SEC Form 4 · accession 0001184592-26-000005

Latigo Biotherapeutics, Inc. · LTGO

Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗

Reporting owner

Beth C Seidenberg

Director · 10% Owner

Period of report

Aug 10, 2026

Accepted (ET)

Aug 10, 2026 · 8:00 pm EDT

Rule 10b5-1 plan

box not checked

Issuer CIK

0002056611

Table I — non-derivative securities

Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F1,F2	Aug 10, 2026	C	938,979	—	A	1,368,532	I	See footnote
Common Stock^F1,F2	Aug 10, 2026	C	3,547,842	—	A	4,916,374	I	See footnote
Common Stock^F1,F2	Aug 10, 2026	C	1,027,635	—	A	5,944,009	I	See footnote
Common Stock^F1,F3	Aug 10, 2026	C	3,464,072	—	A	3,510,927	I	See footnote
Common Stock^F1,F3	Aug 10, 2026	C	1,484,401	—	A	4,995,328	I	See footnote
Common Stock^F4,F3	Aug 10, 2026	C	165,519	—	A	5,160,847	I	See footnote
Common Stock^F1,F5	Aug 10, 2026	C	2,066,857	—	A	2,094,813	I	See footnote

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	D/I
Series Seed Convertible Stock^F1,F2	—	Aug 10, 2026	C	938,979	D	—	—	Common Stock	938,979	I
Series A Convertible Preferred Stock^F1,F2	—	Aug 10, 2026	C	3,547,842	D	—	—	Common Stock	3,547,842	I
Series A-2 Convertible Preferred Stock^F1,F2	—	Aug 10, 2026	C	1,027,635	D	—	—	Common Stock	1,027,635	I
Series A-2 Convertible Preferred Stock^F1,F3	—	Aug 10, 2026	C	3,464,072	D	—	—	Common Stock	3,464,072	I
Series B Convertible Preferred Stock^F1,F3	—	Aug 10, 2026	C	1,484,401	D	—	—	Common Stock	1,484,401	I
Series A-2 Convertible Preferred Stock^F1,F5	—	Aug 10, 2026	C	2,066,857	D	—	—	Common Stock	2,066,857	I
Convertible Promissory Note^F4,F3	—	Aug 10, 2026	C	165,519	D	—	—	Common Stock	165,519	I

Explanation of responses

F1Each share of Series Seed Convertible Preferred Stock, Series A Convertible Preferred Stock, Series A-2 Convertible Preferred Stock and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") converted automatically into 1 share of Common Stock upon the closing of the Issuer's initial public offering without payment of further consideration. Share numbers give effect to such conversion. The Preferred Stock had no expiration date.
F2Shares held directly by Westlake BioPartners Fund I, L.P. (Fund I). The general partner of Fund I is Westlake BioPartners GP I, LLC (GP I). GP I may be deemed to share voting and dispositive power with regard to the shares held directly by Fund I. The Reporting Person is the sole managing director of GP I and has voting and dispositive power over the shares held by Fund I. The Reporting Person disclaims Section 16 beneficial ownership of the shares reported herein except to the extent of her pecuniary interest therein, if any, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of any of the reported shares for purposes of Section 16 or any other purpose.
F3Shares held directly by Westlake BioPartners Fund II, L.P. (Fund II). The general partner of Fund II is Westlake BioPartners GP II, LLC (GP II). GP II may be deemed to share voting and dispositive power with regard to the shares held directly by Fund II. The Reporting Person is the sole managing director of GP II and has voting and dispositive power over the shares held by Fund II. The Reporting Person disclaims Section 16 beneficial ownership of the shares reported herein except to the extent of her pecuniary interest therein, if any, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of any of the reported shares for purposes of Section 16 or any other purpose.
F4Reflects a convertible note that is convertible into shares of Common Stock of the Issuer. The convertible note has a maturity date of June 17, 2027. The principal amount of the convertible note together with any accrued but unpaid interest automatically converted into shares of Common Stock of the Issuer upon the closing of the Issuer's initial public offering at a conversion price equal to the initial public offering price of the Issuer's common stock.
F5Shares held directly by Westlake BioPartners Opportunity Fund I, L.P. (Opportunity Fund). The general partner of Opportunity Fund is Westlake BioPartners Opportunity GP I, LLC (Opportunity GP). Opportunity GP may be deemed to share voting and dispositive power with regard to the shares held directly by Opportunity Fund. The Reporting Person is the sole managing director of Opportunity GP and has voting and dispositive power over the shares held by Opportunity Fund. The Reporting Person disclaims Section 16 beneficial ownership of the shares reported herein except to the extent of her pecuniary interest therein, if any, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of any of the reported shares for purposes of Section 16 or any other purpose.