Blackstone Mortgage Trust Inc美股招股说明书(2025-07-30版)

Dividend Reinvestment and Direct Stock Purchase Plan We are pleased to offer you the opportunity to participate in the Blackstone Mortgage Trust, Inc. Dividend Reinvestment and Direct Stock Purchase Plan, or the“Plan.” The Plan has two components: a dividend reinvestment component and a direct stock purchase component. The dividend reinvestment component provides ourstockholders with an easy and economical way to designate all or any portion of the cash dividends on their shares of our class A common stock, par value $0.01 pershare, or “class A common stock,” for reinvestment in additional shares of our class A common stock. The direct stock purchase component permits our stockholders andnew investors to, in each case, subject to our approval, purchase shares of our class A common stock in an economical and convenient manner. This prospectus supplement relates to up to 9,966,682shares of our class A common stock to be offered for purchase under the Plan. Our class A common stock islisted on the New York Stock Exchange, or “NYSE,” under the trading symbol “BXMT.” The last reported sale price of our class A common stock on the NYSE onJuly29, 2025 was $19.37 per share. Key features of the Plan are that you can: •purchase shares of our class A common stock through the Plan without a personal broker and, in many cases, without paying a commission;•transfer your shares easily;•own and transfer your shares without holding or delivering physical certificates;•through the dividend reinvestment component, automatically reinvest all or any portion of your cash dividends in additional shares of our class A commonstock (subject to any discount from the Purchase Price (as determined under the Plan), inclusive of any applicable sales or brokerage fees we pay on yourbehalf); and•through the direct stock purchase component, at our sole discretion, make optional cash investments of as little as $1,000 per month at a discount from thePurchase Price (as determined under the Plan) that may range from 0% to 5% (inclusive of any applicable sales or brokerage fees we pay on your behalf). To assist us in qualifying as a real estate investment trust, or “REIT,” for United States federal income tax purposes, among other purposes, stockholders generallywill be restricted from owning more than 9.9% in value or number of shares, whichever is more restrictive, of the outstanding shares of our capital stock or of our class Acommon stock. In addition, our charter contains various other restrictions on the ownership and transfer of our class A common stock. See “Description of Capital Stock—Certain Provisions of Our Charter and Bylaws and of Maryland Law” in the accompanying prospectus for a description of these restrictions. Investing in our class A common stock involves risks. See “Risk Factors“ beginning on pageS-6of this prospectus supplement and in thereports we file with the Securities and Exchange Commission, or the “SEC,” pursuant to the Securities Exchange Act of 1934, as amended, orthe “Exchange Act,” incorporated by reference in this prospectus supplement or the accompanying prospectus, to read about factors youshould consider before buying shares of our class A common stock. None of the SEC, any state securities commission, or any other regulatory body has approved or disapproved of these securities or passedupon the accuracy or adequacy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminaloffense. Prospectus Supplement dated July30, 2025 TABLE OF CONTENTS Prospectus Supplement About This Prospectus SupplementForward-Looking StatementsDirect RegistrationSummaryRisk FactorsInformation About the Plan1.What is the purpose of the Plan?2.What options are available under the Plan?3.What are the benefits and disadvantages of the Plan?4.Who is eligible to participate in the Plan?5.Can non-U.S. citizens participate in the Plan?6.How do I enroll in the Plan if I am already a Blackstone Mortgage Trust stockholder?7.I already own shares, but they are held by my bank or broker and registered in “street name.” How can I participate in the Plan?8.I am not currently a Blackstone Mortgage Trust stockholder. How do I enroll in the Plan?9.When will my participation in the Plan begin?10.Are there fees associated with participation in the Plan?11.What are the dividend payment options?12.If I reinvest dividends, will I still owe taxes on the amount reinvested?13.What are the minimum and maximum amounts for Optional Cash Investments?14.How do I make Optional Cash Investments?15.What transactions can I conduct through the Plan Administrator’s online services?16.What is the source of our class A common stock purchased through the Plan?17.When will shares be purchased under the Plan?18.At what price will shares be purchased?19.Will fractional shares be purchased?20.How are payments with “insufficient funds” handled?21.Will interest be paid on Plan accounts?22.Who will hold the additional