🕵️ Gossamer BIO, Inc. ($GOSS)
SEC insider & ownership activity, last 12 months · CIK 1728117 · every row links its SEC filing
Insiders were quiet over the last 12 months – no open-market buys or sells. D. E. SHAW & Co., L.L.C. trimmed 7.0% → 6.0%; D. E. SHAW & Co., L.P. trimmed 7.1% → 6.0%. No red-flag 8-Ks in the window.
Insider flow
0 buyers, $0 (0 lots) · 0 sellers, $0 (0 lots)
No open-market insider transactions in the last 12 months.
5%+ holders
| Holder | Stake | Class | Schedule | Event | |
|---|---|---|---|---|---|
| 683 Capital Management, LLC | 10.0% | 13G | Jun 11, 2026 | filing ↗ | |
| 683 Capital Partners, LP | 10.0% | 13G | Jun 11, 2026 | filing ↗ | |
| Ari Zweiman | 10.0% | 13G | Jun 11, 2026 | filing ↗ | |
| Context Capital Management, LLC | 9.9% | 13G | Jun 9, 2026 | filing ↗ | |
| Michael S. Rosen | 9.9% | 13G | Jun 9, 2026 | filing ↗ | |
| William D. Fertig | 9.9% | 13G | Jun 9, 2026 | filing ↗ | |
| Charles E. Carnegie | 9.9% | 13G | Jun 9, 2026 | filing ↗ | |
| Context Partners Master Fund, L.P. | 9.9% | 13G | Jun 9, 2026 | filing ↗ | |
| Octagon Investments Master Fund | 8.6% | 13G | Feb 5, 2025 | filing ↗ | |
| DeepCurrents Investment Group LLC | 7.7% | 13G | Jun 11, 2026 | filing ↗ | |
| Kai Zheng | 7.7% | 13G | Jun 11, 2026 | filing ↗ | |
| D. E. SHAW & Co., L.L.C. | 6.0% | 13D | Aug 20, 2026 | filing ↗ | |
| D. E. SHAW & Co., L.P. | 6.0% | 13D | Aug 20, 2026 | filing ↗ | |
| David E. Shaw | 6.0% | 13D | Aug 20, 2026 | filing ↗ | |
| D. E. SHAW Valence Portfolios, L.L.C. | 5.7% | 13D | Aug 20, 2026 | filing ↗ | |
| DCIG GP LLC | 5.7% | 13G | Jun 11, 2026 | filing ↗ | |
| DCIG Capital Master Fund LP | 5.7% | 13G | Jun 11, 2026 | filing ↗ | |
| Opaleye Management Inc. | 5.1% | 13G | Jul 29, 2026 | filing ↗ | |
| James Silverman | 5.1% | 13G | Jul 29, 2026 | filing ↗ |
Planned insider sales (Form 144)
No sale notices filed in the last 12 months.
Material events (8-K)
| Item | Event date | |
|---|---|---|
| Officer/director changes (5.02) | Sep 16, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Sep 16, 2026 | filing ↗ |
| Material Modifications to Rights of Security Holders (3.03) | Sep 10, 2026 | filing ↗ |
| Charter/bylaw changes (5.03) | Sep 10, 2026 | filing ↗ |
| Other events (8.01) | Sep 10, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Sep 10, 2026 | filing ↗ |
| Other events (8.01) | Sep 9, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Sep 9, 2026 | filing ↗ |
| Charter/bylaw changes (5.03) | Sep 3, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Sep 3, 2026 | filing ↗ |
| Charter/bylaw changes (5.03) | Aug 24, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Aug 24, 2026 | filing ↗ |
| Material agreement (1.01) | Aug 20, 2026 | filing ↗ |
| Unregistered equity sale (3.02) | Aug 20, 2026 | filing ↗ |
| Charter/bylaw changes (5.03) | Aug 20, 2026 | filing ↗ |
| Reg FD disclosure (7.01) | Aug 20, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Aug 20, 2026 | filing ↗ |
| Earnings (2.02) | Aug 13, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Aug 13, 2026 | filing ↗ |
| Material agreement (1.01) | Jul 23, 2026 | filing ↗ |
| Agreement terminated (1.02) | Jul 23, 2026 | filing ↗ |
| Earnings (2.02) | Jul 23, 2026 | filing ↗ |
| Reg FD disclosure (7.01) | Jul 23, 2026 | filing ↗ |
| Other events (8.01) | Jul 23, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Jul 23, 2026 | filing ↗ |
| Officer/director changes (5.02) | Jul 14, 2026 | filing ↗ |
| Charter/bylaw changes (5.03) | Jul 14, 2026 | filing ↗ |
| Shareholder vote (5.07) | Jul 14, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Jul 14, 2026 | filing ↗ |
| Reg FD disclosure (7.01) | Jul 1, 2026 | filing ↗ |