Castle Biosciences CSTL Institutional Ownership

NASDAQ CSTL

$34.24 +0.15 (+0.45%)

As of: Aug 27, 2026 · 3:59 PM EDT

Institutions by Trading Activity

180 Institutions

Increased 107 59.4%

Unchanged 18 10.0%

Reduced 55 30.6%

Ownership Statistics

13F · as of 30 Jun, 2026

Institutional Ownership

90.85%

▼-1.58 pp QoQ

Shares Held by Institutions

27.62Mn

of 30.40Mn outstanding

▲+4.77% QoQ

Shares Outstanding

30.40Mn

2.78Mn held outside 13F filers

Institutional Investors

180

filed 13F for Jun 2026

▼-6 vs prior quarter

Net Shares Added (QoQ)

+1.26Mn

accumulated since last quarter

Value of Holdings

$941.17Mn

reported market value

Shares Owned by Institutions

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Institutions

Accumulated Distributed

Latest quarter —

Net over range —

Accumulating quarters —

Ownership Summary

Quarter ending 30 Jun, 2026

Castle Biosciences Inc (NASDAQ:CSTL) appears in 184 institutional 13F filings for the quarter ending March 2026.

These investors held 92.4% of outstanding shares in March 2026, down from 95.1% in December 2025.
They increased total shares held in CSTL by 13.17% quarter over quarter, and investors in Castle Biosciences increased 1.66% from a year ago.
Activity in CSTL broke down as 101 buyers, 59 sellers, and 24 unchanged among 184 total holders.
The aggregate institutional position in Castle Biosciences amounted to 27.62Mn shares as of March 2026, up by 3.21Mn shares quarter on quarter, and up 417.79K shares year over year.
As of March 31, 2026, BlackRock, Inc. held the largest stake in Castle Biosciences with 2.98Mn shares, accounting for 9.98% of total shares outstanding.
The most significant purchases of CSTL for the quarter ending March 2026 came from VANGUARD CAPITAL MANAGEMENT LLC (1.18Mn), VANGUARD PORTFOLIO MANAGEMENT LLC (861.77K), RTW INVESTMENTS, LP (643.1K), Qube Research & Technologies Ltd (324.06K), Morgan Stanley (225.36K).
Leading sellers of Castle Biosciences shares for the quarter ending March 2026 were Portolan Capital Management, LLC (379.18K), CITADEL ADVISORS LLC (245.38K), Goldman Sachs Group Inc (233.3K), Bank Of America Corp /De/ (195.21K), SCHRODER INVESTMENT MANAGEMENT GROUP (193.22K).
Per Business Quant data, the top 10 holders of Castle Biosciences for the quarter ending March 2026 are BlackRock, Inc. (2.98Mn), RTW INVESTMENTS, LP (2.76Mn), Principal Financial Group Inc (1.77Mn), Portolan Capital Management, LLC (1.35Mn), VANGUARD CAPITAL MANAGEMENT LLC (1.18Mn), DIMENSIONAL FUND ADVISORS LP (1.04Mn), SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC (940.68K), VANGUARD PORTFOLIO MANAGEMENT LLC (861.77K), Allianz Asset Management GmbH (811.32K), State Street Corp (769.08K).

Form 13F Holdings

180 Institutional Holders

Report period 30 Jun, 2026

Total shares held 27.62Mn

Of outstanding 90.85%

#	Institution	CIK	Shares Held	% of Outstanding	Change (QoQ)	Change (%)	Value (USD)
1	BlackRock, Inc.	0002012383	3,291,963	10.83%	▲309,017	+10.36%	$78.51Mn
2	RTW INVESTMENTS, LP	0001493215	2,778,335	9.14%	▲20,000	+0.73%	$66.26Mn
3	Principal Financial Group Inc	0001126328	1,726,648	5.68%	▼43,229	-2.44%	$41.18Mn
4	VANGUARD CAPITAL MANAGEMENT LLC	0002100119	1,226,497	4.03%	▲48,975	+4.16%	$29.25Mn
5	ACADIAN ASSET MANAGEMENT LLC	0000916542	918,668	3.02%	▲434,227	+89.63%	$21.90K
6	VANGUARD PORTFOLIO MANAGEMENT LLC	0002100121	840,785	2.77%	▼20,986	-2.44%	$20.05Mn
7	SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC	0001638555	824,872	2.71%	▼115,813	-12.31%	$19.67Mn
8	State Street Corp	0000093751	822,079	2.70%	▲53,000	+6.89%	$19.63Mn
9	Allianz Asset Management GmbH	0001535323	811,324	2.67%	0	0.00%	$19.92Mn
10	GEODE CAPITAL MANAGEMENT, LLC	0001214717	795,912	2.62%	▲67,812	+9.31%	$18.99Mn
11	MACKENZIE FINANCIAL CORP	0000919859	793,507	2.61%	▲719,396	+970.70%	$18.93Mn
12	DIMENSIONAL FUND ADVISORS LP	0000354204	791,085	2.60%	▼248,676	-23.92%	$18.87Mn
13	Jefferies Financial Group Inc.	0000096223	647,391	2.13%	▲647,391	0.00%	$15.44Mn
14	Qube Research & Technologies Ltd	0001729829	589,300	1.94%	▲29,717	+5.31%	$14.05Mn
15	AIGH Capital Management LLC	0001835943	545,101	1.79%	▼45,500	-7.70%	$13.00Mn
16	RENAISSANCE TECHNOLOGIES LLC	0001037389	371,200	1.22%	▼161,600	-30.33%	$8.85Mn
17	Goldman Sachs Group Inc	0000886982	358,397	1.18%	▲17,226	+5.05%	$8.55Mn
18	Point72 Asset Management, L.P.	0001603466	357,317	1.18%	▲357,317	0.00%	$8.52Mn
19	KENNEDY CAPITAL MANAGEMENT LLC	0000884589	348,371	1.15%	▲348,371	0.00%	$8.31Mn
20	Connor, Clark & Lunn Investment Management Ltd.	0001596800	331,727	1.09%	▼45,355	-12.03%	$7.91Mn

Showing 1 to 20 of 180 holders