CSTL Castle Biosciences, Inc.

NASDAQ
$34.20

Castle Biosciences, Inc. (CSTL) Institutional Ownership

What the institutions did with CSTL last quarter, from their 13F filings. Counting managers rather than shares is the point: a single index fund adding to a position tells you far less than four hundred separate managers all deciding to. Positions as reported for the quarter ended June 30, 2026.

Managers reporting
201
filed a 13F this quarter
Managers holding
171
-10 on the quarter
Buyers
98
20 opened new
Sellers
86
30 sold out entirely
Buyer share
53.3%
of managers who traded it
Breadth
+6.5
net buyers, as a share of those trading

Every manager below opens. Subscribers can see any firm's whole portfolio — every position, its weight, and what they bought, trimmed and exited last quarter.

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Largest holders

Manager Shares % of reported
BlackRock, Inc. 3.3M 12.1%
RTW INVESTMENTS, LP 2.8M 10.2%
PRINCIPAL FINANCIAL GROUP INC 1.7M 6.3%
VANGUARD CAPITAL MANAGEMENT LLC 1.2M 4.5%
ACADIAN ASSET MANAGEMENT LLC 918.7K 3.4%
VANGUARD PORTFOLIO MANAGEMENT LLC 840.8K 3.1%
SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC 824.9K 3.0%
STATE STREET CORP 822.1K 3.0%
Allianz Asset Management GmbH 811.3K 3.0%
GEODE CAPITAL MANAGEMENT, LLC 795.9K 2.9%
MACKENZIE FINANCIAL CORP 793.5K 2.9%
DIMENSIONAL FUND ADVISORS LP 791.1K 2.9%
Jefferies Financial Group Inc. 647.4K 2.4%
Qube Research & Technologies Ltd 589.3K 2.2%
AIGH Capital Management LLC 545.1K 2.0%
RENAISSANCE TECHNOLOGIES LLC 371.2K 1.4%
GOLDMAN SACHS GROUP INC 358.4K 1.3%
Point72 Asset Management, L.P. 357.3K 1.3%
KENNEDY CAPITAL MANAGEMENT LLC 348.4K 1.3%
Connor, Clark & Lunn Investment Management Ltd. 331.7K 1.2%
MORGAN STANLEY 329.7K 1.2%
Portolan Capital Management, LLC 328.8K 1.2%
PANAGORA ASSET MANAGEMENT INC 301.0K 1.1%
Allspring Global Investments Holdings, LLC 292.5K 1.1%
NORTHERN TRUST CORP 285.2K 1.0%

Largest changes

Manager Action Previous Current Change
Portolan Capital Management, LLC Reduced 1.4M 328.8K -1.0M
MACKENZIE FINANCIAL CORP Increased 74.1K 793.5K +719.4K
Jefferies Financial Group Inc. New 0 647.4K +647.4K
ACADIAN ASSET MANAGEMENT LLC Increased 484.4K 918.7K +434.2K
EVENTIDE ASSET MANAGEMENT, LLC Sold Out 386.4K 0 -386.4K
Point72 Asset Management, L.P. New 0 357.3K +357.3K
KENNEDY CAPITAL MANAGEMENT LLC New 0 348.4K +348.4K
BlackRock, Inc. Increased 3.0M 3.3M +309.0K
PALISADE CAPITAL MANAGEMENT, LP Reduced 535.9K 231.9K -304.0K
SCHRODER INVESTMENT MANAGEMENT GROUP Sold Out 298.9K 0 -298.9K
Nuveen, LLC Reduced 522.1K 231.7K -290.4K
DIMENSIONAL FUND ADVISORS LP Reduced 1.0M 791.1K -248.7K
SG Americas Securities, LLC Sold Out 244.9K 0 -244.9K
TUDOR INVESTMENT CORP ET AL Reduced 223.0K 14.5K -208.5K
WASATCH ADVISORS LP Reduced 455.0K 279.3K -175.7K
RENAISSANCE TECHNOLOGIES LLC Reduced 532.8K 371.2K -161.6K
TWO SIGMA INVESTMENTS, LP Reduced 248.8K 100.4K -148.5K
MILLENNIUM MANAGEMENT LLC Reduced 353.3K 205.4K -148.0K
FIRST TRUST ADVISORS LP New 0 145.1K +145.1K
CITADEL ADVISORS LLC Increased 121.0K 265.4K +144.4K
Campbell & CO Investment Adviser LLC Reduced 148.8K 16.5K -132.3K
Allspring Global Investments Holdings, LLC Increased 160.7K 292.5K +131.8K
SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC Reduced 940.7K 824.9K -115.8K
AQR CAPITAL MANAGEMENT LLC Increased 64.9K 166.6K +101.7K
HRT FINANCIAL LP Increased 15.9K 115.9K +100.0K

13F filings are due 45 days after quarter end and cover long positions in U.S.-listed equities only, so this is a lagged and partial picture: shorts, bonds and foreign listings never appear. Options positions are excluded here rather than folded into the share counts. Political ownership is coming.