# EDGAR Filing Document

**Accession Number:** 0001326732
**File Stem:** 0001326732-26-000019
**Filing Date:** 2026-2
**Character Count:** 32211
**Document Hash:** 81cc6f6dc85577522313153caee67752
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001326732-26-000019.hdr.sgml**: 20260225

**ACCESSION NUMBER**: 0001326732-26-000019

**CONFORMED SUBMISSION TYPE**: S-8

**PUBLIC DOCUMENT COUNT**: 17

**FILED AS OF DATE**: 20260225

**DATE AS OF CHANGE**: 20260225

**EFFECTIVENESS DATE**: 20260225

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Xencor Inc
- **CENTRAL INDEX KEY:** 0001326732
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 201622502
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** S-8
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-293730
- **FILM NUMBER:** 26678596

**BUSINESS ADDRESS:**
- **STREET 1:** 465 N. HALSTEAD ST.
- **STREET 2:** SUITE 200
- **CITY:** PASADENA
- **STATE:** CA
- **ZIP:** 91107
- **BUSINESS PHONE:** 626-305-5900

**MAIL ADDRESS:**
- **STREET 1:** 465 N. HALSTEAD ST.
- **STREET 2:** SUITE 200
- **CITY:** PASADENA
- **STATE:** CA
- **ZIP:** 91107

**As filed with the Securities and Exchange Commission on February 25, 2026**

 **Registration No. 333-**

**UNITED STATES <br>SECURITIES AND EXCHANGE COMMISSION**

Washington, D.C. 20549

___________________________

**FORM S-8**

**REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933**

___________________________

**Xencor, Inc.**

(Exact name of registrant as specified in its charter)

---

| | |
|:---|:---|
| **Delaware** | **20-1622502** |
| (State or other jurisdiction of<br>incorporation or organization) | (I.R.S. Employer<br>Identification No.) |
| **465 North Halstead Street, Suite 200**<br>**Pasadena, CA** | **91107** |
| (Address of Principal Executive Offices) | (Zip Code) |

---

___________________________

**Amended and Restated**

**2023 Equity Incentive Plan**

(Full title of the plan)

___________________________

**Bassil I. Dahiyat, Ph.D.** 

**President and Chief Executive Officer** 

**Xencor, Inc.**

**465 North Halstead Street, Suite 200**

**Pasadena, California 91107**

**(626) 305-5900**

(Name, address and telephone number, including area code, of agent for service)

___________________________

***Copies to:***

---

| | |
|:---|:---|
| **Deyan P. Spiridonov**<br>**Jeffrey T. Hartlin**<br>**Paul Hastings LLP**<br>**4655 Executive Drive, Suite 350**<br>**San Diego, California 92121**<br>**(858) 458-3044** | **Celia E. Eckert**<br>**Senior Vice President, General Counsel & Secretary**<br>**Xencor, Inc.**<br>**465 North Halstead Street, Suite 200**<br>**Pasadena, California 91107**<br>**(626) 305-5900** |

---

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.

&nbsp;&nbsp;&nbsp;&nbsp;

---

| | |
|:---|:---|
| Large accelerated filer ☐ | Accelerated filer ☒ |
| &nbsp;&nbsp;&nbsp;&nbsp;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 provided pursuant to Section 7(a)(2)(B) of the Securities 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 7(a)(2)(B) of the Securities Act. ☐ |

---

------

**EXPLANATORY NOTE**

Xencor, Inc. (the "Registrant") is filing this registration statement on Form S-8 pursuant to and in accordance with General Instruction E of Form S-8 to register 3,000,000 additional shares of its common stock, par value $0.01 per share ("Common Stock"), for issuance under the Xencor, Inc. Amended and Restated 2023 Equity Incentive Plan (the "2023 Plan").

These additional shares of Common Stock have become reserved for issuance pursuant to the stockholder approval received on June 12, 2025 to amend and restate the 2023 Equity Incentive Plan (the "Original 2023 Plan") to increase the number of authorized shares of Common Stock under such plan by 3,000,000 shares.

