AlphAIAlphAI — Financial news for AI agents
SEC EDGAR$CSTL

MAETZOLD DEREK J sold $210K of CSTL (indirect holdings)

MAETZOLD DEREK J (Pres. & Chief Exec. Officer) sold 5,916 indirectly-held shares of CASTLE BIOSCIENCES INC (CSTL) at $35.57 ($0.21M total) across 2 trades on 2026-10-05 under a Rule 10b5-1 trading plan.

Original reporting
SEC EDGAR · MAETZOLD DEREK J
Published Oct 7, 2026, 8:10 PM UTC
Analysis
AlphAI AI DeskAI-generated
Added to AlphAI Oct 7, 2026, 8:16 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
medium confidence
Mentioned
$CSTL
Relevance
3/10
AlphAI data visualization · based on SEC EDGAR
Decision brief

The 30-second read

$CSTLBearishLow
01

Why it matters

Provides a fresh data point on insider holdings but limited trading relevance due to small size.

02

Market read

Routine insider sale with modest size; unlikely to move the stock significantly.

03

What to watch

Potential upcoming clinical data releases that may affect insider sentiment.

Relevance 3/10Novelty 3/10Timing: post‑market today

Background

Form 4 filing discloses insider transactions required by SEC regulations.

Company-level read

Ticker impact

$CSTLBearishMedium confidence
Context

CEO Derek Maetzold sold 5,916 shares for $210,408 via a 10b5‑1 plan, reducing his stake to 6,832 shares.

Expected impact

likely slight pressure as market prices in the insider sell

Evidence & confidence

The sale is modest ($210k) and executed under a pre‑arranged plan, limiting informational value.

Market effects

Sector

Minimal impact on biotech sector; insider activity is routine.

Regional

None

Global

None

Counterpoint

What could challenge this read

The sale could be unrelated to company fundamentals and merely portfolio rebalancing.

Key entities

  • Company
    Castle Biosciences Inc.

    Biotech firm developing diagnostic tests.

  • Executive
    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 →

Related articles

$CSTLMed

DecisionDx®-Melanoma Data at SDPA and Dermato-Onco2026 Support the Test's Ability to Refine Risk Assessment Beyond AJCC Staging

Castle Biosciences presented data on DecisionDx-Melanoma at SDPA and Dermato-Onco2026, showing the test can identify higher-risk patients with thin melanomas and provide individualized five-year recurrence-risk estimates. The studies suggest the test refines risk assessment beyond AJCC staging, aiding personalized care. According to the company, the test has been ordered over 260,000 times and is supported by extensive research.

prnewswire.com
$CSTLMed

Castle Bio (CSTL) Q3 2026 Earnings Call Transcript

Castle Bio (CSTL) reported Q3 2026 revenue of $102.9M, up 24% YoY, driven by 47% growth in TissueCypher test volume. Net cash from operations was $19.7M, with $278M in cash and equivalents. The company raised full-year revenue guidance to $385M-$395M, up from $365M-$375M. DecisionDx-Melanoma saw 5% YoY growth, while TissueCypher is expected to grow 50%-52% for the year.

finance.yahoo.com
$CSTLHigh

Castle Biosciences Reports Third Quarter 2026 Results

CASTLE BIOSCIENCES INC (CSTL) filed an SEC Form 8-K — Results of Operations and Financial Condition. Exhibit 99.1 Castle Biosciences Reports Third Quarter 2026 Results Delivered Q3 2026 revenue of $102.9 million, an increase of 24% over Q3 2025 TissueCypher ® test report volume increased 47% over Q3 2025 Raising full-year 2026 revenue guidance to $385-395 million from $365-375 m

SEC EDGAR 8-K
$CSTLHighAI 8/10

Castle Biosciences Reports Third Quarter 2026 Results

Castle Biosciences reported Q3 2026 revenue of $102.9M, up 24% YoY. TissueCypher test volume rose 47% YoY. The company raised full-year 2026 revenue guidance to $385-395M. Q3 net loss was $4.1M, with Adjusted EBITDA of $12.7M. The company presented new data on its DecisionDx-Melanoma test at EADV Congress 2026.

prnewswire.com
$CSTLMed

Late-Breaking EADV 2026 Data Support Use of DecisionDx®-Melanoma in SLNB Decision-Making and Risk-Aligned Post Surgical Management

Castle Biosciences presented data at EADV 2026 showing DecisionDx-Melanoma's ability to predict low SLN positivity and high recurrence risk in melanoma patients. The study involved 2,799 patients across 29 U.S. centers, with low-risk patients avoiding SLNB showing 99.6% five-year RFS. The test also stratified recurrence risk in early-stage, transected melanomas, supporting tailored surveillance. Castle Biosciences is a Nasdaq-listed company (CSTL).

prnewswire.com