SecBot SecBot
144 ·Filed Jul 1, 2026

CSTL

CASTLE BIOSCIENCES INC
NEUTRAL
Impact 2/10
Horizonimmediate Processed3mo ago SEC0001958244-26-000421
Form 144 — notice of proposed sale of securities
Actionable Insight • Neutral

This is a routine 10b5-1 plan filing with no new directional signal. The CEO's selling is pre-scheduled and has been ongoing for months. Monitor for any acceleration in selling frequency or volume outside the plan parameters, but no immediate action warranted.

DirectionNeutral
Confidencehigh
Horizonimmediate
Final — all horizons settled through T+60d
CSTL ▲ +45.96% at T+60d
NEUTRAL call +45.96% · α vs SPY +42.95% · entry $24.11 → $35.19
Entry = T+0 close
Jul 1, 2026
via day close
T+1d
+0.41%
call +0.41% · α -0.46%
$24.21
settled 4mo ago
T+5d
+1.87%
call +1.87% · α +0.94%
$24.56
settled 4mo ago
T+20d
+11.12%
call +11.12% · α +11.53%
$26.79
settled 3mo ago
T+60d
+45.96%
call +45.96% · α +42.95%
$35.19
settled 5w ago

Price Chart

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Executive Summary

CEO Derek Maetzold filed a Form 144 to sell 23,844 shares (~$589K) under a pre-arranged 10b5-1 trading plan dated December 3, 2025. The filing is a routine continuation of the plan, which has been executing sales since April 2026, and does not signal a change in insider sentiment.

Key Facts

  • CEO Derek Maetzold intends to sell 23,844 shares of common stock with an estimated market value of $589,185.24.
  • Sales are made pursuant to a 10b5-1 trading plan adopted on December 3, 2025.
  • The filing covers shares held directly by Maetzold and through multiple trusts (DM 2020 Irrev Tr, Maetzold Descendants 2020 Tr, and irrevocable trusts for family members).
  • Prior sales under the same plan occurred on multiple dates from April through June 2026, indicating ongoing systematic selling.
  • The proposed sale represents approximately 0.08% of the company's $723M market cap.

Financial Impact

Proposed sale of 23,844 shares valued at ~$589K, less than 0.1% of market cap.

dilution

Risk Factors

  • Insider selling under a plan is not opportunistic, but continued large-scale selling could signal reduced conviction over time.
  • Plan sales may dampen near-term price appreciation if the market misinterprets them as bearish.

Market Snapshot

Exchange
Nasdaq
Sector
Services-Medical Laboratories
Analyst Consensus
93% bullish (14 analysts)

Investment Themes

Documents Analyzed

This report is based on 3 SEC documents filed with EDGAR.

DocumentAccession Number
144 Filing (Primary)0001958244-26-000421
Document: 0001958244-26-000421-index.html0001958244-26-000421
Document: 0001958244-26-000421.txt0001958244-26-000421
31 reports for CSTL
Performance horizon
60% Hit rate @ T+1 6 of 10 directional calls Went positive at some point 9 of 10 best @ T+60▲ +27.32%Mar 5, 2026
Filters
Rows
Reports for CSTL — sortable, filterable
TypeNow
Oct 21, 2026
6d ago
Insider Cluster
NEUTRAL ★ 3/10
$33.19 $33.08▼ −0.33%▲ +0.19%$34.51 (+3.98%)
Oct 5, 2026
22d ago
144
NEUTRAL ★ 4/10
$33.36 $33.00▼ −1.08%▼ −0.84%$34.51 (+3.45%)
Oct 5, 2026
22d ago
Insider Cluster
NEUTRAL ★ 2/10
$33.36 $33.00▼ −1.08%▼ −0.84%$34.51 (+3.45%)
Sep 23, 2026
4w ago
Insider Cluster
BEARISH ★ 4/10
$35.19 $35.81▼ −1.76%▼ −1.22%$34.51 (+1.93%)
Sep 16, 2026
5w ago
Insider Cluster
NEUTRAL ★ 2/10
$36.78 $35.34▼ −3.92%▼ −4.04%$34.51 (−6.17%)
Sep 11, 2026
6w ago
144
NEUTRAL ★ 4/10
$33.44 $35.50▲ +6.16%▲ +6.62%$34.51 (+3.20%)
Sep 3, 2026
7w ago
Insider Cluster
BEARISH ★ 4/10
$32.91 $32.76▲ +0.46%▼ −0.09%$34.51 (−4.86%)
Sep 2, 2026
7w ago
Insider Cluster
NEUTRAL ★ 2/10
$32.65 $32.91▲ +0.80%▲ +1.18%$34.51 (+5.70%)
Sep 1, 2026
8w ago
Insider Cluster
NEUTRAL ★ 2/10
$33.42 $32.65▼ −2.30%▼ −3.35%$34.51 (+3.26%)
Aug 27, 2026
8w ago
Insider Cluster
NEUTRAL ★ 4/10
$33.50 $33.03▼ −1.40%▼ −1.10%$34.51 (+3.01%)
Showing 10 of 31

US Market Status

Market Closed — Opens Wed (< 1m)

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Report published Jul 1, 2026