income tax consequences of the Rights offering to Record Date Shareholders who are U.S. persons for U.S. federal income tax purposes. The following summary supplements the discussion set forth in the accompanying Prospectus and SAI and is subject to the qualifications and assumptions set forth therein. The discussion set forth herein does not constitute tax advice and potential investors are urged to consult their own tax advisers to determine the tax consequences of investing in the Trust.

Please refer to the “Tax Matters” section in the Trust’s Prospectus and SAI for a description of the consequences of investing in the Common Shares of the Trust. Special tax considerations relating to this Rights offering are summarized below:

The foregoing is a general and brief summary of the provisions of the Code and the Treasury Regulations in effect as they directly govern the taxation of the Trust and its Common Shareholders, with respect to U.S. federal income taxation only. Other tax issues such as state and local taxation may apply. Investors are urged to consult their own

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tax advisors to determine the tax consequences of investing in the Trust. These provisions are subject to change by legislative or administrative action, and any such change may be retroactive.

PLAN OF DISTRIBUTION

[Distribution Arrangements

[●] will act as Dealer Manager for this Rights offering. Under the terms and subject to the conditions contained in the Dealer Manager Agreement among the Dealer Manager, the Trust and the Advisor, the Dealer Manager will provide financial structuring and solicitation services in connection with the Rights offering and will solicit the exercise of Rights and participation in the over-subscription privilege. The Rights offering is not contingent upon any number of Rights being exercised. The Dealer Manager will also be responsible for forming and managing a group of selling broker-dealers (each, a “Selling Group Member” and collectively, the “Selling Group Members”), whereby each Selling Group Member will enter into a Selling Group Agreement with the Dealer Manager to solicit the exercise of Rights and to sell Common Shares purchased by the Selling Group Member from the Dealer Manager. In addition, the Dealer Manager will enter into a Soliciting Dealer Agreement with other soliciting broker-dealers (each, a “Soliciting Dealer” and collectively, the “Soliciting Dealers”) to solicit the exercise of Rights. See “—Compensation to Dealer Manager” for a discussion of fees and other compensation to be paid to the Dealer Manager, Selling Group Members and Soliciting Dealers in connection with the Rights offering.

The Trust and the Advisor have each agreed to indemnify the Dealer Manager for losses arising out of certain liabilities, including liabilities under the Securities Act. The Dealer Manager Agreement also provides that the Dealer Manager will not be subject to any liability to the Trust in rendering the services contemplated by the Dealer Manager Agreement except for any act of willful misfeasance, bad faith or gross negligence of the Dealer Manager or reckless disregard by the Dealer Manager of its obligations and duties under the Dealer Manager Agreement.

In order to seek to facilitate the trading market in the Rights for the benefit of non-exercising shareholders, and the placement of the Common Shares to new or existing investors pursuant to the exercise of the Rights, the Dealer Manager Agreement provides for special arrangements with the Dealer Manager. Under these arrangements, the Dealer Manager is expected to purchase Rights on the [●], as well as Rights received by the Rights Agent for sale by Record Date Stockholders and offered to the Dealer Manager and unexercised Rights of Record Date Shareholders whose record addresses are outside the United States that are held by the Subscription Agent and for which no instructions are received. The number of rights, if any, purchased by the Dealer Manager will be determined by the Dealer Manager in its sole discretion. The Dealer Manager is not obligated to purchase Rights or Common Shares as principal for its own account to facilitate the trading market for Rights or for investment purposes. Rather, its purchases are expected to be closely related to interest in acquiring Common Shares generated by the Dealer Manager through its marketing and soliciting activities. The Dealer Manager intends to exercise Rights purchased by it during the Subscription Period but prior to the Expiration Date. The Dealer Manager may exercise those Rights at its option on one or more dates, which are expected to be prior to the Expiration Date. The Subscription Price for the Common Shares issued through the exercise of Rights by the Dealer Manager prior to the Expiration Date will be the greater of [●]% of the last reported sale price of a Common Share on the NYSE on the date of exercise or [●]% of the last reported NAV of a Common Share on the date prior to the date of exercise. The price and timing of these exercises are expected to differ from those described herein for the Rights offering. The Subscription Price will be paid to the Trust and the dealer manager fee with respect to such proceeds will be paid by the Trust on the applicable settlement date(s) of such exercise(s).

In connection with the exercise of Rights and receipt of Common Shares, the Dealer Manager intends to offer those Common Shares for sale to the public and/or through a group of selling members it has established. The Dealer Manager may set the price for those Common Shares at any price that it determines, in its sole discretion. The Dealer Manager has advised that the price at which such Common Shares are offered is expected to be at or slightly below the closing price of the Common Shares on the NYSE on the date the Dealer Manager exercises Rights. No portion of the amount paid to the Dealer Manager or to a Selling Group Member from the sale of Common Shares in this manner will be paid to the Trust. If the sales price of the Common Shares is greater than the Subscription Price paid by the Dealer Manager for such Common Shares plus the costs to purchase Rights for the purpose of acquiring those Common Shares, the Dealer Manager will receive a gain. Alternatively, if the sales price of the Common Shares is less than the Subscription Price for such Common Shares plus the costs to purchase Rights for the purpose

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of acquiring those Common Shares, the Dealer Manager will incur a loss. The Dealer Manager will pay a concession to Selling Group Members in an amount equal to approximately [2.50]% of the aggregate price of the Common Shares sold by the respective Selling Group Member. Neither the Trust nor the Advisor has a role in setting the terms, including the sales price, on which the Dealer Manager offers for sale and sells Common Shares it has acquired through purchasing and exercising Rights or the timing of the exercise of Rights or sales of Common Shares by the Dealer Manager. Persons who purchase Common Shares from the Dealer Manager or the selling group will purchase shares at a price set by the Dealer Manager, which may be more or less than the Subscription Price, and at a time set by the Dealer Manager, which is expected to be prior to the Expiration Date.

The Dealer Manager may purchase Rights as principal or act as agent on behalf of its clients for the resale of such Rights. The Dealer Manager may realize gains (or losses) in connection with the purchase and sale of Rights and the sale of Common Shares, although such transactions are intended by the Dealer Manager to facilitate the trading market in the Rights and the placement of the Common Shares to new or existing investors pursuant to the exercise of the Rights. Any gains (or losses) realized by the Dealer Manager from the purchase and sale of Rights and the sale of Common Shares is independent of and in addition to its fee as Dealer Manager. The Dealer Manager has advised that any such gains (or losses) are expected to be immaterial relative to its fee as Dealer Manager.

