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SEC EDGAR$CSTL

MAETZOLD DEREK J sold $310K of CSTL

MAETZOLD DEREK J (Pres. & Chief Exec. Officer) sold 8,580 shares of CASTLE BIOSCIENCES INC (CSTL) at an average of $36.10 ($36.00–$36.81, $0.31M total) across 2 trades on 2026-11-02 under a Rule 10b5-1 trading plan.

Original reporting
SEC EDGAR · MAETZOLD DEREK J
Published Nov 4, 2026, 9:07 PM UTC
Analysis
AlphAI AI DeskAI-generated
Added to AlphAI Nov 4, 2026, 9:09 PM UTC. Informational, not investment advice.
How this was made
AlphAI summarizes source reporting and applies a structured AI analysis for relevance, timing, sentiment and ticker impact. Always verify material claims with the original publisher.
About AlphAI AI DeskScoring methodologyReport an issue
AlphAI market briefInsider activity
Primary signal
$CSTL
Bearish
high confidence
Mentioned
$CSTL
Relevance
3/10
AlphAI data visualization · based on SEC EDGAR
Decision brief

The 30-second read

$CSTLBearishLow
01

Why it matters

The disclosed sale reduces insider ownership and may create slight downward pressure, though the pre-arranged nature limits interpretive weight.

02

Market read

A routine insider sale with modest dollar value; limited trading relevance.

03

What to watch

No new operational or financial developments accompany the filing.

Relevance 3/10Novelty 3/10Timing: today

Background

Form 4 filing by Castle Biosciences Inc. (CSTL) reporting an insider sale by its CEO.

Company-level read

Ticker impact

$CSTLBearishHigh confidence
Context

SEC Form 4 shows CEO Derek Maetzold sold 8,580 shares for $309,752, reducing his stake to 3,904 shares.

Expected impact

likely modest pressure as the market prices in the insider sell.

Evidence & confidence

The sale is disclosed via a 10b5-1 plan, indicating a pre-arranged transaction rather than a reaction to new information, but the reduction in insider holdings can still weigh on the stock.

Market effects

Sector

Minimal impact on the biotech sector.

Regional

None.

Global

Low.

Counterpoint

What could challenge this read

The sale could be purely mechanical under a 10b5-1 plan and not reflect negative outlook.

Key entities

  • company
    Castle Biosciences Inc.

    Biotech firm listed on NASDAQ under ticker CSTL.

  • person
    Derek J. Maetzold

    President & Chief Executive Officer of Castle Biosciences.

Read at source← All news

Full insider trading history

This story covers one filing. See everything behind it: every insider buy and sell on record, 10b5-1 plans, late filings, and which officers and directors are trading.

CSTL insider trading history →

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