CSTL
CASTLE BIOSCI (CSTL)
NASDAQ
$29.19+$1.19 (+4.25%)
Price as of Aug 03, 2026 10:07 AM EDT
  • $849.2M
    Market Cap
  • 91.13%
    1-Year Change
  • Diagnostics & Research
    Industry

Top Holders

Institutional
Mutual Funds
Holder
Ownership %
Shares Held
Change (Shares, %)
Report Date
WASATCH ADVISORS INC
10.63%
3.2M
-122,185 (-3.79%)
Dec 31, 2022
BLACKROCK INC.
10.04%
3.0M
+449,286 (+14.76%)
Jun 30, 2024
BLACKROCK, INC.
9.83%
3.0M
-122,300 (-4.10%)
Mar 31, 2026
BLACKROCK FUNDING, INC. /DE
9.63%
2.9M
-198,963 (-6.81%)
Dec 31, 2024
RTW INVESTMENTS, LP
9.09%
2.8M
+643,098 (+23.31%)
Mar 31, 2026
VANGUARD GROUP INC
7.25%
2.2M
+27,511 (+1.25%)
Dec 31, 2025
PRINCIPAL FINANCIAL GROUP INC
5.84%
1.8M
-37,767 (-2.13%)
Mar 31, 2026

Current Ownership Distribution

  • Institutions444.8M (75.55%)
  • Mutual Funds140.1M (23.79%)
  • Insiders3.9M (0.66%)
  • Other0 (0.00%)

Insider Transactions

  • 0.66% (3.9M)
    Current InsiderOwnership (%, shares)
  • 0
    Number of InsiderBuying (last 12 months)
  • $0.00
    Amount of InsiderBuying (last 12 months)
  • 4
    Number of InsiderSelling (last 12 months)
  • $74.7M
    Amount of InsiderSelling (last 12 months)
Insider Name & Title
Type
Date
Transaction Value
Shares
Share Price
Shares After Transactions
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Exempt
Jul 27, 2026
$0.00
6,214
$0.00
78,903
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Exempt
Jul 27, 2026
$14,851.46
6,214
$2.39
27,693
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$144,345.66
5,982
$24.13
21,711
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$31,537.91
1,307
$24.13
38,046
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$26,784.30
1,110
$24.13
32,339
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$6,466.84
268
$24.13
11,822
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$6,466.84
268
$24.13
11,822
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$6,466.84
268
$24.13
11,822
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$6,466.84
268
$24.13
11,822
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$5,813.92
232
$25.06
21,479
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$1,253.00
50
$25.06
37,996
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$1,077.58
43
$25.06
32,296
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$250.60
10
$25.06
11,812
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$250.60
10
$25.06
11,812
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$250.60
10
$25.06
11,812
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Jul 27, 2026
$250.60
10
$25.06
11,812
Oelschlager Kristen M
Chief Operating Officer
Sell
Jul 01, 2026
$199,738.40
8,186
$24.40
22,274
Oelschlager Kristen M
Chief Operating Officer
Sell
Jul 01, 2026
$9,912.00
400
$24.78
21,874
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Exempt
Apr 06, 2026
$0.00
6,214
$0.00
7,518
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Exempt
Apr 06, 2026
$14,851.46
6,214
$2.39
27,693
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Apr 06, 2026
$155,536.42
6,214
$25.03
21,479
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Apr 06, 2026
$33,965.71
1,357
$25.03
48,852
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Apr 06, 2026
$28,859.59
1,153
$25.03
41,520
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Apr 06, 2026
$6,958.34
278
$25.03
2,780
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Apr 06, 2026
$6,958.34
278
$25.03
2,780
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Apr 06, 2026
$6,958.34
278
$25.03
2,780
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Apr 06, 2026
$6,958.34
278
$25.03
2,780
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Exempt
Mar 26, 2026
$0.00
550
$0.00
13,732
Cotton Rodney
Exempt
Mar 26, 2026
$0.00
5,329
$0.00
5,330
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Exempt
Mar 26, 2026
$1,314.50
550
$2.39
22,029