Blackstone Holdings III SC 13D/A Blackstone Mortgage Trust, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 10)*

Blackstone Mortgage Trust, Inc.

(Name of Issuer)

Class A Common Stock, par value $0.01 per share

(Title of Class of Securities)

09257W100

(CUSIP Number)

Leon Volchyok

The Blackstone Group Inc.

345 Park Avenue

New York, New York 10154

Tel:(212) 583-5000

with a copy to:

Edgar J. Lewandowski

Simpson Thacher & Bartlett LLP

425 Lexington Avenue

New York, New York 10017

Tel:(212) 455-2000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

November 25, 2019

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of§§240.13d-1(e),240.13d-1(f) or240.13d-1(g), check the following box.  ☐

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See§240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 09257W100

1	NAMES OF REPORTING PERSONS BLACKSTONE TREASURY HOLDINGS III L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.0%
14	TYPE OF REPORTING PERSON (See Instructions) OO

2

CUSIP No. 09257W100

1	NAMES OF REPORTING PERSONS BLACKSTONE HOLDINGS III L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Quebec, Canada

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 3,444,390
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 3,444,390
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,444,390
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 2.6%
14	TYPE OF REPORTING PERSON (See Instructions) PN

3

CUSIP No. 09257W100

1	NAMES OF REPORTING PERSONS BLACKSTONE HOLDINGS III GP L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 3,444,390
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 3,444,390
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,444,390
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 2.6%
14	TYPE OF REPORTING PERSON (See Instructions) PN

4

CUSIP No. 09257W100

1	NAMES OF REPORTING PERSONS BLACKSTONE HOLDINGS III GP MANAGEMENT L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 3,444,390
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 3,444,390
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,444,390
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 2.6%
14	TYPE OF REPORTING PERSON (See Instructions) OO

5

CUSIP No. 09257W100

1	NAMES OF REPORTING PERSONS THE BLACKSTONE GROUP INC. (f/k/a THE BLACKSTONE GROUP L.P.)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 6,757,347
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 6,757,347
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 6,757,347
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.0%
14	TYPE OF REPORTING PERSON (See Instructions) CO

6

CUSIP No. 09257W100

1	NAMES OF REPORTING PERSONS BLACKSTONE GROUP MANAGEMENT L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 6,757,347
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 6,757,347
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 6,757,347
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.0%
14	TYPE OF REPORTING PERSON (See Instructions) OO

7

CUSIP No. 09257W100

1	NAMES OF REPORTING PERSONS STEPHEN A. SCHWARZMAN
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions) (a)  ☐        (b)  ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) ☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States of America

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 6,948,001
	8	SHARED VOTING POWER 0
	9	SOLE DISPOSITIVE POWER 6,948,001
	10	SHARED DISPOSITIVE POWER 0

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 6,948,001
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) ☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.2%
14	TYPE OF REPORTING PERSON (See Instructions) IN

8

This Amendment No. 10 (“Amendment No. 10”) to Schedule 13D relates to the class A common stock, par value $0.01 per share (“Common Stock”), of Blackstone Mortgage Trust, Inc., a Maryland corporation (the “Issuer”), and amends and supplements the initial statement on Schedule 13D filed on December 21, 2012, as amended and supplemented by Amendment No. 1 to Schedule 13D filed on March 27, 2013, Amendment No. 2 to Schedule 13D filed on May 8, 2013, Amendment No. 3 to Schedule 13D filed on May 20, 2013, Amendment No. 4 to Schedule 13D filed on May 31, 2013, Amendment No. 5 to Schedule 13D filed on October 11, 2013, Amendment No. 6 to Schedule 13D filed on January 10, 2014, Amendment No. 7 to Schedule 13D filed on April 16, 2015, Amendment No. 8 to Schedule 13D filed on April 21, 2016, and Amendment No. 9 to Schedule 13D filed on November 17, 2016 (collectively, the “Schedule 13D”). This Amendment reflects, among other things, the conversion of The Blackstone Group L.P., a Delaware limited partnership, into a Delaware corporation named The Blackstone Group Inc., which became effective on July 1, 2019.

