| Item 1. | |
| (a) | Name of issuer:
Office Properties Income Trust |
| (b) | Address of issuer's principal executive offices:
Two Newton Place, 255 Washington Street, Suite 300, Newton, Massachusetts 02458-1643. |
| Item 2. | |
| (a) | Name of person filing:
This Schedule 13G is being jointly filed by and on behalf of each of MSD Partners, L.P. ("MSD Partners"), MSD Special Investment Fund II, L.P. ("MSD Special Investments Fund II"), MSD SIF Holdings II, L.P. ("MSD SIF Holdings II"), MSD RCOF Credit REIT, LLC ("MSD RCOF Credit"), MSD RCOF II Credit REIT, LLC ("MSD RCOF II Credit"), MSD RCOF1 - PC, LLC ("MSD RCOF1 - PC"), MSD RCOF1 - BC, LLC ("MSD RCOF1 - BC"), MSD RCOF2 - PC2, LLC ("MSD RCOF2 - PC2"), MSD RCOF2 - BC2, LLC ("MSD RCOF2 - BC2"), MSD Credit Opportunity Master Fund, L.P. ("MSD Credit Opportunity Master Fund"), Gregg R. Lemkau and Byron D. Trott (collectively, the "Reporting Persons").
MSD Special Investments Fund II, MSD SIF Holdings II, MSD RCOF Credit, MSD RCOF II Credit, MSD RCOF1 - PC, MSD RCOF1 - BC, MSD RCOF2 - PC2, MSD RCOF2 - BC2, and MSD Credit Opportunity Master Fund (collectively, the "MSD Parties") are the direct owners of the securities covered by this statement.
MSD Partners, a wholly-owned subsidiary of BDT & MSD Holdings, L.P. ("BDT & MSD"), is the investment advisor of, and may be deemed to beneficially own the securities beneficially owned by, the MSD Parties. Messrs, Lemkau and Trott are co-CEOs of BDT & MSD; Mr. Trott also serves as Chairman of BDT & MSD. Mr. Lemkau maintains investment discretion over the investments in the Issuer of MSD Credit Opportunity Master Fund, MSD RCOF1 - BC, MSD RCOF1 - PC and MSD RCOF Credit and therefore may be deemed to beneficially own the Issuer's securities beneficially owned by MSD Credit Opportunity Master Fund, MSD RCOF1 - BC, MSD RCOF1 - PC and MSD RCOF Credit. Mr. Trott maintains investment discretion over the investments in the Issuer of MSD RCOF2 - BC2, MSD RCOF2 - PC2, MSD RCOF II Credit, MSD SIF Holdings II and MSD Special Investements Fund II and therefore may be deemed to beneficially own the Issuer's securities beneficially owned by MSD RCOF2 - BC2, MSD RCOF2 - PC2, MSD RCOF II Credit, MSD SIF Holdings II and MSD Special Investments Fund II.
The Reporting Persons have entered into a Joint Filing Agreement, dated August 13, 2025, a copy of which is filed with this Schedule 13G as Exhibit 99.1, pursuant to which the Reporting Persons have agreed to file this statement jointly in accordance with the provisions of Rule 13d-1(k)(1) under the Act.
Neither the filing of this statement nor anything herein shall be construed as an admission that any person other than the Reporting Persons is, for the purposes of Section 13(d) or 13(g) of the Act or any other purpose, the beneficial owner of any securities covered by this statement. |
| (b) | Address or principal business office or, if none, residence:
The address of the principal business office of each of the MSD Parties, MSD Partners and Mr. Lemkau is 550 Madison Ave, 20th Floor, New York, NY 10022.
The address of the principal business office of Mr. Trott is 340 Royal Palm Way, Suite 300, Palm Beach, FL 33480. |
| (c) | Citizenship:
MSD Partners, MSD Special Investments Fund II and MSD SIF Holdings II are each organized as a limited partnership under the laws of the State of Delaware.
MSD RCOF2 - BC2, MSD RCOF2 - PC2, MSD RCOF1 - BC, MSD RCOF1 - PC, MSD RCOF II Credit and MSD RCOF Credit are each organized as a limited liability company under the laws of the State of Delaware.
MSD Credit Opportunity Master Fund is organized as an exempted limited partnership under the laws of the Cayman Islands.