The Registrant first registered the offer and sale of shares of Common Stock in connection with the Original 2023 Plan on its registration statement on Form S-8 (File No. 333-272695) (the "First Registration Statement") filed with the Securities and Exchange Commission (the "Commission") on June 16, 2023 and on each of the following post-effective amendments filed on June 16, 2023: Post-Effective Amendment to Form S-8 (File No. 333-192635) ("POS S-8 1"), Post-Effective Amendment to Form S-8 (File No. 333-216365) ("POS S-8 2"), Post-Effective Amendment to Form S-8 (File No. 333-236607) ("POS S-8 3"), and Post-Effective Amendment to Form S-8 (File No. 333-266498) ("POS S-8 4" and, together with POS S-8 1, POS S-8 2, POS S-8 3 and the First Registration Statement, the "Previous Registration Statements").

In accordance with General Instruction E of Form S-8, the contents of the Previous Registration Statements are hereby incorporated by reference. Only those items of Form S-8 containing new information not contained in the Previous Registration Statements are presented herein.

**PART II**

**INFORMATION REQUIRED IN THE REGISTRATION STATEMENT**

**Item 3. Incorporation of Documents by Reference.**

The following documents filed with the Commission by the Registrant are hereby incorporated herein by reference:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a)the Registrant's Annual Report on <u>[Form 10-K](https://www.sec.gov/ix?doc=/Archives/edgar/data/0001326732/000132673226000015/xncr-20251231.htm)</u> for the fiscal year ended December 31, 2025, filed with the Commission on February 25, 2026; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b)The description of the Registrant's common stock set forth in the Registrant's Registration Statement on <u>[Form 8-A](https://www.sec.gov/Archives/edgar/data/1326732/000110465913082302/a13-23746_18a12b.htm)</u> (File No. 001-36182), filed with the SEC on November 7, 2013, including any amendments or reports filed for the purpose of updating such description, including the description of the Common Stock, contained in <u>[Exhibit 4.3](https://www.sec.gov/Archives/edgar/data/1326732/000132673225000029/xncr-20241231xexx43.htm)</u> to Registrant's Annual Report on Form 10-K for the fiscal year ended December 31, 2024, filed with the Commission on February 27, 2025.

All reports and other documents filed by the Registrant pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, on or after the date of this Registration Statement and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference in this Registration Statement and to be a part hereof from the date of filing of such reports and other documents, except as to any portion of any such report or other document furnished under Items 2.02 or 7.01 of Form 8-K that is not deemed filed under such provisions. Any statement contained in a report or other document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed report or other document that also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

**Item 4. Description of Securities.**

------

Not applicable.

**Item 5. Interests of Named Experts and Counsel.** 

Not applicable.

**Item 6. Indemnification of Directors and Officers.**

The Registrant is incorporated under the laws of the State of Delaware. Section 145 of the DGCL, which provides that a corporation may indemnify any persons, including officers and directors, who are, or are threatened to be made, parties to any threatened, pending or completed legal action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of such corporation), by reason of the fact that such person was an officer, director, employee or agent of such corporation or is or was serving at the request of such corporation as a director, officer, employee or agent of another corporation or enterprise. The indemnity may include expenses (including attorney's fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by such person in connection with such action, suit or proceeding, provided such officer, director, employee or agent acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the corporation's best interest and, for criminal proceedings, had no reasonable cause to believe that his or her conduct was unlawful. A Delaware corporation may indemnify officers and directors in an action by or in the right of the corporation under the same conditions, except that no indemnification is permitted without judicial approval if the officer or director is adjudged to be liable to the corporation. Where an officer or director is successful on the merits or otherwise in the defense of any action referred to above, the corporation must indemnify him against the expenses that such officer or director actually and reasonably incurred.

The Registrant's amended and restated certificate of incorporation and second amended and restated bylaws provide for the indemnification of its directors and officers to the fullest extent permitted under the Delaware General Corporation Law.

Section 102(b)(7) of the Delaware General Corporation Law permits a corporation to provide in its certificate of incorporation that a director of the corporation shall not be personally liable to the corporation or its stockholders for monetary damages for breach of fiduciary duties as a director, except for liability for any:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• transaction from which the director derives an improper personal benefit;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• act or omission not in good faith or that involves intentional misconduct or a knowing violation of law;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• unlawful payment of dividends or redemption of shares; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• breach of a director's duty of loyalty to the corporation or its stockholders.

The Registrant's amended and restated certificate of incorporation includes such a provision. Expenses incurred by any officer or director in defending any such action, suit or proceeding in advance of its final disposition shall be paid by the Registrant upon delivery to it of an undertaking, by or on behalf of such director or officer, to repay all amounts so advanced if it shall ultimately be determined that such director or officer is not entitled to be indemnified by the Registrant.

