Free Writing Prospectus (Form FWP)

Filed Pursuant to Rule 433

Issuer Free Writing Prospectus dated February 26, 2026

Relating to Preliminary Prospectus Supplement dated February 26, 2026 and

Prospectus dated July 11, 2025

Registration No. 333-288640

Blackstone Secured Lending Fund

$400,000,000 5.250% Notes due 2029

PRICING TERM SHEET

February 26, 2026

The following sets forth the final terms of the 5.250% Notes due 2029 (the "Notes") and should only be read together with the preliminary prospectus supplement dated February 26, 2026 (the "Preliminary Prospectus Supplement") related to the Notes, and supersedes the information in the Preliminary Prospectus Supplement to the extent inconsistent with the information in the Preliminary Prospectus Supplement. In all other respects, this pricing term sheet is qualified in its entirety by reference to the Preliminary Prospectus Supplement. Terms used herein but not defined herein shall have the respective meanings as set forth in the Preliminary Prospectus Supplement. All references to dollar amounts are references to U.S. dollars.

Note: *A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision or withdrawal at any time.

Note: **Blackstone Secured Lending Fund expects that delivery of the Notes will be made to investors on or about March 3, 2026, which will be the third business day following the date hereof. Under Rule 15c6-1 under the Exchange Act, trades in the secondary market are required to settle in one business day, unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade notes prior to the business day before the delivery of the Notes will be required, by virtue of the fact that the Notes initially settle in T+3, to specify an alternative arrangement at the time of any such trade to prevent a failed settlement and should consult their own advisors.

Investors are advised to carefully consider the investment objectives, risks, charges and expenses of Blackstone Secured Lending Fund before investing. The Preliminary Prospectus Supplement contains this and other information about Blackstone Secured Lending Fund and should be read carefully before investing.

The information in the Preliminary Prospectus Supplement is not complete and may be changed. The Preliminary Prospectus Supplement and this pricing term sheet are not offers to sell any securities of Blackstone Secured Lending Fund and are not soliciting an offer to buy such securities in any state or jurisdiction where such offer and sale is not permitted. You may obtain these documents for free by visiting EDGAR on the SEC website at www.sec.gov. Alternatively, Blackstone Secured Lending Fund, any

underwriter or any dealer participating in the offering will arrange to send you the Preliminary Prospectus Supplement if you request it from Citigroup Global Markets Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717, Telephone: 1-(800) 831-9146, email: [email protected]; Barclays Capital Inc., 745 Seventh Avenue, New York, New York 10019, Attention: Syndicate Registration, Telephone: 1-(888)-603-5847; J.P. Morgan Securities LLC, 270 Park Avenue, New York, New York 10017, Attn: Investment Grade Syndicate Desk, Telephone: 1-(212) 834-4533; SMBC Nikko Securities America, Inc., Telephone: 1-(888) 868-6856, email: [email protected] or Truist Securities, Inc. 740 Battery Avenue SE, 3rd Floor, Atlanta Georgia, 30339, Attn: Prospectus Department or toll-free at 1-(800) 685-4786 or [email protected].

Any disclaimers or notices that may appear on this term sheet below the text of this legend are not applicable to this term sheet and should be disregarded. Such disclaimers may have been electronically generated as a result of this term sheet having been sent via, or posted on, Bloomberg or another electronic mail system.