Seres Therapeutics, Inc. (MCRB) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

8,727,660Shares Outstanding

1,234,350Shares held by institutions

$10,220,418Value of institutional holdings

29.01%Institutional ownership %

13.61%Shares Changed QoQ

36No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

Seres Therapeutics, Inc. (NASDAQ:MCRB) currently has 36 active institutional owners and shareholders as of today (December 2025), that have filed 13F forms with the Securities Exchange Commission (SEC).

The percentage of Seres Therapeutics owned by institutions changed from 28.1% in September 2025 to 29.0% in December 2025, marking a slight up trend.
On a quarter-over-quarter basis, institutional holdings shifted by 13.61%, with a year-over-year a decrease of 47.83% in the count of filers.
During the quarter, 22 institutions bought more Seres Therapeutics shares, 8 sold shares, and 6 of the 36 total investors held their position steady.
The aggregate institutional position in Seres Therapeutics now stands at 2.53Mn shares as of December 2025, after investors increased their holdings (up by 303.31K shares quarter on quarter which is down 618.29K shares year over year).
With 1.16Mn shares, Flagship Pioneering, LLC commands the largest institutional position in Seres Therapeutics as of December 31, 2025, equating to 13.24% of the company.
Among the most significant buyers of Seres Therapeutics during December 2025 were SUSQUEHANNA INTERNATIONAL GROUP, LLP (179.93K), 683 Capital Management, LLC (52.31K), TWO SIGMA INVESTMENTS, LP (25.75K), AMERICAN CENTURY COMPANIES INC (16.27K), OMERS ADMINISTRATION Corp (14.40K).
Leading sellers of Seres Therapeutics stock in December 2025 included JANE STREET GROUP, LLC (38.20K), UBS Group AG (8.46K), MARSHALL WACE, LLP (5.42K), BANK OF AMERICA CORP /DE/ (5.15K), SIMPLEX TRADING, LLC (1.57K).
The top 10 institutional holders of Seres Therapeutics for the quarter ending December 2025 included Flagship Pioneering, LLC (1.16Mn), VANGUARD GROUP INC (324.21K), SUSQUEHANNA INTERNATIONAL GROUP, LLP (179.93K), MARSHALL WACE, LLP (120.18K), BlackRock, Inc. (103.62K), Vontobel Holding Ltd. (103.23K), GEODE CAPITAL MANAGEMENT, LLC (86.14K), Caption Management, LLC (75.00K), 683 Capital Management, LLC (52.31K), STATE STREET CORP (33.90K).

36 Institutional Holders

1,234,350 Total Shares Held

Rows:

Download Data

Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
Flagship Pioneering, LLC	31 Dec, 2025	1,155,850	0	0.00%	$17,236,411.00
VANGUARD GROUP INC	31 Dec, 2025	324,214	12,325	3.95%	$4,824,304.00
SUSQUEHANNA INTERNATIONAL GROUP, LLP	31 Dec, 2025	179,929	179,929	0.00%	$2,677,344.00
MARSHALL WACE, LLP	31 Dec, 2025	120,177	-5,423	-4.32%	$1,788,234.00
BlackRock, Inc.	31 Dec, 2025	103,621	1,561	1.53%	$1,541,880.00
Vontobel Holding Ltd.	31 Dec, 2025	103,234	4,723	4.79%	$1,536,122.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	86,142	1,160	1.36%	$1,282,308.00
Caption Management, LLC	31 Dec, 2025	75,000	0	0.00%	$1,116,000.00
683 Capital Management, LLC	31 Dec, 2025	52,314	52,314	0.00%	$778,432.00
STATE STREET CORP	31 Dec, 2025	33,901	4,170	14.03%	$504,447.00
Lion Point Capital, LP	31 Dec, 2025	31,570	4,432	16.33%	$469,762.00
CITADEL ADVISORS LLC	31 Dec, 2025	31,418	533	1.73%	$467,500.00
CHARLES SCHWAB INVESTMENT MANAGEMENT INC	31 Dec, 2025	31,369	-34	-0.11%	$466,771.00
JANE STREET GROUP, LLC	31 Dec, 2025	29,905	-38,195	-56.09%	$444,986.00
Schonfeld Strategic Advisors LLC	31 Dec, 2025	29,097	155	0.54%	$432,961.00
TWO SIGMA INVESTMENTS, LP	31 Dec, 2025	25,749	25,749	0.00%	$383,145.00
MORGAN STANLEY	31 Dec, 2025	25,126	6,792	37.05%	$373,874.00
AMERICAN CENTURY COMPANIES INC	31 Dec, 2025	16,271	16,271	0.00%	$242,112.00
NORTHERN TRUST CORP	31 Dec, 2025	14,765	2,664	22.01%	$219,704.00
OMERS ADMINISTRATION Corp	31 Dec, 2025	14,400	14,400	0.00%	$214,272.00

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