BOSTON PROPERTIES LTD PARTNERSHIP

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

For the fiscal year ended December 31, 2025

OR

For the transition period from to

Commission File Number:1-13087 (BXP, Inc.)

Commission File Number:0-50209 (Boston Properties Limited Partnership)

(Exact name of Registrants as specified in its charter)

Prudential Center, 800 Boylston Street, Suite 1900, Boston, Massachusetts 02199-8103

(Address of principal executive offices) (Zip Code)

(617)236-3300

(Registrants’ telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.

BXP, Inc.: Yes ☐No ☒ Boston Properties Limited Partnership: Yes ☐No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

BXP, Inc.:

Large Accelerated Filer ☒ Accelerated Filer ☐ Non-accelerated Filer ☐ Smaller Reporting Company☐

Emerging Growth Company ☐

Boston Properties Limited Partnership:

Large Accelerated Filer ☐ Accelerated Filer ☐Non-accelerated Filer ☒ Smaller Reporting Company☐

Emerging Growth Company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards pursuant to Section 13(a) of the Exchange Act.

BXP, Inc. ☐ Boston Properties Limited Partnership ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.

BXP, Inc.☒ Boston Properties Limited Partnership☒

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements

of the registrant included in the filing reflect the correction of an error to previously issued financial statements.

BXP, Inc.☐ Boston Properties Limited Partnership☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).

BXP, Inc. ☐ Boston Properties Limited Partnership ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).

BXP, Inc.: Yes ☐ No☒ Boston Properties Limited Partnership: Yes ☐ No☒

As of June 30, 2025, the aggregate market value of the 158,043,924 shares of Common Stock held by non-affiliates of BXP, Inc. was $10,663,223,539 based upon the last reported sale price of $67.47 per share on the New York Stock Exchange on June 30, 2025. (For this computation, BXP, Inc. has excluded the market value of all shares of Common Stock reported as beneficially owned by executive officers and directors of BXP, Inc.; such exclusion shall not be deemed to constitute an admission that any such person is an affiliate of BXP, Inc.).

As of February 20, 2026, there were 158,629,124 shares of Common Stock of BXP, Inc. outstanding.

Because no established market for common units of limited partnership of Boston Properties Limited Partnership exists, there is no market value for such units.

Certain information contained in BXP, Inc.’s Proxy Statement relating to its Annual Meeting of Stockholders to be held May 21, 2026 is incorporated by reference in Items 10, 11, 12, 13 and 14 of Part III. BXP, Inc. intends to file such Proxy Stat ement with the Securities and Exchange Commission not later than 120 days after the end of its fiscal year ended December 31, 2025.

EXPLANATORY NOTE

This report combines the Annual Reports on Form 10-K for the fiscal year ended December 31, 2025 of BXP, Inc. and Boston Properties Limited Partnership. Unless stated otherwise or the context otherwise requires, references to “BXP” mean BXP, Inc. (formerly known as Boston Properties, Inc.), a Delaware corporation and real estate investment trust (“REIT”), and references to “BPLP” and the “Operating Partnership” mean Boston Properties Limited Partnership, a Delaware limited partnership. BPLP is the entity through which BXP conducts substantially all of its business and owns, either directly or through subsidiaries, substantially all of its assets. BXP is the sole general partner and also a limited partner of BPLP. As the sole general partner of BPLP, BXP has exclusive control of BPLP’s day-to-day management. Therefore, unless stated otherwise or the context requires, references to the “Company,” “we,” “us” and “our” refer collectively to BXP, BPLP and those subsidiaries consolidated by BXP.

