Each fund directly held a separate block, while voting and dispositive power may also be attributed to the related general partners and their managing director.
Rhea-AI Sentiment reads the wording of the document, how positive or negative its language is on a 1 to 5 scale. The balance of points shown with the takes weighs what the document actually discloses, so the two can disagree, for example when a trial that missed its main goal is described in upbeat language.
Latigo Biotherapeutics, Inc. (LTGO) common stock ownership was reported by three Westlake funds and related entities as of September 30, 2026. Westlake BioPartners Fund I, L.P. directly held 5,944,009 shares (9.0%), Westlake BioPartners Fund II, L.P. directly held 5,160,847 shares (7.8%), and Westlake BioPartners Opportunity Fund I, L.P. directly held 2,094,813 shares (3.2%).
Dr. Beth C. Seidenberg, the sole managing director of the funds’ general partners, reported beneficial ownership of 13,199,669 shares (19.9%) through the funds. The general partners and Seidenberg may be deemed to have voting and dispositive power over shares held directly by the funds.
Key Figures
Fund I shares directly held:5,944,009 sharesFund II shares directly held:5,160,847 sharesOpportunity Fund I shares directly held:2,094,813 shares+1 more
4 metrics
Fund I shares directly held5,944,009 shares9.0% of the class
Fund II shares directly held5,160,847 shares7.8% of the class
Opportunity Fund I shares directly held2,094,813 shares3.2% of the class
Dr. Beth C. Seidenberg beneficially owned shares13,199,669 shares19.9% of the class
Key Terms
beneficially owned, sole voting power, sole dispositive power
3 terms
beneficially ownedfinancial
"Amount beneficially owned"
Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.
sole voting powerfinancial
"may be deemed to have sole voting power"
Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.
sole dispositive powerfinancial
"may be deemed to have sole dispositive power"
Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
How many LTGO shares did Dr. Beth C. Seidenberg report as beneficially owned?
Dr. Beth C. Seidenberg reported beneficial ownership of 13,199,669 shares, or 19.9%, as of September 30, 2026. The shares were held directly by Westlake BioPartners Fund I, L.P., Westlake BioPartners Fund II, L.P., and Westlake BioPartners Opportunity Fund I, L.P.
How many LTGO shares did each Westlake fund directly hold?
Westlake BioPartners Fund I, L.P. directly held 5,944,009 shares (9.0%); Westlake BioPartners Fund II, L.P. directly held 5,160,847 shares (7.8%); and Westlake BioPartners Opportunity Fund I, L.P. directly held 2,094,813 shares (3.2%).
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
Latigo Biotherapeutics, Inc.
(Name of Issuer)
Common Stock, par value $0.0001 per share
(Title of Class of Securities)
517954103
(CUSIP Number)
09/30/2026
(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):
517954103
1
Names of Reporting Persons
Westlake BioPartners Fund I, 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
5,944,009.00
6
Shared Voting Power
5,944,009.00
7
Sole Dispositive Power
5,944,009.00
8
Shared Dispositive Power
5,944,009.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
5,944,009.00
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)
9.0 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: Row 5 - 5,944,009 shares, except that Westlake BioPartners GP I, LLC ("Westlake GP I"), the general partner of Westlake BioPartners Fund I, L.P. ("Westlake Fund I"), may be deemed to have sole voting power, and Dr. Beth C. Seidenberg ("Seidenberg"), the sole managing director of Westlake GP I, may be deemed to have sole power to vote these shares.
Row 7 - 5,944,009 shares, except that Westlake GP I, the general partner of Westlake Fund I, may be deemed to have sole dispositive power, and Seidenberg, the sole managing director of Westlake GP I, may be deemed to have sole power to dispose of these shares.
