Insider cluster selling is small relative to market cap and partly vesting-related. Monitor next quarterly filing for operational updates; the selling pattern does not signal a fundamental deterioration.
Price Chart
Executive Summary
Multiple C-suite insiders at Castle Biosciences sold shares totaling $195K in a cluster over the past week. The CEO, COO, and CCO all sold open-market shares — the COO's trades were linked to derivative exercises — representing approximately 0.02% of market cap. The historical performance of past neutral reports on CSTL shows strong positive drift, suggesting cluster selling is not moving the stock in this case.
Key Financial Metrics
Key Facts
- Cluster of 3 insiders (CEO, COO, CCO) sold shares totaling $195K open-market
- COO Oelschlager sold 4,152 shares for $132K on 2026-09-01 after exercising derivatives
- CCO Juvenal sold 1,730 shares for $57K on 2026-08-31
- CEO Maetzold sold 177 shares for $6K on 2026-08-28
- Total sales are 0.02% of $1.0B market cap — below the 0.1% threshold for materiality
- COO's sales followed scheduled derivative exercise, suggesting planned liquidity not opportunistic timing
Financial Impact
Selling of ~$195K — 0.02% of market cap — below typical insider-sale materiality threshold
Risk Factors
- Insider selling may continue if management adopts 10b5-1 plans post-blackout
- Low volume cluster could be misinterpreted as negative sentiment despite size being immaterial
Market Snapshot
Investment Themes
Documents Analyzed
This report is based on 1 SEC document filed with EDGAR.
| Document | Accession Number |
|---|---|
| CLUSTER Data (Synthetic) | cluster-CSTL-1788505992320 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
Oct 21, 2026 5d ago | Insider Cluster | $33.19 $33.08 | ▼ −0.33% | ▲ +0.19% | $33.30 (+0.33%) |
Oct 5, 2026 21d ago | 144 | $33.36 $33.00 | ▼ −1.08% | ▼ −0.84% | $33.30 (−0.18%) |
Oct 5, 2026 21d ago | Insider Cluster | $33.36 $33.00 | ▼ −1.08% | ▼ −0.84% | $33.30 (−0.18%) |
Sep 23, 2026 4w ago | Insider Cluster | $35.19 $35.81 | ▼ −1.76% | ▼ −1.22% | $33.30 (+5.37%) |
Sep 16, 2026 5w ago | Insider Cluster | $36.78 $35.34 | ▼ −3.92% | ▼ −4.04% | $33.30 (−9.46%) |
Sep 11, 2026 6w ago | 144 | $33.44 $35.50 | ▲ +6.16% | ▲ +6.62% | $33.30 (−0.42%) |
Sep 3, 2026 7w ago | Insider Cluster | $32.91 $32.76 | ▲ +0.46% | ▼ −0.09% | $33.30 (−1.19%) |
Sep 2, 2026 7w ago | Insider Cluster | $32.65 $32.91 | ▲ +0.80% | ▲ +1.18% | $33.30 (+1.99%) |
Sep 1, 2026 7w ago | Insider Cluster | $33.42 $32.65 | ▼ −2.30% | ▼ −3.35% | $33.30 (−0.36%) |
Aug 27, 2026 8w ago | Insider Cluster | $33.50 $33.03 | ▼ −1.40% | ▼ −1.10% | $33.30 (−0.60%) |
US Market Status
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