Section 174 of the Delaware General Corporation Law provides, among other things, that a director who willfully or negligently approves of an unlawful payment of dividends or an unlawful stock purchase or redemption may be held liable for such actions. A director who was either absent when the unlawful actions were approved, or dissented at the time, may avoid liability by causing his or her dissent to such actions to be entered in the books containing minutes of the meetings of the board of directors at the time such action occurred or immediately after such absent director receives notice of the unlawful acts.

As permitted by the Delaware General Corporation Law, the Registrant has entered into indemnity agreements with each of its directors and executive officers that require the Registrant to indemnify such persons against any and all costs and expenses (including attorneys', witness or other professional fees) actually and reasonably incurred by such person in connection with any action, suit or proceeding (including derivative actions), whether actual or threatened, to which any such person may be made a party by reason of the fact that such person is

------

or was a director or officer or is or was acting or serving as an officer, director, employee or agent of the Registrant or any of its affiliated enterprises, provided that such person acted in good faith and in a manner such person reasonably believed to be in or not opposed to the Registrant's best interests and, with respect to any criminal proceeding, had no reasonable cause to believe his or her conduct was unlawful. The indemnification agreements also set forth certain procedures that will apply in the event of a claim for indemnification thereunder.

At present, there is no pending litigation or proceeding involving any of the Registrant's directors or executive officers as to which indemnification is required or permitted, and the Registrant is not aware of any threatened litigation or proceeding that may result in a claim for indemnification.

The Registrant has an insurance policy in place that covers its officers and directors with respect to certain liabilities, including liabilities arising under the Securities Act or otherwise.

**Item 7. Exemption from Registration Claimed.**

Not applicable.

**Item 8. Exhibits.**

The following is a list of exhibits filed as part of this Registration Statement, which are hereby incorporated herein by reference:

---

| | |
|:---|:---|
| **Exhibit<br>Number** | **Description** |
| 4.1 | <u>[Amended and Restated Certificate of Incorporation of Xencor, Inc. (incorporated herein by reference to Exhibit 3.1 to the Registrant's Current Report on Form 8-K, filed with the Commission on December 11, 2013)](https://www.sec.gov/Archives/edgar/data/1326732/000110465913089659/a13-26060_1ex3d1.htm)</u> |
| 4.2 | <u>[Second Amended and Restated Bylaws of Xencor, Inc. (incorporated herein by reference to Exhibit 3.2 to the Registrant's Annual Report on Form 10-K for the fiscal year ended December 31, 2022, filed with the Commission on February 27, 2023)](https://www.sec.gov/Archives/edgar/data/1326732/000162828023005127/xncr-20221231xexx32.htm)</u> |
| 4.3 | <u>[Form of Common Stock Certificate of Xencor, Inc. (incorporated herein by reference to Exhibit 4.1 to the Registrant's Registration Statement on Form S-1, as amended (File No. 333-191689), originally filed with the Commission on October 25, 2013)](https://www.sec.gov/Archives/edgar/data/1326732/000104746913009956/a2217011zex-4_1.htm)</u> |
| 4.4 | <u>[Xencor, Inc. Amended and Restated 2023 Equity Incentive Plan (incorporated herein by reference to Exhibit 10.1 to the Registrant's Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2025, filed with the Commission on August 6, 2025)](https://www.sec.gov/Archives/edgar/data/1326732/000132673225000075/xncr-20250630xexx101.htm)</u>  |
| 5.1\* | <u>[Opinion of Paul Hastings, LLP](xencor-sx8xexhibit51opinion.htm)</u> |
| 23.1 | Consent of Paul Hastings, LLP (included in Exhibit 5.1 to this Registration Statement) |
| 23.2\* | <u>[Consent of Independent Registered Public Accounting Firm (KPMG LLP)](xencor-sx8xexhibit232.htm)</u> |
| 23.3\* | <u>[Consent of Independent Registered Public Accounting Firm (RSM US LLP)](xencor-sx8xex233rsmconsent.htm)</u> |
| 24.1 | Power of Attorney (included on the signature page of this Registration Statement) |
| 107\* | <u>[Filing Fee Table](exfilingfees.htm)</u> |

---

**\***Filed herewith

------

**SIGNATURES**

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Pasadena, State of California, on February 25, 2026.

