Latest Period
Q1 2026
Security Snapshot
Seres Therapeutics, Inc. - COMMON STOCK (MCRB) Institutional Ownership
CUSIP: 81750R201
13F Institutional Holders and Ownership History from Q1 2025 to Q1 2026
Institutions Reporting
32
Shares (Excl. Options)
2,306,457
Price
$8.87
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- Type / Class
- Equity / COMMON STOCK
- Symbol
- MCRB on Nasdaq
- Shares outstanding
- 8,667,871
- Price per share
- $8.44
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 2,306,457
- Total reported value
- $20,458,733
- % of total 13F portfolios
- 0%
- Share change
- -146,091
- Value change
- -$2,224,292
- Number of holders
- 32
- Price from insider filings
- $8.44
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors
Key facts
- MCRB - Seres Therapeutics, Inc. - COMMON STOCK is tracked under CUSIP 81750R201.
- 32 institutions reported positions in Q1 2026.
- 1 significant owner is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 35 to 32 between Q4 2025 and Q1 2026.
- Reported value moved from $36,368,373 to $20,458,733.
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 Form 13F
Open SEC Evidence
Latest holder context comes from 32 institutions filings for Q1 2026.
Security key
81750R201
Latest holder period
Q1 2026
13F holders
32
13D/G owners
1
CIK / CUSIP context first
Open Q1 2026 holders
MCRB full holder history
Seres Therapeutics, Inc. SEC filings
Seres Therapeutics, Inc. company facts
Seres Therapeutics, Inc. insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 81750R201:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
1
Security
MCRB
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| FMR LLC | 3.1% | -43% | $3,377,609 | -$2,827,043 | 268,704 | -46% | FMR LLC | 30 Jun 2025 |
As of 31 Mar 2026, 32 institutional investors reported holding 2,306,457 shares of Seres Therapeutics, Inc. - COMMON STOCK (MCRB). This represents 27% of the company’s total 8,667,871 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
27%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| Flagship Pioneering, LLC | 13% | 1,155,850 | 0% | 0.88% | $10,252,390 |
| VANGUARD CAPITAL MANAGEMENT LLC | 3.4% | 294,143 | 0% | 0% | $2,609,048 |
| MARSHALL WACE, LLP | 1.6% | 139,539 | +16% | 0% | $1,237,710 |
| Vontobel Holding Ltd. | 1.6% | 138,468 | +34% | 0% | $1,228,211 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | 1.2% | 105,339 | -41% | 0% | $934,357 |
| BlackRock, Inc. | 1.2% | 102,026 | -1.5% | 0% | $904,970 |
| GEODE CAPITAL MANAGEMENT, LLC | 0.86% | 74,835 | -13% | 0% | $664,108 |
| AMERICAN CENTURY COMPANIES INC | 0.72% | 62,316 | +283% | 0% | $552,743 |
| VANGUARD FIDUCIARY TRUST CO | 0.46% | 39,643 | 0% | 0% | $351,633 |
| STATE STREET CORP | 0.39% | 33,901 | 0% | 0% | $300,702 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 0.36% | 31,630 | +0.83% | 0% | $280,558 |
| Lion Point Capital, LP | 0.36% | 31,570 | 0% | 1.7% | $280,026 |
| MORGAN STANLEY | 0.25% | 21,700 | -14% | 0% | $192,478 |
| TWO SIGMA INVESTMENTS, LP | 0.22% | 18,794 | -27% | 0% | $166,703 |
| NORTHERN TRUST CORP | 0.17% | 14,765 | 0% | 0% | $130,966 |
| Invesco Ltd. | 0.17% | 14,547 | +1.3% | 0% | $129,032 |
| UBS Group AG | 0.08% | 7,030 | +66% | 0% | $62,357 |
| BARCLAYS PLC | 0.08% | 6,507 | -12% | 0% | $57,717 |
| SBI Securities Co., Ltd. | 0.04% | 3,482 | 0% | 0% | $30,885 |
| SIMPLEX TRADING, LLC | 0.04% | 3,070 | +149% | 0% | $27,230 |
| Vanguard Global Advisers, LLC | 0.02% | 1,975 | 0% | 0% | $17,518 |
| FMR LLC | 0.02% | 1,752 | +0.69% | 0% | $15,540 |
| Rachor Investment Advisory Services, LLC | 0.02% | 1,477 | 0% | 0.01% | $13,101 |
| GROUP ONE TRADING LLC | 0.01% | 824 | 0% | $7,309 | |
| Tower Research Capital LLC (TRC) | 0.01% | 794 | 0% | $7,043 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
5
Latest
Q1 2026
| Period | Reported Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 2,306,457 | $20,458,733 | -$2,224,292 | $8.87 | 32 |
| 2025 Q4 | 2,441,565 | $36,368,373 | +$4,536,402 | $14.88 | 35 |
| 2025 Q3 | 2,125,842 | $40,902,370 | -$2,393,659 | $19.24 | 32 |
| 2025 Q2 | 2,284,946 | $25,385,817 | +$24,555,434 | $11.11 | 33 |
| 2025 Q1 | 145,407 | $101,799 | +$101,799 | $0.70 | 4 |