Faheem Hasnain - 19 Mar 2026 Form 4 Insider Report for Gossamer Bio, Inc. (GOSS)

Reporting relationship: President & CEO, Director
Issuer ticker: GOSS
Reported as of: 19 Mar 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 20 Mar 2026, 16:17:44 UTC
Prior SEC filing: 05 Jan 2026
Next SEC filing: 04 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Jeff Boerneke, Attorney-in-Fact

Key filing fact

Faheem Hasnain filed Form 4 for Gossamer Bio, Inc. (GOSS) on 20 Mar 2026.

Key facts

This page summarizes Faheem Hasnain's Form 4 filing for Gossamer Bio, Inc. (GOSS).
20 reported transactions and 20 derivative rows are listed below.
Accepted by SEC: 20 Mar 2026, 16:17.

Change

Previous filing in this sequence was filed on 05 Jan 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 0001352620 Primary reporting owner

Hasnain Faheem

Relationship: President & CEO, Director
Address: 3115 MERRYFIELD ROW, SUITE 120, SAN DIEGO
Signature: /s/ Jeff Boerneke, Attorney-in-Fact
Signature date: 20 Mar 2026

Reported derivative securities

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

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -1,680,000
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,680,000
Exercise price: $2.88
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -1,540,000
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,540,000
Exercise price: $1.13
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -1,312,500
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,312,500
Exercise price: $0.9700
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -437,500
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 437,500
Exercise price: $0.8380
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -544,500
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 544,500
Exercise price: $1.21
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -544,500
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 544,500
Exercise price: $2.16
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -650,000
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 650,000
Exercise price: $11.94
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -325,000
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 325,000
Exercise price: $9.79
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -47,000
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 47,000
Exercise price: $12.10
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -43,500
Change %: -100%
Price
Shares after: 0
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 43,500
Exercise price: $22.10
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +1,680,000
Change %
Price
Shares after: 1,680,000
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,680,000
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +1,540,000
Change %
Price
Shares after: 1,540,000
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,540,000
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +1,312,500
Change %
Price
Shares after: 1,312,500
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,312,500
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +437,500
Change %
Price
Shares after: 437,500
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 437,500
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +544,500
Change %
Price
Shares after: 544,500
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 544,500
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +544,500
Change %
Price
Shares after: 544,500
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 544,500
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +650,000
Change %
Price
Shares after: 650,000
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 650,000
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +325,000
Change %
Price
Shares after: 325,000
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 325,000
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +47,000
Change %
Price
Shares after: 47,000
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 47,000
Exercise price: $0.4500
Footnotes: F1, F2

GOSS transaction Derivative

Stock Option (Right to Buy)

Award

Transaction value
Shares: +43,500
Change %
Price
Shares after: 43,500
Date: 19 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 43,500
Exercise price: $0.4500
Footnotes: F1, 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

Effective as of March 19, 2026 (the "Repricing Date"), the Issuer approved a one-time repricing of certain outstanding stock options (the "Repriced Options") granted under the Issuer's 2019 Incentive Award Plan (the "2019 Plan"), which reduced the per share exercise price of each Repriced Option to $0.45 (the "Option Repricing"). Except as modified by the Option Repricing, all other terms and conditions of the Repriced Options, including, without limitation, any provisions with respect to vesting and term of the Repriced Options, remain in full force and effect.

Footnote F2

This stock option award was issued pursuant to the 2019 Plan and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.