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Castle Biosciences Inc

CSTL
Exchange
Nasdaq
Industry
Services-Medical Laboratories
SEC CIK
0001447362

In the last 90 days, Castle Biosciences Inc insiders filed 0 open-market purchases and 20 sales; 176 institutions reported holding it in 13F filings for Q2 2026, worth $653.8M in total; no superinvestor holds it.

13F holders, Q1 2026

Institutional positions in Castle Biosciences Inc as of Mar 31, 2026. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works

Institutional holders
186
−7 vs. Q4 2025
Shares held
27.6M
+2.50M (+10.0%) vs. Q4 2025
Total value
$677.8M
−$298.6M (−30.6%) vs. Q4 2025
New holders
29
72 more added
Sold out
36
61 more reduced

2 institutions that held it in Q4 2025 haven't filed for Q1 2026 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.

Compare with Q4 2025: new holders, sold out and not filed yet

Holders and value by quarter

Institutions reporting CSTL on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.

Institutional holdersQ1 2026: 186 institutions
Q1 2021: 175 institutionsQ2 2021: 182 institutionsQ3 2021: 188 institutionsQ4 2021: 159 institutionsQ1 2022: 160 institutionsQ2 2022: 146 institutionsQ3 2022: 157 institutionsQ4 2022: 153 institutionsQ1 2023: 148 institutionsQ2 2023: 130 institutionsQ3 2023: 135 institutionsQ4 2023: 153 institutionsQ1 2024: 151 institutionsQ2 2024: 159 institutionsQ3 2024: 185 institutionsQ4 2024: 197 institutionsQ1 2025: 180 institutionsQ2 2025: 152 institutionsQ3 2025: 173 institutionsQ4 2025: 195 institutionsQ1 2026: 186 institutionsQ2 2026: 176 institutions
Value heldQ1 2026: $677.8M
Q1 2021: $1.46BQ2 2021: $1.52BQ3 2021: $1.42BQ4 2021: $918.6MQ1 2022: $1.02BQ2 2022: $495.0MQ3 2022: $569.8MQ4 2022: $522.0MQ1 2023: $501.9MQ2 2023: $316.6MQ3 2023: $391.0MQ4 2023: $515.4MQ1 2024: $553.2MQ2 2024: $549.4MQ3 2024: $736.9MQ4 2024: $706.4MQ1 2025: $516.3MQ2 2025: $541.8MQ3 2025: $608.3MQ4 2025: $1.06BQ1 2026: $677.8MQ2 2026: $653.8M
Institutions holding CSTL and their total value by quarter
QuarterHoldersValue
Q2 2026176$653.8M
Q1 2026186$677.8M
Q4 2025195$1.06B
Q3 2025173$608.3M
Q2 2025152$541.8M
Q1 2025180$516.3M
Q4 2024197$706.4M
Q3 2024185$736.9M
Q2 2024159$549.4M
Q1 2024151$553.2M
Q4 2023153$515.4M
Q3 2023135$391.0M
Q2 2023130$316.6M
Q1 2023148$501.9M
Q4 2022153$522.0M
Q3 2022157$569.8M
Q2 2022146$495.0M
Q1 2022160$1.02B
Q4 2021159$918.6M
Q3 2021188$1.42B
Q2 2021182$1.52B
Q1 2021175$1.46B

Institutions, Q1 2026

Shares, value and share of portfolio for each institution holding Castle Biosciences Inc; share changes are against Q4 2025.

