Jane Street
MRSN

Jane Street’s Mersana Therapeutics MRSN Stock Holding History

Jane Street’s Portfolio MRSN Stock Details MRSN Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2023
Q4 		– Sell
-1,616
Closed -$51.3K – 9578
2023
Q3 		$51.3K Sell
1,616
-1,764
-52% -$83.8K ﹤0.01% 8148
2023
Q2 		$278K Buy
+3,380
New +$494K ﹤0.01% 7253
2021
Q1 		– Sell
-9,300
Closed -$6.19M – 9413
2020
Q4 		$6.19M Buy
9,300
+8,252
+787% +$4.59M ﹤0.01% 1876
2020
Q3 		$488K Sell
1,048
-5,008
-83% -$2.53M ﹤0.01% 5185
2020
Q2 		$3.54M Buy
+6,056
New +$2.07M ﹤0.01% 2273

Other funds holding MRSN

NI
Nextech Invest Zurich, Switzerland $1.42B AUM 304.47% 1-Year Est. Return
AV
Alamea Verwaltungs Edison, New Jersey $135M AUM 36.32% 1-Year Est. Return
BCLSI
Bain Capital Life Sciences Investors Boston, Massachusetts $1.11B AUM 171.34% 1-Year Est. Return
Vanguard Group
Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return
SSA
Schonfeld Strategic Advisors New York $14.2B AUM 37.17% 1-Year Est. Return
RSCM
Rock Springs Capital Management Baltimore, Maryland $1.7B AUM 93.03% 1-Year Est. Return
Acadian Asset Management
Acadian Asset Management Boston, Massachusetts $70.5B AUM 36% 1-Year Est. Return
SCM
Silverarc Capital Management Boston, Massachusetts $980M AUM 470.8% 1-Year Est. Return
6CM
683 Capital Management New York $1.92B AUM 85.52% 1-Year Est. Return
BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return

Jane Street's MRSN Position: Q3 2025 in Review

Jane Street sold out of Mersana Therapeutics (MRSN) in Q3 2025, closing a stake of 20,447 shares — an estimated $151K sold.

Jane Street first reported a position in MRSN in Q1 2019 and held it in 20 quarters. The position peaked at $2.22M in Q4 2020. 49 funds tracked by Wall St. Rank hold MRSN as of Q3 2025.

  • Jane Street reported no remaining Mersana Therapeutics position as of Q3 2025 after selling out during the quarter.
  • Jane Street sold 20,447 Mersana Therapeutics shares in Q3 2025, an estimated $151K.
  • Jane Street first reported a position in Mersana Therapeutics in Q1 2019 and held it in 20 quarters.
  • Jane Street's Mersana Therapeutics position peaked at $2.22M in Q4 2020.
  • 49 funds tracked by Wall St. Rank held Mersana Therapeutics as of Q3 2025.

Based on Jane Street's 13F filing for Q3 2025, filed 14 Nov 2025.