CSTL
CASTLE BIOSCI (CSTL)
NASDAQ
$34.21+$0.010 (+0.03%)
Price as of Aug 21, 2026 7:30 PM EDT
  • $1.0B
    Market Cap
  • 64.11%
    1-Year Change
  • Diagnostics & Research
    Industry

Top Holders

Institutional
Mutual Funds
Holder
Ownership %
Shares Held
Change (Shares, %)
Report Date
BLACKROCK, INC.
10.78%
3.3M
+309,017 (+9.39%)
Jun 30, 2026
WASATCH ADVISORS INC
10.55%
3.2M
-122,185 (-3.79%)
Dec 31, 2022
BLACKROCK INC.
9.97%
3.0M
+449,286 (+14.76%)
Jun 30, 2024
BLACKROCK FUNDING, INC. /DE
9.56%
2.9M
-198,963 (-6.81%)
Dec 31, 2024
RTW INVESTMENTS, LP
9.09%
2.8M
+20,000 (+0.72%)
Jun 30, 2026
VANGUARD GROUP INC
7.20%
2.2M
+27,511 (+1.25%)
Dec 31, 2025
PRINCIPAL FINANCIAL GROUP INC
5.65%
1.7M
-43,229 (-2.50%)
Jun 30, 2026

Current Ownership Distribution

  • Institutions472.2M (76.60%)
  • Mutual Funds140.3M (22.76%)
  • Insiders4.0M (0.64%)
  • Other0 (0.00%)

Insider Transactions

  • 0.64% (4.0M)
    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)
  • $82.4M
    Amount of InsiderSelling (last 12 months)
Insider Name & Title
Type
Date
Transaction Value
Shares
Share Price
Shares After Transactions
Juvenal Tobin W
Chief Commercial Officer
Sell
Aug 17, 2026
$51,190.70
1,730
$29.59
75,964
Stokes Frank
Chief Financial Officer
Sell
Aug 14, 2026
$741,511.16
24,908
$29.77
35,177
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Exempt
Aug 14, 2026
$0.00
1,100
$0.00
37,757
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Exempt
Aug 14, 2026
$2,629.00
1,100
$2.39
22,579
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Aug 14, 2026
$33,022.00
1,100
$30.02
21,479
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Aug 14, 2026
$81,474.28
2,714
$30.02
20,355
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Aug 14, 2026
$69,226.12
2,306
$30.02
17,301
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Aug 14, 2026
$8,345.56
278
$30.02
11,534
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Aug 14, 2026
$8,345.56
278
$30.02
11,534
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Aug 14, 2026
$8,345.56
278
$30.02
11,534
MAETZOLD DEREK J
Pres. & Chief Exec. Officer
Sell
Aug 14, 2026
$8,345.56
278
$30.02
11,534
Oelschlager Kristen M
Chief Operating Officer
Sell
Aug 03, 2026
$87,360.00
3,000
$29.12
18,874
Oelschlager Kristen M
Chief Operating Officer
Sell
Aug 03, 2026
$134,580.00
4,486
$30.00
14,388
Oelschlager Kristen M
Chief Operating Officer
Sell
Aug 03, 2026
$33,682.00
1,100
$30.62
13,288
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