Gossamer Bio, Inc. SEC filings GOSS
Gossamer Bio, Inc. has 484 filings in SEC EDGAR's recent list, going back to Jan 19, 2018. Its latest annual report, Form ARS, was filed on Apr 24, 2026 for the period ended Apr 24, 2026. The latest quarterly report (Form 10-Q) was filed on Aug 13, 2026, covering the quarter ended Jun 30, 2026. The most recent current report (Form 8-K) was filed on Oct 28, 2026 (shareholder vote results). The company's fiscal year ends on December 31.
| Form | Description | Filed | Period |
|---|---|---|---|
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Oct 29, 2026 | — |
| 8-K |
Current report
Shareholder vote results
|
Oct 28, 2026 | Oct 27, 2026 |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Oct 8, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Sep 28, 2026 | — |
| 8-K |
Current report
Other events
|
Sep 28, 2026 | Sep 25, 2026 |
| 4 | Insider transaction | Sep 25, 2026 | Sep 23, 2026 |
| 4 | Insider transaction | Sep 25, 2026 | Sep 23, 2026 |
| 4 | Insider transaction | Sep 25, 2026 | Sep 23, 2026 |
| 4 | Insider transaction | Sep 25, 2026 | Sep 23, 2026 |
| 4 | Insider transaction | Sep 25, 2026 | Sep 23, 2026 |
| 4 | Insider transaction | Sep 25, 2026 | Sep 23, 2026 |
| 4 | Insider transaction | Sep 25, 2026 | Sep 23, 2026 |
| 8-K |
Current report
Other events
|
Sep 23, 2026 | Sep 23, 2026 |
| 3 | Initial insider ownership | Sep 22, 2026 | Sep 16, 2026 |
| DEF 14A | Proxy statement | Sep 16, 2026 | Oct 27, 2026 |
| 8-K |
Current report
Officer or director change
|
Sep 16, 2026 | Sep 16, 2026 |
| 8-K |
Current report
Change to shareholder rights, Bylaw or fiscal year change, Other events
|
Sep 11, 2026 | Sep 10, 2026 |
| 8-K |
Current report
Other events
|
Sep 9, 2026 | Sep 9, 2026 |
| D | Filing | Sep 4, 2026 | — |
| PRE 14A | Preliminary proxy statement | Sep 3, 2026 | Sep 3, 2026 |
| 8-K |
Current report
Bylaw or fiscal year change
|
Sep 3, 2026 | Sep 3, 2026 |
| 4 | Insider transaction | Aug 26, 2026 | Aug 24, 2026 |
| 4 | Insider transaction | Aug 26, 2026 | Aug 24, 2026 |
| 4 | Insider transaction | Aug 26, 2026 | Aug 24, 2026 |
| 4 | Insider transaction | Aug 26, 2026 | Aug 24, 2026 |
| 4 | Insider transaction | Aug 26, 2026 | Aug 24, 2026 |
| 8-K |
Current report
Bylaw or fiscal year change
|
Aug 26, 2026 | Aug 24, 2026 |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Aug 24, 2026 | — |
| 8-K |
Current report
Material agreement, Unregistered share sale, Bylaw or fiscal year change, Regulation FD disclosure
|
Aug 21, 2026 | Aug 20, 2026 |
| 8-K |
Current report
Results of operations
|
Aug 13, 2026 | Aug 13, 2026 |
| 10-Q | Quarterly report | Aug 13, 2026 | Jun 30, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | Jul 29, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jul 29, 2026 | — |
| 8-K |
Current report
Material agreement, Agreement ended, Results of operations, Regulation FD disclosure, Other events
|
Jul 27, 2026 | Jul 23, 2026 |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Jul 24, 2026 | — |
| 8-K |
Current report
Officer or director change, Bylaw or fiscal year change, Shareholder vote results
|
Jul 15, 2026 | Jul 14, 2026 |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Jul 1, 2026 | — |
| 8-K |
Current report
Regulation FD disclosure
|
Jul 1, 2026 | Jul 1, 2026 |
| 8-K |
Current report
Regulation FD disclosure
|
Jun 17, 2026 | Jun 17, 2026 |
| SCHEDULE 13D | Ownership over 5% (active) | Jun 11, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Jun 11, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Jun 11, 2026 | — |
