Caryn Peterson - 02 Jan 2026 Form 4 Insider Report for Gossamer Bio, Inc. (GOSS)

Reporting relationship: EVP, Regulatory Affairs
Issuer ticker: GOSS
Reported as of: 02 Jan 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 05 Jan 2026, 16:37:17 UTC
Prior SEC filing: 02 Oct 2025
Next SEC filing: 20 Mar 2026
Source filing: View source filing
Reporting owner signature: /s/ Jeff Boerneke, Attorney-in-Fact

Key filing fact

Caryn Peterson filed Form 4 for Gossamer Bio, Inc. (GOSS) on 05 Jan 2026.

Key facts

This page summarizes Caryn Peterson's Form 4 filing for Gossamer Bio, Inc. (GOSS).
2 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 05 Jan 2026, 16:37.

Change

Previous filing in this sequence was filed on 02 Oct 2025.
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 0001857256 Primary reporting owner

Peterson Caryn

Relationship: EVP, Regulatory Affairs
Address: 3115 MERRYFIELD ROW, SUITE 120, SAN DIEGO
Signature: /s/ Jeff Boerneke, Attorney-in-Fact
Signature date: 05 Jan 2026

Reported non-derivative transactions

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

GOSS transaction

Common Stock

Award

Transaction value: $0
Shares: +84,500
Change %: +48%
Price: $0.000000
Shares after: 259,333
Date: 02 Jan 2026
Ownership: Direct
Footnotes: F1

Reported derivative securities

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

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value: $0
Shares: +506,250
Change %
Price: $0.000000
Shares after: 506,250
Date: 02 Jan 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 506,250
Exercise price: $2.88
Footnotes: F2

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 2 footnotes

Footnote F1

Represents restricted stock unit award, which will vest in four equal annual installments in accordance with the terms of the award and subject to the Reporting Person's continuous service to the Issuer on each vesting date.

Footnote F2

25% of the total number of shares subject to the option will vest on January 2, 2027 and 1/48th of the total number of shares subject to the option vest on the last day of each one-month period thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date.