Since neither the Dealer Manager nor persons who purchase Common Shares from the Dealer Manager or members of the selling group were Record Date Shareholders, they would not be able to participate in the over-subscription privilege.

Persons who purchase Common Shares from the Dealer Manager or the selling group will not purchase shares at the Subscription Price based on the formula price mechanism through which Common Shares will be sold in the Rights offering. Instead, those persons will purchase Common Shares at a price set by the Dealer Manager, which may be more or less than the Subscription Price, and will not have the uncertainty of waiting for the determination of the Subscription Price on the Expiration Date.

There is no limit on the number of Rights the Dealer Manager can purchase or exercise. Common Shares acquired by the Dealer Manager pursuant to the exercise of Rights acquired by it will reduce the number of Common Shares available pursuant to the over-subscription privilege, perhaps materially, depending on the number of Rights purchased and exercised by the Dealer Manager.

Although the Dealer Manager can seek to facilitate the trading market for Rights as described above, investors can acquire Common Shares at the Subscription Price by acquiring Rights on the [•] and exercising them in the method described above under “Description of the Rights—Method of Exercise of Rights” and “Description of the Rights—Payment for Shares.”

In the ordinary course of their businesses, the Dealer Manager and/or its affiliates may engage in investment banking or financial transactions with the Trust, the Advisor and their affiliates. In addition, in the ordinary course of their businesses, the Dealer Manager and/or its affiliates may, from time to time, own securities of the Trust or its affiliates.

The principal business address of the Dealer Manager is [●].

Compensation to Dealer Manager

Pursuant to the Dealer Manager Agreement, the Trust has agreed to pay the Dealer Manager a fee for its financial structuring and solicitation services equal to [●]% of the Subscription Price per Common Share for each Common Share issued pursuant to the exercise of Rights, including the over-subscription privilege.

The Dealer Manager will reallow to Selling Group Members in the selling group to be formed and managed by the Dealer Manager selling fees equal to [●]% of the Subscription Price for each Common Share issued pursuant to the Rights offering or the over-subscription privilege as a result of their selling efforts. In addition, the Dealer Manager will reallow to Soliciting Dealers that have executed and delivered a Soliciting Dealer Agreement and have solicited the exercise of Rights, solicitation fees equal to [●]% of the Subscription Price for each Common Share issued

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pursuant to the exercise of Rights as a result of their soliciting efforts, subject to a maximum fee based on the number of Common Shares held by such Soliciting Dealer through [insert depository] on the Record Date. Fees will be paid to the broker-dealer designated on the applicable portion of the subscription certificates or, in the absence of such designation, to the Dealer Manager.

In addition, the Trust, has agreed to pay the Dealer Manager an amount up to $[●] as a partial reimbursement of its expenses incurred in connection with the Rights offering, including reasonable out-of-pocket fees and expenses, if any and not to exceed $[●], incurred by the Dealer Manager, Selling Group Members, Soliciting Dealers and other brokers, dealers and financial institutions in connection with their customary mailing and handling of materials related to the Rights offering to their customers. No other fees will be payable by the Trust or the Advisor to the Dealer Manager in connection with the Rights offering.

LEGAL MATTERS

Certain legal matters in connection with the common shares will be passed upon for the Trust by Willkie Farr & Gallagher LLP, New York, New York, counsel to the Trust. Willkie Farr & Gallagher LLP may rely as to certain matters of Delaware law on the opinion of Morris, Nichols, Arsht & Tunnell LLP, Wilmington, Delaware. [Certain legal matters will be passed on by [●] as special counsel to the Dealer Manager in connection with the Rights offering.]

FINANCIAL STATEMENTS

The audited annual financial statements of the Trust for the fiscal year ended July 31, 202[●] [and the unaudited financial statements for the six months ended January 31, 202[•]] are incorporated by reference into this Prospectus Supplement, the accompanying Prospectus and the SAI. Portions of the Trust’s annual report [and semiannual report] other than the financial statements and related footnotes thereto are not incorporated into, and do not for a part of, this Prospectus Supplement, the accompanying Prospectus or the SAI.

ADDITIONAL INFORMATION

This Prospectus Supplement and the accompanying Prospectus constitute part of a Registration Statement filed by the Trust with the SEC under the Securities Act and the Investment Company Act. This Prospectus Supplement and the accompanying Prospectus omit certain of the information contained in the Registration Statement, and reference is hereby made to the Registration Statement and related exhibits for further information with respect to the Trust and the common shares offered hereby. Any statements contained herein concerning the provisions of any document are not necessarily complete, and, in each instance, reference is made to the copy of such document filed as an exhibit to the Registration Statement or otherwise filed with the SEC. Each such statement is qualified in its entirety by such reference. The complete Registration Statement may be obtained from the SEC upon payment of the fee prescribed by its rules and regulations or free of charge through the SEC’s website (http://www.sec.gov).

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BLACKROCK TAXABLE MUNICIPAL BOND TRUST

[●] Rights for [●] Common Shares of Beneficial Interest

Subscription Rights to Acquire Common Shares of Beneficial Interest

Issuable Upon Exercise of Rights to Subscribe for

Such Common Shares of Beneficial Interest

PROSPECTUS SUPPLEMENT

[●], 2021

Until [            ], 2021 (25 days after the date of this Prospectus Supplement), all dealers that buy, sell or trade the common shares, whether or not participating in this offering, may be required to deliver a prospectus. This is in addition to the dealers’ obligation to deliver a prospectus when acting as underwriters.

BlackRock Taxable Municipal Bond Trust

STATEMENT OF ADDITIONAL INFORMATION

BlackRock Taxable Municipal Bond Trust (the “Trust”) is a diversified, closed-end management investment company. This Statement of Additional Information (“SAI”) relating to the Trust’s common shares of beneficial interest (“common shares”) does not constitute a prospectus, but should be read in conjunction with the prospectus relating thereto dated February 10, 2021 and any related prospectus supplement. This SAI, which is not a prospectus, does not include all information that a prospective investor should consider before purchasing common shares, and investors should obtain and read the Prospectus and any related prospectus supplement prior to purchasing such shares. A copy of the Prospectus and any related prospectus supplement may be obtained without charge by calling (800) 882-0052. You may also obtain a copy of the Prospectus on the Securities and Exchange Commission’s (the “SEC”) website (http://www.sec.gov). Capitalized terms used but not defined in this SAI have the meanings ascribed to them in the Prospectus.

