Mersana Therapeutics, Inc. - MRSN
Detailed investor-level table based on 13F positions.
Early Q1 2026 data: only 1 institutional holders reported so far. The full shareholder list will grow as more funds file with the SEC.
Methodology:
Market value and % of portfolio use SEC reported VALUE ($000).
For PUT/CALL positions this reflects reported underlying exposure, not premium cash paid/received.
Details.
Rows: 0
| Investor | History | Status | Shares held | Market value ($000) | % of portfolio | Previous % | Rank | Change in shares | % change in shares | Source | Date reported |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Nextech Invest, Ltd. | History | No change | 482,689 | 13,964 | 1.35% | 0.57% | 1 | 0 | 0.0% | Q4 2025 | Feb 17, 2026 |
| Bain Capital Life Sciences Investors, LLC | History | No change | 346,545 | 10,025 | 0.77% | 0.18% | 2 | 0 | 0.0% | Q4 2025 | Feb 17, 2026 |
| VANGUARD GROUP INC | History | Reduced | 210,301 | 6,084 | 0.0% | 0.0% | 3 | -92,252 | -30.49% | Q4 2025 | Jan 29, 2026 |
| Rock Springs Capital Management LP | History | No change | 152,586 | 4,414 | 0.23% | 0.07% | 4 | 0 | 0.0% | Q4 2025 | Feb 17, 2026 |
| Alamea Verwaltungs GmbH | History | Reduced | 24,165 | 3,336 | 2.25% | 2.28% | 5 | -405,860 | -94.38% | Q4 2025 | Feb 13, 2026 |
| ACADIAN ASSET MANAGEMENT LLC | History | Reduced | 110,882 | 3,207 | 0.01% | 0.0% | 6 | -31,478 | -22.11% | Q4 2025 | Feb 10, 2026 |
| Affinity Asset Advisors, LLC | History | New | 100,000 | 2,893 | 0.16% | — | 7 | +100,000 | New | Q4 2025 | Feb 13, 2026 |
| BlackRock, Inc. | History | Reduced | 69,210 | 2,002 | 0.0% | 0.0% | 8 | -26,983 | -28.05% | Q4 2025 | Feb 12, 2026 |
| BANK OF AMERICA CORP /DE/ | History | Reduced | 65,749 | 1,902 | 0.0% | 0.0% | 9 | -648 | -0.98% | Q4 2025 | Feb 17, 2026 |
| MILLENNIUM MANAGEMENT LLC | History | Reduced | 63,305 | 1,831 | 0.0% | 0.0% | 10 | -14,684 | -18.83% | Q4 2025 | Feb 17, 2026 |
| Groupe la Francaise | History | New | 61,488 | 1,778 | 0.02% | — | 11 | +61,488 | New | Q4 2025 | Feb 12, 2026 |
| Rangeley Capital, LLC | History | New | 57,098 | 1,651 | 1.37% | — | 12 | +57,098 | New | Q4 2025 | Feb 17, 2026 |
| GABELLI FUNDS LLC | History | New | 47,300 | 1,368 | 0.01% | — | 13 | +47,300 | New | Q4 2025 | Feb 05, 2026 |
| GEODE CAPITAL MANAGEMENT, LLC | History | Added to | 43,920 | 1,270 | 0.0% | 0.0% | 14 | +2,272 | 5.46% | Q4 2025 | Feb 09, 2026 |
| CREDIT INDUSTRIEL ET COMMERCIAL | History | New | 41,392 | 1,197 | 0.09% | — | 15 | +41,392 | New | Q4 2025 | Feb 03, 2026 |
| AQR CAPITAL MANAGEMENT LLC | History | Reduced | 37,264 | 1,078 | 0.0% | 0.0% | 16 | -9,456 | -20.24% | Q4 2025 | Feb 17, 2026 |
| MACKENZIE FINANCIAL CORP | History | Reduced | 33,834 | 967 | 0.0% | 0.0% | 17 | -13,985 | -29.25% | Q4 2025 | Feb 18, 2026 |
