MREO Mereo BioPharma Group plc
Mereo BioPharma Group plc (MREO) Institutional Ownership
What the institutions did with MREO 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 |
|---|---|---|
| Rubric Capital Management LP | 15.3M | 27.0% |
| 683 Capital Management, LLC | 11.8M | 20.8% |
| BANK OF AMERICA CORP /DE/ | 8.2M | 14.5% |
| Defilade Capital Management, L.P. | 7.6M | 13.4% |
| Newtyn Management, LLC | 3.0M | 5.3% |
| Tejara Capital Ltd | 2.0M | 3.6% |
| UBS Group AG | 1.4M | 2.6% |
| TWO SIGMA INVESTMENTS, LP | 1.3M | 2.3% |
| EcoR1 Capital, LLC | 1.0M | 1.8% |
| JANE STREET GROUP, LLC | 774.9K | 1.4% |
| Ishara Investments LP | 768.8K | 1.4% |
| Wealthspire Advisors, LLC | 765.0K | 1.4% |
| CITADEL ADVISORS LLC | 444.2K | 0.8% |
| Rangeley Capital, LLC | 329.2K | 0.6% |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | 213.3K | 0.4% |
| MARSHALL WACE, LLP | 179.9K | 0.3% |
| XTX Topco Ltd | 174.5K | 0.3% |
| GROUP ONE TRADING LLC | 167.5K | 0.3% |
| STATE STREET CORP | 134.8K | 0.2% |
| NOMURA HOLDINGS INC | 104.4K | 0.2% |
| James J. Burns & Company, LLC | 95.4K | 0.2% |
| Quarry LP | 93.8K | 0.2% |
| GOLDMAN SACHS GROUP INC | 85.2K | 0.2% |
| JMN Financial LLC | 76.7K | 0.1% |
| BlackRock, Inc. | 69.7K | 0.1% |
Largest changes
| Manager | Action | Previous | Current | Change |
|---|---|---|---|---|
| EcoR1 Capital, LLC | Reduced | 13.4M | 1.0M | -12.4M |
| Newtyn Management, LLC | Reduced | 7.1M | 3.0M | -4.1M |
| MILLENNIUM MANAGEMENT LLC | Sold Out | 3.6M | 0 | -3.6M |
| TWO SIGMA INVESTMENTS, LP | Increased | 187.8K | 1.3M | +1.1M |
| Ishara Investments LP | New | 0 | 768.8K | +768.8K |
| JANE STREET GROUP, LLC | Increased | 140.0K | 774.9K | +635.0K |
| MARSHALL WACE, LLP | Reduced | 687.0K | 179.9K | -507.1K |
| CITADEL ADVISORS LLC | New | 0 | 444.2K | +444.2K |
| Knott David M Jr | Sold Out | 300.3K | 0 | -300.3K |
| BlackRock, Inc. | Reduced | 303.0K | 69.7K | -233.3K |
| 683 Capital Management, LLC | Reduced | 12.0M | 11.8M | -222.1K |
| ACADIAN ASSET MANAGEMENT LLC | Sold Out | 209.1K | 0 | -209.1K |
| GROUP ONE TRADING LLC | Reduced | 335.8K | 167.5K | -168.3K |
| ADAR1 Capital Management, LLC | Sold Out | 150.0K | 0 | -150.0K |
| Forefront Analytics, LLC | Sold Out | 127.8K | 0 | -127.8K |
| Virtus Investment Advisers, LLC | Sold Out | 125.7K | 0 | -125.7K |
| NOMURA HOLDINGS INC | New | 0 | 104.4K | +104.4K |
| James J. Burns & Company, LLC | New | 0 | 95.4K | +95.4K |
| Quarry LP | New | 0 | 93.8K | +93.8K |
| GEODE CAPITAL MANAGEMENT, LLC | Sold Out | 92.5K | 0 | -92.5K |
| XTX Topco Ltd | Increased | 84.5K | 174.5K | +90.0K |
| GOLDMAN SACHS GROUP INC | New | 0 | 85.2K | +85.2K |
| JMN Financial LLC | New | 0 | 76.7K | +76.7K |
| Caption Management, LLC | Sold Out | 64.1K | 0 | -64.1K |
| SmartHarvest Portfolios, LLC | Sold Out | 49.5K | 0 | -49.5K |
| UBS Group AG | Reduced | 1.5M | 1.4M | -42.5K |
| StoneX Group Inc. | Sold Out | 36.9K | 0 | -36.9K |
| JPMORGAN CHASE & CO | Increased | 21.8K | 58.5K | +36.7K |
| Independent Advisor Alliance | Sold Out | 35.2K | 0 | -35.2K |
| Wealthspire Advisors, LLC | Reduced | 796.0K | 765.0K | -31.0K |
| Virtu Financial LLC | Increased | 36.5K | 61.3K | +24.8K |
| Three Magnolias Financial Advisors, LLC | Sold Out | 19.0K | 0 | -19.0K |
| SIMPLEX TRADING, LLC | New | 0 | 18.8K | +18.8K |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Increased | 195.9K | 213.3K | +17.4K |
| TWO SIGMA SECURITIES, LLC | New | 0 | 12.9K | +12.9K |
| J. Safra Sarasin Holding AG | New | 0 | 12.8K | +12.8K |
| SG Americas Securities, LLC | New | 0 | 12.8K | +12.8K |
| Baader Bank Aktiengesellschaft | Sold Out | 12.3K | 0 | -12.3K |
| GAMMA Investing LLC | Reduced | 19.3K | 9.3K | -10.0K |
| RHUMBLINE ADVISERS | Increased | 19.6K | 26.8K | +7.2K |
| Significant Wealth Partners LLC | Increased | 25.6K | 32.7K | +7.0K |
| RENAISSANCE TECHNOLOGIES LLC | Increased | 48.4K | 52.1K | +3.7K |
| Clear Harbor Asset Management, LLC | Reduced | 35.0K | 32.0K | -3.0K |
| BARCLAYS PLC | Sold Out | 2.5K | 0 | -2.5K |
| Arax Advisory Partners | Increased | 4.0K | 5.8K | +1.8K |
| STATE STREET CORP | Increased | 133.4K | 134.8K | +1.4K |
| MAI Capital Management | Sold Out | 309 | 0 | -309 |
| MORGAN STANLEY | Increased | 16.4K | 16.7K | +306 |
| Sound Income Strategies, LLC | Sold Out | 66 | 0 | -66 |
| CITIGROUP INC | New | 0 | 52 | +52 |
| NATIONAL BANK OF CANADA /FI/ | Sold Out | 46 | 0 | -46 |
| BANK OF AMERICA CORP /DE/ | Reduced | 8.2M | 8.2M | -6 |
| Engineers Gate Manager LP | Reduced | 24.0K | 24.0K | -1 |
| Caitong International Asset Management Co., Ltd | New | 0 | 1 | +1 |
| WELLS FARGO & COMPANY/MN | Increased | 230 | 231 | +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.