References to the Investment Company Act of 1940, as amended (the “Investment Company Act”), or other applicable law, will include any rules promulgated thereunder and any guidance, interpretations or modifications by the SEC, SEC staff or other authority with appropriate jurisdiction, including court interpretations, and exemptive, no-action or other relief or permission from the SEC, SEC staff or other authority.

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TABLE OF CONTENTS

This Statement of Additional Information is dated February 10, 2021.

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THE TRUST

The Trust is a non-diversified, closed-end management investment company registered under the Investment Company Act. The Trust was formed as a Delaware statutory trust on June 7, 2010 pursuant to an initial Agreement and Declaration of Trust of the Trust and the Certificate of Trust filed with the Secretary of State of the State of Delaware and is governed by pursuant to the Trust’s Agreement and Declaration of Trust which is governed by the laws of the State of Delaware. The Trust’s investment adviser is BlackRock Advisors, LLC (the “Advisor”).

The common shares of the Trust are listed on the New York Stock Exchange (“NYSE”) under the symbol “BBN.” As of February 9, 2021, the Trust has outstanding 57,217,439 common shares.

INVESTMENT OBJECTIVES AND POLICIES

Investment Restrictions

The Trust has adopted restrictions and policies relating to the investment of the Trust’s assets and its activities. Certain of the restrictions are fundamental policies of the Trust and may not be changed without the approval of the holders of a majority of the Trust’s outstanding voting securities (which for this purpose and under the Investment Company Act means the lesser of (i) 67% of the shares represented at a meeting at which more than 50% of the outstanding shares are represented or (ii) more than 50% of the outstanding shares), including class approval by a majority of the Trust’s outstanding shares of preferred shares (“preferred shares”), if any (which for this purpose and under the Investment Company Act means the lesser of (i) 67% of the preferred shares, as a single class, represented at a meeting at which more than 50% of the Trust’s outstanding preferred shares are represented or (ii) more than 50% of the outstanding preferred shares).

Fundamental Investment Restrictions. Under these fundamental investment restrictions, the Trust may not:

For purposes of applying the limitation set forth in subparagraph (1) above, securities of the U.S. Government, any state government or their respective agencies, or instrumentalities and securities backed by the credit of any federal or state governmental entity are not considered to represent industries. However, obligations backed only by the assets and revenues of non-governmental issuers may for this purpose be deemed to be issued by such non-governmental issuers. Thus, the 25% limitation would apply to such obligations. It is nonetheless possible that the Trust may invest more than 25% of its total assets in a broader economic sector of the market for municipal

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obligations, such as revenue obligations of hospitals and other health care facilities or electrical utility revenue obligations.

For the purpose of applying the limitation set forth in subparagraph (1) above, a governmental issuer shall be deemed the sole issuer of a security when its assets and revenues are separate from other governmental entities and its securities are backed only by its assets and revenues. Similarly, in the case of a non-governmental issuer, such as an industrial corporation or a privately owned or operated hospital, if the security is backed only by the assets and revenues of the non-governmental issuer, then such non-governmental issuer would be deemed to be the sole issuer. Where a security is backed by the enforceable obligation of a superior or unrelated governmental entity, it will be included in the computation of securities owned that are issued by such governmental entity. When a security is backed by the enforceable obligation of a superior or unrelated non-governmental entity (other than a bond insurer), it will also be included in the computation of securities owned that are issued by such non-governmental entity. Where a security is guaranteed by a governmental entity or some other facility, such as a bank guarantee or letter of credit, such a guarantee or letter of credit would be considered a separate security and would be treated as an issue of such government, other entity or bank. When a municipal security is insured by bond insurance, it shall not be considered a security that is issued or guaranteed by the insurer; instead, the issuer of such municipal security will be determined in accordance with the principles set forth above. The foregoing restrictions do not limit the percentage of the Trust’s assets that may be invested in municipal securities insured by any given insurer.

Under the Investment Company Act, the Trust may invest up to 10% of its total assets in the aggregate in shares of other investment companies and up to 5% of its total assets in any one investment company, provided the investment does not represent more than 3% of the voting stock of the acquired investment company at the time such shares are purchased. The Trust may invest a greater percentage of its assets in money market funds to the extent permitted by the Investment Company Act or the Securities and Exchange Commission.

Non-Fundamental Investment Restrictions. Additional investment restrictions adopted by the Trust, which may be changed by the Trust’s Board of Trustees (the “Board”) without shareholder approval, provide that the Trust may not:

The restrictions and other limitations set forth in the Trust’s Prospectus and in this SAI will apply only at the time of purchase of securities and will not be considered violated unless an excess or deficiency occurs or exists immediately after and as a result of the acquisition of securities. Any investment policy or restriction described in the Prospectus or in this SAI is deemed to be a non-fundamental policy or restriction of the Trust, unless otherwise stated.

In addition, to comply with Federal tax requirements for qualification as a “regulated investment company,” the Trust’s investments will be limited in a manner such that at the close of each quarter of each taxable year, (a) no more than 25% of the value of the Trust’s total assets are invested in the securities (other than United States government securities or securities of other regulated investment companies) of a single issuer or two or more issuers controlled by the Trust and engaged in the same, similar or related trades or businesses and (b) with regard to at least 50% of the Trust’s total assets, no more than 5% of its total assets are invested in the securities (other than United States government securities or securities of other regulated investment companies) of a single issuer and such securities do not represent more than 10 percent of the voting securities of such issuer. These tax-related

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limitations may be changed by the trustees to the extent appropriate in light of changes to applicable tax requirements.

If the Trust offers preferred shares, it may apply for ratings for such preferred shares from Moody’s, S&P and/or Fitch. In order to obtain and maintain the required ratings, the Trust may be required to comply with investment quality, diversification and other guidelines established by Moody’s, S&P and/or Fitch. Such guidelines may be more restrictive than the restrictions set forth above. The Trust does not anticipate that such guidelines would have a material adverse effect on the Trust’s holders of common shares or its ability to achieve its investment objectives. The Trust presently anticipates that any preferred shares issued would be initially given the highest ratings by Moody’s (Aaa) or by S&P or Fitch (AAA), but no assurance can be given that such ratings will be obtained. No minimum rating is required for the issuance of preferred shares by the Trust. Moody’s, S&P and Fitch receive fees in connection with their ratings issuances.

INVESTMENT POLICIES AND TECHNIQUES

The following information supplements the discussion of the Trust’s investment objectives, policies and techniques that are described in the Prospectus.

