Jim Simons
MRSN

Jim Simons’s Mersana Therapeutics MRSN Stock Holding History

Jim Simons’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
2025
Q4 		– Sell
-88,465
Closed -$686K – 3566
2025
Q3 		$686K Sell
88,465
-25,543
-22% -$192K ﹤0.01% 2663
2025
Q2 		$844K Buy
114,008
+80,411
+239% +$707K ﹤0.01% 2592
2025
Q1 		$289K Buy
33,597
+9,346
+39% +$144K ﹤0.01% 2938
2024
Q4 		$867K Buy
24,251
+4,542
+23% +$235K ﹤0.01% 2575
2024
Q3 		$931K Sell
19,709
-38,220
-66% -$1.69M ﹤0.01% 2487
2024
Q2 		$2.91M Buy
57,929
+816
+1% +$59K ﹤0.01% 1630
2024
Q1 		$6.4M Buy
57,113
+22,484
+65% +$2.24M 0.01% 1254
2023
Q4 		$2.01M Sell
34,629
-2,408
-7% -$96.9K ﹤0.01% 1951
2023
Q3 		$1.18M Sell
37,037
-4,880
-12% -$232K ﹤0.01% 2191
2023
Q2 		$3.45M Sell
41,917
-8,104
-16% -$1.19M 0.01% 1640
2023
Q1 		$5.14M Buy
50,021
+27,152
+119% +$3.81M 0.01% 1463
2022
Q4 		$3.35M Sell
22,869
-5,084
-18% -$859K ﹤0.01% 1747
2022
Q3 		$4.72M Buy
27,953
+5,140
+23% +$835K 0.01% 1480
2022
Q2 		$2.63M Sell
22,813
-13,955
-38% -$1.31M ﹤0.01% 1993
2022
Q1 		$3.67M Buy
36,768
+23,064
+168% +$2.69M ﹤0.01% 1793
2021
Q4 		$2.13M Buy
+13,704
New +$2.67M ﹤0.01% 2096
2020
Q4 		– Sell
-2,860
Closed -$1.33M – 3599
2020
Q3 		$1.33M Sell
2,860
-10,751
-79% -$5.43M ﹤0.01% 2350
2020
Q2 		$7.96M Sell
13,611
-17,732
-57% -$6.06M 0.01% 1363
2020
Q1 		$4.57M Buy
31,343
+2,552
+9% +$446K ﹤0.01% 1619
2019
Q4 		$4.12M Sell
28,791
-1,878
-6% -$137K ﹤0.01% 1977
2019
Q3 		$1.21M Buy
30,669
+20,028
+188% +$1.46M ﹤0.01% 2517
2019
Q2 		$1.08M Buy
10,641
+3,660
+52% +$431K ﹤0.01% 2641
2019
Q1 		$918K Buy
+6,981
New +$878K ﹤0.01% 2709

Other funds holding MRSN

NI
Nextech Invest Zurich, Switzerland $1.42B AUM 304.47% 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
RSCM
Rock Springs Capital Management Baltimore, Maryland $1.7B AUM 93.03% 1-Year Est. Return
AV
Alamea Verwaltungs Edison, New Jersey $135M AUM 36.32% 1-Year Est. Return
Acadian Asset Management
Acadian Asset Management Boston, Massachusetts $70.5B AUM 36% 1-Year Est. Return
AAA
Affinity Asset Advisors New York $1.94B AUM 374.45% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Bank of America
Bank of America Charlotte, North Carolina $1.37T AUM 24.88% 1-Year Est. Return
Millennium Management
Millennium Management New York $240B AUM 35.51% 1-Year Est. Return

Jim Simons's MRSN Position: Q4 2025 in Review

Jim Simons sold out of Mersana Therapeutics (MRSN) in Q4 2025, closing a stake of 88,465 shares — an estimated $686K sold.

Jim Simons first reported a position in MRSN in Q1 2019 and held it in 23 quarters. The position peaked at $7.96M in Q2 2020. 51 funds tracked by Wall St. Rank hold MRSN as of Q4 2025.

  • Jim Simons reported no remaining Mersana Therapeutics position as of Q4 2025 after selling out during the quarter.
  • Jim Simons sold 88,465 Mersana Therapeutics shares in Q4 2025, an estimated $686K.
  • Jim Simons first reported a position in Mersana Therapeutics in Q1 2019 and held it in 23 quarters.
  • Jim Simons's Mersana Therapeutics position peaked at $7.96M in Q2 2020.
  • 51 funds tracked by Wall St. Rank held Mersana Therapeutics as of Q4 2025.

Based on Renaissance Technologies's 13F filing for Q4 2025, filed 12 Feb 2026.