Messrs, Lemkau and Trott are United States citizens. |
| (d) | Title of class of securities:
Common Shares of Beneficial Interest, $.01 par value per share |
| (e) | CUSIP No.:
67623C109 |
| Item 3. | If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: |
| (a) |  Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
|
| (b) | Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
|
| (c) | Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
|
| (d) | Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
|
| (e) | An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
|
| (f) | An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
|
| (g) | A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
|
| (h) | A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
|
| (i) | A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
|
| (j) | A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
|
| (k) | Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
|
| | |
| Item 4. | Ownership |
| (a) | Amount beneficially owned:
MSD Partners - 0
MSD SIF Holdings II - 0
MSD Special Investments Fund II - 0
MSD RCOF Credit - 0
MSD RCOF II Credit - 0
MSD RCOF1 - PC - 0
MSD RCOF1 - BC - 0
MSD RCOF2 - PC2 - 0
MSD RCOF2 - BC2 - 0
MSD Credit Opportunity Master Fund - 0
Gregg R. Lemkau - 0
Byron D. Trott - 0 |
| (b) | Percent of class:
MSD Partners - 0
MSD SIF Holdings II - 0
MSD Special Investments Fund II - 0
MSD RCOF Credit - 0
MSD RCOF II Credit - 0
MSD RCOF1 - PC - 0
MSD RCOF1 - BC - 0
MSD RCOF2 - PC2 - 0
MSD RCOF2 - BC2 - 0
MSD Credit Opportunity Master Fund - 0
Gregg R. Lemkau - 0
Byron D. Trott - 0 |
| (c) | Number of shares as to which the person has:
|
| | (i) Sole power to vote or to direct the vote:
MSD Partners - 0
MSD SIF Holdings II - 0
MSD Special Investments Fund II - 0
MSD RCOF Credit - 0
MSD RCOF II Credit - 0
MSD RCOF1 - PC - 0
MSD RCOF1 - BC - 0
MSD RCOF2 - PC2 - 0
MSD RCOF2 - BC2 - 0
MSD Credit Opportunity Master Fund - 0
Gregg R. Lemkau - 0
Byron D. Trott - 0
|
| | (ii) Shared power to vote or to direct the vote:
MSD Partners - 0
MSD SIF Holdings II - 0
MSD Special Investments Fund II - 0
MSD RCOF Credit - 0
MSD RCOF II Credit - 0
MSD RCOF1 - PC - 0
MSD RCOF1 - BC - 0
MSD RCOF2 - PC2 - 0
MSD RCOF2 - BC2 - 0
MSD Credit Opportunity Master Fund - 0
Gregg R. Lemkau - 0
Byron D. Trott - 0
|
| | (iii) Sole power to dispose or to direct the disposition of:
MSD Partners - 0
MSD SIF Holdings II - 0
MSD Special Investments Fund II - 0
MSD RCOF Credit - 0
MSD RCOF II Credit - 0
MSD RCOF1 - PC - 0
MSD RCOF1 - BC - 0
MSD RCOF2 - PC2 - 0
MSD RCOF2 - BC2 - 0
MSD Credit Opportunity Master Fund - 0
Gregg R. Lemkau - 0
Byron D. Trott - 0
|
| | (iv) Shared power to dispose or to direct the disposition of:
MSD Partners - 0
MSD SIF Holdings II - 0
MSD Special Investments Fund II - 0
MSD RCOF Credit - 0
MSD RCOF II Credit - 0
MSD RCOF1 - PC - 0
MSD RCOF1 - BC - 0
MSD RCOF2 - PC2 - 0
MSD RCOF2 - BC2 - 0
MSD Credit Opportunity Master Fund - 0
Gregg R. Lemkau - 0
Byron D. Trott - 0
|
| Item 5. | Ownership of 5 Percent or Less of a Class. |
| | 
Ownership of 5 percent or less of a class
|
| Item 6. | Ownership of more than 5 Percent on Behalf of Another Person. |
| |
Not Applicable
|
| Item 7. | Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person. |
| |
Not Applicable
|
| Item 8. | Identification and Classification of Members of the Group. |
| |
Not Applicable
|
| Item 9. | Notice of Dissolution of Group. |
| |
Not Applicable
|