Beth C. Seidenberg - 10 Aug 2026 Form 4 Insider Report for Latigo Biotherapeutics, Inc. (LTGO)

Reporting relationship
Director, 10%+ Owner
Issuer ticker
LTGO
Reported as of
10 Aug 2026
Net transaction value
$0
Source evidence Original filing metadata and source links for verification. 4 source fields
SEC form
4
Accepted by SEC
10 Aug 2026, 20:00:06 UTC
Prior SEC filing
06 Aug 2026
Source filing
View source filing
Reporting owner 1 detail
Reporting owner signature
/s/ Sabrina Nieder, Attorney-in-Fact

Key filing fact

Beth C. Seidenberg filed Form 4 for Latigo Biotherapeutics, Inc. (LTGO) on 10 Aug 2026.

Key facts

  • This page summarizes Beth C. Seidenberg's Form 4 filing for Latigo Biotherapeutics, Inc. (LTGO).
  • 14 reported transactions and 7 derivative rows are listed below.
  • Accepted by SEC: 10 Aug 2026, 20:00.

Change

  • Previous filing in this sequence was filed on 06 Aug 2026.
  • Current net transaction value: $0.

Research use

  • This tells you what this filing adds before you inspect full transaction and derivative tables.
  • You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001184592 Primary reporting owner

SEIDENBERG BETH C

Relationship
Director, 10%+ Owner
Address
C/O LATIGO BIOTHERAPEUTICS, INC., 1300 RANCHO CONEJO BLVD., SUITE 305, THOUSAND OAKS
Signature
/s/ Sabrina Nieder, Attorney-in-Fact
Signature date
10 Aug 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

LTGO transaction

Common Stock

Conversion of derivative security

Transaction value
Shares
+938,979
Change %
+219%
Price
Shares after
1,368,532
Date
10 Aug 2026
Ownership
See footnote
Footnotes
F1, F2
LTGO transaction

Common Stock

Conversion of derivative security

Transaction value
Shares
+3,547,842
Change %
+259%
Price
Shares after
4,916,374
Date
10 Aug 2026
Ownership
See footnote
Footnotes
F1, F2
LTGO transaction

Common Stock

Conversion of derivative security

Transaction value
Shares
+1,027,635
Change %
+21%
Price
Shares after
5,944,009
Date
10 Aug 2026
Ownership
See footnote
Footnotes
F1, F2
LTGO transaction

Common Stock

Conversion of derivative security

Transaction value
Shares
+3,464,072
Change %
+7393%
Price
Shares after
3,510,927
Date
10 Aug 2026
Ownership
See footnote
Footnotes
F1, F3
LTGO transaction

Common Stock

Conversion of derivative security

Transaction value
Shares
+1,484,401
Change %
+42%
Price
Shares after
4,995,328
Date
10 Aug 2026
Ownership
See footnote
Footnotes
F1, F3
LTGO transaction

Common Stock

Conversion of derivative security

Transaction value
Shares
+165,519
Change %
+3.3%
Price
Shares after
5,160,847
Date
10 Aug 2026
Ownership
See footnote
Footnotes
F3, F4
LTGO transaction

Common Stock

Conversion of derivative security

Transaction value
Shares
+2,066,857
Change %
+7393%
Price
Shares after
2,094,813
Date
10 Aug 2026
Ownership
See footnote
Footnotes
F1, F5

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

LTGO transaction Derivative

Series Seed Convertible Stock

Conversion of derivative security

Transaction value
Shares
-938,979
Change %
-100%
Price
Shares after
0
Date
10 Aug 2026
Ownership
See footnote
Underlying class
Common Stock
Underlying amount
938,979
Exercise price
Footnotes
F1, F2
LTGO transaction Derivative

Series A Convertible Preferred Stock

Conversion of derivative security

Transaction value
Shares
-3,547,842
Change %
-100%
Price
Shares after
0
Date
10 Aug 2026
Ownership
See footnote
Underlying class
Common Stock
Underlying amount
3,547,842
Exercise price
Footnotes
F1, F2
LTGO transaction Derivative

Series A-2 Convertible Preferred Stock

Conversion of derivative security

Transaction value
Shares
-1,027,635
Change %
-100%
Price
Shares after
0
Date
10 Aug 2026
Ownership
See footnote
Underlying class
Common Stock
Underlying amount
1,027,635
Exercise price
Footnotes
F1, F2
LTGO transaction Derivative

Series A-2 Convertible Preferred Stock

Conversion of derivative security

Transaction value
Shares
-3,464,072
Change %
-100%
Price
Shares after
0
Date
10 Aug 2026
Ownership
See footnote
Underlying class
Common Stock
Underlying amount
3,464,072
Exercise price
Footnotes
F1, F3
LTGO transaction Derivative

Series B Convertible Preferred Stock

Conversion of derivative security

Transaction value
Shares
-1,484,401
Change %
-100%
Price
Shares after
0
Date
10 Aug 2026
Ownership
See footnote
Underlying class
Common Stock
Underlying amount
1,484,401
Exercise price
Footnotes
F1, F3
LTGO transaction Derivative

Series A-2 Convertible Preferred Stock

Conversion of derivative security

Transaction value
Shares
-2,066,857
Change %
-100%
Price
Shares after
0
Date
10 Aug 2026
Ownership
See footnote
Underlying class
Common Stock
Underlying amount
2,066,857
Exercise price
Footnotes
F1, F5
LTGO transaction Derivative

Convertible Promissory Note

Conversion of derivative security

Transaction value
Shares
-165,519
Change %
-100%
Price
Shares after
0
Date
10 Aug 2026
Ownership
See footnote
Underlying class
Common Stock
Underlying amount
165,519
Exercise price
Footnotes
F3, F4
* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 5 footnotes

Footnote F1

Each 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.

Footnote F2

Shares 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.

Footnote F3

Shares 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.

Footnote F4

Reflects 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.

Footnote F5

Shares 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.

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