Mersana Therapeutics
MRSN
MRSN was delisted on the 5th of January, 2026.
128 hedge funds and large institutions have $144M invested in Mersana Therapeutics in 2023 Q3 according to their latest regulatory filings, with 26 funds opening new positions, 35 increasing their positions, 43 reducing their positions, and 45 closing their positions.
1,963% more call options, than puts
Call options by funds: $1.57M | Put options by funds: $76K
0% more funds holding in top 10
Funds holding in top 10: 1 → 1 (0)
0.16% less ownership
Funds ownership: 3.93% → 3.78% (-0.16%)
13% less funds holding
Funds holding: 147 → 128 (-19)
19% less repeat investments, than reductions
Existing positions increased: 35 | Existing positions reduced: 43
42% less first-time investments, than exits
New positions opened: 26 | Existing positions closed: 45
61% less capital invested
Capital invested by funds: $370M → $144M (-$226M)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
EC
EcoR1 Capital
San Francisco,
California
|
+$36.8M |
| 2 |
VA
VR Adviser
New York
|
+$21.5M |
| 3 |
SCM
Silverarc Capital Management
Boston,
Massachusetts
|
+$7.61M |
| 4 |
AAA
Affinity Asset Advisors
New York
|
+$5.42M |
| 5 |
PCM
Philosophy Capital Management
Alamo,
California
|
+$4.45M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
O
OrbiMed
New York
|
-$23.7M |
| 2 |
ACA
Avoro Capital Advisors
New York
|
-$21M |
| 3 |
APM
Avidity Partners Management
Dallas,
Texas
|
-$12.5M |
| 4 |
AG
Artal Group
Luxembourg
|
-$9.97M |
| 5 |
DM
Deerfield Management
New York
|
-$9.49M |
MRSN Hedge Fund Activity: Q3 2023 in Review
128 of the 6,310 institutional investors tracked by Wall St. Rank reported a position in Mersana Therapeutics (MRSN) for Q3 2023, worth a combined $144M — down 61% from $370M a quarter earlier.
Sellers outnumbered buyers: 45 funds closed out of MRSN and 26 opened new positions — a net loss of 19 holders — while 43 trimmed existing stakes and 35 added.
The largest buyer was EcoR1 Capital, opening a new position worth an estimated $36.8M. The largest seller was OrbiMed, exiting entirely with an estimated $23.7M sold.
- 128 institutional investors held Mersana Therapeutics (MRSN) as of Q3 2023, down from 147 in Q2 2023.
- Funds reported $144M of Mersana Therapeutics stock for Q3 2023, down 61% quarter-over-quarter.
- 26 funds opened new Mersana Therapeutics positions in Q3 2023 and 45 closed out, a net change of -19 holders.
- The largest Mersana Therapeutics buyer in Q3 2023 was EcoR1 Capital, an estimated $36.8M added.
- The largest Mersana Therapeutics seller in Q3 2023 was OrbiMed, an estimated $23.7M sold.
Based on aggregated 13F filings for Q3 2023.