---

| | |
|:---|:---|
| **XENCOR, INC.** | **XENCOR, INC.** |
| By: | /s/ Bassil I. Dahiyat, Ph.D. |
| Name: | Bassil I. Dahiyat, Ph.D. |
| Title: | President and Chief Executive Officer |

---

**POWER OF ATTORNEY**

**KNOW ALL PERSONS BY THESE PRESENTS**, that each person whose signature appears below constitutes and appoints Bassil I. Dahiyat, Ph.D. and Bart Jan Cornelissen, and each of them, as his or her true and lawful attorneys-in-fact and agents, each with the full power of substitution, for him or her and in his or her name, place or stead, in any and all capacities, to sign any and all amendments to this Registration Statement (including post-effective amendments), and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or their or his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

------

---

| | | |
|:---|:---|:---|
| **Signature** | **Title** | **Date** |
| /s/ Bassil I. Dahiyat, Ph.D. | President, Chief Executive Officer and Director | February 25, 2026 |
| Bassil I. Dahiyat, Ph.D. | *(Principal Executive Officer)* | February 25, 2026 |
| /s/ Bart Jan Cornelissen | Sr. Vice President & Chief Financial Officer | February 25, 2026 |
| Bart Jan Cornelissen | *(Principal Financial and Accounting Officer)* | February 25, 2026 |
| /s/ A. Bruce Montgomery, MD | Director | February 25, 2026 |
| A. Bruce Montgomery, MD | Director | February 25, 2026 |
| /s/ Kurt A. Gustafson | Director | February 25, 2026 |
| Kurt A. Gustafson | Director | February 25, 2026 |
| /s/ Kevin C. Gorman, Ph.D. | Director | February 25, 2026 |
| Kevin C. Gorman, Ph.D. | Director | February 25, 2026 |
| /s/ Richard J. Ranieri | Director | February 25, 2026 |
| Richard J. Ranieri | Director | February 25, 2026 |
| /s/ Ellen G. Feigal, M.D. | Director | February 25, 2026 |
| Ellen G. Feigal, M.D. | Director | February 25, 2026 |
| /s/ Barbara Klencke | Director | February 25, 2026 |
| Barbara Klencke | Director | February 25, 2026 |
| /s/ Todd Simpson | Director | February 25, 2026 |
| Todd Simpson | Director | February 25, 2026 |
| /s/ Raymond J. Deshaies | Director | February 25, 2026 |
| Raymond J. Deshaies | Director | February 25, 2026 |

---

## Ex-Filing

?xml version='1.0' encoding='ASCII'? exfilingfees

**Exhibit 107** 

**Calculation of Filing Fee Tables** 

**<u>Form S-8</u>**

(Form Type)

**<u>Xencor, Inc.</u>**

(Exact Name of Registrant as Specified in its Charter)

<u>Table 1: Newly Registered and Carry Forward Securities</u> 

---

| | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| | | **Security Type** | **Security Class**<br>**Title** | **Fee<br>Calculation <br> or Carry Forward Rule** | **Amount<br>Registered** | **Proposed<br>Maximum<br>Offering<br>Price Per<br>Unit** | **Maximum<br>Aggregate<br>Offering Price** | **Fee Rate** | **Amount of<br>Registration<br>Fee** |
| **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** | **Newly Registered Securities** |
| Fees to Be Paid | 1 | Equity | Common Stock, $0.01 par value per share | 457(h) | 3000000 | $11.48 | $34440000.00 | 0.00013810 | $4756.16 |
| Fees Previously Paid |  |  |  |  |  |  |  |  |  |
| **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** | **Carry Forward Securities** |
| Carry Forward Securities |  |  |  |  |  |  |  |  |  |
|  |  | Total Offering Amounts | Total Offering Amounts | Total Offering Amounts | Total Offering Amounts |  | $34440000.00 |  | $4756.16 |
|  |  | Total Fees Previously Paid | Total Fees Previously Paid | Total Fees Previously Paid | Total Fees Previously Paid |  |  |  |  |
|  |  | Total Fee Offsets | Total Fee Offsets | Total Fee Offsets | Total Fee Offsets |  |  |  |  |
|  |  | Net Fee Due | Net Fee Due | Net Fee Due | Net Fee Due |  |  |  | $4756.16 |

