According to recent filings covering the 90 days ending February 19, 2026, the three most significant insider holders at Seres Therapeutics are TenPercentOwner Health Ltp Fund General Partner Llc Nutritional (291.27K shares), Director Eric D. Shaff (11.11K shares), Chief Financial Officer David Arkowitz (9.12K 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 | Nan | 3,879 | 19 Aug, 2024 |
| Richard N Kender | 3,175 | 06 Jul, 2022 | |
| Paul Biondi | 2,381 | 06 Jul, 2022 | |
| Paula Cloghessy | Nan | 2,284 | 31 Oct, 2023 |
| Moltke Lisa Von | Nan | 1,994 | 19 Feb, 2025 |
| Meryl Zausner | 1,587 | 06 Jul, 2022 | |
| Willard H Dere | 1,587 | 06 Jul, 2022 | |
| Eric D. Shaff | 11,113 | 18 Nov, 2025 | |
| Teresa L. Young | Nan | 8,401 | 18 Nov, 2025 |
| Thomas Desrosier | Nan | 7,623 | 18 Nov, 2025 |
| Matthew R Henn | Nan | 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 | Thomas Desrosier | Common Stock | A | 132 | - | 7,587 | D | M |
| 15 Nov, 2025 | Thomas Desrosier | Common Stock | D | 76 | $17.30 | 7,623 | D | S |
| 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 | Eric D. Shaff | Common Stock | D | 217 | $17.30 | 11,113 | D | S |
| 15 Nov, 2025 | Eric D. Shaff | Common Stock | A | 390 | - | 10,999 | D | M |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | A | 98 | - | 8,784 | D | M |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | A | 140 | - | 8,686 | D | M |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | D | 1,257 | $17.30 | 7,527 | D | S |
| 15 Nov, 2025 | Matthew R Henn | Common Stock | A | 3,998 | - | 8,546 | D | M |
| 15 Nov, 2025 | Teresa L. Young | Common Stock | A | 3,998 | - | 9,213 | D | M |
| 15 Nov, 2025 | Teresa L. Young | Common Stock | D | 1,042 | $17.30 | 8,401 | D | S |
| 15 Nov, 2025 | Teresa L. Young | Common Stock | A | 132 | - | 9,345 | D | M |
| 15 Nov, 2025 | Teresa L. Young | Common Stock | A | 98 | - | 9,443 | D | M |
| 18 Aug, 2025 | Thomas Desrosier | Common Stock | D | 76 | $16.65 | 7,455 | D | S |
| 18 Aug, 2025 | Eric D. Shaff | Common Stock | D | 217 | $16.65 | 10,609 | D | S |
| 18 Aug, 2025 | Matthew R Henn | Common Stock | D | 73 | $16.65 | 4,548 | D | S |
| 18 Aug, 2025 | Teresa L. Young | Common Stock | D | 59 | $16.65 | 5,215 | D | S |
| 15 Aug, 2025 | Thomas Desrosier | Common Stock | A | 133 | - | 7,420 | D | M |
| 15 Aug, 2025 | Thomas Desrosier | Common Stock | A | 111 | - | 7,531 | D | M |