As of December 31, 2025, BXP owned an approximate 89.7% ownership interest in BPLP. The remaining approximate 10.3% interest was owned by limited partners. The other limited partners of BPLP (1) contributed their direct or indirect interests in properties to BPLP in exchange for common units of limited partnership interest in BPLP or (2) received long-term incentive plan units of BPLP pursuant to BXP’s Stock Option and Incentive Plans, or both. Under the limited partnership agreement of BPLP, unitholders may present their common units of BPLP for redemption at any time (subject to covenants agreed upon at the time of issuance of the units that may restrict such right for a period of time, generally one year from issuance). Upon presentation of a common unit for redemption, BPLP must redeem the unit for cash equal to the then value of a share of BXP’s common stock. In lieu of a cash redemption by BPLP, however, BXP may elect to acquire any common units so tendered by issuing shares of BXP common stock in exchange for the common units. If BXP so elects, its common stock will be exchanged for common units on a one-for-one basis. This one-for-one exchange ratio is subject to specified adjustments to prevent dilution. BXP generally expects that it will elect to issue its common stock in connection with each such presentation for redemption rather than having BPLP pay cash. With each such exchange or redemption, BXP’s percentage ownership in BPLP will increase. In addition, whenever BXP issues shares of its common stock other than to acquire common units of BPLP, BXP must contribute any net proceeds it receives to BPLP and BPLP must issue to BXP a number of common units of BPLP that equals the number of shares of BXP common stock so issued. This structure is commonly referred to as an umbrella partnership REIT, or UPREIT.

The Company believes that combining the Annual Reports on Form 10-K of BXP and BPLP into this single report:

•enhances investors’ understanding of BXP and BPLP by enabling them to view the business as a whole in the same manner as management views and operates the business;

•eliminates duplicative disclosure and provides a more concise and readable presentation because a substantial portion of the disclosure applies to both BXP and BPLP; and

•creates time and cost efficiencies through the preparation of one combined report instead of two separate reports.

The Company believes it is important to understand the few differences between BXP and BPLP in the context of how BXP and BPLP operate as a consolidated company. The financial results of BPLP are consolidated into the financial statements of BXP. BXP does not have any other significant assets, liabilities or operations, other than its investment in BPLP, nor does it have employees of its own. BPLP, not BXP, generally executes all significant business relationships other than transactions involving the securities of BXP. BPLP holds substantially all of the assets of BXP, including ownership interests in subsidiaries and joint ventures. BPLP conducts the operations of the business and is structured as a partnership with no publicly traded equity. Except for the net proceeds from equity issuances by BXP, which are contributed to the capital of BPLP in exchange for common or preferred units of partnership in BPLP, as applicable, BPLP generates all remaining capital required by the Company’s business. These sources include working capital, net cash provided by operating activities, borrowings under its credit facilities, the issuance of secured and unsecured debt and equity securities and proceeds received from the disposition of certain properties and interests in joint ventures.

Shareholders’ equity, partners’ capital and noncontrolling interests are the main areas of difference between the consolidated financial statements of BXP and BPLP. The limited partners of BPLP are accounted for as partners’ capital in BPLP’s financial statements and as noncontrolling interests in BXP’s financial statements. The noncontrolling interests in BPLP’s financial statements include the interests of unaffiliated partners in various consolidated partnerships. The noncontrolling interests in BXP’s financial statements include the same noncontrolling interests in BPLP and limited partners of BPLP. The differences between shareholders’ equity and partners’ capital result from differences in the equity issued by each of BXP and BPLP.

In addition, the consolidated financial statements of BXP and BPLP differ in total real estate assets resulting from previously applied acquisition accounting by BXP for the issuance of common stock in connection with non-sponsor redemptions of common units of BPLP. This accounting resulted in a step-up of the real estate assets of BXP at the time of such redemptions, resulting in a difference between the net real estate of BXP as compared to BPLP of approximately $223.8 million, or 1.1% at December 31, 2025, and a corresponding difference in depreciation expense, impairment losses and gains on sales of real estate upon the sale of these properties having an allocation of the real estate step-up. The acquisition accounting was nullified on a prospective basis beginning in 2009 as a result of the Company’s adoption of a new accounting standard requiring any subsequent redemptions to be accounted for solely as an equity transaction.

To help investors better understand the key differences between BXP and BPLP, the following items in this report present information separately for BXP and BPLP:

•Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities;

•Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations and Liquidity and Capital Resources, which includes information specific to each entity, where applicable;

•Item 8. Financial Statements and Supplementary Data, which includes the following specific disclosures for BXP and BPLP:

•Note 2. Summary of Significant Accounting Policies;

•Note 3. Real Estate;

•Note 11. Stockholders’ Equity / Partners’ Capital;

•Note 12. Segment Information; and

•Note 13. Earnings Per Share / Common Unit; and

•Item 15. Financial Statement Schedule—Schedule 3.

This report also includes separate Part II, Item 9A. Controls and Procedures, as well as separate Exhibit 23 consents of the independent registered public accounting firm and Exhibits 31 and 32 certifications for each of BXP and BPLP.