---

------

(1) Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "Securities Act"), this Registration Statement shall also cover any additional shares of the Registrant's common stock, $0.01 par value per share ("Common Stock") that become issuable under the Xencor, Inc. Amended and Restated 2023 Equity Incentive Plan by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without receipt of consideration that increases the number of the Registrant's outstanding shares of Common Stock. The proposed maximum aggregate offering price per unit is estimated pursuant to Rule 457(h) and Rule 457(c) of the Securities Act solely for purposes of calculating the registration fee. The price per share and aggregate offering price are based upon the average of the high and low prices of the Common Stock on February 20, 2026, as reported by the Nasdaq Stock Market, LLC.

## Exhibit 5.1

![image_1a.jpg](image_1a.jpg)

**Exhibit 5.1**

February 25, 2026

Xencor, Inc.

465 North Halstead Street, Suite 200

Pasadena, CA 91107

Re:&nbsp;&nbsp;&nbsp;&nbsp;Xencor, Inc. Registration Statement on Form S-8

Ladies and Gentlemen:

We have acted as counsel to Xencor, Inc., a Delaware corporation (the "***Company***"), in connection with the preparation of the Registration Statement on Form S-8 to be filed by the Company with the U.S. Securities and Exchange Commission (the "***Commission***") on or about the date hereof (the "***Registration Statement***") to effect the registration under the Securities Act of 1933, as amended (the "***Securities Act***"), of 3,000,000 shares (the "***Shares***") of the Company's common stock, $0.01 par value per share (the "***Common Stock***"), reserved for future issuance under to the Company's Amended and Restated 2023 Equity Incentive Plan (the "***2023 Plan***").

As such counsel and for purposes of our opinion set forth below, we have examined and relied upon originals or copies, certified or otherwise identified to our satisfaction, of such documents, resolutions, certificates and instruments of the Company and corporate records furnished to us by the Company, and have reviewed certificates of public officials, statutes, records and such other instruments and documents as we have deemed necessary or appropriate as a basis for the opinion set forth below, including, without limitation:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i)&nbsp;&nbsp;&nbsp;&nbsp;the Registration Statement;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii)&nbsp;&nbsp;&nbsp;&nbsp;the Amended and Restated Certificate of Incorporation of the Company (the "***Amended and Restated Certificate of Incorporation***"), as certified by the Office of the Secretary of State of the State of Delaware on February 25, 2026;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(iii)&nbsp;&nbsp;&nbsp;&nbsp;the Second Amended and Restated Bylaws of the Company as presently in effect, as certified by an officer of the Company on February 25, 2026;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(iv)&nbsp;&nbsp;&nbsp;&nbsp;the 2023 Plan and the forms of award agreements related thereto;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(v)&nbsp;&nbsp;&nbsp;&nbsp;a certificate, dated as of February 25, 2026, from the Office of the Secretary of State of the State of Delaware, certifying as to the existence and good standing of the Company in the State of Delaware (the "***Good Standing Certificate***"); and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(vi)&nbsp;&nbsp;&nbsp;&nbsp;resolutions adopted by the Company's board of directors (or a committee thereof) and approvals by the stockholders of the Company regarding the 2023 Plan and other matters related thereto, in each case, as certified by an officer of the Company on February 25, 2026.

&nbsp;&nbsp;&nbsp;&nbsp;![image_2a.jpg](image_2a.jpg)

------

![image_1a.jpg](image_1a.jpg)

Xencor, Inc.

February 25, 2026

In addition to the foregoing, we have made such investigations of law as we have deemed necessary or appropriate as a basis for the opinion set forth in this opinion letter.

