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RTW Investments’s Castle Biosciences CSTL Stock Holding History

RTW Investments’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
Q2 		$66.3M Buy
2,778,335
+20,000
+0.7% +$445K 0.57% 40
2026
Q1 		$67.7M Buy
2,758,335
+643,098
+30% +$21.1M 0.67% 38
2025
Q4 		$82.3M Buy
+2,115,237
New +$68.2M 0.82% 35
2023
Q2 		– Sell
-258,498
Closed -$5.87M – 64
2023
Q1 		$5.87M Sell
258,498
-258,497
-50% -$6.32M 0.12% 49
2022
Q4 		$12.2M Hold
516,995
– – 0.25% 44
2022
Q3 		$13.5M Sell
516,995
-396,794
-43% -$11.1M 0.31% 46
2022
Q2 		$20.1M Buy
913,789
+417,114
+84% +$9.69M 0.52% 42
2022
Q1 		$22.3M Sell
496,675
-102,334
-17% -$4.23M 0.46% 49
2021
Q4 		$25.7M Hold
599,009
– – 0.38% 59
2021
Q3 		$39.8M Sell
599,009
-200,000
-25% -$14.1M 0.6% 47
2021
Q2 		$58.6M Hold
799,009
– – 0.88% 31
2021
Q1 		$54.7M Hold
799,009
– – 0.85% 34
2020
Q4 		$53.7M Buy
799,009
+55,367
+7% +$3M 0.9% 34
2020
Q3 		$38.3M Sell
743,642
-59,868
-7% -$2.66M 0.92% 33
2020
Q2 		$30.3M Buy
803,510
+105,392
+15% +$3.6M 0.85% 34
2020
Q1 		$20.8M Buy
698,118
+67,046
+11% +$2.02M 0.9% 34
2019
Q4 		$21.7M Sell
631,072
-113,973
-15% -$2.79M 0.82% 31
2019
Q3 		$13.5M Buy
+745,045
New +$16.5M 0.8% 30

Other funds holding CSTL

BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Principal Financial Group
Principal Financial Group Des Moines, Iowa $204B AUM 27.99% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
Acadian Asset Management
Acadian Asset Management Boston, Massachusetts $84.2B AUM 55.88% 1-Year Est. Return
Allianz Asset Management
Allianz Asset Management Munich, Germany $123B AUM 45.23% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
SPPAM
Summit Partners Public Asset Management Boston, Massachusetts $5.69B AUM 259.25% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
Mackenzie Financial
Mackenzie Financial Toronto Ontario, Ontario, Canada $100B AUM 36.93% 1-Year Est. Return

RTW Investments's CSTL Position: Q2 2026 in Review

RTW Investments increased its Castle Biosciences (CSTL) stake by 0.73% in Q2 2026, buying an estimated $445K and bringing the position to 2,778,335 shares worth $66.3M. The position accounts for 0.57% of the portfolio, ranked #40.

RTW Investments first reported a position in CSTL in Q3 2019 and has held it in 18 quarters since. The position peaked at $82.3M in Q4 2025. 177 funds tracked by Wall St. Rank hold CSTL as of Q2 2026.

  • RTW Investments held 2,778,335 shares of Castle Biosciences worth $66.3M as of Q2 2026.
  • RTW Investments bought 20,000 Castle Biosciences shares in Q2 2026, an estimated $445K.
  • Castle Biosciences made up 0.57% of RTW Investments's portfolio in Q2 2026, its #40 holding.
  • RTW Investments first reported a position in Castle Biosciences in Q3 2019 and has held it in 18 quarters since.
  • RTW Investments's Castle Biosciences position peaked at $82.3M in Q4 2025.
  • 177 funds tracked by Wall St. Rank held Castle Biosciences as of Q2 2026.

Based on RTW Investments's 13F filing for Q2 2026, filed 14 Aug 2026.