BlackRock
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BlackRock’s Castle Biosciences CSTL Stock Holding History

BlackRock’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 		$78.5M Buy
3,291,963
+309,017
+10% +$6.88M ﹤0.01% 2367
2026
Q1 		$73.2M Sell
2,982,946
-122,300
-4% -$4.01M ﹤0.01% 2293
2025
Q4 		$121M Sell
3,105,246
-84,650
-3% -$2.73M ﹤0.01% 1997
2025
Q3 		$72.6M Buy
3,189,896
+35,217
+1% +$715K ﹤0.01% 2276
2025
Q2 		$64.4M Buy
3,154,679
+171,139
+6% +$3.17M ﹤0.01% 2311
2025
Q1 		$59.7M Buy
2,983,540
+62,231
+2% +$1.54M ﹤0.01% 2279
2024
Q4 		$77.9M Sell
2,921,309
-198,963
-6% -$6.06M ﹤0.01% 2220
2024
Q3 		$89M Buy
3,120,272
+75,299
+2% +$1.92M ﹤0.01% 2156
2024
Q2 		$66.3M Buy
3,044,973
+449,286
+17% +$10M ﹤0.01% 2257
2024
Q1 		$57.5M Buy
2,595,687
+312,488
+14% +$6.8M ﹤0.01% 2358
2023
Q4 		$49.3M Buy
2,283,199
+147,019
+7% +$2.59M ﹤0.01% 2481
2023
Q3 		$36.1M Buy
2,136,180
+4,480
+0.2% +$78.4K ﹤0.01% 2591
2023
Q2 		$29.2M Buy
2,131,700
+12,143
+0.6% +$246K ﹤0.01% 2793
2023
Q1 		$48.2M Sell
2,119,557
-4,131
-0.2% -$101K ﹤0.01% 2473
2022
Q4 		$50M Buy
2,123,688
+81,864
+4% +$1.9M ﹤0.01% 2460
2022
Q3 		$53.3M Buy
2,041,824
+17,569
+0.9% +$493K ﹤0.01% 2392
2022
Q2 		$44.4M Buy
2,024,255
+241,717
+14% +$5.62M ﹤0.01% 2567
2022
Q1 		$80M Sell
1,782,538
-18,849
-1% -$779K ﹤0.01% 2277
2021
Q4 		$77.2M Buy
1,801,387
+45,379
+3% +$2.37M ﹤0.01% 2379
2021
Q3 		$117M Buy
1,756,008
+64,010
+4% +$4.5M ﹤0.01% 2111
2021
Q2 		$124M Buy
1,691,998
+328,162
+24% +$21.7M ﹤0.01% 2117
2021
Q1 		$93.4M Buy
1,363,836
+222,089
+19% +$16.7M ﹤0.01% 2232
2020
Q4 		$76.7M Buy
1,141,747
+142,085
+14% +$7.7M ﹤0.01% 2232
2020
Q3 		$51.4M Buy
999,662
+177,685
+22% +$7.9M ﹤0.01% 2283
2020
Q2 		$31M Buy
821,977
+106,782
+15% +$3.65M ﹤0.01% 2556
2020
Q1 		$21.3M Buy
715,195
+280,021
+64% +$8.45M ﹤0.01% 2572
2019
Q4 		$15M Buy
435,174
+228,228
+110% +$5.58M ﹤0.01% 3043
2019
Q3 		$3.74M Buy
+206,946
New +$4.59M ﹤0.01% 3569

Other funds holding CSTL

RI
RTW Investments New York $11.7B AUM 174.13% 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
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
Allianz Asset Management
Allianz Asset Management Munich, Germany $112B AUM 36.28% 1-Year Est. Return
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

BlackRock's CSTL Position: Q2 2026 in Review

BlackRock increased its Castle Biosciences (CSTL) stake by 10% in Q2 2026, buying an estimated $6.88M and bringing the position to 3,291,963 shares worth $78.5M. The position accounts for ﹤0.01% of the portfolio, ranked #2367.

BlackRock first reported a position in CSTL in Q3 2019 and has held it in 28 quarters since. The position peaked at $124M in Q2 2021. 176 funds tracked by Wall St. Rank hold CSTL as of Q2 2026.

  • BlackRock held 3,291,963 shares of Castle Biosciences worth $78.5M as of Q2 2026.
  • BlackRock bought 309,017 Castle Biosciences shares in Q2 2026, an estimated $6.88M.
  • Castle Biosciences made up ﹤0.01% of BlackRock's portfolio in Q2 2026, its #2367 holding.
  • BlackRock first reported a position in Castle Biosciences in Q3 2019 and has held it in 28 quarters since.
  • BlackRock's Castle Biosciences position peaked at $124M in Q2 2021.
  • 176 funds tracked by Wall St. Rank held Castle Biosciences as of Q2 2026.

Based on BlackRock's 13F filing for Q2 2026, filed 7 Aug 2026.