CSTL CLUSTER SEC Filing Analysis

Final — all horizons settled through T+60d ⚠ clustered

CSTL ▼ -22.89% at T+60d

NEUTRAL call ✗ call lost -22.89% · α vs SPY -33.20% · entry $27.57 → $21.26

Last close $20.12 (close Jun 8) · -27.02% from $27.57 entry

Entry anchored
Mar 2, 03:59 PM ET
via Databento tick

T+1d

+2.18%

call +2.18% · α +1.41%

$28.17

settled 3mo ago

T+5d

-3.52%

call -3.52% · α -3.04%

$26.60

settled 3mo ago

T+20d

-10.95%

call -10.95% · α -6.55%

$24.55

settled 2mo ago

T+60d

-22.89%

call -22.89% · α -33.20%

$21.26

settled 14d ago

Price Chart

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Executive Summary

Castle Biosciences insiders executed a cluster of transactions over the past week, primarily involving derivative exercises, share grants, and tax-related share withholdings. The only open-market sales were $135K by a director and $144.8K by the CFO, both relatively small in context. Most activity represents non-cash, routine equity events tied to compensation.

Key Financial Metrics

Direction

selling

Total Value

$279.8K

Insiders

5

Actionable Insight

No material insider selling pressure detected — open-market sales are small (<0.1% of $806M market cap) and likely routine. Monitor for continued open-market selling in future filings; current activity aligns with normal equity compensation management.

Key Facts

Director Cole G Bradley sold 4,748 shares for $135,033 in an open-market transaction.
CFO Frank Stokes sold 5,300 shares for $144,796 in an open-market transaction.
CEO, COO, CCO, and CFO exercised stock options and received new share grants (non-cash events).
CEO Maetzkold surrendered 19,043 shares ($525K value) to cover tax obligations on a grant.
All other transactions (grants, exercises, tax withholdings) are non-cash and routine for executive compensation.

Financial Impact

$279.8K in total open-market selling; $692K in tax-related share surrenders; $0 in net cash impact from grants/exercises.

insider ownershipshare countinsider sentiment

Risk Factors

Perception of insider selling if context is misunderstood (e.g., conflating tax withholding with profit-taking).
Potential for increased share dilution over time from repeated share grants.

Market Snapshot

Exchange

Nasdaq

Documents Analyzed

This report is based on 1 SEC document filed with EDGAR.

Document	Accession Number
CONTEXT: Insider Cluster Data (20 trades, 7d window)	cluster-CSTL-1773087200506

10 reports for CSTL

T+1T+5T+20T+60

83% Hit rate 5 of 6 directional calls best @ T+60▲ +24.87%Mar 5, 2026

Filters

Reports for CSTL — sortable, filterable
	Type				Now
Jun 1, 2026 8d ago	144 NEUTRAL ★ 4/10	$19.71 $20.39	▲ +3.45%	▲ +4.17%	$20.12 (+2.08%)
May 7, 2026 4w ago	144 NEUTRAL ★ 3/10	$19.83 $19.04	▼ −3.98%	▼ −4.22%	$20.12 (+1.46%)
Apr 8, 2026 8w ago	DEFA14A NEUTRAL ★ 3/10	$25.19 $23.43	▼ −6.99%	▼ −7.56%	$20.12 (−20.13%)
Mar 13, 2026 12w ago	Press Release BULLISH ★ 7/10	$25.56 $25.83	▲ +1.06%	▲ +0.03%	$20.12 (−21.28%)
Mar 12, 2026 12w ago	Insider Cluster BEARISH ★ 6/10	$25.32 $25.56	▼ −0.95%	▼ −1.55%	$20.12 (+20.54%)
Mar 12, 2026 12w ago	Insider Cluster BEARISH ★ 7/10	$25.32 $25.56	▼ −0.95%	▼ −1.55%	$20.12 (+20.54%)
Mar 9, 2026 13w ago	Press Release BULLISH ★ 7/10	$27.02 $26.60	▼ −1.55%	▼ −1.37%	$20.12 (−25.54%)
Mar 5, 2026 13w ago	Insider Cluster BEARISH ★ 7/10	$27.91 $27.12	▲ +2.83%	▲ +1.52%	$20.12 (+27.91%)
Mar 5, 2026 13w ago	Insider Cluster BEARISH ★ 5/10	$27.91 $27.12	▲ +2.83%	▲ +1.52%	$20.12 (+27.91%)
Mar 3, 2026 14w ago	Insider Cluster NEUTRAL ★ 3/10	$27.57 $28.17	▲ +2.18%	▲ +1.41%	$20.12 (−27.02%)

US Market Status

Market Closed — Opens in 8h 12m

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