Shaff Eric D. sold Seres Therapeutics ($MCRB) shares on the open market four times over the last year, for a total of $11,162. His most recent insider sale occurred on February 15, 2026. These transactions rank 11,249th out of 11,678 individual insiders by sale value, well below the average of nearly $8.6 million and 6.4 sales per insider. Shaff Eric D. made no open market purchases of $MCRB stock in the period.
| Transaction Date | Company | Ticker | Insider Name | Title | Transaction Type | Security | Shares | Price | Shares Owned Following | Total Shares Outstanding | % of Owned | % of Outstanding |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feb. 15, 2026 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Common Stock | 723 | $0.00 | 11,836.0000 | 9,046,519 | 6.51% | 0.01% |
| Feb. 15, 2026 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | S | Common Stock | 259 | $8.47 | 11,577.0000 | 9,046,519 | 2.19% | 0.00% |
| Feb. 15, 2026 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Restricted Stock Units | 391 | $0.00 | 1,564.0000 | 9,046,519 | 20.00% | 0.00% |
| Feb. 15, 2026 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Restricted Stock Units | 333 | $0.00 | 2,656.0000 | 9,046,519 | 11.14% | 0.00% |
| Nov. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Common Stock | 390 | $0.00 | 10,999.0000 | 9,046,519 | 3.68% | 0.00% |
| Nov. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Restricted Stock Units | 331 | $0.00 | 2,989.0000 | 9,046,519 | 9.97% | 0.00% |
| Nov. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Restricted Stock Units | 390 | $0.00 | 1,954.0000 | 9,046,519 | 16.64% | 0.00% |
| Nov. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | S | Common Stock | 217 | $17.30 | 11,113.0000 | 9,046,519 | 1.92% | 0.00% |
| Nov. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Common Stock | 331 | $0.00 | 11,330.0000 | 9,046,519 | 3.01% | 0.00% |
| Aug. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Restricted Stock Units | 333 | $0.00 | 3,320.0000 | 174,358,753 | 9.12% | 0.00% |
| Aug. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Restricted Stock Units | 391 | $0.00 | 2,344.0000 | 174,358,753 | 14.30% | 0.00% |
| Aug. 18, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | S | Common Stock | 217 | $16.65 | 10,609.0000 | 174,358,753 | 2.00% | 0.00% |
| Aug. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Common Stock | 391 | $0.00 | 10,493.0000 | 174,358,753 | 3.87% | 0.00% |
| Aug. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | Not found | M | Common Stock | 333 | $0.00 | 10,826.0000 | 174,358,753 | 3.17% | 0.00% |
| May 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 331 | $0.00 | 10,322.0000 | 174,358,753 | 3.31% | 0.00% |
| May 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 390 | $0.00 | 9,991.0000 | 174,358,753 | 4.06% | 0.00% |
| May 16, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | S | Common Stock | 220 | $7.28 | 10,102.0000 | 174,358,753 | 2.13% | 0.00% |
| May 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 390 | $0.00 | 2,735.0000 | 174,358,753 | 12.48% | 0.00% |
| May 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 331 | $0.00 | 3,653.0000 | 174,358,753 | 8.31% | 0.00% |
| Feb. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 7813 | $0.00 | 178,202.0000 | 0 | 4.59% | 0.00% |
| Feb. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 26563 | $0.00 | 204,765.0000 | 0 | 14.91% | 0.00% |
| Feb. 18, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | S | Common Stock | 12726 | $0.81 | 192,039.0000 | 0 | 6.21% | 0.00% |
| Feb. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 7813 | $0.00 | 62,500.0000 | 0 | 11.11% | 0.00% |
| Feb. 15, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 26563 | $0.00 | 79,687.0000 | 0 | 25.00% | 0.00% |
| Feb. 7, 2025 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | A | Stock Option (Right to Buy) | 1950000 | $0.00 | 1,950,000.0000 | 0 | 9999.99% | 0.00% |
| Nov. 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 7812 | $0.00 | 70,313.0000 | 0 | 10.00% | 0.00% |
| Nov. 18, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | S | Common Stock | 2505 | $0.54 | 170,389.0000 | 0 | 1.45% | 0.00% |
| Nov. 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 7812 | $0.00 | 172,894.0000 | 0 | 4.73% | 0.00% |
| Oct. 27, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 27837 | $0.00 | 173,830.0000 | 0 | 19.07% | 0.00% |
| Oct. 28, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | S | Common Stock | 8748 | $0.69 | 165,082.0000 | 0 | 5.03% | 0.00% |
| Oct. 27, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 27837 | $0.00 | 0.0000 | 0 | 100.00% | 0.00% |
| Aug. 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 7813 | $0.00 | 148,511.0000 | 0 | 5.55% | 0.00% |
| Aug. 16, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | S | Common Stock | 2518 | $0.84 | 145,993.0000 | 0 | 1.70% | 0.00% |
| Aug. 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 7813 | $0.00 | 78,125.0000 | 0 | 9.09% | 0.00% |
| May 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 7812 | $0.00 | 85,938.0000 | 0 | 8.33% | 0.00% |
| May 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 7812 | $0.00 | 143,133.0000 | 0 | 5.77% | 0.00% |
| May 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | S | Common Stock | 2435 | $0.94 | 140,698.0000 | 0 | 1.70% | 0.00% |
| Feb. 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 31250 | $0.00 | 146,870.0000 | 0 | 27.03% | 0.00% |
| Feb. 14, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | A | Stock Option (Right to Buy) | 822580 | $0.00 | 822,580.0000 | 0 | 9999.99% | 0.00% |
| Feb. 14, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | A | Stock Option (Right to Buy) | 637500 | $0.00 | 637,500.0000 | 0 | 9999.99% | 0.00% |
| Feb. 16, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | S | Common Stock | 11549 | $1.08 | 135,321.0000 | 0 | 7.86% | 0.00% |
| Feb. 15, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 31250 | $0.00 | 93,750.0000 | 0 | 25.00% | 0.00% |
| Feb. 14, 2024 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | A | Restricted Stock Units | 106250 | $0.00 | 106,250.0000 | 0 | 9999.99% | 0.00% |
| Oct. 27, 2023 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Common Stock | 27838 | $0.00 | 124,172.0000 | 0 | 28.90% | 0.00% |
| Oct. 30, 2023 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | S | Common Stock | 8552 | $1.35 | 115,620.0000 | 0 | 6.89% | 0.00% |
| April 27, 2023 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | A | Restricted Stock Units | 55675 | $0.00 | 55,675.0000 | 0 | 9999.99% | 0.00% |
| Oct. 27, 2023 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | M | Restricted Stock Units | 27838 | $0.00 | 27,837.0000 | 0 | 50.00% | 0.00% |
| Feb. 3, 2023 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | A | Restricted Stock Units | 125000 | $0.00 | 125,000.0000 | 0 | 9999.99% | 0.00% |
| Feb. 3, 2023 | Seres Therapeutics, Inc. | $MCRB | Shaff Eric D. | CEO and President | A | Stock Option (Right to Buy) | 250000 | $0.00 | 250,000.0000 | 0 | 9999.99% | 0.00% |