What is CUSIP 81750R102?

CUSIP 81750R102 is the security identifier used in SEC filing datasets for MCRB - Seres Therapeutics, Inc. - COMMON STOCK.

Who owns MCRB - Seres Therapeutics, Inc. - COMMON STOCK based on 13F filings?

Open this security page to review the newest available 13F ownership history, top reported holders, and period-by-period changes.

Security Snapshot

Seres Therapeutics, Inc. - COMMON STOCK (MCRB) Institutional Ownership

CUSIP: 81750R102

13F Institutional Holders and Ownership History from Q2 2015 to Q4 2025

13F reference period

n/a

Institutions Reporting

Shares (Excl. Options)

Price

$0.37

The headline uses the Q2 2026 reference period after its reporting deadline. Available reports may still be incomplete or amended.

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Security type / class: Equity / COMMON STOCK
Symbol: MCRB on Nasdaq
Shares outstanding: 170,403,883
SEC-reported price per share: $0.37
Insider filing price: $0.37

13F Shares, Excluding Options vs Price

13F Value, Excluding Options

Total Investors

Filing notes and source

Key facts

MCRB - Seres Therapeutics, Inc. - COMMON STOCK is tracked under CUSIP 81750R102.
13F reference-period holder data is not available.
1 significant owner is listed from Schedule 13D/13G reporting.

Change

Holder data for the Q2 2026 reference period is not available.
Available periods remain in the history table; they do not substitute for the headline period.

Research use

You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.

Evidence

Source: SEC Schedule 13D/G

Ownership context comes from Schedule 13D/G and available holder history for this CUSIP.

Open SEC evidence

Security key

81750R102

13F reference period

n/a

13F holders

13D/G owners

CIK / CUSIP context first

MCRB full holder history Seres Therapeutics, Inc. SEC filings Seres Therapeutics, Inc. company facts Seres Therapeutics, Inc. insider transactions

Broader feeds

Latest 13F filings Latest 13D/G filings All securities

Recent Quarterly Holder Reports

Open recent reporting periods for CUSIP 81750R102:

Q4 2025 (0 holders) Q3 2025 (1 holder) Q2 2025 (0 holders) Q1 2025 (59 holders) Q4 2024 (69 holders) Q3 2024 (73 holders) Q2 2024 (90 holders) Q1 2024 (95 holders) Q4 2023 (102 holders) Q3 2023 (134 holders)

13D/G owners

Significant owners

Large-stake holder rows connected to Schedule 13D/G evidence.

Rows

Security

MCRB

Filer	Ownership	Change %	Holdings Value	Net Change	Nb Shares	Change %	Reporting Name	Report Period
FMR LLC	13%		$8,070,328		21,811,697		FMR LLC	31 Dec 2024

Quarter history

Institutional holders across reporting periods

Holder count, reported shares/value, and median price by quarter.

Periods

Headline period

n/a

Rows shown

1-25 of 43

Period	13F Shares, Excl. Options	Value, Excl. Options	Value Change	Puts Notional Value	Calls Notional Value	Price (Median)	Investors
2025 Q4	0	$0	-$1,509			$0.37	0
2025 Q3	1,595	$1,509	+$1,509			$0.95	1
2025 Q2	0	$0	-$42,948,707	$0	$0	$0.37	0
2025 Q1	61,356,952	$42,953,245	-$1,247,523	$37,103	$72,171	$0.70	59
2024 Q4	63,076,393	$52,464,054	-$352,556	$189,334	$2,453,586	$0.83	69
2024 Q3	63,393,718	$59,956,736	-$4,727,275	$445,772	$286,923	$0.95	73
2024 Q2	69,128,714	$50,037,075	-$12,264,173	$335,801	$86,060	$0.72	90
2024 Q1	85,696,040	$66,339,394	-$6,635,322	$367,010	$28,564	$0.77	95
2023 Q4	89,516,690	$125,390,235	-$44,011,416	$302,540	$564,340	$1.40	102
2023 Q3	107,395,553	$255,568,518	-$20,522,942	$846,192	$1,180,718	$2.38	134
2023 Q2	112,314,465	$538,060,686	+$33,902,491	$2,821,138	$3,314,515	$4.79	138
2023 Q1	104,749,292	$593,914,430	-$2,181,787	$1,557,549	$1,586,466	$5.67	123
2022 Q4	105,102,786	$588,350,790	+$1,172,569	$679,840	$1,182,160	$5.60	124
2022 Q3	104,748,081	$671,698,908	+$112,916,464	$828,000	$1,320,000	$6.42	116
2022 Q2	90,405,204	$310,011,091	+$47,546,456	$627,000	$621,000	$3.43	120
2022 Q1	75,453,926	$537,205,498	-$11,701,157	$1,568,000	$2,894,000	$7.12	126
2021 Q4	77,171,897	$642,797,804	-$22,035,256	$2,205,000	$3,031,000	$8.33	142
2021 Q3	65,171,447	$453,652,143	-$219,705,817	$1,606,000	$3,013,000	$6.96	125
2021 Q2	66,583,026	$1,580,837,215	-$104,738,997	$5,026,000	$40,217,000	$23.85	139
2021 Q1	74,799,926	$1,540,145,276	+$72,736,725	$3,913,000	$26,204,000	$20.59	148
2020 Q4	71,626,700	$1,756,568,482	+$156,621,977	$5,216,000	$16,288,000	$24.50	147
2020 Q3	85,851,784	$2,426,035,273	+$414,565,041	$14,006,000	$66,942,000	$28.31	111
2020 Q2	71,964,573	$342,248,262	+$20,268,937	$2,855,000	$3,200,000	$4.76	90
2020 Q1	67,788,912	$241,901,175	+$6,595,767	$0		$3.57	74
2019 Q4	65,932,368	$227,461,925	+$4,749,334	$144,000	$0	$3.45	75