Security Snapshot

CASTLE BIOSCIENCES INC - Common Stock, $0.001 par value per share (CSTL) Institutional Ownership

CUSIP: 14843C105

13F Institutional Holders and Ownership History from Q3 2019 to Q3 2026

13F reference period

Q3 2026

Institutions Reporting

104

Shares (Excl. Options)

10.49MFull value: 10,486,093 · shares · 30 Sep 2026

Price

$35.53

The headline uses the Q3 2026 reference period after its reporting deadline. Available reports may still be incomplete or amended.

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Security type / class
Equity / Common Stock, $0.001 par value per share
Symbol
CSTL on Nasdaq
All holders as of 30 Sep 2026
Q3 2026
Total 13F shares
10,486,093
Latest holder snapshot 5 signals
Total 13F value
$372,528,583
Portfolio coverage rank
0%
Share change
-735,914
Value change
-$16,777,758
Number of holders
104
Issuer context Names, identifiers, and filing context for this profile. 3 identity fields
Shares outstanding
30,630,551
SEC-reported price per share
$35.53
Insider filing price
$35.53
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Filing notes and source

Key facts

  • CSTL - CASTLE BIOSCIENCES INC - Common Stock, $0.001 par value per share is tracked under CUSIP 14843C105.
  • 104 institutions reported positions in Q3 2026.
  • 6 significant owners is listed from Schedule 13D/13G reporting.

Change

  • Holder count moved from 176 to 104 between Q2 2026 and Q3 2026.
  • SEC-reported value moved from
    $653.81MFull value: $653,809,607 · USD · 30 Jun 2026
    to
    $372.53MFull value: $372,528,583 · USD · 30 Sep 2026
    .

Research use

  • You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
  • 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.

Evidence

Source: SEC Form 13F

Latest holder context comes from 104 institutions filings for Q3 2026.

Open SEC evidence

Security key

14843C105

13F reference period

Q3 2026

13F holders

104

13D/G owners

6

CIK / CUSIP context first

Open Q3 2026 holders CSTL full holder history CASTLE BIOSCIENCES INC SEC filings CASTLE BIOSCIENCES INC company facts CASTLE BIOSCIENCES INC insider transactions

Broader feeds

Latest 13F filings Latest 13D/G filings All securities

13D/G owners

Significant owners

Large-stake holder rows connected to Schedule 13D/G evidence.

Rows
6
Security
CSTL
Filer Ownership Change % Holdings Value Net Change Nb Shares Change % Reporting Name Report Period
RTW INVESTMENTS, LP 9.3% +30% $67,717,124 +$15,788,056 2,758,335 +30% RTW Investments, LP 31 Mar 2026
BlackRock, Inc. 8.2% $47,017,281 2,338,005 BlackRock, Inc. 31 Mar 2025
PRINCIPAL GLOBAL INVESTORS 4.9% $53,326,870 1,500,897 PRINCIPAL GLOBAL INVESTORS 30 Sep 2026
Portolan Capital Management, LLC 4.4% -20% $33,149,448 -$6,403,033 1,350,283 -16% Portolan Capital Management, LLC 31 Mar 2026
DIMENSIONAL FUND ADVISORS LP 3.9% -24% $44,494,010 -$12,848,347 1,143,799 -22% Dimensional Fund Advisors LP 31 Dec 2025
WASATCH ADVISORS LP 3.5% $20,078,930 998,455 WASATCH ADVISORS LP 31 Mar 2025
As of 30 Sep 2026, 104 institutional investors reported holding
10.49MFull value: 10,486,093 · shares · 30 Sep 2026
shares of CASTLE BIOSCIENCES INC - Common Stock, $0.001 par value per share (CSTL). This represents 34% of the company’s total
30.63MFull value: 30,630,551 · shares · Stored outstanding share count
outstanding shares.

13F concentration

Top 25 institutional shareholders

Largest 13F positions for this security by reported shares and value.