Capitalized terms used but not defined in this Amendment No. 10 shall have the same meanings ascribed to them in the Schedule 13D.

Item 2. Identity and Background

Item 2 of the Schedule 13D is hereby amended and restated as follows:

(a) – (b) This Schedule 13D is being filed by:

• (i) Blackstone Treasury Holdings III L.L.C., a Delaware limited liability company (“Blackstone Treasury Holdings III”), (ii) Blackstone Holdings III L.P., a Quebec, Canada, limited partnership (“Blackstone Holdings III”), (ii) Blackstone Holdings III GP L.P., a Delaware limited partnership, (iv) Blackstone Holdings III GP Management L.L.C., a Delaware limited liability company, (v) The Blackstone Group Inc. (f/k/a The Blackstone Group L.P.), a Delaware corporation (“Blackstone”), and (vi) Blackstone Group Management L.L.C., a Delaware limited liability company (collectively, the “ Blackstone Entities”); and

• Stephen A. Schwarzman, who is a United States citizen.

The principal business address of each of the Reporting Persons is c/o The Blackstone Group, Inc., 345 Park Avenue, New York, New York 10154.

Information regarding each director and executive officer of The Blackstone Group Inc. is set forth onSchedule I attached hereto.

(c) The principal business of Blackstone Treasury Holdings III is performing certain treasury related activities for Blackstone Holdings III and other affiliated Blackstone entities. Blackstone Holdings III is performing the functions of, and serving as, the sole member of Blackstone Treasury Holdings III and other affiliated Blackstone entities. The principal business of Blackstone Holdings III GP L.P. is performing the functions of, and serving as, the general partner of Blackstone Holdings III and other affiliated Blackstone entities. The principal business of Blackstone Holdings III GP Management L.L.C. is performing the functions of, and serving as, the general partner of Blackstone Holdings III GP L.P. and other affiliated Blackstone entities. The principal business of Blackstone is performing the functions of, and serving as, the managing member of Blackstone Holdings III GP Management L.L.C. and other affiliated Blackstone entities. The principal business of Blackstone Group Management L.L.C. is performing the functions of, and serving as, the sole holder of Class C common stock of Blackstone.

The principal occupation of Mr. Schwarzman is serving as an executive of Blackstone and Blackstone Group Management L.L.C.

(d) During the last five years, none of the Reporting Persons or, to the best knowledge of the Reporting Persons, any of the other persons set forth onSchedule I attached hereto, has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

(e) During the last five years, none of the Reporting Persons or, to the best knowledge of the Reporting Persons, any of the other persons set forth onSchedule I attached hereto, has been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and, as a result of such proceeding, was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(f) See Item 2(a)-(b) above for citizenship or place of organization, as applicable, of each of the Reporting Persons.

Item 3. Source and Amount of Funds or Other Consideration.

Item 3 of the Schedule 13D is hereby supplemented as follows:

On January 4, 2016, Blackstone Treasury Holdings III L.L.C. (“Blackstone Treasury Holdings III”) distributed the 3,444,390 shares of Common Stock it previously held to Blackstone Holdings III L.P. (“Blackstone Holdings III”), its sole member.

Item 4 of the Schedule 13D is incorporated herein by reference.

Item 4. Purpose of Transaction.

Item 4 of the Schedule 13D is hereby supplemented as follows:

On December 6, 2017, the Issuer granted 464,042 restricted shares of Common Stock to BXMT Advisors L.L.C. (the “Manager”), an indirect subsidiary of Blackstone and the manager of the Issuer, under its 2016 Manager Incentive Plan and 30,381 restricted shares of Common Stock to Stephen A. Schwarzman under its 2016 Stock Incentive Plan.

