Xencor Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2025

or

For the transition period from to

Commission file number:001-36182

(Exact Name of Registrant as Specified in its Charter)

(626)305-5900

(Registrant’s 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: None

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

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yeso No x

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. Yes x Noo

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). Yes x Noo

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.

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 provided pursuant to Section 13(a) of the Exchange Act. o

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. x

If securities are registered pursuant to Section 12(b) of the Exchange 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.☐

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).☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Securities Exchange Act of 1934). Yeso Nox

The aggregate market value of the voting and non-voting common equity held by non-affiliates computed by reference to the price at which the common equity was last sold as of June 30, 2025 was $555,937,423.

The number of outstanding shares of the registrant’s common stock, par value $0.01 per share, as of February 17, 2026 was 73,338,642.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s proxy statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A in connection with the registrant’s 2026 Annual Meeting of Stockholders, which will be filed subsequent to the date hereof, are incorporated by reference into Part III of this Form 10-K. Such proxy statement will be filed with the Securities and Exchange Commission not later than 120 days following the end of the registrant’s fiscal year ended December 31, 2025.

TABLE OF CONTENTS

Xencor, XmAb and Proteins by Design are registered trademarks of Xencor, Inc. All other product and company names are trademarks of their respective companies. References in this Annual Report on Form 10-K to “we”, “our”, “us”, “Xencor” or “the Company” refer to Xencor, Inc.

FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, and we intend that such forward-looking statements be subject to the safe harbors created thereby. Any statements contained in this Annual Report on Form 10-K except for historical information, including statements regarding our future results of operations and financial position, our business strategy and plans, and our objectives for future operations, may be deemed to be forward-looking statements. Without limiting the generality of the foregoing, words such as “may,” “might,” “will,” “expect,” “believe,” “anticipate,” “goal,” “endeavor,” “strive,” “intend,” “plan,” “project,” “could,” “estimate,” “target,” “forecast,” or “continue” or the negative of these words or other variations thereof or comparable terminology are intended to identify forward-looking statements. Such statements may include, but are not limited to, statements concerning the following:

•the effects of inflation on our financial condition, results of operations, cash flows and performance;

•our ability to execute on our plans to research, develop and commercialize our product candidates;

•the success of our ongoing and planned clinical trials;

•the timing of and our ability to obtain and maintain regulatory approvals for our product candidates;

•our ability to identify additional products or product candidates with significant commercial potential that are consistent with our business objectives;

•our ability to receive research funding and achieve anticipated milestones under our collaborations;

•our partners’ abilities to advance drug candidates into, and successfully complete, clinical trials;

•our ability to attract collaborators with development, regulatory, and commercialization expertise;

•our ability to protect our intellectual property position;

•the rate and degree of market acceptance and clinical utility of our products;

•costs of compliance and our failure to comply with new and existing governmental regulations;

•the capabilities and strategy of our suppliers and vendors including key manufacturers of our clinical drug supplies;

•significant competition in our industry;

•the potential loss or retirement of key members of management;

•our failure to successfully execute our growth strategy including any delays in our planned future growth;

•our failure to maintain effective internal controls, which led to the restatement of our financial statements, and the risk that we may experience additional material weaknesses; and

•our ability to accurately estimate expenses, future revenues, capital requirements and needs for additional financing.

The forward-looking statements included herein are based on current expectations of the Company’s management based on available information and involve a number of risks and uncertainties, all of which are difficult or impossible to predict accurately, and many of which are beyond its control. As such, the Company’s actual results and timing of certain events may differ materially from the results discussed, projected, anticipated or indicated in any forward-looking statements. Forward-looking statements are not guarantees of future performance and the Company’s actual results of operations, financial condition and cash flows may differ materially. Factors that may cause or contribute to such differences include, but are not limited to, those discussed in more detail in Item 1A. “Risk Factors” of Part I of this Annual Report on Form 10-K. Readers should carefully review these risks, as well as the additional risks described in other documents the Company files from time to time with the Securities and Exchange Commission (the “SEC”). In light of the significant risks and uncertainties inherent in the forward-looking information included herein, the inclusion of such information should not be regarded as a representation by the Company or any other person that such results will be achieved, and readers are cautioned not to place undue reliance on such forward-looking information. Statements made herein are as of the date of the filing of this Annual Report on Form 10-K with the SEC and should not be relied upon as of any subsequent date. Except as may be required by law, the Company disclaims any intent to revise the forward-looking statements contained herein to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events.