Robert Paul Smith Jr. - 24 Aug 2026 Form 4 Insider Report for Gossamer Bio, Inc. (GOSS)

Reporting relationship: Chief Commercial Officer
Issuer ticker: GOSS
Reported as of: 24 Aug 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 26 Aug 2026, 18:11:29 UTC
Prior SEC filing: 20 Mar 2026
Source filing: View source filing
Reporting owner signature: /s/ Jeff Boerneke, Attorney-in-Fact

Key filing fact

Robert Paul Smith Jr. filed Form 4 for Gossamer Bio, Inc. (GOSS) on 26 Aug 2026.

Key facts

This page summarizes Robert Paul Smith Jr.'s Form 4 filing for Gossamer Bio, Inc. (GOSS).
1 reported transaction and 1 derivative row are listed below.
Accepted by SEC: 26 Aug 2026, 18:11.

Change

Previous filing in this sequence was filed on 20 Mar 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 0002003059 Primary reporting owner

Smith Robert Paul JR

Relationship: Chief Commercial Officer
Address: 3115 MERRYFIELD ROW, SUITE 120, SAN DIEGO
Signature: /s/ Jeff Boerneke, Attorney-in-Fact
Signature date: 26 Aug 2026

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
Shares: +5,800,051
Change %
Price: $0.000000^*
Shares after: 5,800,051
Date: 24 Aug 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 5,800,051
Exercise price: $0.1750
Footnotes: F1

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

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

50% of the total number of shares subject to the option will vest upon FDA approval of seralutinib, and 1/24th of the remaining 50% of the total number of shares subject to the option will vest on the last day of each one-month period after such FDA approval, in each case subject to the Reporting Person's continuous service to the Issuer on each such vesting date. To the extent FDA approval of seralutinib does not occur on or prior to the date that is two years following the grant date of the option, 1/24th of the total number of shares subject to the option will vest on the last day of each one-month period following the date that is two years following the grant date of the option, subject to the Reporting Person's continuous service to the Issuer on each such vesting date.