| DEF 14A | Proxy statement | Jun 9, 2026 | Jul 14, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | Jun 9, 2026 | — |
| 4 | Insider transaction | Jun 5, 2026 | Jun 4, 2026 |
| 4 | Insider transaction | Jun 5, 2026 | Jun 4, 2026 |
| 4 | Insider transaction | Jun 5, 2026 | Jun 4, 2026 |
| 4 | Insider transaction | Jun 5, 2026 | Jun 4, 2026 |
| 4 | Insider transaction | Jun 5, 2026 | Jun 4, 2026 |
| 4 | Insider transaction | Jun 5, 2026 | Jun 4, 2026 |
| 8-K |
Current report
Material agreement, Agreement ended, New debt, Unregistered share sale, Regulation FD disclosure
|
Jun 5, 2026 | Jun 3, 2026 |
| 8-K |
Current report
Shareholder vote results
|
Jun 5, 2026 | Jun 4, 2026 |
| 8-K |
Current report
Other events
|
Jun 2, 2026 | Jun 2, 2026 |
| PRE 14A | Preliminary proxy statement | May 18, 2026 | May 18, 2026 |
| DEFA14A | Additional proxy material | May 18, 2026 | — |
| 8-K |
Current report
Material agreement, Results of operations, Officer or director change, Regulation FD disclosure, Other events
|
May 18, 2026 | May 18, 2026 |
| 10-Q | Quarterly report | May 15, 2026 | Mar 31, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | May 14, 2026 | — |
| ARS | Annual report to shareholders | Apr 24, 2026 | Apr 24, 2026 |
| DEFA14A | Additional proxy material | Apr 24, 2026 | — |
| DEF 14A | Proxy statement | Apr 24, 2026 | Apr 24, 2026 |
| 8-K |
Current report
Listing notice
|
Apr 9, 2026 | Apr 8, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Mar 27, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Mar 24, 2026 | — |
| 4 | Insider transaction | Mar 20, 2026 | Mar 19, 2026 |
| 4 | Insider transaction | Mar 20, 2026 | Mar 19, 2026 |
| 4 | Insider transaction | Mar 20, 2026 | Mar 19, 2026 |
| 4 | Insider transaction | Mar 20, 2026 | Mar 19, 2026 |
| 4 | Insider transaction | Mar 20, 2026 | Mar 19, 2026 |
| 4 | Insider transaction | Mar 20, 2026 | Mar 19, 2026 |
| EFFECT | Filing | Mar 18, 2026 | — |
| POS AM | Filing | Mar 17, 2026 | — |
| 8-K |
Current report
Results of operations
|
Mar 17, 2026 | Mar 17, 2026 |
| 10-K | Annual report | Mar 17, 2026 | Dec 31, 2025 |
| POSASR | Filing | Mar 17, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Mar 2, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Feb 24, 2026 | — |
| 8-K |
Current report
Other events
|
Feb 23, 2026 | Feb 23, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 17, 2026 | — |
| S-3ASR | Automatic shelf registration | Jan 28, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jan 21, 2026 | — |
| 4 | Insider transaction | Jan 5, 2026 | Jan 2, 2026 |
| 4 | Insider transaction | Jan 5, 2026 | Jan 2, 2026 |
| 4 | Insider transaction | Jan 5, 2026 | Jan 2, 2026 |
| 4 | Insider transaction | Jan 5, 2026 | Jan 2, 2026 |
| 4 | Insider transaction | Jan 5, 2026 | Jan 2, 2026 |
| 4 | Insider transaction | Jan 5, 2026 | Jan 2, 2026 |
| 8-K |
Current report
Results of operations
|
Nov 5, 2025 | Nov 5, 2025 |
| 10-Q | Quarterly report | Nov 5, 2025 | Sep 30, 2025 |
| 4 | Insider transaction | Oct 2, 2025 | Oct 1, 2025 |
| 4 | Insider transaction | Oct 2, 2025 | Oct 1, 2025 |
| 4 | Insider transaction | Oct 2, 2025 | Oct 1, 2025 |
| 4 | Insider transaction | Oct 2, 2025 | Oct 1, 2025 |
| 4 | Insider transaction | Oct 2, 2025 | Oct 1, 2025 |
| 4 | Insider transaction | Oct 2, 2025 | Oct 1, 2025 |
| 8-K |
Current report
Unregistered share sale
|
Sep 25, 2025 | Sep 24, 2025 |
| 4 | Insider transaction | Aug 20, 2025 | Aug 19, 2025 |
| 8-K |
Current report
Results of operations
