Welcome to our dedicated page for Seres Therapeutics SEC filings (Ticker: MCRB), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Seres Therapeutics, Inc. filings document the disclosure record of a Nasdaq-listed biotechnology company focused on live biotherapeutic and microbiome-based therapeutic programs. Its Form 8-K reports furnish quarterly and annual financial results, operational updates, Regulation FD corporate presentations, and material-event disclosures involving pipeline priorities, clinical and regulatory matters, capital allocation, cost-reduction actions, and financing or partnership activity.
The company’s proxy materials cover annual meeting mechanics, stockholder voting, board governance, executive compensation, and equity-award information. SEC filings also identify Seres’ common stock registered under the Exchange Act and traded on the Nasdaq Global Select Market under the symbol MCRB.
Seres Therapeutics, Inc. officer Thomas DesRosier reported a small set of equity transactions. He sold 79 shares of common stock at $7.53 per share in an open-market sale executed under a pre-arranged Rule 10b5-1 plan intended to cover taxes from restricted stock unit (RSU) vesting.
On the same date, RSUs covering 244 shares were converted into common stock at a $0.00 exercise price, and additional RSUs for 111 and 133 shares converted into common stock. After these transactions, he directly holds 7,954 common shares plus remaining RSU awards that continue to vest over time.
Seres Therapeutics director Eric D. Shaff reported routine stock transactions tied to vesting of restricted stock units. On May 18, 2026, he sold 259 shares of common stock at $7.53 per share in an open-market sale executed under a pre-arranged Rule 10b5-1 instruction adopted to cover taxes from RSU vesting.
On May 15, 2026, Shaff exercised derivative awards to acquire 722 shares of common stock at a conversion price of $0.00 as RSUs vested and settled. Following these transactions, he directly holds 12,040 shares of common stock, and additional RSUs remain outstanding that continue to vest in quarterly installments.
Seres Therapeutics officer Brady Kelly reported routine equity compensation activity and a small tax-related sale. On May 15, 2026, Kelly exercised restricted stock units, converting 180 shares in total into common stock at a stated price of $0.00 per share. The filing explains that each restricted stock unit is a right to receive one share of Seres common stock and describes quarterly vesting schedules for grants that began vesting on February 15, 2024 and February 15, 2025. On May 18, 2026, Kelly sold 59 shares of common stock at $7.53 per share, specifically to cover taxes tied to the RSU vesting. Following these transactions, Kelly directly holds 8,562 shares of common stock, indicating that the sale was small relative to the overall position.
Seres Therapeutics, Inc. officer Matthew R. Henn reported several equity transactions. On May 15, 2026, he exercised restricted stock units (RSUs) that converted into 238 shares of common stock at a conversion price of $0.00 per share. The RSUs each represent a contingent right to one share of common stock and vest in quarterly installments. On May 18, 2026, he completed an open-market sale of 77 common shares at $7.53 per share, executed under a pre-arranged Rule 10b5-1 instruction adopted to cover taxes related to RSU vesting. Following these transactions, he directly held 7,838 common shares and 422 RSUs as reported in the filing, indicating a relatively small sale compared with his remaining equity position.
Seres Therapeutics, Inc. reported a net loss of $19.9 million for the three months ended March 31, 2026, compared with net income of $32.7 million a year earlier, as revenue totaled only $0.4 million from a government grant.
Cash and cash equivalents were $29.8 million as of March 31, 2026, and management disclosed that these resources, together with forecasted cash flows, raise substantial doubt about the company’s ability to continue as a going concern without additional funding. Operating activities used $16.4 million of cash in the quarter.
The company continues to focus on live biotherapeutic product candidates SER-155, SER-603, SER-428 and SER-147 after the prior sale of its VOWST business. It implemented cost-reduction measures, including a workforce reduction of about 30%, incurring $0.9 million in restructuring charges, and modestly raised equity through an at-the-market program.
Seres Therapeutics reported first quarter 2026 results showing a return to operating losses as it invests in its microbiome pipeline. Revenue was modest at $358,000, all from grants, while operating expenses totaled $21.3 million, driven by $13.2 million in research and development and $8.1 million in general and administrative costs.
The company posted a net loss of $19.9 million, compared with net income of $32.7 million a year earlier, when results benefited from a gain on the sale of the VOWST business. As of March 31, 2026, Seres held $29.8 million in cash and cash equivalents and expects this to fund operations through the third quarter of 2026.
Operationally, Seres highlighted an upcoming clinical readout in the coming weeks from an investigator-sponsored study of SER-155 in immune checkpoint inhibitor-related enterocolitis, Phase 2 readiness of SER-155 in allo-HSCT, and IND-enabling progress for SER-603 in inflammatory bowel disease, while actively pursuing partnerships and additional capital.
Seres Therapeutics, Inc. is asking stockholders to approve several items at its virtual 2026 annual meeting on June 9, 2026. Holders of 9,632,111 shares of common stock outstanding as of April 13, 2026 may vote, with one vote per share.
Stockholders will vote on electing three Class II directors to serve until the 2029 meeting, ratifying PricewaterhouseCoopers LLP as independent auditor for 2026, and approving an advisory say-on-pay resolution on named executive officer compensation. The board recommends voting in favor of each item.
A key proposal seeks to amend and restate the 2025 Incentive Award Plan to add 900,000 shares, bringing the total plan reserve to 3,130,243 shares, which the company notes equals 9.34% of shares outstanding as of April 13, 2026. The plan supports employee, executive and director equity awards and includes features such as no discounted options, no liberal share recycling and caps on director compensation.
The company has granted conditional stock options covering 118,750 shares, including 50,000 options to Executive Chair and Interim CEO Richard N. Kender at an exercise price of $9.13 per share, which will only become exercisable if stockholders approve the share increase. An adjournment proposal would allow more time to solicit votes if support for the plan amendment is initially insufficient.
MCRB Form 144 notice reports proposed sales of Common restricted and performance shares totaling 8,553 shares, with venue indicated as NASDAQ. The filing shows 75 Common shares sold by Teresa L. Young on 02/17/2026 at $635.25 per share. The excerpt lists 9,586,298 shares with a date of 03/17/2026 (as shown in the row).
Seres Therapeutics, Inc. has scheduled its 2026 annual meeting of stockholders for June 9, 2026. Stockholders who hold common shares as of the close of business on April 13, 2026 will be entitled to vote at the meeting.
Because the 2026 meeting will occur more than 30 days after the 2025 meeting anniversary, the company has set a revised deadline for qualified stockholder proposals under SEC Rule 14a-8. Proposals must be received at the company’s principal executive office by the close of business on March 26, 2026 to be considered for inclusion in the 2026 proxy statement.
Seres Therapeutics files its annual report describing a shift toward early-stage microbiome drugs while warning of substantial doubt about its ability to continue as a going concern. The company says it will need additional funding or partnerships and may pursue alternatives including potential bankruptcy or a wind-down.
Seres sold rights to its approved microbiome drug VOWST to Nestlé Health Science in 2024 and is now focused on live biotherapeutic candidates SER-155, SER-603, SER-147 and a liquid ICU formulation. Phase 1b data for SER-155 in allo-HSCT showed a 77% relative risk reduction in bacterial bloodstream infections and won Fast Track and Breakthrough Therapy designations, but a planned Phase 2 trial is paused pending financing.