Institutions holding CSTL in Q1 2026
InstitutionSharesValue% of portfolioChange in sharesAction
Quantbot Technologies LP22,060$541.6K0.02%+22,013+46,836.2%Added
Legal & General Group Plc23,184$569.2K0.00%−6,551−22.0%Reduced
Magnetar Financial LLC23,332$572.8K0.01%+23,332New
Y-Intercept (Hong Kong) Ltd23,501$577.0K0.01%+10,255+77.4%Added
Truist Financial Corp23,781$583.8K0.00%+153+0.6%Added
Deutsche Bank AG24,164$593.2K0.00%+1,780+8.0%Added
STRS Ohio25,000$613.8K0.00%+12,400+98.4%Added
Fox Run Management, L.L.C.26,247$618.1K0.11%+4,363+19.9%Added
Harbor Capital Advisors, Inc.25,614$629.0K0.05%+12,182+90.7%Added
Barclays PLC26,810$658.2K0.00%−45,339−62.8%Reduced
Arrowstreet Capital, Limited Partnership27,142$666.3K0.00%+20,113+286.1%Added
California State Teachers Retirement System27,513$675.4K0.00%−212−0.8%Reduced
CI Private Wealth, LLC31,870$782.4K0.00%+31,870New
ExodusPoint Capital Management, LP32,608$800.5K0.01%+32,608New
Universal- Beteiligungs- und Servicegesellschaft mbH34,387$844.2K0.00%+5,030+17.1%Added
Algert Global LLC34,778$853.8K0.01%+15,800+83.3%Added
SEI Investments Co35,046$860.4K0.00%−4,681−11.8%Reduced
Nomura Holdings Inc35,748$877.6K0.01%+35,748New
KBC Group NV36,932$907.0K0.00%+36,932New
Price T Rowe Associates Inc37,792$928.0K0.00%+3,654+10.7%Added
Rhumbline Advisers38,378$942.2K0.00%−90−0.2%Reduced
Alliancebernstein L.P.25,270$983.0K0.00%00.0%Unchanged
Schonfeld Strategic Advisors LLC42,413$1.04M0.01%+20,937+97.5%Added
Jane Street Group, LLC42,562$1.04M0.00%−126,084−74.8%Reduced
Quantinno Capital Management LP45,476$1.12M0.00%+36,144+387.3%Added
Formula Growth Ltd46,000$1.13M0.51%+46,000New
Man Group plc47,138$1.16M0.00%+35,553+306.9%Added
UBS Group AG49,163$1.21M0.00%−92,710−65.3%Reduced
FMR LLC50,412$1.24M0.00%+8,126+19.2%Added
Swiss National Bank57,300$1.41M0.00%00.0%Unchanged
Invesco Ltd.61,012$1.50M0.00%−74,449−55.0%Reduced
Envestnet Asset Management Inc61,865$1.52M0.00%−101−0.2%Reduced
AQR Capital Management LLC64,880$1.59M0.00%+999+1.6%Added
UBS Asset Management Americas Inc64,964$1.59M0.00%−4,664−6.7%Reduced
SummitTX Capital, L.P.67,033$1.65M0.05%+49,623+285.0%Added
Bank of America Corp67,810$1.66M0.00%−195,209−74.2%Reduced
Mackenzie Financial Corp74,111$1.82M0.00%+36,794+98.6%Added
Brinker Capital Investments, LLC74,896$1.84M0.02%+243+0.3%Added
American Century Companies Inc79,107$1.94M0.00%+1,339+1.7%Added
JPMorgan Chase & Co88,771$2.09M0.00%−1,261−1.4%Reduced
Bank of New York Mellon Corp88,654$2.18M0.00%+1,670+1.9%Added
Franklin Resources Inc90,909$2.23M0.00%+10,306+12.8%Added
Citadel Advisors LLC120,977$2.97M0.00%−245,379−67.0%Reduced
BNP Paribas Arbitrage, SA122,156$3.00M0.00%−27,855−18.6%Reduced
Parkman Healthcare Partners LLC126,150$3.10M0.32%−24,408−16.2%Reduced
Trexquant Investment LP130,434$3.20M0.02%+65,829+101.9%Added
Empowered Funds, LLC132,184$3.25M0.02%+10,264+8.4%Added
Campbell & CO Investment Adviser LLC148,824$3.65M0.21%+148,824New
Allspring Global Investments Holdings, LLC160,663$3.94M0.01%+1,492+0.9%Added
Vanguard Fiduciary Trust Co188,211$4.62M0.00%+188,211New
