Based on data from the past 90 days ending December 12, 2025, Seres Therapeutics's three largest insider shareholders are Director Eric D. Shaff (11.11K shares), Officer Teresa L. Young (8.40K shares), Officer Thomas Desrosier (7.62K shares).
| Holder | Position | Shares | Report Date |
|---|---|---|---|
| Health Ltp Fund General Partner Llc Nutritional | 291,275 | 07 Jul, 2022 | |
| David Arkowitz | Chief Financial Officer | 9,122 | 16 Feb, 2024 |
| David S. Ege | 3,879 | 19 Aug, 2024 | |
| Richard N Kender | 3,175 | 06 Jul, 2022 | |
| Paul Biondi | 2,381 | 06 Jul, 2022 | |
| Paula Cloghessy | 2,284 | 31 Oct, 2023 | |
| Moltke Lisa Von | 1,994 | 19 Feb, 2025 | |
| Willard H Dere | 1,587 | 06 Jul, 2022 | |
| Meryl Zausner | 1,587 | 06 Jul, 2022 | |
| Eric D. Shaff | 11,113 | 18 Nov, 2025 | |
| Teresa L. Young | 8,401 | 18 Nov, 2025 | |
| Thomas Desrosier | 7,623 | 18 Nov, 2025 | |
| Matthew R Henn | 7,527 | 18 Nov, 2025 |
* 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 |
|---|---|---|---|---|---|---|---|---|
| 15 Nov, 2025 | Teresa L. Young | Common Stock | A | 3,998 | - | 9,213 | D | M |
| 15 Nov, 2025 | Eric D. Shaff | Common Stock | A | 390 | - | 10,999 | D | M |
| 15 Nov, 2025 | Thomas Desrosier | Common Stock | A | 132 | - | 7,587 | D | M |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | A | 3,998 | - | 8,546 | 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 |
| 15 Nov, 2025 | Thomas Desrosier | Common Stock | A | 112 | - | 7,699 | D | M |
| 15 Nov, 2025 | Eric D. Shaff | Common Stock | A | 331 | - | 11,330 | D | M |
| 15 Nov, 2025 | Thomas Desrosier | Common Stock | D | 76 | $17.30 | 7,623 | D | S |
| 15 Nov, 2025 | Eric D. Shaff | Common Stock | D | 217 | $17.30 | 11,113 | D | S |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | A | 98 | - | 8,784 | D | M |
| 15 Nov, 2025 | Teresa L. Young | Common Stock | A | 98 | - | 9,443 | D | M |
| 15 Nov, 2025 | Teresa L. Young | Common Stock | D | 1,042 | $17.30 | 8,401 | D | S |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | D | 1,257 | $17.30 | 7,527 | D | S |
| 15 Aug, 2025 | Eric D. Shaff | Common Stock | A | 391 | - | 10,493 | D | M |
| 15 Aug, 2025 | Teresa L. Young | Common Stock | A | 133 | - | 5,177 | D | M |
| 15 Aug, 2025 | Matthew R Henn | Common Stock | A | 141 | - | 4,524 | D | M |
| 15 Aug, 2025 | Thomas Desrosier | Common Stock | A | 133 | - | 7,420 | D | M |
| 15 Aug, 2025 | Eric D. Shaff | Common Stock | A | 333 | - | 10,826 | D | M |
| 15 Aug, 2025 | Thomas Desrosier | Common Stock | A | 111 | - | 7,531 | D | M |