Portfolio Investments

Municipal Securities

Municipal security bonds are either general obligation or revenue bonds and typically are issued to finance public projects, such as roads or public buildings, to pay general operating expenses or to refinance outstanding debt. Municipal security bonds may also be issued for private activities, such as housing, medical and educational facility construction or for privately owned industrial development and pollution control projects. General obligation bonds are backed by the full faith and credit, or taxing authority, of the issuer and may be repaid from any revenue source. Revenue bonds may be repaid only from the revenues of a specific facility or source.

Issuers of securities rated Ba/BB or below are regarded as having current capacity to make principal and interest payments but are subject to business, financial or economic conditions which could adversely affect such payment capacity. Municipal securities rated Baa/BBB or better are considered “investment grade” securities; municipal securities rated Baa are considered medium grade obligations which lack outstanding investment characteristics and have speculative characteristics, while municipal securities rated BBB are regarded as having adequate capacity to pay principal and interest. Municipal securities rated AAA in which the Trust may invest may have been so rated on the basis of the existence of insurance guaranteeing the timely payment, when due, of all principal and interest. Municipal securities rated below investment grade quality (Ba/BB or lower) are obligations of issuers that are considered predominantly speculative with respect to the issuer’s capacity to pay interest and repay principal according to the terms of the obligation and, therefore, carry greater investment risk, including the possibility of issuer default and bankruptcy and increased market price volatility. Municipal securities rated below investment grade tend to be less marketable than higher-quality securities because the market for them is less broad. The market for unrated municipal securities is even narrower. During periods of thin trading in these markets, the spread between bid and ask prices is likely to increase significantly and the Trust may have greater difficulty selling its portfolio securities. The Trust will be more dependent on the research and analysis of the Advisor.

A general description of Moody’s, S&P’s and Fitch’s ratings of municipal securities is set forth in Appendix A hereto. The ratings of Moody’s, S&P and Fitch represent their opinions as to the quality of the municipal securities they rate. It should be emphasized, however, that ratings are general and are not absolute standards of quality. Consequently, municipal securities with the same maturity, coupon and rating may have different yields while obligations of the same maturity and coupon with different ratings may have the same yield.

The Trust will opportunistically manage the maturity and/or duration of its securities and the average weighted maturity and/or duration may be shortened or lengthened from time to time depending on market conditions. As a result, the Trust’s portfolio at any given time may include both long-term and intermediate-term municipal securities. Moreover, during temporary defensive periods (e.g., times when, in the Advisor’s opinion, temporary imbalances of supply and demand or other temporary dislocations in the municipal securities market adversely affect

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the price at which long-term or intermediate-term municipal securities are available), and in order to keep cash on hand fully invested, including the period during which the net proceeds of the offering of common shares or securities in connection with leverage, if any, are being invested, the Trust may invest any percentage of its assets in short-term investments including high quality, short-term securities which may be either tax-exempt or taxable and securities of other open- or closed-end investment companies that invest primarily in municipal securities of the type in which the Trust may invest directly.

Obligations of issuers of municipal securities are subject to the provisions of bankruptcy, insolvency and other laws affecting the rights and remedies of creditors, such as the Bankruptcy Reform Act of 2005. In addition, the obligations of such issuers may become subject to the laws enacted in the future by Congress, state legislatures or referenda extending the time for payment of principal or interest, or both, or imposing other constraints upon enforcement of such obligations or upon municipalities to levy taxes. There is also the possibility that, as a result of legislation or other conditions, the power or ability of any issuer to pay, when due, the principal of and interest on its municipal securities may be materially affected.

Short-Term Taxable Fixed Income Securities

For temporary defensive purposes or to keep cash on hand fully invested, the Trust may invest up to 100% of its Managed Assets in cash equivalents and short-term taxable fixed income securities. The Trust may also invest in these instruments to achieve its investment objectives. Short-term taxable fixed income investments are defined to include, without limitation, the following:

(1) U.S. Government securities, including bills, notes and bonds differing as to maturity and rates of interest that are either issued or guaranteed by the U.S. Treasury or by U.S. Government agencies or instrumentalities. U.S. Government securities include securities issued by (a) the Federal Housing Administration, Farmers Home Administration, Export-Import Bank of the United States, Small Business Administration, and Government National Mortgage Association, whose securities are supported by the full faith and credit of the United States; (b) the Federal Home Loan Banks, Federal Intermediate Credit Banks, and Tennessee Valley Authority, whose securities are supported by the right of the agency to borrow from the U.S. Treasury; (c) the Federal National Mortgage Association, whose securities are supported by the discretionary authority of the U.S. Government to purchase certain obligations of the agency or instrumentality; and (d) the Student Loan Marketing Association, whose securities are supported only by its credit. While the U.S. Government provides financial support to such U.S. Government-sponsored agencies or instrumentalities, no assurance can be given that it always will do so since it is not so obligated by law. The U.S. Government, its agencies and instrumentalities do not guarantee the market value of their securities. Consequently, the value of such securities may fluctuate.

(2) Certificates of deposit issued against funds deposited in a bank or a savings and loan association. Such certificates are for a definite period of time, earn a specified rate of return, and are normally negotiable. The issuer of a certificate of deposit agrees to pay the amount deposited plus interest to the bearer of the certificate on the date specified thereon. Certificates of deposit purchased by the Trust may not be fully insured by the Federal Deposit Insurance Corporation.

(3) Repurchase agreements, which involve purchases of debt securities. At the time the Trust purchases securities pursuant to a repurchase agreement, it simultaneously agrees to resell and redeliver such securities to the seller, who also simultaneously agrees to buy back the securities at a fixed price and time. This assures a predetermined yield for the Trust during its holding period, since the resale price is always greater than the purchase price and reflects an agreed-upon market rate. Such actions afford an opportunity for the Trust to invest temporarily available cash. The Trust may enter into repurchase agreements only with respect to obligations of the U.S. Government, its agencies or instrumentalities; certificates of deposit; or bankers’ acceptances in which the Trust may invest. Repurchase agreements may be considered loans to the seller, collateralized by the underlying securities. The risk to the Trust is limited to the ability of the seller to pay the agreed-upon sum on the repurchase date; in the event of default, the repurchase agreement provides that the Trust is entitled to sell the underlying collateral. If the value of the collateral declines after the agreement is entered into, and if the seller defaults under a repurchase agreement when the value of the underlying collateral is less than the repurchase price, the Trust could incur a loss of both principal and interest. The Advisor monitors the value of the collateral at the time the action is entered into and at all times during the term of the repurchase agreement. The Advisor does so in an effort to determine that the value of the collateral always equals or exceeds the agreed-upon repurchase price to be paid to the Trust. If the seller were to be subject to

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a Federal bankruptcy proceeding, the ability of the Trust to liquidate the collateral could be delayed or impaired because of certain provisions of the bankruptcy laws.

