Mersana Therapeutics, Inc. - MRSN
Detailed investor-level table based on 13F positions.
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| VANGUARD GROUP INC | History | No change | 210,301 | 6,084 | 0.0% | 0.0% | 1 | 0 | 0.0% | Q4 2025 | Jan 29, 2026 |
| Nextech Invest, Ltd. | History | Closed out | 0 | 0 | — | 1.35% | — | -482,689 | -100.0% | Q1 2026 | May 15, 2026 |
| Bain Capital Life Sciences Investors, LLC | History | Closed out | 0 | 0 | — | 0.77% | — | -346,545 | -100.0% | Q1 2026 | May 15, 2026 |
| Rock Springs Capital Management LP | History | Closed out | 0 | 0 | — | 0.23% | — | -152,586 | -100.0% | Q1 2026 | May 15, 2026 |
| Knott David M Jr | History | Closed out | 0 | 0 | — | 0.2% | — | -111,686 | -100.0% | Q1 2026 | May 14, 2026 |
| ACADIAN ASSET MANAGEMENT LLC | History | Closed out | 0 | 0 | — | 0.01% | — | -110,882 | -100.0% | Q1 2026 | May 13, 2026 |
| Affinity Asset Advisors, LLC | History | Closed out | 0 | 0 | — | 0.16% | — | -100,000 | -100.0% | Q1 2026 | May 14, 2026 |
| BlackRock, Inc. | History | Closed out | 0 | 0 | — | 0.0% | — | -69,210 | -100.0% | Q1 2026 | May 13, 2026 |
| BANK OF AMERICA CORP /DE/ | History | Closed out | 0 | 0 | — | 0.0% | — | -65,749 | -100.0% | Q1 2026 | May 15, 2026 |
| MILLENNIUM MANAGEMENT LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -63,305 | -100.0% | Q1 2026 | May 15, 2026 |
| Groupe la Francaise | History | Closed out | 0 | 0 | — | 0.02% | — | -61,488 | -100.0% | Q1 2026 | May 21, 2026 |
| Rangeley Capital, LLC | History | Closed out | 0 | 0 | — | 1.37% | — | -57,098 | -100.0% | Q1 2026 | May 15, 2026 |
| GABELLI FUNDS LLC | History | Closed out | 0 | 0 | — | 0.01% | — | -47,300 | -100.0% | Q1 2026 | May 14, 2026 |
| GEODE CAPITAL MANAGEMENT, LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -43,920 | -100.0% | Q1 2026 | May 15, 2026 |
| CREDIT INDUSTRIEL ET COMMERCIAL | History | Closed out | 0 | 0 | — | 0.09% | — | -41,392 | -100.0% | Q1 2026 | Apr 29, 2026 |
| AQR CAPITAL MANAGEMENT LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -37,264 | -100.0% | Q1 2026 | May 15, 2026 |
| MACKENZIE FINANCIAL CORP | History | Closed out | 0 | 0 | — | 0.0% | — | -33,834 | -100.0% | Q1 2026 | May 13, 2026 |
| Yakira Capital Management, Inc. | History | Closed out | 0 | 0 | — | 0.32% | — | -32,663 | -100.0% | Q1 2026 | May 14, 2026 |
| Alamea Verwaltungs GmbH | History | Closed out | 0 | 0 | — | 2.25% | — | -24,165 | -100.0% | Q1 2026 | May 11, 2026 |
| CITADEL ADVISORS LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -22,493 | -100.0% | Q1 2026 | May 15, 2026 |
| EQUITEC PROPRIETARY MARKETS, LLC | History | Closed out | 0 | 0 | — | 0.34% | — | -20,593 | -100.0% | Q1 2026 | May 11, 2026 |
| STATE STREET CORP | History | Closed out | 0 | 0 | — | 0.0% | — | -19,543 | -100.0% | Q1 2026 | May 15, 2026 |
| MORGAN STANLEY | History | Closed out | 0 | 0 | — | 0.0% | — | -18,496 | -100.0% | Q1 2026 | May 15, 2026 |
