MCRB (Seres Therapeutics, Inc.)
Insider Trading Activity
Every open-market purchase and sale reported by MCRB officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.
Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.
| Filed | Insider | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-08-18 | Eric D. Shaff | Director | MIXED | — | — |
| 2026-08-18 | Matthew R Henn | See Remarks | MIXED | — | — |
| 2026-08-18 | Kelly Brady | See Remarks | MIXED | — | — |
| 2026-08-18 | Thomas DesRosier | See Remarks | MIXED | — | — |
| 2026-07-10 | Eric D. Shaff | Director | A | — | — |
| 2026-07-10 | Thomas DesRosier | See Remarks | A | — | — |
| 2026-07-10 | Matthew R Henn | See Remarks | A | — | — |
| 2026-07-10 | Richard N Kender | See Remarks | A | — | — |
| 2026-07-10 | Stephen Berenson | Director | A | — | — |
| 2026-07-10 | Robert L. Rosiello | Director | A | — | — |
| 2026-07-10 | Kurt Graves | Director | A | — | — |
| 2026-07-10 | Willard H Dere | Director | A | — | — |
| 2026-07-10 | Marella Thorell | See Remarks | A | — | — |
| 2026-07-10 | Claire Fraser | Director | A | — | — |
| 2026-07-10 | Dennis A Ausiello | Director | A | — | — |
| 2026-07-10 | Kelly Brady | See Remarks | A | — | — |
| 2026-07-02 | Robert L. Rosiello | Director | A | — | — |
| 2026-07-02 | Dennis A Ausiello | Director | A | — | — |
| 2026-07-02 | Stephen Berenson | Director | A | — | — |
| 2026-05-19 | Eric D. Shaff | Director | MIXED | — | — |
| 2026-05-19 | Thomas DesRosier | See Remarks | MIXED | — | — |
| 2026-05-19 | Matthew R Henn | See Remarks | MIXED | — | — |
| 2026-05-19 | Kelly Brady | See Remarks | MIXED | — | — |
| 2026-03-11 | Kelly Brady | See Remarks | A | — | — |
| 2026-03-06 | Thomas DesRosier | See Remarks | A | — | — |
| 2026-03-06 | Matthew R Henn | See Remarks | A | — | — |
| 2026-03-06 | Richard N Kender | See Remarks | A | — | — |
| 2026-03-06 | Marella Thorell | See Remarks | A | — | — |
| 2026-02-18 | Eric D. Shaff | Director | MIXED | — | — |
| 2026-02-18 | Teresa L. Young | See Remarks | MIXED | — | — |
| 2026-02-18 | Matthew R Henn | See Remarks | MIXED | — | — |
| 2026-02-18 | Thomas DesRosier | See Remarks | MIXED | — | — |
| 2025-11-18 | Thomas DesRosier | See Remarks | MIXED | — | — |
| 2025-11-18 | Teresa L. Young | See Remarks | MIXED | — | — |
| 2025-11-18 | Matthew R Henn | See Remarks | MIXED | — | — |
| 2025-11-18 | Eric D. Shaff | Director | MIXED | — | — |
| 2025-09-30 | Teresa L. Young | See Remarks | A | — | — |
| 2025-09-30 | Matthew R Henn | See Remarks | A | — | — |
| 2025-08-19 | Matthew R Henn | See Remarks | MIXED | — | — |
| 2025-08-19 | Thomas DesRosier | See Remarks | MIXED | — | — |
| 2025-08-19 | Eric D. Shaff | Director | MIXED | — | — |
| 2025-08-19 | Teresa L. Young | See Remarks | MIXED | — | — |
| 2025-08-06 | Robert L. Rosiello | Director | A | — | — |
| 2025-07-02 | Dennis A Ausiello | Director | A | — | — |
| 2025-07-02 | Stephen Berenson | Director | A | — | — |
| 2025-07-02 | Claire Fraser | Director | A | — | — |
| 2025-05-19 | Teresa L. Young | See Remarks | MIXED | — | — |
| 2025-05-19 | Thomas DesRosier | Chief Legal Officer and EVP | MIXED | — | — |
| 2025-05-19 | Eric D. Shaff | CEO and President | MIXED | — | — |
| 2025-05-19 | Matthew R Henn | See Remarks | MIXED | — | — |
| Insider | Role | Shares Held | Value |
|---|---|---|---|
| — | Director | 401,878 | — |
| — | 10%+ Owner | 344,444 | — |
| — | 10%+ Owner | 277,778 | — |
| — | 10%+ Owner | 148,148 | — |
| — | 10%+ Owner | 136,750 | — |
| — | 10%+ Owner | 110,280 | — |
| — | Director | 12,762 | — |
| — | President and CEO | 10,699 | — |
| — | Chief Financial Officer | 9,122 | — |
| — | See Remarks | 8,679 | — |
| — | See Remarks | 8,632 | — |
| — | See Remarks | 8,117 | — |
| — | See Remarks | 8,076 | — |
| — | See Remarks | 7,372 | — |
| — | Chief Technology Officer & EVP | 5,262 | — |
| — | See Remarks | 3,935 | — |
| — | See Remarks | 3,175 | — |
| — | Director | 2,381 | — |
| — | See Remarks | 2,284 | — |
| — | See Remarks | 2,215 | — |
| — | Director | 1,587 | — |
| — | Director | 1,587 | — |
| — | See Remarks | 430 | — |
| — | See Remarks | 375 | — |
| — | Director | 179 | — |
Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.
Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.
Full filing history and per-insider positions are on the MCRB quote page; the site-wide leaderboard is on the insider transactions hub.