(4) Commercial paper, which consists of short-term unsecured promissory notes, including variable rate master demand notes issued by corporations to finance their current operations. Master demand notes are direct lending arrangements between the Trust and a corporation. There is no secondary market for such notes. However, they are redeemable by the Trust at any time. The Advisor will consider the financial condition of the corporation (e.g., earning power, cash flow and other liquidity ratios) and will continuously monitor the corporation’s ability to meet all of its financial obligations, because the Trust’s liquidity might be impaired if the corporation were unable to pay principal and interest on demand. Investments in commercial paper will be limited to commercial paper rated in the highest categories by a major rating agency and which mature within one year of the date of purchase or carry a variable or floating rate of interest.

Short-Term Tax-Exempt Fixed Income Securities

For temporary defensive purposes or to keep cash on hand fully invested, the Trust may invest up to 100% of its Managed Assets in cash equivalents and short-term tax-exempt fixed income securities. The Trust may also invest in these instruments to achieve its investment objectives. Short-term tax-exempt fixed income securities are securities that are exempt from regular Federal income tax and mature within three years or less from the date of issuance. Short-term tax-exempt fixed income securities are defined to include, without limitation, the following:

Bond Anticipation Notes (“BANs”) are usually general obligations of state and local governmental issuers which are sold to obtain interim financing for projects that will eventually be funded through the sale of long-term debt obligations or bonds. The ability of an issuer to meet its obligations on its BANs is primarily dependent on the issuer’s access to the long-term municipal bond market and the likelihood that the proceeds of such bond sales will be used to pay the principal and interest on the BANs.

Tax Anticipation Notes (“TANs”) are issued by state and local governments to finance the current operations of such governments. Repayment is generally to be derived from specific future tax revenues. TANs are usually general obligations of the issuer. A weakness in an issuer’s capacity to raise taxes due to, among other things, a decline in its tax base or a rise in delinquencies could adversely affect the issuer’s ability to meet its obligations on outstanding TANs.

Revenue Anticipation Notes (“RANs”) are issued by governments or governmental bodies with the expectation that future revenues from a designated source will be used to repay the notes. In general, they also constitute general obligations of the issuer. A decline in the receipt of projected revenues, such as anticipated revenues from another level of government, could adversely affect an issuer’s ability to meet its obligations on outstanding RANs. In addition, the possibility that the revenues would, when received, be used to meet other obligations could affect the ability of the issuer to pay the principal and interest on RANs.

Construction Loan Notes are issued to provide construction financing for specific projects. Frequently, these notes are redeemed with funds obtained from the Federal Housing Administration.

Bank Notes are notes issued by local government bodies and agencies such as those described above to commercial banks as evidence of borrowings. The purposes for which the notes are issued are varied but they are frequently issued to meet short-term working capital or capital-project needs. These notes may have risks similar to the risks associated with TANs and RANs.

Tax-Exempt Commercial Paper (“municipal paper”) represents very short-term unsecured, negotiable promissory notes, issued by states, municipalities and their agencies. Payment of principal and interest on issues of municipal paper may be made from various sources, to the extent the funds are available therefrom. Maturities on municipal paper generally will be shorter than the maturities of TANs, BANs or RANs. There is a limited secondary market for issues of municipal paper.

Certain municipal securities may carry variable or floating rates of interest whereby the rate of interest is not fixed but varies with changes in specified market rates or indices, such as a bank prime rate or tax-exempt money market indices.

While the various types of notes described above as a group represent the major portion of the tax-exempt note market, other types of notes are available in the marketplace and the Trust may invest in such other types of notes to

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the extent permitted under its investment objective, policies and limitations. Such notes may be issued for different purposes and may be secured differently from those mentioned above.

Strategic Transactions and Other Management Techniques

Consistent with its investment objectives and policies set forth herein, the Trust may also enter into certain hedging and risk management transactions or transactions to enhance total return. In particular, the Trust may purchase and sell futures contracts, exchange-listed and over-the-counter put and call options on securities, financial indices and futures contracts, forward foreign currency contracts, and may enter into various interest rate transactions (collectively, “Strategic Transactions”). Strategic Transactions may be used to attempt to protect against possible changes in the market value of the Trust’s portfolio resulting from fluctuations in the debt securities markets and changes in interest rates, to protect the Trust’s unrealized gains in the value of its portfolio securities, to facilitate the sale of such securities for investment purposes and to establish a position in the securities markets as a temporary substitute for purchasing particular securities. Any or all of these Strategic Transactions may be used at any time whether for hedging and risk management or to enhance total return. There is no particular strategy that requires use of one technique rather than another. Use of any Strategic Transaction is a function of market conditions. The Strategic Transactions that the Trust may use are described below. The ability of the Trust to hedge them successfully will depend on the Advisor’s ability to predict pertinent market movements as well as sufficient correlation among the instruments, which cannot be assured.

Interest Rate Transactions. The Trust may enter into interest rate swaps and purchase or sell interest rate caps and floors primarily to preserve a return or spread on a particular investment or portion of its portfolio as a duration management technique or to protect against any increase in the price of securities the Trust anticipates purchasing at a later date. The Trust intends to use these transactions for duration and risk management purposes and not as a speculative investment. The Trust will not sell interest rate caps or floors that it does not own. Interest rate swaps involve the exchange by the Trust with another party of their respective commitments to pay or receive interest, e.g., an exchange of floating rate payments for fixed rate payments with respect to a notional amount of principal. The purchase of an interest rate cap entitles the purchaser, to the extent that a specified index exceeds a predetermined interest rate, to receive payments of interest on a notional principal amount from the party selling such interest rate cap. The purchase of an interest rate floor entitles the purchaser, to the extent that a specified index falls below a predetermined interest rate, to receive payments of interest on a notional principal amount from the party selling such interest rate floor.

