MCRB Seres Therapeutics, Inc.
Seres Therapeutics, Inc. (MCRB) Institutional Ownership
What the institutions did with MCRB last quarter, from their 13F filings. Counting managers rather than shares is the point: a single index fund adding to a position tells you far less than four hundred separate managers all deciding to. Positions as reported for the quarter ended June 30, 2026.
Every manager below opens. Subscribers can see any firm's whole portfolio — every position, its weight, and what they bought, trimmed and exited last quarter.
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Each block is one manager, sized by shares held and colored by how much they moved the position last quarter. Green added, red cut, grey stood pat.
Largest holders
| Manager | Shares | % of reported |
|---|---|---|
| Flagship Pioneering, LLC | 1.2M | 50.9% |
| VANGUARD CAPITAL MANAGEMENT LLC | 287.8K | 12.7% |
| MARSHALL WACE, LLP | 172.2K | 7.6% |
| Vontobel Holding Ltd. | 123.0K | 5.4% |
| BlackRock, Inc. | 111.0K | 4.9% |
| GEODE CAPITAL MANAGEMENT, LLC | 80.0K | 3.5% |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | 58.3K | 2.6% |
| VANGUARD FIDUCIARY TRUST CO | 48.7K | 2.1% |
| STATE STREET CORP | 33.9K | 1.5% |
| Lion Point Capital, LP | 31.6K | 1.4% |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 31.0K | 1.4% |
| AMERICAN CENTURY COMPANIES INC | 28.3K | 1.2% |
| XTX Topco Ltd | 20.7K | 0.9% |
| GOLDMAN SACHS GROUP INC | 15.2K | 0.7% |
| NORTHERN TRUST CORP | 14.8K | 0.7% |
| Invesco Ltd. | 13.0K | 0.6% |
| MORGAN STANLEY | 12.1K | 0.5% |
| CITADEL ADVISORS LLC | 10.5K | 0.5% |
| SIMPLEX TRADING, LLC | 4.6K | 0.2% |
| SBI Securities Co., Ltd. | 4.2K | 0.2% |
| GROUP ONE TRADING LLC | 3.7K | 0.2% |
| JPMORGAN CHASE & CO | 3.6K | 0.2% |
| Vanguard Global Advisers, LLC | 2.0K | 0.1% |
| FMR LLC | 1.5K | 0.1% |
| Rachor Investment Advisory Services, LLC | 1.5K | 0.1% |
Largest changes
| Manager | Action | Previous | Current | Change |
|---|---|---|---|---|
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | 105.3K | 58.3K | -47.0K |
| AMERICAN CENTURY COMPANIES INC | Reduced | 62.3K | 28.3K | -34.0K |
| MARSHALL WACE, LLP | Increased | 139.5K | 172.2K | +32.7K |
| XTX Topco Ltd | New | 0 | 20.7K | +20.7K |
| TWO SIGMA INVESTMENTS, LP | Sold Out | 18.8K | 0 | -18.8K |
| Vontobel Holding Ltd. | Reduced | 138.5K | 123.0K | -15.5K |
| GOLDMAN SACHS GROUP INC | New | 0 | 15.2K | +15.2K |
| CITADEL ADVISORS LLC | New | 0 | 10.5K | +10.5K |
| MORGAN STANLEY | Reduced | 21.7K | 12.1K | -9.6K |
| VANGUARD FIDUCIARY TRUST CO | Increased | 39.6K | 48.7K | +9.0K |
| BlackRock, Inc. | Increased | 102.0K | 111.0K | +9.0K |
| UBS Group AG | Reduced | 7.0K | 484 | -6.5K |
| VANGUARD CAPITAL MANAGEMENT LLC | Reduced | 294.1K | 287.8K | -6.4K |
| BARCLAYS PLC | Reduced | 6.5K | 167 | -6.3K |
| GEODE CAPITAL MANAGEMENT, LLC | Increased | 74.8K | 80.0K | +5.1K |
| JPMORGAN CHASE & CO | New | 0 | 3.6K | +3.6K |
| GROUP ONE TRADING LLC | Increased | 824 | 3.7K | +2.9K |
| Invesco Ltd. | Reduced | 14.5K | 13.0K | -1.6K |
| SIMPLEX TRADING, LLC | Increased | 3.1K | 4.6K | +1.5K |
| SBI Securities Co., Ltd. | Increased | 3.5K | 4.2K | +700 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | Reduced | 31.6K | 31.0K | -581 |
| Tower Research Capital LLC (TRC) | Reduced | 794 | 316 | -478 |
| FMR LLC | Reduced | 1.8K | 1.5K | -224 |
| Physician Wealth Advisors, Inc. | Sold Out | 142 | 0 | -142 |
| ROYAL BANK OF CANADA | Reduced | 107 | 11 | -96 |
| Continuum Advisory, LLC | New | 0 | 47 | +47 |
| Sound Income Strategies, LLC | Sold Out | 8 | 0 | -8 |
| Arax Advisory Partners | Sold Out | 6 | 0 | -6 |
| Larson Financial Group LLC | New | 0 | 5 | +5 |
| Allworth Financial LP | Sold Out | 4 | 0 | -4 |
| WHITTIER TRUST CO OF NEVADA INC | New | 0 | 1 | +1 |
13F filings are due 45 days after quarter end and cover long positions in U.S.-listed equities only, so this is a lagged and partial picture: shorts, bonds and foreign listings never appear. Options positions are excluded here rather than folded into the share counts. Political ownership is coming.