SCHEDULE 13G
CUSIP Number(s):
517954103
1
Names of Reporting Persons
Westlake BioPartners GP I, 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
5,944,009.00
6
Shared Voting Power
5,944,009.00
7
Sole Dispositive Power
5,944,009.00
8
Shared Dispositive Power
5,944,009.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
5,944,009.00
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)
9.0 %
12
Type of Reporting Person (See Instructions)
OO
Comment for Type of Reporting Person: Row 5 - 5,944,009 shares, all of which are owned directly by Westlake Fund I. Westlake GP I, the general partner of Westlake Fund I, may be deemed to have sole voting power, and Seidenberg, the sole managing director of Westlake GP I, may be deemed to have sole power to vote these shares.
Row 7 - 5,944,009 shares, all of which are owned directly by Westlake Fund I. Westlake GP I, the general partner of Westlake Fund I, may be deemed to have sole dispositive power, and Seidenberg, the sole managing director of Westlake GP I, may be deemed to have sole power to dispose of these shares.
SCHEDULE 13G
CUSIP Number(s):
517954103
1
Names of Reporting Persons
Westlake BioPartners Fund II, 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
5,160,847.00
6
Shared Voting Power
5,160,847.00
7
Sole Dispositive Power
5,160,847.00
8
Shared Dispositive Power
5,160,847.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
5,160,847.00
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)
7.8 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: Row 5 - 5,160,847 shares, except that Westlake BioPartners GP II, LLC ("Westlake GP II"), the general partner of Westlake BioPartners Fund II, L.P. ("Westlake Fund II"), may be deemed to have sole voting power, and Seidenberg, the sole managing director of Westlake GP II, may be deemed to have sole power to vote these shares.
Row 7 - 5,160,847 shares, except that Westlake GP II, the general partner of Westlake Fund II, may be deemed to have sole dispositive power, and Seidenberg, the sole managing director of Westlake GP II, may be deemed to have sole power to dispose of these shares.
SCHEDULE 13G
CUSIP Number(s):
517954103
1
Names of Reporting Persons
Westlake BioPartners GP II, 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
5,160,847.00
6
Shared Voting Power
5,160,847.00
7
Sole Dispositive Power
5,160,847.00
8
Shared Dispositive Power
5,160,847.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
5,160,847.00
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)
7.8 %
12
Type of Reporting Person (See Instructions)
OO
Comment for Type of Reporting Person: Row 5 - 5,160,847 shares, all of which are owned directly by Westlake Fund II. Westlake GP II, the general partner of Westlake Fund II, may be deemed to have sole voting power, and Seidenberg, the sole managing director of Westlake GP II, may be deemed to have shared power to vote these shares.
Row 7 - 5,160,847 shares, all of which are owned directly by Westlake Fund II. Westlake GP II, the general partner of Westlake Fund II, may be deemed to have sole dispositive power, and Seidenberg, the sole managing director of Westlake GP II, may be deemed to have shared power to dispose of these shares.
SCHEDULE 13G
CUSIP Number(s):
517954103
1
Names of Reporting Persons
Westlake BioPartners Opportunity Fund I, 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
2,094,813.00
6
Shared Voting Power
2,094,813.00
7
Sole Dispositive Power
2,094,813.00
8
Shared Dispositive Power
2,094,813.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,094,813.00
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)
3.2 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: Row 5 - 2,094,813 shares, except that Westlake BioPartners Opportunity GP I, LLC ("Westlake Opportunity GP I"), the general partner of Westlake BioPartners Opportunity Fund I, L.P. ("Westlake Opportunity Fund I"), may be deemed to have sole voting power, and Seidenberg, the sole managing director of Westlake Opportunity GP I, may be deemed to have sole power to vote these shares.
Row 7 - 2,094,813 shares, except that Westlake Opportunity GP I, the general partner of Westlake Opportunity Fund I, may be deemed to have sole dispositive power, and Seidenberg, the sole managing director of Westlake Opportunity GP I, may be deemed to have sole power to dispose of these shares.