Top holder share
31%
Institution Ownership % Shares Held Share Change % Portfolio % Holdings Value
VANGUARD CAPITAL MANAGEMENT LLC 4% 1,237,951 +0.93% 0% $43,984,399
STATE STREET CORP 2.6% 804,682 -2.1% 0% $28,590,351
GEODE CAPITAL MANAGEMENT, LLC 2.6% 793,904 -0.25% 0% $28,213,299
VANGUARD PORTFOLIO MANAGEMENT LLC 2.3% 716,665 -15% 0% $25,463,107
DIMENSIONAL FUND ADVISORS LP 2.3% 692,104 -13% 0% $24,588,715
Jefferies Financial Group Inc. 2.1% 647,391 0% 0.31% $23,001,802
MACKENZIE FINANCIAL CORP 1.9% 568,440 -28% 0.02% $20,196,673
Qube Research & Technologies Ltd 1.5% 474,773 -19% 0.02% $16,868,685
Connor, Clark & Lunn Investment Management Ltd. 1.2% 369,641 +11% 0.02% $13,133,345
KENNEDY CAPITAL MANAGEMENT LLC 1.1% 339,263 -2.6% 0.23% $12,054,014
PANAGORA ASSET MANAGEMENT INC 1.1% 331,811 +10% 0.04% $11,789,245
RENAISSANCE TECHNOLOGIES LLC 1.1% 322,400 -13% 0.02% $11,454,872
EVENTIDE ASSET MANAGEMENT, LLC 0.98% 300,000 0.15% $10,659,000
WASATCH ADVISORS LP 0.91% 279,343 -0% 0.07% $9,925,057
KORNITZER CAPITAL MANAGEMENT INC /KS 0.86% 264,806 +0.22% 0.2% $9,408,557
Advisors Capital Management, LLC 0.76% 231,920 -2.6% 0.08% $8,240,117
VANGUARD FIDUCIARY TRUST CO 0.65% 200,628 +1.6% 0% $7,128,313
Empowered Funds, LLC 0.49% 148,857 +4.6% 0.02% $5,288,889
MORGAN STANLEY 0.48% 145,590 -56% 0% $5,172,841
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.45% 137,188 +48% 0% $4,874,290
Jump Financial, LLC 0.44% 133,300 0.04% $4,736,149
BNP PARIBAS FINANCIAL MARKETS 0.42% 127,892 0% $4,544,003
FRANKLIN TEMPLETON INC 0.38% 116,912 +20% 0% $4,179,604
Orion Porfolio Solutions, LLC 0.26% 78,366 +13% 0.02% $2,784,344
AMERICAN CENTURY COMPANIES INC 0.22% 66,143 +1.1% 0% $2,350,061

Quarter history

Institutional holders across reporting periods

Holder count, reported shares/value, and median price by quarter.

Periods
29
Headline period
Q3 2026
Rows shown
1-25 of 29
Period 13F Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2026 Q3 10,486,093 $372,528,583 -$16,777,758 $35.53 104
2026 Q2 27,409,255 $653,809,607 -$4,071,537 $23.85 176
2026 Q1 27,584,532 $676,774,747 -$6,568,772 $24.55 185
2025 Q4 27,312,273 $1,062,104,151 +$35,010,645 $38.90 196
2025 Q3 26,525,698 $603,808,247 +$704,267 $22.77 170
2025 Q2 26,536,136 $541,803,165 +$16,367,707 $20.42 151
2025 Q1 25,785,418 $516,159,447 -$22,608,207 $20.02 180
2024 Q4 26,505,010 $706,396,254 +$8,987,296 $26.65 197
2024 Q3 25,823,597 $736,872,924 +$15,687,154 $28.52 185
2024 Q2 25,237,547 $549,387,569 +$5,246,303 $21.77 158
2024 Q1 24,977,542 $553,239,171 +$24,692,740 $22.15 148
2023 Q4 23,883,435 $515,429,989 +$17,867,692 $21.58 150
2023 Q3 23,151,664 $391,032,725 +$7,780,165 $16.89 133
2023 Q2 22,797,205 $312,778,898 -$3,698,099 $13.72 128
2023 Q1 22,094,408 $501,938,865 +$5,568,015 $22.72 148
2022 Q4 22,279,170 $524,435,055 +$5,715,957 $23.54 152
2022 Q3 21,906,465 $571,186,085 -$14,799,148 $26.08 152
2022 Q2 22,558,449 $495,033,707 -$115,268,932 $21.95 141
2022 Q1 22,780,568 $1,019,269,661 +$62,738,499 $44.86 153
2021 Q4 21,449,510 $918,308,511 -$59,908,643 $42.87 153
2021 Q3 20,974,973 $1,396,164,362 +$40,585,506 $66.50 182
2021 Q2 20,801,213 $1,521,315,172 -$4,483,937 $73.33 176
2021 Q1 21,328,263 $1,459,495,488 +$90,506,347 $68.46 173
2020 Q4 19,063,994 $1,280,953,552 +$376,683,100 $67.15 160
2020 Q3 13,395,783 $689,395,356 +$88,062,594 $51.45 144
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