As of September 29, 2026, Gossamer Bio's top three insider holders are Faheem Hasnain (President Ceo, 67.60K shares), Faheem Hasnain (President Ceo, 10.47K shares), Waage Christian (Evp, Tech Ops And Admin, 10.18K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Faheem Hasnain | President Ceo | 10,472 | 0 | 10,472 | 26.5% | 05 Jan, 2026 |
| 2 | Waage Christian | Evp, Tech Ops And Admin | 10,176 | 0 | 10,176 | 25.8% | 05 Jan, 2026 |
| 3 | Richard Aranda | Chief Medical Officer | 5,789 | 0 | 5,789 | 14.7% | 05 Jan, 2026 |
| 4 | Bryan Giraudo | Coo/Cfo | 4,872 | 0 | 4,872 | 12.3% | 05 Jan, 2026 |
| 5 | Robert Paul Jr Smith | Chief Commercial Officer | 3,261 | 0 | 3,261 | 8.3% | 05 Jan, 2026 |
| 6 | Caryn Peterson | Evp, Regulatory Affairs | 3,242 | 0 | 3,242 | 8.2% | 05 Jan, 2026 |
| 7 | Laura Carter | Chief Scientific Officer | 953 | 0 | 953 | 2.4% | 20 Mar, 2023 |
| 8 | Sandra Milligan | Director | 726 | 0 | 726 | 1.8% | 20 Aug, 2025 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 23 Sep, 2026 | Gregory Austin Ciongoli | Director | Acquired A | 30,000 | $0.00 | $0 | 30,000 | Direct |
| 23 Sep, 2026 | Thomas O Daniel | Director | Acquired A | 10,000 | $0.00 | $0 | 10,000 | Direct |
| 23 Sep, 2026 | John D Quisel | Director | Acquired A | 10,000 | $0.00 | $0 | 10,000 | Direct |
| 23 Sep, 2026 | Skye Drynan | Director | Acquired A | 10,000 | $0.00 | $0 | 10,000 | Direct |
| 23 Sep, 2026 | Sandra Milligan | Director | Acquired A | 10,000 | $0.00 | $0 | 10,000 | Direct |
| 23 Sep, 2026 | Steven D Nathan | Director | Acquired A | 10,000 | $0.00 | $0 | 10,000 | Direct |
| 23 Sep, 2026 | Russell J. Cox | Director | Acquired A | 10,000 | $0.00 | $0 | 10,000 | Direct |
| 24 Aug, 2026 | Robert Paul Jr Smith | Chief Commercial Officer | Acquired A | 5,800,051 | $0.00 | $0 | 72,501 | Direct |
| 24 Aug, 2026 | Caryn Peterson | Chief Development Officer | Acquired A | 5,800,051 | $0.00 | $0 | 72,501 | Direct |
| 24 Aug, 2026 | Faheem Hasnain | President Ceo | Acquired A | 166 | $79,999.92 | $13.28Mn | 2 | Indirect |
| 24 Aug, 2026 | Bryan Giraudo | Coo/Cfo | Acquired A | 25 | $79,999.92 | $2.00Mn | 0 | Indirect |
| 24 Aug, 2026 | Bryan Giraudo | Coo/Cfo | Acquired A | 5,800,051 | $0.00 | $0 | 72,501 | Direct |
| 24 Aug, 2026 | Faheem Hasnain | President Ceo | Acquired A | 5,800,051 | $0.00 | $0 | 72,501 | Direct |
| 24 Aug, 2026 | Waage Christian | Evp, Tech Ops And Admin | Acquired A | 2,900,026 | $0.00 | $0 | 36,250 | Direct |
| 04 Jun, 2026 | Russell J. Cox | Director | Acquired A | 115,000 | $0.00 | $0 | 1,438 | Direct |
| 04 Jun, 2026 | Sandra Milligan | Director | Acquired A | 115,000 | $0.00 | $0 | 1,438 | Direct |
| 04 Jun, 2026 | Thomas O Daniel | Director | Acquired A | 115,000 | $0.00 | $0 | 1,438 | Direct |
| 04 Jun, 2026 | John D Quisel | Director | Acquired A | 115,000 | $0.00 | $0 | 1,438 | Direct |
| 04 Jun, 2026 | Skye Drynan | Director | Acquired A | 115,000 | $0.00 | $0 | 1,438 | Direct |
| 04 Jun, 2026 | Steven D Nathan | Director | Acquired A | 115,000 | $0.00 | $0 | 1,438 | Direct |