The Trust may enter into interest rate swaps, caps and floors on either an asset-based or liability-based basis, depending on whether it is offsetting volatility with respect to its assets or liabilities, and will usually enter into interest rate swaps on a net basis, i.e., the two payment streams are netted out, with the Trust receiving or paying, as the case may be, only the net amount of the two payments on the payment dates. In as much as these Strategic Transactions are entered into for good faith risk management purposes, the Advisor and the Trust believe such obligations do not constitute senior securities and, accordingly, will not treat them as being subject to its borrowing restrictions. The Trust will accrue the net amount of the excess, if any, of the Trust’s obligations over its entitlements with respect to each interest rate swap on a daily basis and will designate on its books and records with a custodian an amount of cash or liquid high grade securities having an aggregate net asset value at all times at least equal to the accrued excess. The Trust will not enter into any interest rate swap, cap or floor transaction unless the unsecured senior debt or the claims-paying ability of the other party thereto is rated in the highest rating category of at least one nationally recognized statistical rating organization at the time of entering into such transaction. If there is a default by the other party to such a transaction, the Trust will have contractual remedies pursuant to the agreements related to the transaction. The swap market has grown substantially in recent years with a large number of banks and investment banking firms acting both as principals and as agents utilizing standardized swap documentation. Caps and floors are more recent innovations for which standardized documentation has not yet been developed and, accordingly, they are less liquid than swaps.

Futures Contracts and Options on Futures Contracts. In connection with its hedging and other risk management strategies, the Trust may also enter into contracts for the purchase or sale for future delivery (“futures contracts”) of debt securities, aggregates of debt securities or indices or prices thereof, other financial indices and U.S. Government debt securities or options on the above. The Trust primarily intends to engage in such transactions for bona fide hedging or risk management and other portfolio management purposes.

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Calls on Securities, Indices and Futures Contracts. In order to enhance income or reduce fluctuations on net asset value, the Trust may sell or purchase call options (“calls”) on municipal securities and indices based upon the prices of futures contracts and debt securities that are traded on U.S. and foreign securities exchanges and in the over-the-counter markets. A call option gives the purchaser of the option the right to buy, and obligates the seller to sell, the underlying security, futures contract or index at the exercise price at any time or at a specified time during the option period. All such calls sold by the Trust must be “covered” as long as the call is outstanding (i.e., the Trust must own the instrument subject to the call or other securities or assets acceptable for applicable segregation and coverage requirements). A call sold by the Trust exposes the Trust during the term of the option to possible loss of opportunity to realize appreciation in the market price of the underlying security, index or futures contract and may require the Trust to hold an instrument which it might otherwise have sold. The purchase of a call gives the Trust the right to buy a security, futures contract or index at a fixed price. Calls on futures on municipal securities must also be covered by assets or instruments acceptable under applicable segregation and coverage requirements.

Puts on Securities, Indices and Futures Contracts. As with calls, the Trust may purchase put options (“puts”) that relate to municipal securities (whether or not it holds such securities in its portfolio), indices or futures contracts. For the same purposes, the Trust may also sell puts on municipal securities, indices or futures contracts on such securities if the Trust’s contingent obligations on such puts are secured by segregated assets consisting of cash or liquid high grade debt securities having a value not less than the exercise price. The Trust will not sell puts if, as a result, more than 50% of the Trust’s total assets would be required to cover its potential obligations under its hedging and other investment transactions. In selling puts, there is a risk that the Trust may be required to buy the underlying security at a price higher than the current market price.

Credit Derivatives. The Trust may engage in credit derivative transactions. There are two broad categories of credit derivatives: default price risk derivatives and market spread derivatives. Default price risk derivatives are linked to the price of reference securities or loans after a default by the issuer or borrower, respectively. Market spread derivatives are based on the risk that changes in market factors, such as credit spreads, can cause a decline in the value of a security, loan or index. There are three basic transactional forms for credit derivatives: swaps, options and structured instruments. The use of credit derivatives is a highly specialized activity which involves strategies and risks different from those associated with ordinary portfolio security transactions. If the Advisor is incorrect in its forecasts of default risks, market spreads or other applicable factors, the investment performance of the Trust would diminish compared with what it would have been if these techniques were not used. Moreover, even if the Advisor is correct in its forecasts, there is a risk that a credit derivative position may correlate imperfectly with the price of the asset or liability being hedged. There is no limit on the amount of credit derivative transactions that may be entered into by the Trust. The Trust’s risk of loss in a credit derivative transaction varies with the form of the transaction. For example, if the Trust purchases a default option on a security, and if no default occurs with respect to the security, the Trust’s loss is limited to the premium it paid for the default option. In contrast, if there is a default by the grantor of a default option, the Trust’s loss will include both the premium that it paid for the option and the decline in value of the underlying security that the default option hedged.

Municipal Market Data Rate Locks. The Trust may purchase and sell Municipal Market Data Rate Locks (“MMD Rate Locks”). An MMD Rate Lock permits the Trust to lock in a specified municipal interest rate for a portion of its portfolio to preserve a return on a particular investment or a portion of its portfolio as a duration management technique or to protect against any increase in the price of securities to be purchased at a later date. The Trust will ordinarily use these transactions as a hedge or for duration or risk management although it is permitted to enter into them to enhance income or gain. An MMD Rate Lock is a contract between the Trust and an MMD Rate Lock provider pursuant to which the parties agree to make payments to each other on a notional amount, contingent upon whether the Municipal Market Data AAA General Obligation Scale is above or below a specified level on the expiration date of the contract. For example, if the Trust buys an MMD Rate Lock and the Municipal Market Data AAA General Obligation Scale is below the specified level on the expiration date, the counterparty to the contract will make a payment to the Trust equal to the specified level minus the actual level, multiplied by the notional amount of the contract. If the Municipal Market Data AAA General Obligation Scale is above the specified level on the expiration date, the Trust will make a payment to the counterparty equal to the actual level minus the specified level, multiplied by the notional amount of the contract. In entering into MMD Rate Locks, there is a risk that municipal yields will move in the direction opposite of the direction anticipated by the Trust. The Trust will not enter into MMD Rate Locks if, as a result, more than 50% of its total assets would be required to cover its potential obligations under its hedging and other investment transactions.

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New Products. The financial markets continue to evolve and financial products continue to be developed. The Trust reserves the right to invest in new financial products as they are developed or become more widely accepted. As with any new financial product, these products will entail risks, including risks to which the Trust currently is not subject.

The principal risks relating to the use of futures contracts and other Strategic Transactions are: (a) less than perfect correlation between the prices of the instrument and the market value of the securities in the Trust’s portfolio; (b) possible lack of a liquid secondary market for closing out a position in such instruments; (c) losses resulting from interest rate or other market movements not anticipated by the Advisor; and (d) the obligation to meet additional variation margin or other payment requirements, all of which could result in the Trust being in a worse position than if such techniques had not been used.

Certain provisions of the Code may restrict or affect the ability of the Trust to engage in Strategic Transactions. See “Tax Matters.”