On November 7, 2018, the Issuer granted 501,796 restricted shares of Common Stock to the Manager under its 2018 Manager Incentive Plan and 31,980 restricted shares of Common Stock to Stephen A. Schwarzman, under its 2018 Stock Incentive Plan.

On November 25, 2019, the Issuer granted 527,930 restricted shares of Common Stock to the Manager under its 2018 Manager Incentive Plan and 33,313 restricted shares of Common Stock to Stephen A. Schwarzman, under its 2018 Stock Incentive Plan.

Item 5. Interest in Securities of the Issuer.

Item 5 of the Schedule 13D is hereby amended and restated as follows:

(a) – (b) As of the date hereof, Blackstone Holdings III directly holds 3,444,390 shares of Common Stock, the Manager directly holds 2,946,046 shares of Common Stock (including 1,055,811 restricted shares subject to vesting pursuant to the terms of the Issuer’s applicable management incentive plans), Mr. Schwarzman directly holds 190,654 shares of Common Stock (including 67,291 restricted shares subject to vesting pursuant to the terms of the Issuer’s applicable stock incentive plans), and Blackstone may be deemed to indirectly beneficially own an additional 366,911 shares of Common Stock held in a separately managed account over which it may be deemed to have indirect voting and dispositive power.

Blackstone Holdings III GP L.P. is the general partner of Blackstone Holdings III. Blackstone Holdings III GP Management L.L.C. is the general partner of Blackstone Holdings III GP L.P. Blackstone is the sole member of Blackstone Holdings III GP Management L.L.C. Blackstone Group Management L.L.C. is the sole holder of Class C common stock of Blackstone. Blackstone Group Management L.L.C. is wholly-owned by Blackstone’s senior managing directors and controlled by its founder, Stephen A. Schwarzman. The Manager is an indirect subsidiary of Blackstone.

The aggregate number and percentage of the shares of Common Stock beneficially owned by each Reporting Person and, for each Reporting Person, the number of shares as to which there is sole power to vote or to direct the vote, shared power to vote or to direct the vote, sole power to dispose or to direct the disposition, or shared power to dispose or to direct the disposition are set forth on rows 7 through 11 and row 13 of the cover pages of this Schedule 13D and are incorporated herein by reference. The above assumes the Reporting Persons have full dispositive power over any restricted shares of Common Stock held by them.

The percentage of shares of Common Stock is calculated based on 134,288,919 shares of Common Stock outstanding as of October 16, 2019, as reported in the Quarterly Report on Form10-Q filed by the Issuer on October 23, 2019.

Each of the Blackstone Entities and Mr. Schwarzman may be deemed to beneficially own the shares of Common Stock beneficially owned by Blackstone Holdings III and each of Blackstone, Blackstone Group Management L.L.C. and Mr. Schwarzman may be deemed to beneficially own the shares of Common Stock beneficially owned by the Manager and Blackstone.

Neither the filing of this Schedule 13D nor any of its contents shall be deemed to constitute an admission that any of the Reporting Persons (other than Blackstone Holdings III and Mr. Schwarzman, to the extent they directly hold shares of Common Stock reported on this Schedule 13D) is the beneficial owner of the Common Stock referred to herein for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, or for any other purpose, and such beneficial ownership is expressly disclaimed.

Any beneficial ownership of Common Stock by any of the persons listed onSchedule I is set forth onSchedule I attached hereto.

(c) Except as set forth in this Schedule 13D, none of the Reporting Persons or, to the best knowledge of the Reporting Persons, any other person named inSchedule I, has effected any transaction in the past 60 days in Common Stock.

(d) Not applicable.

