As of March 23, 2026, Seres Therapeutics's top three insider holders are David S. Ege (See Remarks, 77.58K shares), Paul Biondi (Director, 47.62K shares), Paula Cloghessy (See Remarks, 45.68K shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| David S. Ege | See Remarks | 77,575 | 0 | 19 Aug, 2024 |
| Paul Biondi | 47,619 | 0 | 06 Jul, 2022 | |
| Paula Cloghessy | See Remarks | 45,684 | 0 | 31 Oct, 2023 |
| Moltke Lisa Von | See Remarks | 39,875 | 0 | 19 Feb, 2025 |
| Meryl Zausner | 31,746 | 0 | 06 Jul, 2022 | |
| Eric D. Shaff | 11,577 | 0 | 18 Feb, 2026 | |
| Teresa L. Young | See Remarks | 8,557 | 0 | 18 Feb, 2026 |
| Matthew R Henn | See Remarks | 7,677 | 0 | 18 Feb, 2026 |
* 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 |
|---|---|---|---|---|---|---|---|---|
| 04 Mar, 2026 | Kelly Brady | Stock Option (right to buy) | A | 56,250 | $0.00 | 56,250 | D | A |
| 04 Mar, 2026 | Matthew R Henn | Stock Option (right to buy) | A | 75,000 | $0.00 | 75,000 | D | A |
| 04 Mar, 2026 | Marella Thorell | Stock Option (right to buy) | A | 22,500 | $0.00 | 22,500 | D | A |
| 15 Feb, 2026 | Eric D. Shaff | Common Stock | A | 723 | - | 11,836 | D | M |
| 15 Feb, 2026 | Teresa L. Young | Common Stock | A | 231 | - | 8,632 | D | M |
| 15 Feb, 2026 | Matthew R Henn | Common Stock | A | 239 | - | 7,766 | D | M |
| 15 Feb, 2026 | Eric D. Shaff | Common Stock | D | 259 | $8.47 | 11,577 | D | S |
| 15 Feb, 2026 | Matthew R Henn | Common Stock | D | 89 | $8.47 | 7,677 | D | S |
| 15 Feb, 2026 | Teresa L. Young | Common Stock | D | 75 | $8.47 | 8,557 | D | S |
| 15 Feb, 2026 | Teresa L. Young | Restricted Stock Units | D | 133 | $0.00 | 531 | D | M |
| 15 Feb, 2026 | Eric D. Shaff | Restricted Stock Units | D | 391 | $0.00 | 1,564 | D | M |
| 15 Feb, 2026 | Matthew R Henn | Restricted Stock Units | D | 141 | $0.00 | 563 | D | M |
| 15 Feb, 2026 | Eric D. Shaff | Restricted Stock Units | D | 333 | $0.00 | 2,656 | D | M |
| 15 Feb, 2026 | Matthew R Henn | Restricted Stock Units | D | 98 | $0.00 | 780 | D | M |
| 15 Feb, 2026 | Teresa L. Young | Restricted Stock Units | D | 98 | $0.00 | 780 | D | M |
| 15 Nov, 2025 | Teresa L. Young | Common Stock | A | 3,998 | - | 9,213 | D | M |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | A | 3,998 | - | 8,546 | D | M |
| 15 Nov, 2025 | Eric D. Shaff | Common Stock | A | 390 | - | 10,999 | D | M |
| 15 Nov, 2025 | Teresa L. Young | Common Stock | A | 132 | - | 9,345 | D | M |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | A | 140 | - | 8,686 | D | M |