|
Aug 5, 2025 | Aug 5, 2025 |
| 10-Q | Quarterly report | Aug 5, 2025 | Jun 30, 2025 |
| SCHEDULE 13G | Ownership over 5% (passive) | Jul 29, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Jul 17, 2025 | — |
| 4 | Insider transaction | Jun 26, 2025 | Jun 25, 2025 |
| 4 | Insider transaction | Jun 26, 2025 | Jun 25, 2025 |
| 4 | Insider transaction | Jun 26, 2025 | Jun 25, 2025 |
| 4 | Insider transaction | Jun 26, 2025 | Jun 25, 2025 |
| 4 | Insider transaction | Jun 26, 2025 | Jun 25, 2025 |
| 4 | Insider transaction | Jun 26, 2025 | Jun 25, 2025 |
| 8-K |
Current report
Officer or director change, Shareholder vote results
|
Jun 25, 2025 | Jun 25, 2025 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Jun 16, 2025 | Jun 16, 2025 |
| 8-K |
Current report
Results of operations
|
May 15, 2025 | May 15, 2025 |
| 10-Q | Quarterly report | May 15, 2025 | Mar 31, 2025 |
| ARS | Annual report to shareholders | Apr 29, 2025 | Apr 28, 2025 |
| DEFA14A | Additional proxy material | Apr 29, 2025 | — |
| DEF 14A | Proxy statement | Apr 29, 2025 | Apr 28, 2025 |
| S-8 | Employee stock plan registration | Mar 13, 2025 | — |
| 8-K |
Current report
Results of operations
|
Mar 13, 2025 | Mar 13, 2025 |
| 10-K | Annual report | Mar 13, 2025 | Dec 31, 2024 |
| 4 | Insider transaction | Mar 6, 2025 | Mar 4, 2025 |
| 4 | Insider transaction | Mar 6, 2025 | Mar 4, 2025 |
| 4 | Insider transaction | Mar 6, 2025 | Mar 4, 2025 |
| 4 | Insider transaction | Mar 6, 2025 | Mar 4, 2025 |
| 4 | Insider transaction | Mar 6, 2025 | Mar 4, 2025 |
| 4 | Insider transaction | Mar 6, 2025 | Mar 4, 2025 |
| 8-K |
Current report
Other events
|
Feb 19, 2025 | Feb 19, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 12, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Feb 5, 2025 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jan 30, 2025 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Nov 12, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Nov 12, 2024 | — |
| 8-K |
Current report
Results of operations
|
Nov 7, 2024 | Nov 7, 2024 |
| 10-Q | Quarterly report | Nov 7, 2024 | Sep 30, 2024 |
| 8-K |
Current report
Listing notice
|
Sep 13, 2024 | Sep 11, 2024 |
| 8-K |
Current report
Results of operations
|
Aug 12, 2024 | Aug 12, 2024 |
| 10-Q | Quarterly report | Aug 12, 2024 | Jun 30, 2024 |
| SC 13G/A | Amended ownership over 5% (passive) | Aug 2, 2024 | — |
| 8-K |
Current report
Other events
|
Jul 18, 2024 | Jul 18, 2024 |
| 4 | Insider transaction | Jun 25, 2024 | Jun 24, 2024 |
| 4 | Insider transaction | Jun 24, 2024 | Jun 21, 2024 |
| 4 | Insider transaction | Jun 20, 2024 | Jun 18, 2024 |
| 4 | Insider transaction | Jun 20, 2024 | Jun 17, 2024 |
| 8-K |
Current report
Shareholder vote results
|
Jun 10, 2024 | Jun 6, 2024 |
| 4 | Insider transaction | Jun 6, 2024 | Jun 6, 2024 |
| 4 | Insider transaction | Jun 6, 2024 | Jun 6, 2024 |
| 4 | Insider transaction | Jun 6, 2024 | Jun 6, 2024 |
| 4 | Insider transaction | Jun 6, 2024 | Jun 6, 2024 |
| 8-K |
Current report
Listing notice
|
May 24, 2024 | May 22, 2024 |
| 8-K |
Current report
Results of operations
|
May 7, 2024 | May 7, 2024 |
| 10-Q | Quarterly report | May 7, 2024 | Mar 31, 2024 |
| 8-K |
Current report
Material agreement, Agreement ended, Unregistered share sale, Other events
|
May 6, 2024 | May 3, 2024 |
| ARS | Annual report to shareholders | Apr 26, 2024 | Apr 26, 2024 |
| DEFA14A | Additional proxy material | Apr 24, 2024 | — |
| DEF 14A | Proxy statement | Apr 24, 2024 | Apr 16, 2024 |