| DELTEC ASSET MANAGEMENT LLC | History | Closed out | 0 | 0 | — | 0.09% | — | -18,000 | -100.0% | Q1 2026 | Apr 24, 2026 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | History | Closed out | 0 | 0 | — | 0.0% | — | -15,400 | -100.0% | Q1 2026 | May 15, 2026 |
| IEQ CAPITAL, LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -12,955 | -100.0% | Q1 2026 | May 14, 2026 |
| XTX Topco Ltd | History | Closed out | 0 | 0 | — | 0.01% | — | -11,948 | -100.0% | Q1 2026 | May 15, 2026 |
| Point72 Asset Management, L.P. | History | Closed out | 0 | 0 | — | 0.0% | — | -10,364 | -100.0% | Q1 2026 | May 15, 2026 |
| GAMCO INVESTORS, INC. ET AL | History | Closed out | 0 | 0 | — | 0.0% | — | -10,000 | -100.0% | Q1 2026 | May 14, 2026 |
| NORTHERN TRUST CORP | History | Closed out | 0 | 0 | — | 0.0% | — | -8,586 | -100.0% | Q1 2026 | May 14, 2026 |
| OMERS ADMINISTRATION Corp | History | Closed out | 0 | 0 | — | 0.0% | — | -7,900 | -100.0% | Q1 2026 | May 15, 2026 |
| CWM, LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -2,286 | -100.0% | Q1 2026 | May 14, 2026 |
| BNP PARIBAS FINANCIAL MARKETS | History | Closed out | 0 | 0 | — | 0.0% | — | -1,090 | -100.0% | Q1 2026 | May 12, 2026 |
| GROUP ONE TRADING LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -1,073 | -100.0% | Q1 2026 | May 13, 2026 |
| Mint Tower Capital Management B.V. | History | Closed out | 0 | 0 | — | 0.0% | — | -1,035 | -100.0% | Q1 2026 | May 04, 2026 |
| Tower Research Capital LLC (TRC) | History | Closed out | 0 | 0 | — | 0.0% | — | -376 | -100.0% | Q1 2026 | May 15, 2026 |
| UBS Group AG | History | Closed out | 0 | 0 | — | 0.0% | — | -221 | -100.0% | Q1 2026 | May 05, 2026 |
| ROYAL BANK OF CANADA | History | Closed out | 0 | 0 | — | 0.0% | — | -168 | -100.0% | Q1 2026 | May 15, 2026 |
| JPMORGAN CHASE & CO | History | Closed out | 0 | 0 | — | 0.0% | — | -112 | -100.0% | Q1 2026 | May 13, 2026 |
| OSAIC HOLDINGS, INC. | History | Closed out | 0 | 0 | — | 0.0% | — | -103 | -100.0% | Q1 2026 | May 15, 2026 |
| Lion Point Capital, LP | History | Closed out | 0 | 0 | — | 0.01% | — | -100 | -100.0% | Q1 2026 | May 15, 2026 |
| FLAGSHIP HARBOR ADVISORS, LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -76 | -100.0% | Q1 2026 | Apr 28, 2026 |
| SBI Securities Co., Ltd. | History | Closed out | 0 | 0 | — | 0.0% | — | -53 | -100.0% | Q1 2026 | Apr 27, 2026 |
| WELLS FARGO & COMPANY/MN | History | Closed out | 0 | 0 | — | 0.0% | — | -40 | -100.0% | Q1 2026 | Jul 08, 2026 |
| HUNTINGTON NATIONAL BANK | History | Closed out | 0 | 0 | — | — | — | -32 | -100.0% | Q1 2026 | May 15, 2026 |
| SHP Wealth Management | History | Closed out | 0 | 0 | — | — | — | -25 | -100.0% | Q1 2026 | May 08, 2026 |
| FMR LLC | History | Closed out | 0 | 0 | — | — | — | -8 | -100.0% | Q1 2026 | May 15, 2026 |
| DANSKE BANK A/S | History | Closed out | 0 | 0 | — | — | — | -1 | -100.0% | Q1 2026 | May 12, 2026 |
| IFP Advisors, Inc | History | No change | 3 | 0 | — | — | — | 0 | 0.0% | Q1 2026 | Apr 13, 2026 |