As of March 23, 2026, the three largest insider holders of GBIO are Douglas Kerr (Chief Medical Officer, 385.63K shares), Matthew Stanton (Chief Scientific Officer, 247.32K shares), Matthew Norkunas (Chief Financial Officer, 57.35K shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Douglas Kerr | Chief Medical Officer | 385,628 | 0 | 31 Jan, 2024 |
| Matthew Stanton | Chief Scientific Officer | 247,319 | 0 | 17 Oct, 2024 |
| Matthew Norkunas | Chief Financial Officer | 57,348 | 0 | 17 Oct, 2024 |
| Tracy Zimmermann | Chief Development Officer | 49,164 | 0 | 31 Jan, 2024 |
| Phillip Samayoa | Chief Scientific Officer | 14,138 | 0 | 17 Oct, 2025 |
| Antoinette Paone | Chief Operating Officer | 3,658 | 0 | 17 Oct, 2025 |
| Venture Associates X, L.P. Atlas | 0 | 608 | 29 Sep, 2021 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 09 Feb, 2026 | Donald William Nicholson | Common Stock | D | 21,357 | - | 0 | D | U |
| 09 Feb, 2026 | Catherine Stehman-Breen | Common Stock | D | 4,752 | - | 0 | D | U |
| 09 Feb, 2026 | Dannielle Appelhans | Common Stock | D | 1,263 | - | 0 | D | U |
| 09 Feb, 2026 | Geoff Mcdonough | Common Stock | D | 138,492 | - | 0 | D | U |
| 09 Feb, 2026 | Venture Fund X, L.P. Atlas | Common Stock | D | 711,193 | - | 0 | D | U |
| 09 Feb, 2026 | Jeffrey M Jonas | Stock Option (right to buy) | D | 3,000 | - | 0 | D | D |
| 09 Feb, 2026 | Yalonda Howze | Common Stock | D | 3,759 | - | 0 | D | U |
| 09 Feb, 2026 | Anthony G. Quinn | Common Stock | D | 29,928 | - | 0 | D | U |
| 09 Feb, 2026 | Charles A Jr Rowland | Common Stock | D | 53,475 | - | 0 | D | U |
| 09 Feb, 2026 | Kevin John Conway | Common Stock | D | 2,072 | - | 0 | D | U |
| 09 Feb, 2026 | Jason P Rhodes | Common Stock | D | 711,193 | - | 0 | I | U |
| 09 Feb, 2026 | Ronald Harold Wilfred Cooper | Common Stock | D | 950 | - | 0 | D | U |
| 09 Feb, 2026 | Geoff Mcdonough | Common Stock | D | 22,646 | - | 0 | I | U |
| 09 Feb, 2026 | Catherine Stehman-Breen | Stock Option (right to buy) | D | 3,000 | - | 0 | D | D |
| 09 Feb, 2026 | Anthony G. Quinn | Common Stock | D | 7,283 | - | 0 | I | U |
| 09 Feb, 2026 | Ronald Harold Wilfred Cooper | Stock Option (right to buy) | D | 3,000 | - | 0 | D | D |
| 09 Feb, 2026 | Dannielle Appelhans | Common Stock | D | 736 | - | 0 | I | U |
| 09 Feb, 2026 | Donald William Nicholson | Stock Option (right to buy) | D | 3,000 | - | 0 | D | D |
| 09 Feb, 2026 | Venture Fund X, L.P. Atlas | Common Stock | D | 116,693 | - | 0 | I | U |
| 09 Feb, 2026 | Charles A Jr Rowland | Stock Option (right to buy) | D | 3,000 | - | 0 | D | D |