BVF Partners and affiliated funds report a significant passive stake in Xencor Inc. As of December 31, 2025, Biotechnology Value Fund, BVF2 and Biotechnology Value Trading Fund OS together beneficially owned 7,133,720 shares of Xencor common stock. This represents approximately 9.99% of the 71,410,469 shares outstanding as of October 30, 2025.
Individually, BVF held 3,798,627 shares (about 5.3% of the class) and BVF2 held 2,787,735 shares (about 3.9%), with additional shares held by Trading Fund OS and a Partners managed account. The filing is signed by Mark N. Lampert, who may be deemed to share beneficial ownership through various BVF entities.
The reporting group certifies that the securities were not acquired and are not held for the purpose of changing or influencing control of Xencor, indicating a passive investment stance under Schedule 13G.
Positive
None.
Negative
None.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 1)
Xencor Inc
(Name of Issuer)
Common Stock, par value $0.01 per share
(Title of Class of Securities)
98401F105
(CUSIP Number)
12/31/2025
(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)
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
BIOTECHNOLOGY VALUE FUND 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
3,798,627.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,798,627.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,798,627.00
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)
5.3 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
BVF I GP 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
3,798,627.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,798,627.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,798,627.00
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)
5.3 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
BIOTECHNOLOGY VALUE FUND II LP
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
2,787,735.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,787,735.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,787,735.00
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)
3.9 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
BVF II GP 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
2,787,735.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,787,735.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,787,735.00
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)
3.9 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
Biotechnology Value Trading Fund OS LP
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
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
439,372.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
439,372.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
439,372.00
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)
0.6 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
BVF Partners OS Ltd.
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
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
439,372.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
439,372.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
439,372.00
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)
0.6 %
12
Type of Reporting Person (See Instructions)
CO
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
BVF GP HOLDINGS 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
6,586,362.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
6,586,362.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
6,586,362.00
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)
9.2 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
BVF PARTNERS L P/IL
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
7,133,720.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
7,133,720.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
7,133,720.00
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)
9.99 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
BVF INC/IL
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
7,133,720.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
7,133,720.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
7,133,720.00
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)
9.99 %
12
Type of Reporting Person (See Instructions)
CO
SCHEDULE 13G
CUSIP No.
98401F105
1
Names of Reporting Persons
LAMPERT MARK N
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
7,133,720.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
7,133,720.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
7,133,720.00
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)
9.99 %
12
Type of Reporting Person (See Instructions)
IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Xencor Inc
(b)
Address of issuer's principal executive offices:
465 N. HALSTEAD ST., SUITE 200, PASADENA, CA 91107
Item 2.
(a)
Name of person filing:
Biotechnology Value Fund, L.P. ("BVF")
BVF I GP LLC ("BVF GP")
Biotechnology Value Fund II, L.P. ("BVF2")
BVF II GP LLC ("BVF2 GP")
Biotechnology Value Trading Fund OS LP ("Trading Fund OS")
BVF Partners OS Ltd. ("Partners OS")
BVF GP Holdings LLC ("BVF GPH")
BVF Partners L.P. ("Partners")
BVF Inc.
Mark N. Lampert ("Mr. Lampert")
Each of the foregoing is referred to as a "Reporting Person" and collectively as the "Reporting Persons."
(b)
Address or principal business office or, if none, residence:
Biotechnology Value Fund, L.P.
44 Montgomery St., 40th Floor
San Francisco, California 94104
BVF I GP LLC
44 Montgomery St., 40th Floor
San Francisco, California 94104
Biotechnology Value Fund II, L.P.
44 Montgomery St., 40th Floor
San Francisco, California 94104
BVF II GP LLC
44 Montgomery St., 40th Floor
San Francisco, California 94104
Biotechnology Value Trading Fund OS LP
PO Box 309 Ugland House
Grand Cayman, KY1-1104
Cayman Islands
BVF Partners OS Ltd.
PO Box 309 Ugland House
Grand Cayman, KY1-1104
Cayman Islands
BVF GP Holdings LLC
44 Montgomery St., 40th Floor
San Francisco, California 94104
BVF Partners L.P.
44 Montgomery St., 40th Floor
San Francisco, California 94104
BVF Inc.
44 Montgomery St., 40th Floor
San Francisco, California 94104
Mark N. Lampert
44 Montgomery St., 40th Floor
San Francisco, California 94104
(c)
Citizenship:
Biotechnology Value Fund, L.P.
Delaware
BVF I GP LLC
Delaware
Biotechnology Value Fund II, L.P.
Delaware
BVF II GP LLC
Delaware
Biotechnology Value Trading Fund OS LP
Cayman Islands
BVF Partners OS Ltd.
Cayman Islands
BVF GP Holdings LLC
Delaware
BVF Partners L.P.
Delaware
BVF Inc.