| 4 | Insider transaction | Mar 28, 2024 | Mar 27, 2024 |
| 4 | Insider transaction | Mar 28, 2024 | Mar 27, 2024 |
| 4 | Insider transaction | Mar 28, 2024 | Mar 27, 2024 |
| 4 | Insider transaction | Mar 19, 2024 | Mar 18, 2024 |
| 4 | Insider transaction | Mar 19, 2024 | Mar 18, 2024 |
| 4 | Insider transaction | Mar 12, 2024 | Mar 11, 2024 |
| 4 | Insider transaction | Mar 12, 2024 | Mar 11, 2024 |
| 3 | Initial insider ownership | Mar 12, 2024 | Mar 11, 2024 |
| 3 | Initial insider ownership | Mar 12, 2024 | Mar 11, 2024 |
| 8-K |
Current report
Officer or director change
|
Mar 12, 2024 | Mar 11, 2024 |
| S-8 | Employee stock plan registration | Mar 5, 2024 | — |
| 10-K | Annual report | Mar 5, 2024 | Dec 31, 2023 |
| 8-K |
Current report
Results of operations
|
Mar 5, 2024 | Mar 5, 2024 |
| 8-K |
Current report
Other events
|
Mar 4, 2024 | Mar 4, 2024 |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 14, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 13, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 9, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Feb 9, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Jan 11, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Jan 11, 2024 | — |
| 4 | Insider transaction | Jan 4, 2024 | Jan 2, 2024 |
| 4 | Insider transaction | Jan 4, 2024 | Jan 2, 2024 |
| 4 | Insider transaction | Jan 4, 2024 | Jan 2, 2024 |
| 4 | Insider transaction | Jan 4, 2024 | Jan 2, 2024 |
| 4 | Insider transaction | Jan 4, 2024 | Jan 2, 2024 |
| 4 | Insider transaction | Dec 5, 2023 | Dec 4, 2023 |
| 3 | Initial insider ownership | Dec 5, 2023 | Dec 4, 2023 |
| 4 | Insider transaction | Nov 29, 2023 | Nov 28, 2023 |
| 3 | Initial insider ownership | Nov 29, 2023 | Nov 28, 2023 |
| 8-K |
Current report
Officer or director change
|
Nov 29, 2023 | Nov 28, 2023 |
| 8-K |
Current report
Officer or director change, Bylaw or fiscal year change
|
Nov 27, 2023 | Nov 20, 2023 |
| 4 | Insider transaction | Nov 22, 2023 | Nov 20, 2023 |
| 4 | Insider transaction | Nov 22, 2023 | Nov 20, 2023 |
| 4 | Insider transaction | Nov 22, 2023 | Nov 20, 2023 |
| 4 | Insider transaction | Nov 22, 2023 | Nov 20, 2023 |
| 4 | Insider transaction | Nov 22, 2023 | Nov 20, 2023 |
| 4 | Insider transaction | Nov 17, 2023 | Nov 15, 2023 |
| 4 | Insider transaction | Nov 14, 2023 | Nov 13, 2023 |
| 10-Q | Quarterly report | Nov 9, 2023 | Sep 30, 2023 |
| 8-K |
Current report
Results of operations
|
Nov 9, 2023 | Nov 9, 2023 |
| 8-K |
Current report
Listing notice
|
Oct 20, 2023 | Oct 19, 2023 |
| 8-K |
Current report
Officer or director change
|
Sep 7, 2023 | Sep 6, 2023 |
| EFFECT | Filing | Aug 28, 2023 | — |
| 424B3 | Prospectus | Aug 28, 2023 | — |
| UPLOAD | Letter from the SEC | Aug 24, 2023 | — |
| CORRESP | Letter to the SEC | Aug 24, 2023 | — |
| DEL AM | Filing | Aug 21, 2023 | — |
| S-3 | Shelf registration | Aug 18, 2023 | — |
Showing 200 filings, the most recent 200. Main filings leave out insider and ownership forms such as Form 4; choose a type above to see them. Each form opens on SEC.gov. Older filings are on SEC EDGAR.
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Company profile
- Industry
- Pharmaceutical Preparations (SIC 2834)
- Listed as
- GOSS (Nasdaq)
- Fiscal year ends
- December 31
- Incorporated in
- DE
- Headquarters
- San Diego, CA
- SEC filer status
- Non-accelerated filer, Smaller reporting company
- SEC CIK
- 1728117
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Source: SEC EDGAR filings. This is company-reported data, not investment advice.