Mersana Therapeutics, Inc.
MRSNDelisted Jan 6, 2026- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001442836
Mersana Therapeutics, Inc. was delisted on Jan 6, 2026; its insiders filed their last Form 4 on Jan 6, 2026; 51 institutions reported holding it in 13F filings for Q4 2025, worth $64.8M in total; no superinvestor held it.
Holders of 5% or more of MRSN
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Mersana Therapeutics, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Nextech Crossover I GP S.a r.l. | 13G/A | 10.40%12.1M shares | – | Dec 26, 20241 filing | Dec 26, 2024 | SEC |
| 683 Capital Management, LLC | 13G/A | 7.03%351.3K shares | +1.56 ppfrom 5.47% | Nov 24, 20252 filings | Feb 17, 2026 | SEC |
| Vanguard Group Inc | 13G/A | 6.72%8.38M shares | – | Apr 30, 20251 filing | Apr 30, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
16 Schedule 13D and 13G filings on Mersana Therapeutics, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Feb 17, 20264:31 PM ET | Schonfeld Strategic Advisors LLC | 13G/A | 0.00%0 shares | −5.48 ppfrom 5.48%Below 5% | Dec 31, 2025 | SEC |
| Feb 17, 202610:09 AM ET | 683 Capital Management, LLCand 2 others | 13G/A | 7.03%351.3K shares | +1.56 ppfrom 5.47% | Dec 31, 2025 | SEC |
| Nov 24, 20255:12 PM ET | 683 Capital Management, LLCand 2 others | 13G | 5.47%273.4K shares | New | Nov 17, 2025 | SEC |
| Nov 14, 20254:15 PM ET | Schonfeld Strategic Advisors LLC | 13G | 5.48%273.6K shares | +0.93 ppfrom 4.55% | Sep 30, 2025 | SEC |
| Nov 13, 20256:45 PM ET | Bain Capital Life Sciences Fund II, L.P.and 2 others | 13D/A | 4.00%198.7K shares | –Below 5% | Nov 12, 2025 | SEC |
| Aug 14, 20254:31 PM ET | Schonfeld Strategic Advisors LLC | 13G/A | 4.55%5.67M shares | −1.56 ppfrom 6.11%Below 5% | Jun 30, 2025 | SEC |
| Jul 17, 20257:54 PM ET | BlackRock, Inc. | 13G/A | 3.00%3.76M shares | −3.70 ppfrom 6.70%Below 5% | Jun 30, 2025 | SEC |
| May 15, 20255:48 PM ET | Venrock Healthcare Capital Partners III, L.P.and 6 others | 13G/A | 2.90%3.57M shares | −5.40 ppfrom 8.30%Below 5% | Mar 31, 2025 | SEC |
| May 15, 20254:31 PM ET | Schonfeld Strategic Advisors LLC | 13G | 6.11%7.61M shares | New | Mar 31, 2025 | SEC |
| May 15, 20252:16 PM ET | EcoR1 Capital, LLCand 2 others | 13G/A | 0.00%0 shares | −9.99 ppfrom 9.99%Below 5% | Mar 31, 2025 | SEC |
| Apr 30, 202511:23 AM ET | Vanguard Group Inc | 13G/A | 6.72%8.38M shares | – | Mar 31, 2025 | SEC |
| Apr 17, 20259:35 AM ET | BlackRock, Inc. | 13G/A | 6.70%8.32M shares | −1.30 ppfrom 8.00% | Mar 31, 2025 | SEC |
| Feb 14, 20256:15 PM ET | Venrock Healthcare Capital Partners III, L.P.and 6 others | 13G/A | 8.30%10.3M shares | – | Dec 31, 2024 | SEC |
| Feb 5, 20251:23 PM ET | BlackRock, Inc. | 13G/A | 8.00%9.21M shares | – | Dec 31, 2024 | SEC |
| Dec 26, 20244:29 PM ET | Nextech Crossover I GP S.a r.l.and 4 others | 13G/A | 10.40%12.1M shares | – | Dec 20, 2024 | SEC |
| Dec 23, 20247:50 PM ET | EcoR1 Capital, LLCand 2 others | 13G/A | 9.99%11.6M shares | – | Dec 19, 2024 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Mersana Therapeutics, Inc. shares.
No Form 144 notices for Mersana Therapeutics, Inc. are on file.