D. E. Shaw & Co., Inc.211,966$5.20M0.00%+52,257+32.7%Added
Panagora Asset Management Inc222,353$5.46M0.02%+176,358+383.4%Added
Tudor Investment Corp Et Al222,982$5.47M0.03%+55,804+33.4%Added
New York State Common Retirement Fund233,046$5.72M0.01%00.0%Unchanged
Charles Schwab Investment Management Inc241,880$5.94M0.00%−655−0.3%Reduced
SG Americas Securities, LLC244,886$6.01M0.01%+223,624+1,051.8%Added
Advisors Capital Management, LLC248,376$6.10M0.07%−2,301−0.9%Reduced
Two Sigma Investments, LP248,840$6.11M0.01%+164,774+196.0%Added
Bridgeway Capital Management, LLC255,184$6.26M0.13%+8,264+3.3%Added
Kornitzer Capital Management Inc264,396$6.49M0.14%−3,337−1.2%Reduced
Silvercrest Asset Management Group LLC268,535$6.59M0.05%+63,533+31.0%Added
Northern Trust Corp273,101$6.70M0.00%+10,858+4.1%Added
Schroder Investment Management Group298,941$7.04M0.01%−193,220−39.3%Reduced
Goldman Sachs Group Inc341,171$8.38M0.00%+53,936+18.8%Added
Millennium Management LLC353,319$8.67M0.01%+44,405+14.4%Added
Connor, Clark & Lunn Investment Management Ltd.377,082$9.26M0.02%−11,409−2.9%Reduced
Eventide Asset Management, LLC386,425$9.49M0.16%+81,425+26.7%Added
Morgan Stanley428,934$10.5M0.00%+225,357+110.7%Added
Wasatch Advisors Inc455,036$11.2M0.07%−82,205−15.3%Reduced
Acadian Asset Management LLC484,441$11.9M0.02%+94,035+24.1%Added
Nuveen, LLC522,127$12.8M0.00%−2,554−0.5%Reduced
Renaissance Technologies LLC532,800$13.1M0.02%+39,700+8.1%Added
Palisade Capital Management LLC535,884$13.2M0.44%−31,893−5.6%Reduced
Qube Research & Technologies Ltd559,583$13.7M0.02%+324,065+137.6%Added
AIGH Capital Management LLC590,601$14.5M2.97%−34,118−5.5%Reduced
Geode Capital Management, LLC728,100$17.9M0.00%+13,187+1.8%Added
State Street Corp769,079$18.9M0.00%+32,625+4.4%Added
Allianz Asset Management GmbH811,324$19.9M0.02%+189,025+30.4%Added
Vanguard Portfolio Management LLC861,771$21.2M0.00%+861,771New
Summit Partners Public Asset Management, LLC940,685$23.1M1.07%−118,040−11.1%Reduced
Dimensional Fund Advisors LP1,039,761$25.5M0.01%−104,038−9.1%Reduced
Vanguard Capital Management LLC1,177,522$28.9M0.00%+1,177,522New
Portolan Capital Management, LLC1,350,283$33.1M1.76%−379,180−21.9%Reduced
Principal Financial Group Inc1,769,877$43.5M0.02%−37,767−2.1%Reduced
RTW Investments, LP2,758,335$67.7M0.67%+643,098+30.4%Added
BlackRock, Inc.2,982,946$73.2M0.00%−122,300−3.9%Reduced
Wellington Management Group LLP0$00.00%−218,560−100.0%Sold out
Braidwell LP0$00.00%−177,183−100.0%Sold out
Point72 Asset Management, L.P.0$00.00%−119,458−100.0%Sold out
EAM Investors, LLC0$00.00%−74,138−100.0%Sold out
Squarepoint Ops LLC0$00.00%−55,118−100.0%Sold out
Ameriprise Financial Inc0$00.00%−35,368−100.0%Sold out
Two Sigma Advisers, LP0$00.00%−29,899−100.0%Sold out
Caxton Associates LLP0$00.00%−22,464−100.0%Sold out
HSBC Holdings PLC0$00.00%−19,486−100.0%Sold out
Quest Partners LLC0$00.00%−17,116−100.0%Sold out
Verition Fund Management LLC0$00.00%−16,811−100.0%Sold out
Counterpoint Mutual Funds LLC0$00.00%−12,952−100.0%Sold out
Intech Investment Management LLC0$00.00%−11,718−100.0%Sold out
Stephens Inc0$00.00%−11,122−100.0%Sold out