Thomas DesRosier files SEC Form 4 disclosures for Seres Therapeutics, Inc.. They have made 6 open-market trades across 3 companies since 2008, most recently 2026-08-17.
CIK 0001435744
Unrated. We grade insiders only on stock they chose to buy on the open market. Grants, option exercises and vesting say nothing about timing, so they don't count — which is why someone can file often and still have no grade. It isn't a bad sign: unrated buys beat every graded tier below A.
0 open-market purchases, against 6 sales. Too few scored purchases to measure a record yet.
| Ticker | Shares | Value |
|---|---|---|
| ARIA | 55,000 | $1.4M |
| MCRB | 8,117 | $20K |
| CBST | 7,967 | — |
| GENZ | 11,375 | — |
| Total | $1.4M |
Shares reported on the most recent Form 4, priced at the 2026-08-18 close. 2 holdings could not be priced and are excluded from the total.
Counted per filing, not per execution lot — a purchase filled in several tranches is one decision.
| Ticker | Type | Traded | Filed | Price | Value | 7d Stock | 30d Stock | 90d Stock |
|---|---|---|---|---|---|---|---|---|
| MCRB | SELL · 10b5-1 | 2026-08-17 | 2026-08-18 | $4.55 | $373 | +13.1% | -8.2% | — |
| MCRB | SELL · 10b5-1 | 2026-05-18 | 2026-05-19 | $7.53 | $595 | -4.3% | -13.0% | -40.6% |
| MCRB | SELL | 2026-02-15 | 2026-02-18 | $8.47 | $661 | +8.9% | +2.7% | -9.1% |
| MCRB | SELL · 10b5-1 | 2025-11-15 | 2025-11-18 | $17.30 | $1K | -27.1% | -35.8% | -65.2% |
| MCRB | SELL · 10b5-1 | 2025-08-18 | 2025-08-19 | $16.65 | $1K | +16.3% | +10.7% | +32.9% |
| MCRB | SELL · 10b5-1 | 2025-05-15 | 2025-05-19 | $7.28 | $575 | -11.2% | -2.6% | +122.8% |
| MCRB | SELL · 10b5-1 | 2025-02-18 | 2025-02-19 | $0.81 | $3K | -8.7% | -13.2% | -49.8% |
| MCRB | SELL · 10b5-1 | 2024-11-18 | 2024-11-19 | $0.54 | $474 | +35.8% | +34.9% | +21.8% |
| MCRB | SELL · 10b5-1 | 2024-10-28 | 2024-10-29 | $0.69 | $3K | -5.4% | +29.7% | +11.4% |
| MCRB | SELL · 10b5-1 | 2024-08-16 | 2024-08-19 | $0.84 | $733 | -13.4% | +15.1% | -36.5% |
| MCRB | SELL · 10b5-1 | 2024-05-15 | 2024-05-17 | $0.94 | $792 | +6.4% | -26.7% | -3.3% |
| MCRB | SELL · 10b5-1 | 2024-02-16 | 2024-02-16 | $1.08 | $4K | +5.6% | -29.8% | -14.4% |
| MCRB | SELL · 10b5-1 | 2023-10-30 | 2023-10-31 | $1.35 | $6K | -32.8% | -31.1% | -17.2% |
| MCRB | SELL | 2019-01-28 | 2019-01-29 | $5.75 | $31K | -0.7% | +1.7% | +15.3% |
| MCRB | SELL | 2018-01-26 | 2018-01-30 | $11.02 | $38K | -20.1% | -9.7% | -27.4% |
| CBST | SELL | 2014-04-16 | 2014-04-16 | $64.00 | $49K | N/A | N/A | N/A |
| GENZ | SELL | 2010-05-25 | 2010-05-26 | $45.60 | $90K | N/A | N/A | N/A |
| GENZ | SELL | 2008-08-07 | 2008-08-08 | $78.99 | $847K | N/A | N/A | N/A |
Grouped by shared companies and similar filing behaviour. This is a similarity measure, not a ranking or a performance signal.