| Yakira Capital Management, Inc. | History | New | 32,663 | 944 | 0.32% | — | 18 | +32,663 | New | Q4 2025 | Feb 13, 2026 |
| CITADEL ADVISORS LLC | History | New | 22,493 | 650 | 0.0% | — | 19 | +22,493 | New | Q4 2025 | Feb 17, 2026 |
| EQUITEC PROPRIETARY MARKETS, LLC | History | New | 20,593 | 595 | 0.34% | — | 20 | +20,593 | New | Q4 2025 | Feb 17, 2026 |
| STATE STREET CORP | History | Reduced | 19,543 | 565 | 0.0% | 0.0% | 21 | -10,300 | -34.51% | Q4 2025 | Feb 13, 2026 |
| MORGAN STANLEY | History | Reduced | 18,496 | 535 | 0.0% | 0.0% | 22 | -29,831 | -61.73% | Q4 2025 | Feb 13, 2026 |
| DELTEC ASSET MANAGEMENT LLC | History | New | 18,000 | 520 | 0.09% | — | 23 | +18,000 | New | Q4 2025 | Jan 29, 2026 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | History | New | 15,400 | 445 | 0.0% | — | 24 | +15,400 | New | Q4 2025 | Feb 17, 2026 |
| Knott David M Jr | History | New | 111,686 | 437 | 0.2% | — | 25 | +111,686 | New | Q4 2025 | Feb 12, 2026 |
| IEQ CAPITAL, LLC | History | Reduced | 12,955 | 374 | 0.0% | 0.0% | 26 | -2,285 | -14.99% | Q4 2025 | Feb 13, 2026 |
| XTX Topco Ltd | History | New | 11,948 | 345 | 0.01% | — | 27 | +11,948 | New | Q4 2025 | Feb 17, 2026 |
| Point72 Asset Management, L.P. | History | New | 10,364 | 299 | 0.0% | — | 28 | +10,364 | New | Q4 2025 | Feb 17, 2026 |
| GAMCO INVESTORS, INC. ET AL | History | New | 10,000 | 289 | 0.0% | — | 29 | +10,000 | New | Q4 2025 | Feb 05, 2026 |
| NORTHERN TRUST CORP | History | New | 8,586 | 248 | 0.0% | — | 30 | +8,586 | New | Q4 2025 | Feb 17, 2026 |
| OMERS ADMINISTRATION Corp | History | New | 7,900 | 228 | 0.0% | — | 31 | +7,900 | New | Q4 2025 | Feb 13, 2026 |
| CWM, LLC | History | Reduced | 2,286 | 66 | 0.0% | 0.0% | 32 | -592 | -20.57% | Q4 2025 | Jan 26, 2026 |
| BNP PARIBAS FINANCIAL MARKETS | History | Added to | 1,090 | 31 | 0.0% | 0.0% | 34 | +559 | 105.27% | Q4 2025 | Feb 10, 2026 |
| GROUP ONE TRADING LLC | History | Added to | 1,073 | 31 | 0.0% | 0.0% | 33 | +112 | 11.65% | Q4 2025 | Feb 12, 2026 |
| Mint Tower Capital Management B.V. | History | New | 1,035 | 30 | 0.0% | — | 35 | +1,035 | New | Q4 2025 | Feb 12, 2026 |
| Tower Research Capital LLC (TRC) | History | Reduced | 376 | 10 | 0.0% | 0.0% | 36 | -1,186 | -75.93% | Q4 2025 | Feb 17, 2026 |
| UBS Group AG | History | Reduced | 221 | 6 | 0.0% | 0.0% | 37 | -8,388 | -97.43% | Q4 2025 | Jan 29, 2026 |
| ROYAL BANK OF CANADA | History | New | 168 | 5 | 0.0% | — | 38 | +168 | New | Q4 2025 | Feb 17, 2026 |
| JPMORGAN CHASE & CO | History | Reduced | 112 | 3 | 0.0% | 0.0% | 39 | -5,996 | -98.17% | Q4 2025 | Feb 11, 2026 |
| Lion Point Capital, LP | History | Reduced | 100 | 2 | 0.01% | 1.13% | 40 | -25,660 | -99.61% | Q4 2025 | Feb 17, 2026 |