Short Sales

The Trust may make short sales of municipal securities and other securities. A short sale is a transaction in which the Trust sells a security it does not own in anticipation that the market price of that security will decline. The Trust may make short sales to hedge positions, for duration and risk management, in order to maintain portfolio flexibility or to enhance income or gain.

When the Trust makes a short sale, it must borrow the security sold short and deliver it to the broker-dealer through which it made the short sale as collateral for its obligation to deliver the security upon conclusion of the sale. The Trust may have to pay a fee to borrow particular securities and is often obligated to pay over any payments received on such borrowed securities.

The Trust’s obligation to replace the borrowed security will be secured by collateral deposited with the broker-dealer, usually cash, U.S. Government securities or other liquid securities. The Trust will also be required to designate on its books and records similar collateral with its custodian to the extent, if any, necessary so that the aggregate collateral value is at all times at least equal to the current market value of the security sold short. Depending on arrangements made with the broker-dealer from which it borrowed the security regarding payment over of any payments received by the Trust on such security, the Trust may not receive any payments (including interest) on its collateral deposited with such broker-dealer.

If the price of the security sold short increases between the time of the short sale and the time the Trust replaces the borrowed security, the Trust will incur a loss; conversely, if the price declines, the Trust will realize a gain. Any gain will be decreased, and any loss increased, by the transaction costs described above. Although the Trust’s gain is limited to the price at which it sold the security short, its potential loss is theoretically unlimited.

The Trust will not make a short sale if, after giving effect to such sale, the market value of all securities sold short exceeds 25% of the value of its total assets or the Trust’s aggregate short sales of a particular class of securities exceeds 25% of the outstanding securities of that class. The Trust may also make short sales “against the box” without respect to such limitations. In this type of short sale, at the time of the sale, the Trust owns or has the immediate and unconditional right to acquire at no additional cost the identical security.

Environmental, Social and Governance (“ESG”) Integration

Although the Trust does not seek to implement a specific ESG, impact or sustainability strategy, Trust management will consider ESG characteristics as part of the investment process for actively managed funds such as the Trust. These considerations will vary depending on a fund’s particular investment strategies and may include consideration of third-party research as well as consideration of proprietary research of the Advisor across the ESG risks and opportunities regarding an issuer. Trust management will consider those ESG characteristics it deems relevant or additive when making investment decisions for the Trust. The ESG characteristics utilized in the Trust’s investment process are anticipated to evolve over time and one or more characteristics may not be relevant with respect to all issuers that are eligible for investment.

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ESG characteristics are not the sole considerations when making investment decisions for the Trust. Further, investors can differ in their views of what constitutes positive or negative ESG characteristics. As a result, the Trust may invest in issuers that do not reflect the beliefs and values with respect to ESG of any particular investor. ESG considerations may affect the Trust’s exposure to certain companies or industries and the Trust may forego certain investment opportunities. While Trust management views ESG considerations as having the potential to contribute to the Trust’s long-term performance, there is no guarantee that such results will be achieved.

OTHER INVESTMENT POLICIES AND TECHNIQUES

Restricted and Illiquid Investments

The Trust may invest in investments that lack an established secondary trading market or otherwise are considered illiquid. Liquidity of an investment relates to the ability to dispose easily of the investment and the price to be obtained upon disposition of the investment, which may be less than would be obtained for a comparable more liquid investment. Illiquid investments may trade at a discount from comparable, more liquid investments. Investment of the Trust’s assets in illiquid investments may restrict the ability of the Trust to dispose of its investments in a timely fashion and for a fair price as well as its ability to take advantage of market opportunities. The risks associated with illiquidity will be particularly acute where the Trust’s operations require cash, such as when the Trust pays dividends, and could result in the Trust borrowing to meet short-term cash requirements or incurring capital losses on the sale of illiquid investments.

The Trust may invest in securities that are not registered under the Securities Act (“restricted securities”). Restricted securities may be sold in private placement transactions between issuers and their purchasers and may be neither listed on an exchange nor traded in other established markets. In many cases, privately placed securities may not be freely transferable under the laws of the applicable jurisdiction or due to contractual restrictions on resale. As a result of the absence of a public trading market, privately placed securities may be less liquid and more difficult to value than publicly traded securities. To the extent that privately placed securities may be resold in privately negotiated transactions, the prices realized from the sales, due to illiquidity, could be less than those originally paid by the Trust or less than their fair market value. In addition, issuers whose securities are not publicly traded may not be subject to the disclosure and other investor protection requirements that may be applicable if their securities were publicly traded. If any privately placed securities held by the Trust are required to be registered under the securities laws of one or more jurisdictions before being resold, the Trust may be required to bear the expenses of registration. Where registration is required for restricted securities, a considerable time period may elapse between the time the Trust decides to sell the security and the time it is actually permitted to sell the security under an effective registration statement. If during such period, adverse market conditions were to develop, the Trust might obtain less favorable pricing terms than when it decided to sell the security. Transactions in restricted securities may entail other transaction costs that are higher than those for transactions in unrestricted securities. Certain of the Trust’s investments in private placements may consist of direct investments and may include investments in smaller, less seasoned issuers, which may involve greater risks. These issuers may have limited product lines, markets or financial resources, or they may be dependent on a limited management group. In making investments in such securities, the Trust may obtain access to material nonpublic information, which may restrict the Trust’s ability to conduct portfolio transactions in such securities.

Reverse Repurchase Agreements

The Trust may enter into reverse repurchase agreements with respect to its portfolio investments subject to the investment restrictions set forth herein and in the Prospectus. Reverse repurchase agreements involve the sale of securities held by the Trust with an agreement by the Trust to repurchase the securities at an agreed upon price, date and interest payment. At the time the Trust enters into a reverse repurchase agreement, it may designate on its books and records liquid instruments having a value not less than the repurchase price (including accrued interest). If the Trust establishes and maintains such a segregated account, a reverse repurchase agreement will not be considered a borrowing by the Trust; however, under certain circumstances in which the Trust does not establish and maintain such a segregated account, such reverse repurchase agreement will be considered a borrowing for the purpose of the Trust’s limitation on borrowings. The use by the Trust of reverse repurchase agreements involves many of the same risks of leverage since the proceeds derived from such reverse repurchase agreements may be invested in additional securities. Reverse repurchase agreements involve the risk that the market value of the securities acquired in

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connection with the reverse repurchase agreement may decline below the price of the securities the Trust has sold but is obligated to repurchase. Also, reverse repurchase agreements involve the risk that the market value of the securities retained in lieu of sale by the Trust in connection with the reverse repurchase agreement may decline in price.

