Xencor: EcoR1 Reports 2.9% Stake

Xencor Inc ownership disclosure: EcoR1 Capital, LLC and related filers report beneficial ownership of 2,183,000 shares (EcoR1 and Oleg Nodelman) representing 2.9% and 2,041,033 shares (EcoR1 Capital Fund Qualified, L.P.) representing 2.8%.

Rhea-AI Filing Summary

Xencor Inc ownership disclosure: EcoR1 Capital, LLC and related filers report beneficial ownership of 2,183,000 shares (EcoR1 and Oleg Nodelman) representing 2.9% and 2,041,033 shares (EcoR1 Capital Fund Qualified, L.P.) representing 2.8%. The percentages are calculated based on 71,141,596 shares outstanding as of May 1, 2026 per the issuer's Form 10-Q for the quarter ended March 31, 2026. The filing states shared voting and dispositive power for the reported amounts and includes customary disclaimers about group membership and beneficial ownership.

Insights

Governance Analyst

Passive stake disclosure by an institutional holder with shared control.

EcoR1 and related reporting persons disclose 2,183,000 shares and shared voting/dispositive power rather than sole control. The filing emphasizes it is not intended to change control and includes disclaimers of group beneficial ownership.

Subsequent filings may clarify any changes; timing and transaction history are not included here.

Investor Relations Specialist

Small institutional position under 5% with standard disclosures.

The positions represent 2.9% and 2.8% of outstanding common stock as calculated on May 1, 2026. The filing notes shared voting and dispositive power, consistent with an adviser/partner structure.

Material impact on control is explicitly disclaimed in the statement accompanying the signatures.

Key Figures

EcoR1 reported shares: 2,183,000 shares Qualified Fund reported shares: 2,041,033 shares Shares outstanding (denominator): 71,141,596 shares +2 more

5 metrics

EcoR1 reported shares 2,183,000 shares Amount beneficially owned by EcoR1 and Oleg Nodelman

Qualified Fund reported shares 2,041,033 shares Amount beneficially owned by EcoR1 Capital Fund Qualified, L.P.

Shares outstanding (denominator) 71,141,596 shares Outstanding common stock used to calculate percentages as of <date>May 1, 2026</date>

EcoR1 percentage 2.9% Percent of class for EcoR1 and Oleg Nodelman

Qualified Fund percentage 2.8% Percent of class for Qualified Fund

Key Terms

Schedule 13G/A, beneficial ownership, shared dispositive power, shared voting power

4 terms

Schedule 13G/A regulatory

"Amendment No. 6 ) Xencor Inc Common Stock"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

beneficial ownership regulatory

"Amount beneficially owned: EcoR1: 2,183,000"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

shared dispositive power regulatory

"Shared Dispositive Power 2,183,000.00"

shared voting power regulatory

"Shared Voting Power 2,183,000.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake did EcoR1 report in Xencor (XNCR)?

EcoR1 Capital and related filers reported beneficial ownership of 2,183,000 shares representing 2.9%. The filing lists a separate Qualified Fund position of 2,041,033 shares representing 2.8%, calculated using 71,141,596 shares outstanding as of May 1, 2026.

Does the filing say EcoR1 seeks to change control of Xencor?

No. The filing includes a signed certification stating the securities were not acquired to change or influence control and disclaims group control. The signatories expressly state the positions are not held to effect a control change under the cited rule.

What voting or dispositive power does EcoR1 claim over Xencor shares?

The filing reports shared voting power and shared dispositive power of the reported share amounts (e.g., 2,183,000 shares). Sole voting and sole dispositive powers are reported as 0 for the named reporting persons in this schedule.

What outstanding share count was used to calculate the percentages?

The percentages are based on 71,141,596 shares outstanding as of May 1, 2026, cited from Xencor's Form 10-Q for the quarter ended March 31, 2026. That outstanding count is the denominator for the reported 2.9% and 2.8% figures.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/15/2026 - 02:24 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 6)

Xencor Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

98401F105

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 98401F105

1

Names of Reporting Persons

EcoR1 Capital, LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 2,183,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,183,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,183,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

2.9 %

12

Type of Reporting Person (See Instructions)

IA, OO

Comment for Type of Reporting Person: Percentage calculated based on 71,141,596 shares of Common Stock outstanding on May 1, 2026, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2026.

SCHEDULE 13G

CUSIP Number(s): 98401F105

1

Names of Reporting Persons

Oleg Nodelman

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 2,183,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,183,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,183,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

2.9 %

12

Type of Reporting Person (See Instructions)

HC, IN

Comment for Type of Reporting Person: Percentage calculated based on 71,141,596 shares of Common Stock outstanding on May 1, 2026, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2026.

SCHEDULE 13G

CUSIP Number(s): 98401F105

1

Names of Reporting Persons

EcoR1 Capital Fund Qualified, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 2,041,033.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,041,033.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,041,033.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

2.8 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: Percentage calculated based on 71,141,596 shares of Common Stock outstanding on May 1, 2026, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 31, 2026.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Xencor Inc
(b)	Address of issuer's principal executive offices: 465 North Halstead Street, Suite 200, Pasadena, CA 91107
Item 2.
(a)	Name of person filing: EcoR1 Capital, LLC, a Delaware limited liability company ("EcoR1") EcoR1 Capital Fund Qualified, L.P., a Delaware limited partnership ("Qualified Fund") Oleg Nodelman Qualified Fund is filing this statement jointly with the other reporting persons, but not as a member of a group, and it expressly disclaims membership in a group. In addition, the filing of this Schedule 13G on behalf of Qualified Fund should not be construed as an admission that it is, and it disclaims that it is, a beneficial owner, as defined in Rule 13d-3 under the Act, of any securities covered by this Schedule 13G. Each reporting person also disclaims beneficial ownership of the securities reported herein except to the extent of that person's pecuniary interest therein.
(b)	Address or principal business office or, if none, residence: 357 Tehama Street #3 San Francisco, CA 94103
(c)	Citizenship: See Item 4 of the cover sheet for each reporting person.
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 98401F105
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: EcoR1: 2,183,000 Oleg Nodelman: 2,183,000 Qualified Fund: 2,041,033
(b)	Percent of class: EcoR1: 2.9% Oleg Nodelman: 2.9% Qualified Fund: 2.8%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0
	(ii) Shared power to vote or to direct the vote: EcoR1: 2,183,000 Oleg Nodelman: 2,183,000 Qualified Fund: 2,041,033
	(iii) Sole power to dispose or to direct the disposition of: EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0
	(iv) Shared power to dispose or to direct the disposition of: EcoR1: 2,183,000 Oleg Nodelman: 2,183,000 Qualified Fund: 2,041,033
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.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. EcoR1 is the general partner and investment adviser of investment funds, including Qualified Fund. Mr. Nodelman is the control person of EcoR1.
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

EcoR1 Capital, LLC

Signature:	/s/ Oleg Nodelman
Name/Title:	Manager
Date:	05/14/2026

Oleg Nodelman

Signature:	/s/ Oleg Nodelman
Name/Title:	Reporting person
Date:	05/14/2026

EcoR1 Capital Fund Qualified, L.P.

Signature:	/s/ Oleg Nodelman
Name/Title:	Manager of the General Partner, EcoR1 Capital, LLC
Date:	05/14/2026

Exhibit Information

EXHIBIT 99.1 - AGREEMENT REGARDING JOINT FILING OF STATEMENT ON SCHEDULE 13D OR 13G