BlackRock Core Bond Trust : BHK) SAI

BlackRock Core Bond Trust

STATEMENT OF ADDITIONAL INFORMATION

BlackRock Core 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 9, 2022 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.

TABLE OF CONTENTS

This Statement of Additional Information is dated February 9, 2022.

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 October 12, 2001 pursuant to an 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"). BlackRock International Limited ("BIL") and BlackRock (Singapore) Limited ("BSL" and together with BIL, the "Sub-Advisors" and collectively with the Advisor, the "Advisors") serve as the Trust's sub-advisors.

The common shares of the Trust are listed on the New York Stock Exchange ("NYSE") under the symbol "BHK." As of January 31, 2022, the Trust has outstanding 54,010,702 common shares.

INVESTMENT OBJECTIVE 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 of each class of shares are represented or (ii) more than 50% of the outstanding shares).

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

1. Invest 25% or more of the value of its total managed assets in any one industry.
2. With respect to 75% of its total managed assets, invest more than 5% of the value of its total managed assets in the securities of any single issuer or purchase more than 10% of the outstanding voting securities of any one issuer.
3. Issue senior securities or borrow money other than as permitted by the Investment Company Act or pledge its assets other than to secure such issuances or in connection with hedging transactions, short sales, when-issued and forward commitment transactions and similar investment strategies.
4. Make loans of money or property to any person, except through loans of portfolio securities, the purchase of fixed income securities consistent with the Trust's investment objective and policies or the entry into repurchase agreements.
5. Underwrite the securities of other issuers, except to the extent that in connection with the disposition of portfolio securities or the sale of its own securities the Trust may be deemed to be an underwriter.
6. Purchase or sell real estate or interests therein other than municipal securities secured by real estate or interests therein, provided that the Trust may hold and sell any real estate acquired in connection with its investment in portfolio securities.
7. Purchase or sell commodities or commodity contracts for any purposes except as, and to the extent, permitted by applicable law without the Trust becoming subject to registration with the Commodity Futures Trading Commission (the "CFTC") as a commodity pool.

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.

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For purposes of applying the limitation set forth in subparagraph (2) above, the Trust will regard each state and each political subdivision, agency or instrumentality of such state and each multi-state agency of which such state is a member and each public authority which issues securities on behalf of a private entity as a separate issuer, except that if the security is backed only by the assets and revenues of a non-government entity then the entity with the ultimate responsibility for the payment of interest and principal may be regarded as the sole issuer.

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-FundamentalInvestment 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:

1. Make any short sale of securities except in conformity with applicable laws, rules and regulations and unless after giving effect to such sale, the market value of all securities sold short does not exceed 25% of the value of the Trust's total managed assets and the Trust's aggregate short sales of a particular class of securities does not exceed 25% of the then 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.
2. Purchase securities of open-end or closed-end investment companies except in compliance with the Investment Company Act or any regulations promulgated or exemptive relief obtained thereunder.
3. Purchase securities of companies for the purpose of exercising control.

As a non-fundamental policy, under normal market conditions, the Trust invests at least 80% of its assets in bonds. Bonds held by the Trust may take the form of bonds, notes, bills, debentures, convertible securities, warrants attached to bonds, bank debt obligations, loan participations and assignments, trust preferred securities and securities issued by entities organized and operated for the purpose of restructuring the investment characteristics of securities. The Trust has adopted a policy to provide shareholders of the Trust at least 60 days prior notice of any change in this investment policy.

The restrictions and other limitations set forth above 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.

The percentage limitations applicable to the Trust's portfolio described herein apply only at the time of investment, and the Trust will not be required to sell securities due to subsequent changes in the value of securities it owns.

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

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INVESTMENT POLICIES AND TECHNIQUES

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

Mortgage-Related and Asset-Backed Securities

The Trust may make significant investments in residential and commercial mortgage-related securities issued by governmental entities and private issuers.

The yield and maturity characteristics of mortgage-related and other asset-backed securities differ from traditional debt securities. A major difference is that the principal amount of the obligations may normally be prepaid at any time because the underlying assets (i.e., loans) generally may be prepaid at any time. In calculating the average weighted maturity of the Trust, the maturity of mortgage-related and other asset-backed securities held by the Trust will be based on estimates of average life which take prepayments into account. The average life of a mortgage-related instrument, in particular, is likely to be substantially less than the original maturity of the mortgage pools underlying the securities as the result of scheduled principal payments and mortgage prepayments. In general, the collateral supporting non-mortgageasset-backed securities is of shorter maturity than mortgage loans and is less likely to experience substantial prepayments. Like other fixed-income securities, when interest rates rise the value of an asset-backed security generally will decline; however, when interest rates decline, the value of an asset-backed security with prepayment features may not increase as much as that of other fixed-income securities.

The relationship between prepayments and interest rates may give some high-yieldingmortgage-related and asset-backed securities less potential for growth in value than conventional bonds with comparable maturities. In addition, in periods of falling interest rates, the rate of prepayments tends to increase. During such periods, the reinvestment of prepayment proceeds by the Trust will generally be at lower rates than the rates that were carried by the obligations that have been prepaid. Because of these and other reasons, mortgage-related and asset-backed security's total return and maturity may be difficult to predict precisely. To the extent that the Trust purchases mortgage-related and asset-backed securities at a premium, prepayments (which may be made without penalty) may result in loss of the Trust's principal investment to the extent of premium paid.

Mortgage-BackedSecurities. Mortgage-backed securities ("MBS") include structured debt obligations collateralized by pools of commercial ("CMBS") or residential ("RMBS") mortgages. Pools of mortgage loans and mortgage-backed loans, such as mezzanine loans, are assembled as securities for sale to investors by various governmental, government-related and private organizations. MBS include complex instruments such as collateralized mortgage obligations ("CMOs"), stripped MBS, mortgage pass-through securities and interests in Real Estate Mortgage Investment Conduits ("REMICs"). The MBS in which the Trust may invest include those with fixed, floating or variable interest rates, those with interest rates that change based on multiples of changes in a specified reference interest rate or index of interest rates and those with interest rates that change inversely to changes in interest rates, as well as those that do not bear interest. The Trust may invest in RMBS and CMBS issued by governmental entities and private issuers, including subordinated MBS and residual interests. The Trust may invest in sub-prime mortgages or MBS that are backed by sub-prime mortgages.

In general, losses on a mortgaged property securing a mortgage loan included in a securitization will be borne first by the equity holder of the property, then by a cash reserve fund or letter of credit, if any, then by the holder of a mezzanine loan or B-Note, if any, then by the "first loss" subordinated security holder (generally, the "B-Piece" buyer) and then by the holder of a higher rated security. The Trust may invest in any class of security included in a securitization. In the event of default and the exhaustion of any equity support, reserve fund, letter of credit, mezzanine loans or B-Notes, and any classes of securities junior to those in which the Trust invests, the Trust will not be able to recover all of its investment in the MBS it purchases. MBS in which the Trust invests may not contain reserve funds, letters of credit, mezzanine loans and/or junior classes of securities. The prices of

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