If the buyer of securities under a reverse repurchase agreement files for bankruptcy or becomes insolvent, such buyer or its trustee or receiver may receive an extension of time to determine whether to enforce the Trust’s obligation to repurchase the securities, and the Trust’s use of the proceeds of the reverse repurchase agreement may effectively be restricted pending such decision. Also, the Trust would bear the risk of loss to the extent that the proceeds of the reverse repurchase agreement are less than the value of the securities subject to such agreement.

Repurchase Agreements

As temporary investments, the Trust may invest in repurchase agreements. A repurchase agreement is a contractual agreement whereby the seller of securities agrees to repurchase the same security at a specified price on a future date agreed upon by the parties. The agreed-upon repurchase price determines the yield during the Trust’s holding period. Repurchase agreements are considered to be loans collateralized by the underlying security that is the subject of the repurchase contract. The Trust will only enter into repurchase agreements with registered securities dealers or domestic banks that, in the opinion of the Advisor, present minimal credit risk. The risk to the Trust is limited to the ability of the issuer to pay the agreed-upon repurchase price on the delivery date; however, although the value of the underlying collateral at the time the transaction is entered into always equals or exceeds the agreed-upon repurchase price, if the value of the collateral declines there is a risk of loss of both principal and interest. In the event of default, the collateral may be sold but the Trust might incur a loss if the value of the collateral declines, and might incur disposition costs or experience delays in connection with liquidating the collateral. In addition, if bankruptcy proceedings are commenced with respect to the seller of the security, realization upon the collateral by the Trust may be delayed or limited. The Advisor will monitor the value of the collateral at the time the transaction is entered into and at all times subsequent during the term of the repurchase agreement in an effort to determine that such value always equals or exceeds the agreed-upon repurchase price. In the event the value of the collateral declines below the repurchase price, the Advisor will demand additional collateral from the issuer to increase the value of the collateral to at least that of the repurchase price, including interest.

Lending of Securities

The Trust may lend its portfolio securities to banks or dealers which meet the creditworthiness standards established by the Board (“Qualified Institutions”). By lending its portfolio securities, the Trust attempts to increase its income through the receipt of interest on the loan. Any gain or loss in the market price of the securities loaned that may occur during the term of the loan will be for the account of the Trust. The Trust may lend its portfolio securities so long as the terms and the structure of such loans are not inconsistent with requirements of the Investment Company Act, which currently require that (i) the borrower pledge and maintain with the Trust collateral consisting of cash, a letter of credit issued by a domestic U.S. Bank, or securities issued or guaranteed by the U.S. Government having a value at all times not less than 100% of the value of the securities loaned, (ii) the borrower add to such collateral whenever the price of the securities loaned rises (i.e., the value of the loan is “marked to the market” on a daily basis), (iii) the loan be made subject to termination by the Trust at any time and (iv) the Trust receive reasonable interest on the loan (which may include the Trust’s investing any cash collateral in interest bearing short term investments), any distributions on the loaned securities and any increase in their market value. The Trust will not lend portfolio securities if, as a result, the aggregate of such loans exceeds 331/3% of the value of the Trust’s total assets (including such loans). Loan arrangements made by the Trust will comply with all other applicable regulatory requirements, including the rules of the New York Stock Exchange, which rules presently require the borrower, after notice, to redeliver the securities within the normal settlement time of five business days. All relevant facts and circumstances, including the creditworthiness of the Qualified Institution, will be monitored by the Advisor, and will be considered in making decisions with respect to lending securities, subject to review by the Board.

The Trust may pay reasonable negotiated fees in connection with loaned securities, so long as such fees are set forth in a written contract and approved by the Board. In addition, voting rights may pass with the loaned securities, but if a material event were to occur affecting such a loan, the loan must be called and the securities voted.

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High Yield Securities

The Trust may invest up to 20% of its Managed Assets in securities rated below investment grade, such as those rated Ba or below by Moody’s or BB or below by S&P or Fitch or securities comparably rated by other rating agencies or in unrated securities determined by the Advisor to be of comparable quality. Securities rated Ba and below by Moody’s and Fitch are judged to have speculative elements, their future cannot be considered as well assured and often the protection of interest and principal payments may be very moderate. Securities rated BB by S&P are regarded as having predominantly speculative characteristics and, while such obligations have less near-term vulnerability to default than other speculative grade debt, they face major ongoing uncertainties or exposure to adverse business, financial or economic conditions, which could lead to inadequate capacity to meet timely interest and principal payments.

Lower grade securities, though high yielding, are characterized by high risk. They may be subject to certain risks with respect to the issuing entity and to greater market fluctuations than certain lower yielding, higher rated securities. The retail secondary market for lower grade securities may be less liquid than that of higher rated securities; adverse conditions could make it difficult at times for the Trust to sell certain securities or could result in lower prices than those used in calculating the Trust’s net asset value.

The prices of debt securities generally are inversely related to interest rate changes; however, the price volatility caused by fluctuating interest rates of securities also is inversely related to the coupons of such securities. Accordingly, below investment grade securities may be relatively less sensitive to interest rate changes than higher quality securities of comparable maturity because of their higher coupon. This higher coupon is what the investor receives in return for bearing greater credit risk. The higher credit risk associated with below investment grade securities potentially can have a greater effect on the value of such securities than may be the case with higher quality issues of comparable maturity.

Lower grade securities may be particularly susceptible to economic downturns. It is likely that an economic recession could severely disrupt the market for such securities and may have an adverse impact on the value of such securities. In addition, it is likely that any such economic downturn could adversely affect the ability of the issuers of such securities to repay principal and pay interest thereon and increase the incidence of default for such securities.

The ratings of Moody’s, S&P and other rating agencies represent their opinions as to the quality of the obligations which they undertake to rate. Ratings are relative and subjective and, although ratings may be useful in evaluating the safety of interest and principal payments, they do not evaluate the market value risk of such obligations. Although these ratings may be an initial criterion for selection of portfolio investments, the Advisor also will independently evaluate these securities and the ability for the issuers of such securities to pay interest and principal. To the extent that the Trust invests in lower grade securities that have not been rated by a rating agency, the Trust’s ability to achieve its investment objectives will be more dependent on the Advisor’s credit analysis than would be the case when the Trust invests in rated securities.

ADDITIONAL RISK FACTORS

Risk Factors in Strategic Transactions and Derivatives

The Trust’s use of derivative instruments involves risks different from, and possibly greater than, the risks associated with investing directly in securities and other traditional investments. Derivatives are subject to a number of risks such as credit risk, leverage risk, illiquidity risk, correlation risk and index risk as described below:

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