Seres Therapeutics, Inc. (MCRB) Institutional Ownership

Ownership Summary

Seres Therapeutics, Inc. (NASDAQ:MCRB) currently has 35 active institutional owners and shareholders as of today (September 2025), that have filed 13F forms with the Securities Exchange Commission (SEC).

• Seres Therapeutics saw its institutional ownership percentage rose to 28.1% in September 2025 from 26.2% in June 2025.
• Quarterly data indicates a 11.54% shift in institutional share volume, and the annual owner count reflects a decrease of 53.95%.
• A review of institutional activity for Seres Therapeutics shows 22 of 35 filers increasing their positions, while 7 reduced their stake, and 6 remained unchanged.
• The total number of shares held by institutions in Seres Therapeutics increased to 2.46Mn as of September 2025, a net change of up by 254.14K shares quarter on quarter, and down 713.97K shares year over year.
• With 1.16Mn shares, Flagship Pioneering Inc. commands the largest institutional position in Seres Therapeutics as of September 30, 2025, equating to 13.20% of the company.
• Among the most significant buyers of Seres Therapeutics during September 2025 were HAP TRADING, LLC (125.00K), J. Goldman & Co LP (88.90K), Caption Management, LLC (75.00K), JANE STREET GROUP, LLC (68.10K), MARSHALL WACE, LLP (34.20K).
• Leading sellers of Seres Therapeutics stock in September 2025 included FMR LLC (266.82K), ROYAL BANK OF CANADA (6.66K), GEODE CAPITAL MANAGEMENT, LLC (6.62K), CHARLES SCHWAB INVESTMENT MANAGEMENT INC (3.47K), NORTHERN TRUST CORP (2.98K).
• The top 10 institutional holders of Seres Therapeutics for the quarter ending September 2025 included Flagship Pioneering Inc. (1.16Mn), VANGUARD GROUP INC (311.89K), MARSHALL WACE, LLP (125.60K), HAP TRADING, LLC (125.00K), BlackRock, Inc. (102.06K), Vontobel Holding Ltd. (98.51K), J. Goldman & Co LP (88.90K), GEODE CAPITAL MANAGEMENT, LLC (84.98K), Caption Management, LLC (75.00K), JANE STREET GROUP, LLC (68.10K).