SCHEDULE 13G
CUSIP Number(s):
517954103
1
Names of Reporting Persons
Westlake BioPartners Opportunity GP I, 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
2,094,813.00
6
Shared Voting Power
2,094,813.00
7
Sole Dispositive Power
2,094,813.00
8
Shared Dispositive Power
2,094,813.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,094,813.00
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)
3.2 %
12
Type of Reporting Person (See Instructions)
OO
Comment for Type of Reporting Person: Row 5 - 2,094,813 shares, all of which are owned directly by Westlake Opportunity Fund I. Westlake Opportunity GP I, the general partner of Westlake Opportunity Fund I, may be deemed to have sole voting power, and Seidenberg, the sole managing director of Westlake Opportunity GP I, may be deemed to have sole power to vote these shares.
Row 7 - 2,094,813 shares, all of which are owned directly by Westlake Opportunity Fund I. Westlake Opportunity GP I, the general partner of Westlake Opportunity Fund I, may be deemed to have sole dispositive power, and Seidenberg, the sole managing director of Westlake Opportunity GP I, may be deemed to have sole power to dispose of these shares.
SCHEDULE 13G
CUSIP Number(s):
517954103
1
Names of Reporting Persons
Dr. Beth C. Seidenberg
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
13,199,669.00
6
Shared Voting Power
13,199,669.00
7
Sole Dispositive Power
13,199,669.00
8
Shared Dispositive Power
13,199,669.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
13,199,669.00
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)
19.9 %
12
Type of Reporting Person (See Instructions)
IN
Comment for Type of Reporting Person: Row 5 - 13,199,669 shares, of which 5,944,009 shares are held directly by Westlake Fund I, 5,160,847 shares are held directly by Westlake Fund II and 2,094,813 shares are held directly by Westlake Opportunity Fund I. Westlake GP I is the general partner of Westlake Fund I, Westlake GP II is the general partner of Westlake Fund II and Westlake Opportunity GP I is the general partner of Westlake Opportunity Fund I. Seidenberg, as the sole managing director of each of Westlake GP I, Westlake GP II and Westlake Opportunity GP I, may be deemed to have sole voting power over the shares held directly by each of Westlake Fund I, Westlake Fund II and Westlake Opportunity Fund I.
Row 7 - 13,199,669 shares, of which 5,944,009 shares are held directly by Westlake Fund I, 5,160,847 shares are held directly by Westlake Fund II and 2,094,813 shares are held directly by Westlake Opportunity Fund I. Westlake GP I is the general partner of Westlake Fund I, Westlake GP II is the general partner of Westlake Fund II and Westlake Opportunity GP I is the general partner of Westlake Opportunity Fund I. Seidenberg, as the sole managing director of each of Westlake GP I, Westlake GP II and Westlake Opportunity GP I, may be deemed to have sole dispositive power over the shares held directly by each of Westlake Fund I, Westlake Fund II and Westlake Opportunity Fund I.
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Latigo Biotherapeutics, Inc.
(b)
Address of issuer's principal executive offices:
1300 Rancho Conejo Boulevard, Suite 305 Thousand Oaks, CA 91320
Item 2.
(a)
Name of person filing:
This Statement is being filed by Westlake BioPartners Fund I, L.P. ("Westlake Fund I"), Westlake BioPartners GP I, LLC ("Westlake GP I"), Westlake BioPartners Fund II, L.P. ("Westlake Fund II"), Westlake BioPartners GP II, LLC ("Westlake GP II"), Westlake BioPartners Opportunity Fund I, L.P. ("Westlake Opportunity Fund I"), Westlake BioPartners Opportunity GP I, LLC ("Westlake Opportunity GP I") and Dr. Beth C. Seidenberg ("Seidenberg") (collectively, the "Reporting Persons").
(b)
Address or principal business office or, if none, residence:
The address of the principal business office of each Reporting Person is c/o Westlake BioPartners, LLC, 3075 Townsgate Road, Suite 140, Westlake Village, California 91361.
