BLACKSTONE MORTGAGE TRUST INC

Section 13(r) Disclosure

Pursuant to Section 219 of the Iran Threat Reduction and Syria Human Rights Act of 2012, which added Section 13(r) of the Exchange Act, we hereby incorporate by reference herein Exhibit 99.1 of this report, which includes disclosures regarding activities at Mundys S.p.A., which may be, or may have been at the time considered to be, an affiliate of Blackstone and, therefore, our affiliate.

Rule 10b5-1 Trading Arrangements

On August 8, 2024, Katharine A. Keenan, our Chief Executive Officer, terminated three separate “Rule 10b5-1 trading arrangements,” as defined in Item 408(c) of Regulation S-K, each of which was intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act and provided for the automatic sale of shares of class A common stock in order to satisfy tax withholding obligations arising from vesting of three separate grants to Ms. Keenan of 52,000 shares of restricted stock each. The terminated arrangements were adopted on February 17, 2022, February 22, 2023 and March 15,

2024, and such arrangements were to automatically terminate on the earlier of December 31, 2024, December 31, 2025 and December 31, 2026, respectively, or, with respect to each such arrangement, the completion of all of the contemplated transactions set forth therein.

Subsequently on August 8, 2024, Ms. Keenan adopted a new Rule 10b5-1 trading arrangement, which is intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act, that provides for the automatic sale of shares of class A common stock in order to satisfy tax withholding obligations arising from vesting of an aggregate of 51,999 shares of restricted stock previously granted to Ms. Keenan on various dates. The number of shares to be sold under the new arrangement is unknown, as the number of shares will vary based on the extent to which vesting conditions are satisfied and the market price of our class A common stock at the time of vesting. The new arrangement will expire on December 31, 2026, subject to the arrangement’s earlier expiration or completion in accordance with its terms.

The new arrangement relates to sales to cover tax withholding obligations arising from vesting events scheduled to occur after February 5, 2025, six months following the date Ms. Keenan purchased shares of our class A common stock on the open market. All of these sales would have been covered by the terminated arrangements if they had not been terminated.