---
schema_version: "secwatch.filing_event.v1"
accession: "0001447362-22-000074"
form_type: "8-K"
ticker: "CSTL"
cik: "0001447362"
company_name: "CASTLE BIOSCIENCES INC"
filed_at: "2022-05-02T23:59:59+00:00"
generated_at: "2026-06-26T02:00:33.530699+00:00"
event_type: "m_and_a"
sentiment: "neutral"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Castle Biosciences completes AltheaDx acquisition; issues 763,887 shares

## Summary
- $65M initial consideration: $32.5M cash and $32.5M in stock (763,887 shares).
- Up to $75M in milestone payments through Dec 31, 2024; 50% cash, 50% stock.
- Max shares issuable capped at 1,271,718; up to 507,831 more for milestones.
- Shares unregistered under Section 4(a)(2)/Reg D; resale registration due in 40 days.

## SEC filing metadata
- accession: 0001447362-22-000074
- form_type: 8-K
- ticker: CSTL
- cik: 0001447362
- company_name: CASTLE BIOSCIENCES INC
- filed_at: 2022-05-02T23:59:59+00:00
- event_type: m_and_a
- sentiment: neutral
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 3.02
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1447362/000144736222000074/0001447362-22-000074-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1447362/000144736222000074/cstl-20220426.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001447362-22-000074
- JSON: https://secwatch.observer/filing/0001447362-22-000074.json
- Plain text: https://secwatch.observer/filing/0001447362-22-000074.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.