Form SCHEDULE 13D Service Properties Trust Filed by: RMR Group LLC

Except as otherwise set forth in Annex A, the principal business office of each of the Reporting Persons and Covered Persons is Two Newton Place, 255 Washington Street, Suite 300, Newton, Massachusetts 02458.

RMR LLC's principal business is providing management services and RMR LLC is the business and property manager of the Issuer. RMR Inc.'s principal business is holding membership interests in RMR LLC. ABP Trust's principal business is holding shares of capital stock of RMR Inc., holding membership interests in RMR LLC and investing in real estate. Mr. Portnoy's principal occupation is president and chief executive officer of RMR Inc.

During the last five years, none of the Reporting Persons and, to the best of the Reporting Persons' knowledge, none of the Covered Persons, has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

During the last five years, none of the Reporting Persons and, to the best of the Reporting Persons' knowledge, none of the Covered Persons, was 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.

See Row 4 of each of the cover pages and Annex A.

The information set forth in Items 4 and 6 of this Schedule 13D is incorporated herein by reference. On April 2, 2026, in connection with an underwritten public offering (the "Offering") of Common Shares by the Issuer pursuant to an underwriting agreement, dated as of March 31, 2026 (the "Underwriting Agreement"), between the Issuer and Yorkville Securities, LLC, as representative of the several underwriters named therein, RMR LLC purchased 41,666,666 Common Shares from the underwriters at the public offering price of $1.20 per share, for an aggregate purchase price of approximately $50,000,000. RMR LLC funded the purchase of the Common Shares using cash on hand and borrowings under its revolving credit facility.

The information set forth in Items 3, 5 and 6 of this Schedule 13D is incorporated herein by reference. In connection with the Offering, also on April 2, 2026, Christopher J. Bilotto, executive vice president of RMR Inc., executive vice president of RMR LLC and one of the Issuer's Managing Trustees and its President and Chief Executive Officer, and Brian E. Donley, senior vice president of RMR LLC and the Issuer's Chief Financial Officer and Treasurer, as well as certain of the Issuer's Trustees, purchased from the underwriters an aggregate of 248,333 Common Shares, including 100,000 Common Shares acquired by Mr. Bilotto, at the public offering price of $1.20 per share. In connection with the Offering, RMR LLC, Messrs. Bilotto, Donley and Portnoy, and certain of the Trustees of the Issuer entered into lock-up agreements with the underwriters, pursuant to which each agreed, without the prior written consent of Yorkville Securities, LLC and subject to certain exceptions, not to sell, transfer or otherwise dispose of any Common Shares beneficially owned by them for a period of 90 days after March 31, 2026, the date of the Underwriting Agreement. The Reporting Persons acquired the Common Shares reported herein for investment purposes. In addition to Mr. Portnoy's role as a Managing Trustee of the Issuer, the Reporting Persons may from time to time engage in discussions with the Issuer, its Trustees and officers, other shareholders of the Issuer and other persons on matters that relate to the management, operations, business, assets, capitalization, financial condition, strategic plans, governance and the future of the Issuer and/or its subsidiaries. The Reporting Persons and their affiliates may acquire or dispose of Common Shares, other shares of capital stock or equity interests of the Issuer and/or its subsidiaries, from time to time, in the open market, private transactions, or otherwise, depending upon various factors, including, without limitation, the Issuer's business, prospects and financial condition, the market for such shares or interests, actions taken by the Issuer's trustees, general economic and stock market conditions, proposals from time to time sought by or presented to them, the existence of any lock-up periods and other factors. Each Reporting Person intends to closely monitor its or his investments and may from time to time take advantage of opportunities presented to it or him. Except as otherwise described above in this Item 4 and with respect to Mr. Portnoy, other than as may have arisen in his capacity as a Trustee of the Issuer or in connection with his role with RMR LLC as a provider of services for or on behalf of the Issuer, the Reporting Persons currently have no plan(s) or proposal(s) that relate to, or would result in, any of the events or transactions described in Item 4 of Schedule 13D, although each Reporting Person may, at any time and from time to time, review or reconsider such Reporting Person's position and/or change such Reporting Person's purpose and/or formulate plans or proposals with respect thereto. To the extent Mr. Portnoy may be involved in the formulation or approval of such plans or proposals as a Trustee of the Issuer or in connection with his role with RMR LLC as a provider of services for or on behalf of the Issuer, Mr. Portnoy does not expect to disclose such developments or his involvement by amending this Schedule 13D unless he also participates in developing or making such plans or proposals in his capacity as an investor in the Issuer.

Amount beneficially owned and percentage of class: RMR LLC directly holds 41,666,666 Common Shares, representing approximately 6.44% of the Common Shares outstanding as of April 2, 2026. ABP Trust directly holds 1,672,783 Common Shares and Adam D. Portnoy is the direct owner of 358,881 Common Shares. Voting and investment power with respect to the Common Shares owned by RMR LLC may be deemed to be shared by RMR Inc., ABP Trust and Adam D. Portnoy. ABP Trust may be deemed to beneficially own an aggregate of 43,339,449 Common Shares, consisting of the 1,672,783 Common Shares it directly holds and the 41,666,666 Common Shares held by RMR LLC, representing approximately 6.70% of the Common Shares outstanding as of April 2, 2026. Voting and investment power with respect to the Common Shares beneficially owned by ABP Trust may be deemed to be shared by Adam D. Portnoy as the president, controlling shareholder and sole trustee of ABP Trust. Therefore, Adam D. Portnoy may be deemed to beneficially own an aggregate of 43,698,330 Common Shares, consisting of the 358,881 Common Shares he directly holds and the 43,339,449 Common Shares beneficially owned by ABP Trust, representing approximately 6.75% of the Common Shares outstanding as of April 2, 2026.

See responses to Rows 7 through 10 of the cover pages and Annex A.

During the past 60 days, except as described in Items 3 and 4, the Reporting Persons have not engaged in any transaction with respect to Common Shares.

No other person is known to have the right to receive, or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities covered by this Schedule 13D.

Not applicable.

The information set forth under Item 4 of this Schedule 13D is incorporated herein by reference. Mr. Portnoy and certain other Covered Persons are eligible to receive awards of Common Shares pursuant to the Issuer's equity compensation plan for their services to the Issuer or its taxable real estate investment trust subsidiaries.

Exhibit Description of Exhibit 99.1 Agreement of Joint Filing, dated as of April 9, 2026, by and among The RMR Group LLC, The RMR Group Inc., ABP Trust and Adam D. Portnoy (Filed Herewith) 99.2 Underwriting Agreement, dated as of March 31, 2026, between the Issuer and Yorkville Securities, LLC (including the form of Lock-up Agreement) (Incorporated by reference to Exhibit 1.1 to the Current Report on Form 8-K filed by the Issuer on April 2, 2026)