| FLAGSHIP HARBOR ADVISORS, LLC | History | New | 76 | 2 | 0.0% | — | 42 | +76 | New | Q4 2025 | Jan 21, 2026 |
| OSAIC HOLDINGS, INC. | History | No change | 103 | 2 | 0.0% | — | 41 | 0 | 0.0% | Q4 2025 | Feb 17, 2026 |
| WELLS FARGO & COMPANY/MN | History | Reduced | 40 | 1 | 0.0% | 0.0% | 43 | -1,200 | -96.77% | Q4 2025 | Feb 13, 2026 |
| SBI Securities Co., Ltd. | History | Reduced | 53 | 1 | 0.0% | — | 44 | -1 | -1.85% | Q4 2025 | Feb 03, 2026 |
| Schonfeld Strategic Advisors LLC | History | Closed out | 0 | 0 | — | 0.01% | — | -273,579 | -100.0% | Q3 2025 | Nov 14, 2025 |
| SILVERARC CAPITAL MANAGEMENT, LLC | History | Closed out | 0 | 0 | — | 0.14% | — | -133,636 | -100.0% | Q3 2025 | Nov 12, 2025 |
| 683 Capital Management, LLC | History | Closed out | 0 | 0 | — | 0.04% | — | -100,000 | -100.0% | Q3 2025 | Nov 14, 2025 |
| RENAISSANCE TECHNOLOGIES LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -88,465 | -100.0% | Q3 2025 | Nov 13, 2025 |
| 5AM Venture Management, LLC | History | Closed out | 0 | 0 | — | 0.15% | — | -52,200 | -100.0% | Q3 2025 | Nov 14, 2025 |
| TWO SIGMA ADVISERS, LP | History | Closed out | 0 | 0 | — | 0.0% | — | -40,640 | -100.0% | Q3 2025 | Nov 14, 2025 |
| TWO SIGMA INVESTMENTS, LP | History | Closed out | 0 | 0 | — | 0.0% | — | -30,688 | -100.0% | Q3 2025 | Nov 14, 2025 |
| DRW Securities, LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -13,851 | -100.0% | Q3 2025 | Nov 14, 2025 |
| Voleon Capital Management LP | History | Closed out | 0 | 0 | — | 0.0% | — | -13,200 | -100.0% | Q3 2025 | Nov 14, 2025 |
| FMR LLC | History | Reduced | 8 | 0 | — | 0.0% | — | -4,856 | -99.84% | Q4 2025 | Feb 17, 2026 |
| China Universal Asset Management Co., Ltd. | History | Closed out | 0 | 0 | — | 0.0% | — | -875 | -100.0% | Q3 2025 | Nov 10, 2025 |
| BARCLAYS PLC | History | Closed out | 0 | 0 | — | 0.0% | — | -198 | -100.0% | Q3 2025 | Mar 31, 2026 |
| Mirae Asset Global Investments Co., Ltd. | History | Closed out | 0 | 0 | — | 0.0% | — | -193 | -100.0% | Q3 2025 | Nov 03, 2025 |
| Arax Advisory Partners | History | Closed out | 0 | 0 | — | 0.0% | — | -157 | -100.0% | Q3 2025 | Nov 14, 2025 |
| CITIGROUP INC | History | Closed out | 0 | 0 | — | — | — | -106 | -100.0% | Q3 2025 | Nov 10, 2025 |
| GF FUND MANAGEMENT CO. LTD. | History | Closed out | 0 | 0 | — | — | — | -94 | -100.0% | Q3 2025 | Nov 07, 2025 |
| SHP Wealth Management | History | New | 25 | 0 | — | — | — | +25 | New | Q4 2025 | Mar 04, 2026 |
| IFP Advisors, Inc | History | Reduced | 3 | 0 | — | — | — | -2 | -40.0% | Q4 2025 | Feb 06, 2026 |
| HUNTINGTON NATIONAL BANK | History | No change | 32 | 0 | — | — | — | 0 | 0.0% | Q4 2025 | Feb 09, 2026 |
| DANSKE BANK A/S | History | No change | 1 | 0 | — | — | — | 0 | 0.0% | Q4 2025 | Feb 02, 2026 |