// company-profile

Castle Biosciences Inc

CSTL
ExchangeNasdaqSectorServices-Medical LaboratoriesInc.DEFilings233Insiders12
// api This Castle Biosciences Inc insider-trading data is served live by the Form4API insider trading API. Get the same data via API.

// activity-summary

Recent insider activity is bullish. Over the last 30 days, 7 insiders purchased shares. Buying was led by Cole G Bradley.

// 90-day insight

Over the last 90 days, Castle Biosciences Inc insiders bought $38K across 23 transactions with no open-market sales.

  • Most active insider: MAETZOLD DEREK J with 26 transactions totaling $346K.
  • Largest single sale: $178K by Oelschlager Kristen M on Jun 16, 2026.
  • 100% of recent sales were pre-scheduled 10b5-1 trades — typically less informative than open-market activity.

Activity skews bullish — buys outpace sales.

Institutional Ownership

Top 13F-HR holders of Castle Biosciences Inc as of 2026-03-31

↓ decreasing
Total reported AUM
$626.9M
QoQ change
-32.0%
Reporting period
2026-03-31
#1
RTW INVESTMENTS, LP
CIK 1493215
$67.7M
2.8M shares
#2
PRINCIPAL FINANCIAL GROUP INC
CIK 1126328
$43.4M
1.8M shares
#3
BlackRock, Inc.
CIK 2012383
$34.6M
1.4M shares

Data source: SEC Form 13F-HR filings. Joined with insider activity above — see who's loading up institutionally while insiders are trading. Full 13F-HR API →

Insider Transactions

Sourced from SEC EDGAR Form 4 filings. Updated hourly.

DateInsiderCompanyTypeSharesPriceValue
Jun 16, 2026Oelschlager Kristen MCSTL
Sale10b5
8,587$20.71$178K
Jun 15, 2026MAETZOLD DEREK JCSTL
Sale10b5
1,153$20.66$24K
Jun 15, 2026MAETZOLD DEREK JCSTL
Option Exercise10b5
550$2.39$1K
Jun 15, 2026MAETZOLD DEREK JCSTL
Sale10b5
550$20.66$11K
Jun 15, 2026MAETZOLD DEREK JCSTL
Sale10b5
1,357$20.66$28K

45 more transactions hidden

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