(e) As of January 4, 2016, Blackstone Treasury Holdings III ceased to beneficially own more than five percent of the outstanding shares of Common stock.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: November 27, 2019	BLACKSTONE TREASURY HOLDINGS III L.L.C.
	By:	Blackstone Holdings III L.P., its sole member
	By:	Blackstone Holdings III GP L.P., its general partner
	By:	Blackstone Holdings III GP Management L.L.C., its general partner
		By:	/s/ John G. Finley
		Name:	John G. Finley
		Title:	Chief Legal Officer
	BLACKSTONE HOLDINGS III L.P.
	By:	Blackstone Holdings III GP L.P., its general partner
	By:	Blackstone Holdings III GP Management L.L.C., its general partner
		By:	/s/ John G. Finley
		Name:	John G. Finley
		Title:	Chief Legal Officer
	BLACKSTONE HOLDINGS III GP L.P.
	By:	Blackstone Holdings III GP Management L.L.C., its general partner
		By:	/s/ John G. Finley
		Name:	John G. Finley
		Title:	Chief Legal Officer
	BLACKSTONE HOLDINGS III GP MANAGEMENT L.L.C.
		By:	/s/ John G. Finley
		Name:	John G. Finley
		Title:	Chief Legal Officer

[Blackstone Mortgage Trust, Inc. – Schedule 13D/A]

THE BLACKSTONE GROUP INC.
	By:	/s/ John G. Finley
	Name:	John G. Finley
	Title:	Chief Legal Officer
BLACKSTONE GROUP MANAGEMENT L.L.C.
	By:	/s/ John G. Finley
	Name:	John G. Finley
	Title:	Chief Legal Officer
/s/ Stephen A. Schwarzman
STEPHEN A. SCHWARZMAN

[Blackstone Mortgage Trust, Inc. – Schedule 13D/A]

SCHEDULE I

Executive Officers and Directors of The Blackstone Group Inc.

The name and principal occupation of each director and executive officer of The Blackstone Group Inc. are set forth below. The address for each person listed below is c/o The Blackstone Group Inc., 345 Park Avenue, New York, New York 10154. All executive officers and directors listed are United States citizens other than The Honorable Brian Mulroney, who is a citizen of Canada, and Sir John Antony Hood, who is a citizen of New Zealand.

OFFICERS:

Name	Present Principal Occupation or Employment
Stephen A. Schwarzman	Founder, Chairman and Chief Executive Officer of The Blackstone Group Inc.
Jonathan D. Gray	President, Chief Operating Officer of The Blackstone Group Inc.
Hamilton E. James	Executive Vice Chairman of The Blackstone Group Inc.
Bennett J. Goodman	Senior Managing Director andCo-Founder of GSO Capital Partners
Michael S. Chae	Chief Financial Officer of The Blackstone Group Inc.
John G. Finley	Chief Legal Officer of The Blackstone Group Inc.
Joan Solotar	Senior Managing Director — Head of Private Wealth Solutions and External Relations of The Blackstone Group Inc.

DIRECTORS:

Name	Present Principal Occupation or Employment
Stephen A. Schwarzman	Founder, Chairman and Chief Executive Officer of The Blackstone Group Inc.
Jonathan D. Gray	President, Chief Operating Officer of The Blackstone Group Inc.
Hamilton E. James	Executive Vice Chairman of The Blackstone Group Inc.
Bennett J. Goodman	Senior Managing Director andCo-Founder of GSO Capital Partners of The Blackstone Group Inc.
Kelly A. Ayotte	Former United States Senator from New Hampshire
James W. Breyer	Founder and Chief Executive Officer of Breyer Capital
Sir John Antony Hood	President and Chief Executive Officer of the Robertson Foundation and Chair of the Rhodes Trust

Rochelle B. Lazarus	Chairman Emeritus & Former Chief Executive Officer, Ogilvy & Mather Worldwide
Jay O. Light	Dean Emeritus, Harvard Business School
The Right Honorable Brian Mulroney	Senior Partner and International Business Consultant for the Montreal law firm, Norton Rose Canada LLP
William G. Parrett	Retired CEO and Senior Partner, Deloitte (Deloitte Touche Tohmatsu)

Except as set forth in this Schedule 13D, to the best knowledge of the Reporting Persons, none of the individuals listed above beneficially owns any shares of Common Stock.