(c)
Citizenship:
Each of Westlake GP I, Westlake GP II and Westlake Opportunity GP I is a limited liability company organized under the laws of the State of Delaware. Each of Westlake Fund I, Westlake Fund II and Westlake Opportunity Fund I is a limited partnership organized under the laws of the State of Delaware. Seidenberg is a citizen of the United States of America.
(d)
Title of class of securities:
Common Stock, par value $0.0001 per share
(e)
CUSIP Number(s):
517954103
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:
See Row 9 of the cover page for each Reporting Person.*
(b)
Percent of class:
See Row 11 of the cover page for each Reporting Person.*
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
See Row 5 of the cover page for each Reporting Person.*
(ii) Shared power to vote or to direct the vote:
See Row 6 of the cover page for each Reporting Person.*
(iii) Sole power to dispose or to direct the disposition of:
See Row 7 of the cover page for each Reporting Person.*
(iv) Shared power to dispose or to direct the disposition of:
See Row 8 of the cover page for each Reporting Person.*
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.
Under certain circumstances set forth in the limited partnership agreement of each of Westlake Fund I, Westlake Fund II and Westlake Opportunity Fund I and the limited liability company agreement of each of Westlake GP I, Westlake GP II and Westlake Opportunity GP I, the general and limited partners or members, as the case may be, of each of such entities may be deemed to have the right to receive dividends from, or the proceeds from, the sale of securities of the Issuer owned by each such entity of which they are a partner or member, as the case may be.
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.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
Not Applicable
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.
Westlake BioPartners Fund I, L.P.
Signature:
Westlake BioPartners GP I, LLC
Name/Title:
General Partner
Date:
10/27/2026
Signature:
/s/ Jennifer L. Kercher
Name/Title:
Jennifer L. Kercher/Attorney-in-Fact*
Date:
10/27/2026
Westlake BioPartners GP I, LLC
Signature:
/s/ Jennifer L. Kercher
Name/Title:
Jennifer L. Kercher/Attorney-in-Fact*
Date:
10/27/2026
Westlake BioPartners Fund II, L.P.
Signature:
Westlake BioPartners GP II, LLC
Name/Title:
General Partner
Date:
10/27/2026
Signature:
/s/ Jennifer L. Kercher
Name/Title:
Jennifer L. Kercher/Attorney-in-Fact*
Date:
10/27/2026
Westlake BioPartners GP II, LLC
Signature:
/s/ Jennifer L. Kercher
Name/Title:
Jennifer L. Kercher/Attorney-in-Fact*
Date:
10/27/2026
Westlake BioPartners Opportunity Fund I, L.P.
Signature:
Westlake BioPartners Opportunity GP I, LLC
Name/Title:
General Partner
Date:
10/27/2026
Signature:
/s/ Jennifer L. Kercher
Name/Title:
Jennifer L. Kercher/Attorney-in-Fact*
Date:
10/27/2026
Westlake BioPartners Opportunity GP I, LLC
Signature:
/s/ Jennifer L. Kercher
Name/Title:
Jennifer L. Kercher/Attorney-in-Fact*
Date:
10/27/2026
Dr. Beth C. Seidenberg
Signature:
/s/ Jennifer L. Kercher
Name/Title:
Jennifer L. Kercher/Attorney-in-Fact*
Date:
10/27/2026
Exhibit Information
EXHIBIT INDEX
Exhibit Description
1 Joint Filing Agreement
2 Power of Attorney - Westlake BioPartners Fund I, L.P. and Westlake BioPartners GP I, LLC
3 Power of Attorney - Westlake BioPartners Opportunity Fund I, L.P. and Westlake BioPartners
Opportunity GP I, LLC
4 Power of Attorney - Westlake BioPartners Fund II, L.P. and Westlake BioPartners GP II, LLC
