Jim Simons
CSTL icon

Jim Simons’s Castle Biosciences CSTL Stock Holding History

Jim Simons’s Portfolio CSTL Stock Details CSTL Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$13.1M Buy
532,800
+39,700
+8% +$1.3M 0.02% 829
2025
Q4 		$19.2M Sell
493,100
-69,500
-12% -$2.24M 0.03% 618
2025
Q3 		$12.8M Sell
562,600
-107,900
-16% -$2.19M 0.02% 963
2025
Q2 		$13.7M Sell
670,500
-30,700
-4% -$568K 0.02% 889
2025
Q1 		$14M Buy
701,200
+16,200
+2% +$401K 0.02% 832
2024
Q4 		$18.3M Buy
685,000
+195,438
+40% +$5.95M 0.03% 715
2024
Q3 		$14M Buy
489,562
+188,062
+62% +$4.79M 0.02% 870
2024
Q2 		$6.56M Buy
301,500
+96,800
+47% +$2.16M 0.01% 1140
2024
Q1 		$4.53M Buy
204,700
+92,300
+82% +$2.01M 0.01% 1480
2023
Q4 		$2.43M Buy
112,400
+5,600
+5% +$98.6K ﹤0.01% 1836
2023
Q3 		$1.8M Sell
106,800
-65,600
-38% -$1.15M ﹤0.01% 1931
2023
Q2 		$2.37M Buy
172,400
+136,000
+374% +$2.76M ﹤0.01% 1884
2023
Q1 		$827K Buy
36,400
+14,300
+65% +$349K ﹤0.01% 2598
2022
Q4 		$520K Buy
22,100
+5,100
+30% +$118K ﹤0.01% 2930
2022
Q3 		$443K Sell
17,000
-400
-2% -$11.2K ﹤0.01% 2997
2022
Q2 		$382K Sell
17,400
-7,600
-30% -$177K ﹤0.01% 3313
2022
Q1 		$1.12M Sell
25,000
-109,281
-81% -$4.52M ﹤0.01% 2662
2021
Q4 		$5.76M Buy
+134,281
New +$7.02M 0.01% 1437
2021
Q2 		– Sell
-27,500
Closed -$1.88M – 3503
2021
Q1 		$1.88M Buy
+27,500
New +$2.07M ﹤0.01% 2271
2020
Q4 		– Sell
-3,900
Closed -$201K – 3427
2020
Q3 		$201K Sell
3,900
-38,936
-91% -$1.73M ﹤0.01% 3109
2020
Q2 		$1.61M Buy
42,836
+9,636
+29% +$329K ﹤0.01% 2296
2020
Q1 		$990K Buy
+33,200
New +$1M ﹤0.01% 2430

Other funds holding CSTL

BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
RI
RTW Investments New York $10B AUM 135.35% 1-Year Est. Return
Principal Financial Group
Principal Financial Group Des Moines, Iowa $204B AUM 27.99% 1-Year Est. Return
PCM
Portolan Capital Management Boston, Massachusetts $1.88B AUM 115.74% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
Dimensional Fund Advisors
Dimensional Fund Advisors Austin, Texas $552B AUM 44.19% 1-Year Est. Return
SPPAM
Summit Partners Public Asset Management Boston, Massachusetts $3.72B AUM 162.29% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
Allianz Asset Management
Allianz Asset Management Munich, Germany $95.4B AUM 38.74% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return

Jim Simons's CSTL Position: Q1 2026 in Review

Jim Simons increased its Castle Biosciences (CSTL) stake by 8.1% in Q1 2026, buying an estimated $1.3M and bringing the position to 532,800 shares worth $13.1M. The position accounts for 0.02% of the portfolio, ranked #829.

Jim Simons first reported a position in CSTL in Q1 2020 and has held it in 22 quarters since. The position peaked at $19.2M in Q4 2025. 186 funds tracked by Wall St. Rank hold CSTL as of Q1 2026.

  • Jim Simons held 532,800 shares of Castle Biosciences worth $13.1M as of Q1 2026.
  • Jim Simons bought 39,700 Castle Biosciences shares in Q1 2026, an estimated $1.3M.
  • Castle Biosciences made up 0.02% of Jim Simons's portfolio in Q1 2026, its #829 holding.
  • Jim Simons first reported a position in Castle Biosciences in Q1 2020 and has held it in 22 quarters since.
  • Jim Simons's Castle Biosciences position peaked at $19.2M in Q4 2025.
  • 186 funds tracked by Wall St. Rank held Castle Biosciences as of Q1 2026.

Based on Renaissance Technologies's 13F filing for Q1 2026, filed 14 May 2026.