Seres Therapeutics Inc SEC Filings

Seres Therapeutics, Inc. director reports RSU vesting and small share sale. On 11/15/2025, the reporting person exercised restricted stock units that converted into 390 and 331 shares of common stock, increasing direct holdings and reflecting ongoing equity compensation. On the same date, 217 shares of common stock were sold at $17.30 per share under a pre-arranged Rule 10b5-1 trading instruction intended solely to cover taxes tied to the RSU vesting. After these transactions, the director directly beneficially owned 11,113 shares of common stock, along with 1,954 and 2,989 restricted stock units that vest in scheduled quarterly installments.

Seres Therapeutics, Inc. (MCRB) reported insider equity activity by its Chief Legal Officer, EVP, Co-Chief Executive Officer, and Co-President on 11/15/2025. The filing shows the exercise and settlement of restricted stock units into 132 shares and 112 shares of common stock, each RSU granting one share upon vesting. On the same date, 76 shares of common stock were sold at $17.30 per share under a Rule 10b5-1 trading instruction adopted on March 2, 2023, solely to cover taxes tied to RSU vesting. After these transactions, the reporting person directly owned 7,623 shares of common stock and retained 664 and 1,001 restricted stock units, which vest in scheduled quarterly installments and have no expiration date.

Seres Therapeutics (MCRB)November 15, 2025, several blocks of restricted stock units (RSUs) were converted into common stock, including 3,998, 140, and 98 shares. After these transactions and a sale, Henn held 7,527 shares of common stock directly.

The filing shows a sale of 1,257 shares of common stock at $17.30 per share. According to the explanation, these sales were made under a pre-arranged Rule 10b5-1 instruction adopted on April 13, 2023, and were executed solely to cover taxes arising from RSU vesting. The RSUs vest over time in scheduled installments, with certain awards having no expiration date and vesting quarterly after initial 25% vesting dates.

Seres Therapeutics (MCRB) reported Q3 2025 results. The company posted net income from continuing operations of $8.2 million for the quarter, driven by a $27.2 million gain on sale related to the VOWST business and $2.8 million of other income that included TSA reimbursements, against $22.8 million of operating expenses. Grant revenue was $351 thousand in Q3 2025, reflecting a CARB-X award tied to SER-155 development.

For the nine months ended September 30, 2025, net income from continuing operations was $21.0 million, including a year‑to‑date $79.6 million gain on the VOWST sale. Cash and cash equivalents were $47.6 million as of September 30, 2025, and total stockholders’ equity rose to $43.7 million from $13.8 million at year‑end 2024. The company disclosed substantial doubt about its ability to continue as a going concern based on current cash resources and forecasted operations.

Seres is advancing SER‑155, supported by a CARB‑X grant of up to $3.6 million, and recorded $1.0 million of restructuring costs tied to a ~25% workforce reduction announced on September 23, 2025. Shares outstanding were 8,764,664 as of September 30, 2025, and 9,046,519 as of October 31, 2025.

Seres Therapeutics (MCRB) furnished an update via Form 8-K announcing financial results for the quarter ended September 30, 2025 and providing operational updates. The company also shared an updated corporate presentation for investors.

The press release is furnished as Exhibit 99.1 and the investor slide deck as Exhibit 99.2. Consistent with Items 2.02 and 7.01, these materials are furnished, not filed, and are not subject to Section 18 liabilities or incorporation by reference except as expressly stated.

Matthew R. Henn, Chief Scientific Officer and EVP of Seres Therapeutics (MCRB), was granted 3,998 restricted stock units (RSUs) on 09/26/2025. Each RSU converts to one share of common stock and the award was reported as acquired at a $0 price. The RSUs are scheduled to vest in a single installment on 11/15/2025, subject to satisfaction of the award agreement terms, and the RSUs have no expiration date. Following the reported transaction the filing shows beneficial ownership of 3,998 shares reported as direct.

Eric D. Shaff, a director of Seres Therapeutics (MCRB), received and reported the settlement of restricted stock units and a small sale of common stock under a 10b5-1 plan. On 08/15/2025 he had two non-derivative acquisitions: 391 and 333 shares issued on settlement of restricted stock units, increasing his beneficial ownership to 10,493 and 10,826 shares respectively. On 08/18/2025 he sold 217 shares at $16.65 each, which the form states were executed under a Rule 10b5-1 instruction adopted to cover taxes related to RSU vesting. The RSUs vest in scheduled installments (25% earlier vesting followed by quarterly vesting) and have no expiration date.

Insider transactions at Seres Therapeutics (MCRB): Thomas J. DesRosier, a senior executive identified as Chief Legal Officer, EVP, Co‑CEO and Co‑President, reported restricted stock unit vesting and a small sale under a preexisting Rule 10b5‑1 plan. On 08/15/2025 DesRosier had 133 and 111 restricted stock units settle into common shares (total 244 shares) and beneficially owned 7,420 and 7,531 shares respectively after those settlements. On 08/18/2025 he sold 76 shares at $16.65 per share pursuant to the 10b5‑1 instruction to cover taxes related to vesting. The filings state the RSUs vest in scheduled quarterly installments and have no expiration.