Seres Therapeutics, Inc. (MCRB) Stock

Seres Therapeutics, Inc. (MCRB) is a Healthcare stock trading at $4.57 (as of 2026-08-21), with a market capitalization of $45.43M. Figures are sourced from first-party U.S. SEC EDGAR filings and market data.

Seres Therapeutics, Inc., a microbiome therapeutics platform company, engages in developing bacterial consortia that are designed to functionally interact with host cells and tissues to treat disease. The company's lead product candidate is the SER-109, an oral microbiome therapeutic candidate that has completed Phase III clinical trial for the treatment of clostridium difficile infection (CDI). It is also developing SER-155, a cultivated bacteria microbiome drug, which is Phase Ib clinical trial to reduce incidences of gastrointestinal infections, bloodstream infections, and graft versus host diseases in immunocompromised patients receiving allogeneic hematopoietic stem cell transplantation and solid organ transplants. In addition, the company engages in the development of SER-287 and SER-301 that are in Phase Ib to treat ulcerative colitis; SER-401 for patients with metastatic melanoma; and SER-262 to treat Clostridioides difficile infection. It has license and collaboration agreements with Nestec Ltd. and Memorial Sloan Kettering Cancer Center. The company was formerly known as Seres Health, Inc. and changed its name to Seres Therapeutics, Inc. in May 2015. Seres Therapeutics, Inc. was incorporated in 2010 and is headquartered in Cambridge, Massachusetts.

Understand Seres Therapeutics, Inc.: how it makes money

Seres Therapeutics develops microbiome therapeutics, including an oral microbiome drug candidate (SER-109) and a cultivated bacteria drug candidate (SER-155), and it makes money from collaboration revenue and VOWST net sales.

The company’s near-term revenue mix appears to depend on (1) collaboration revenue and (2) VOWST commercial net sales, while long-term outcomes hinge on clinical development progress for SER-109 (Phase III completed for CDI) and SER-155 (Phase Ib for reducing gastrointestinal, bloodstream, and graft versus host related infections).

Revenue by segment (latest quarter)
Collab$0.1B
VOWST Net$0.0B
Grants$0.0B

Business quality (Weak): Good operating-measure visibility (VOWST units and patient starts, plus clinical-style response and safety metrics), but the dataset shows reported total revenue of 0.0B while segment values for the same period are non-zero, which makes segment-to-total reconciliation unclear.

Bull case

  • VOWST commercialization indicators are provided (Units Sold and New Patient Starts): In the provided operating data, VOWST Units Sold is 642 and VOWST New Patient Starts is 1,083, which suggests an identifiable commercial ramp signal.
  • SER-109 has completed Phase III for CDI, and SER-155 is in Phase Ib for infection reduction: SER-109 completed Phase III for clostridium difficile infection (CDI). SER-155 is in Phase Ib to reduce incidences of gastrointestinal infections, bloodstream infections, and graft versus host.
  • Clinical-style performance and safety metrics are included for SER-155 and an ECOSPOR-4 study: For SER-155, Relative Risk Reduction (Bacterial Bloodstream Infections) is 77% with an Odds Ratio of 0.15 and P-value of 0.04. For ECOSPOR-4, Sustained Clinical Response Rate is 91% up to Week 8 and Individuals Remaining Free of Clostridioides difficile Infection Through Week 24 (ECOSPOR-4) is 95%.

Bear case

  • The company’s operating profitability is deeply negative in the latest period: The provided operating margin for 2026-03-31 is -5839.9, indicating substantial operating losses.
  • Safety outcomes include non-trivial adverse event rates: Severe Adverse Event Rate in ECOSPOR-4 is 12.5%, and the incidence of Febrile Neutropenia (Treatment Arm) is 65% versus 78.6% in the placebo group (SEER-155).
  • Revenue visibility may be concentrated in a small number of lines: Segmented revenue shown in the dataset is limited to Collaboration Revenue (0.13B), VOWST Net Sales (0.01B), and Grant Revenue (0.0B), so any change in either collaboration activity or VOWST sales could materially affect total revenue.
Valuation — source: SEC EDGAR (first-party)
Price$4.57
Market Cap$45.43M
Price / Book1.32
Price / Sales25.20
FCF Yield-123.0%
Profitability & Growth — source: SEC EDGAR
Revenue (TTM)$789000.00
Net Margin721.9%
Revenue Growth (YoY)-80.1%
FCF Growth (YoY)-100.6%
Financial Health — source: SEC EDGAR
Altman Z-Score-11.55 (distress)
Valuation vs Sector & Industry
Sector P/E (Healthcare)21.7
Industry P/E (Pharmaceutical Products)17.0
Smart-Money Activity — SEC Form 4 / 13F / Congressional disclosures
Top Institutional HolderBlackRock Fund Advisors ($10.92M)
Institutional Holders Tracked10
Company
SectorHealthcare
IndustryPharmaceutical Products
CEOThomas J. DesRosier
Employees103
CountryUS
IPO Date2015-06-26

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MCRB earnings history · MCRB institutional & insider holders · MCRB KPIs & operating metrics · MCRB financials · MCRB investor presentations & press releases · MCRB SEC filings · MCRB peers · Congress trades · Insider trades · Short interest · Stock screener

Data as of 2026-08-21.

Figures sourced from U.S. Securities and Exchange Commission (SEC EDGAR) filings and market data. Not personalized investment advice.