Delaware
Mark N. Lampert
United States
(d)
Title of class of securities:
Common Stock, par value $0.01 per share
(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:
As of the close of business on December 31, 2025, (i) BVF beneficially owned 3,798,627 shares of the Issuer's Common Stock, par value $0.01 per share (the "Shares"), (ii) BVF2 beneficially owned 2,787,735 Shares and (iii) Trading Fund OS beneficially owned 439,372 Shares.
BVF GP, as the general partner of BVF, may be deemed to beneficially own the 3,798,627 Shares beneficially owned by BVF.
BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 2,787,735 Shares beneficially owned by BVF2.
Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 439,372 Shares beneficially owned by Trading Fund OS.
BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 6,586,362 Shares beneficially owned in the aggregate by BVF and BVF2.
Partners, as the investment manager of BVF, BVF2 and Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the 7,133,720 Shares beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS and held in a certain Partners managed account (the "Partners Managed Account"), including 107,986 Shares held in the Partners Managed Account.
BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 7,133,720 Shares beneficially owned by Partners.
Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 7,133,720 Shares beneficially owned by BVF Inc.
The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account, and the filing of this statement shall not be construed as an admission that any such person or entity is the beneficial owner of any such securities.
(b)
Percent of class:
The following percentages are based on 71,410,469 Shares outstanding as of October 30, 2025, which is the total number of Shares outstanding as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 5, 2025.
As of the close of business on December 31, 2025, (i) BVF beneficially owned approximately 5.3% of the outstanding Shares, (ii) BVF2 beneficially owned approximately 3.9% of the outstanding Shares, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding Shares, (iv) BVF GP may be deemed to beneficially own approximately 5.3% of the outstanding Shares, (v) BVF2 GP may be deemed to beneficially own approximately 3.9% of the outstanding Shares, (vi) Partners OS may be deemed to beneficially own less than 1% of the outstanding Shares, (vii) BVF GPH may be deemed to beneficially own approximately 9.2% of the outstanding Shares, and (viii) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 9.99% of the outstanding Shares (less than 1% of the outstanding Shares are held in the Partners Managed Account).
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
See Cover Pages Items 5-9.
(ii) Shared power to vote or to direct the vote:
See Cover Pages Items 5-9.
(iii) Sole power to dispose or to direct the disposition of:
See Cover Pages Items 5-9.
(iv) Shared power to dispose or to direct the disposition of:
See Cover Pages Items 5-9.
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
If any 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, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
BVF GP, BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF. BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF2. Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by Trading Fund OS and held in the Partners Managed Account.
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.
See Exhibit 99.1 to the Schedule 13G filed with the Securities and Exchange Commission on October 17, 2025.
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 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.
What ownership stake in Xencor Inc (XNCR) does BVF report in this Schedule 13G/A?
BVF and affiliated funds report beneficial ownership of 7,133,720 Xencor shares, representing approximately 9.99% of the outstanding common stock. This total combines holdings of Biotechnology Value Fund, BVF2, Biotechnology Value Trading Fund OS and a Partners managed account, as detailed in the filing.
How much of Xencor (XNCR) does each main BVF fund beneficially own?
Biotechnology Value Fund beneficially owns 3,798,627 Xencor shares, or about 5.3% of the class. Biotechnology Value Fund II owns 2,787,735 shares, about 3.9%. Biotechnology Value Trading Fund OS owns 439,372 shares, described as less than 1% of the outstanding shares.
What percentage of Xencor (XNCR) do BVF Partners, BVF Inc. and Mark N. Lampert each control?
BVF Partners, BVF Inc. and Mark N. Lampert may each be deemed to beneficially own approximately 9.99% of Xencor’s outstanding common stock. This percentage is based on 7,133,720 shares aggregated across BVF, BVF2, Trading Fund OS and a Partners managed account.
Is BVF’s position in Xencor (XNCR) reported as passive or for control purposes?
The position is certified as passive. The reporting group states the Xencor securities were not acquired and are not held to change or influence control of the issuer, and are not part of any transaction having that purpose, other than activities solely connected with a nomination under Rule 240.14a-11.
What share count did BVF use to calculate its ownership percentage in Xencor (XNCR)?
Ownership percentages are calculated using 71,410,469 Xencor common shares outstanding as of October 30, 2025. This figure comes from Xencor’s Quarterly Report on Form 10-Q filed on November 5, 2025, and is explicitly cited as the basis for BVF’s percentage calculations.
Who signed the Xencor (XNCR) Schedule 13G/A on behalf of the BVF entities?
Mark N. Lampert signed the Schedule 13G/A multiple times as an authorized signatory for the BVF entities, and once as Mark N. Lampert individually. The signatures are dated February 17, 2026, confirming the accuracy of the ownership information to the best of his knowledge and belief.