In such examination and in rendering the opinion expressed below, we have assumed, without independent investigation or verification: (i) the genuineness of all signatures on all agreements, instruments, corporate records, certificates and other documents submitted to us; (ii) the authenticity and completeness of all agreements, instruments, corporate records, certificates and other documents submitted to us as originals; (iii) that all agreements, instruments, corporate records, certificates and other documents submitted to us as certified, electronic, facsimile, conformed, photostatic or other copies conform to originals thereof, and that such originals are authentic and complete; (iv) the legal capacity and authority of all persons or entities (other than the Company) executing all agreements, instruments, corporate records, certificates and other documents submitted to us; (v) the due authorization, execution and delivery of all agreements, instruments, corporate records, certificates and other documents by all parties thereto (other than the Company); (vi) that no documents submitted to us have been amended or terminated orally or in writing except as has been disclosed to us in writing; (vii) that the statements contained in the certificates and comparable documents of public officials, officers and representatives of the Company and other persons on which we have relied for the purposes of this opinion letter are true and correct; (viii) that there has not been any change in the good standing status of the Company from that reported in the Good Standing Certificate; and (ix) that each of the officers and directors of the Company has properly exercised his or her fiduciary duties. As to all questions of fact material to this opinion letter, and as to the materiality of any fact or other matter referred to herein, we have relied (without independent investigation or verification) upon representations and certificates or comparable documents of officers and representatives of the Company. Our knowledge of the Company and its legal and other affairs is limited by the scope of our engagement, which scope includes the delivery of this opinion letter. We do not represent the Company with respect to all legal matters or issues. The Company may employ other independent counsel and, to our knowledge, handles certain legal matters and issues without the assistance of independent counsel. We have also assumed that the individual issuances, grants and awards under the 2023 Plan will be duly authorized by all necessary corporate action of the Company and duly issued, granted or awarded and/or exercised in accordance with the requirements of law, the 2023 Plan and the agreements, forms of instrument, awards and grants duly adopted thereunder. We have also assumed that upon the issuance of any Shares, the total number of shares of Common Stock issued and outstanding will not exceed the total number of shares of Common Stock that the Company is then authorized to issue under the Amended and Restated Certificate of Incorporation.

Based upon the foregoing, and in reliance thereon, and subject to the assumptions, limitations, qualifications and exceptions set forth herein, we are of the opinion that the Shares are duly authorized and, when issued and sold as described in the Registration Statement and in accordance with the 2023 Plan and the applicable award agreements or forms of instrument evidencing purchase rights thereunder (including the receipt by the Company of the full consideration therefor), will be validly issued, fully paid and nonassessable.

Without limiting any of the other limitations, exceptions, assumptions and qualifications stated elsewhere herein, we express no opinion with regard to the applicability or effect of the laws of any jurisdiction other than the General Corporation Law of the State of Delaware, as in effect on the date of this opinion letter.

------

![image_1a.jpg](image_1a.jpg)

Xencor, Inc.

February 25, 2026

This opinion letter deals only with the specified legal issues expressly addressed herein, and you should not infer any opinion that is not explicitly stated herein from any matter addressed in this opinion letter.

This opinion letter is rendered solely in connection with the issuance and delivery of the Shares as described in the Registration Statement and in accordance with the terms of the 2023 Plan and the applicable award agreement thereunder. This opinion letter is rendered as of the date hereof, and we assume no obligation to advise you or any other person with regard to any change after the date hereof in the circumstances or the law that may bear on the matters set forth herein even if the change may affect the legal analysis or a legal conclusion or other matters in this opinion letter.

We hereby consent to the filing of this opinion letter as Exhibit 5.1 to the Registration Statement. In giving such consent, we do not hereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules or regulations of the Commission thereunder.

Very truly yours,

/s/ Paul Hastings LLP

## Exhibit 23.2

**Exhibit 23.2**

**Consent of Independent Registered Public Accounting Firm**

We consent to the use of our Report dated February 25, 2026, with respect to the consolidated financial statements of Xencor, Inc., and the effectiveness of internal control over financial reporting, incorporated herein by reference.

/s/ KPMG LLP

San Diego, California

February 25, 2026

## Exhibit 23.3

**Exhibit 23.3**

**Consent of Independent Registered Public Accounting Firm**

We consent to the incorporation by reference in this Registration Statement on Form S-8 of our report dated February 26, 2025, relating to the consolidated financial statements of Xencor, Inc. (the Company), as of December 31, 2024 and each of the two years then ended, appearing in the Annual Report on Form 10-K of the Company for the year ended December 31, 2025.

As disclosed in Note 14 to the 2025 financial statements, the financial statements for the years ended December 31, 2024 and 2023, have been retrospectively adjusted to apply changes in disclosures to segment reporting and related information. We have not audited the adjustments in the 2025 financial statements for the years ended December 31, 2024 and 2023, to retrospectively adjust for changes in disclosures to segment reporting, as disclosed in Note 14.

RSM US LLP

Los Angeles, CA

February 25, 2026

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