---
schema_version: "secwatch.filing_event.v1"
accession: "0001447362-25-000099"
form_type: "8-K"
ticker: "CSTL"
cik: "0001447362"
company_name: "CASTLE BIOSCIENCES INC"
filed_at: "2025-08-08T23:59:59+00:00"
generated_at: "2026-05-17T16:17:54.664701+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.25
calibrated_materiality_score: 0.25
confidence: "high"
source: SEC EDGAR
---

# Castle Biosciences adopts amended bylaws with changes to meeting procedures and governance

## Summary
- Board adopted amended and restated bylaws effective August 5, 2025, modifying quorum, advance notice, and proxy rules.
- Advance notice window for stockholder proposals widened: meeting delayed >70 days (previously 30) triggers alternative deadline.
- Quorum changed from majority of outstanding shares to majority of voting power; default approval threshold now majority of votes cast.
- Universal proxy rules under Rule 14a-19 incorporated; stockholder nominees limited to number of directors to be elected.
- Indemnification obligations expanded to maximum extent allowed by law; mandatory advancement of expenses clarified.

## SEC filing metadata
- accession: 0001447362-25-000099
- form_type: 8-K
- ticker: CSTL
- cik: 0001447362
- company_name: CASTLE BIOSCIENCES INC
- filed_at: 2025-08-08T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.25
- calibrated_materiality_score: 0.25
- confidence: high
- sec_items: 5.03, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1447362/000144736225000099/0001447362-25-000099-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1447362/000144736225000099/cstl-20250805.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001447362-25-000099
- JSON: https://secwatch.observer/filing/0001447362-25-000099.json
- Plain text: https://secwatch.observer/filing/0001447362-25-000099.txt

## Key facts
- Governance Changes
  CASTLE BIOSCIENCES INC: Adopted amended and restated bylaws effective August 5, 2025, with multiple changes including stockholder meeting procedures, quorum thresholds, and nomination requirements (effective 2025-08-05).
  - Change: bylaw amendment
  - Effective: 2025-08-05
  source text: On August 5, 2025, the board of directors (the “Board”) of Castle Biosciences, Inc. (the “Company”) adopted amended and restated bylaws of the Company (as amended and restated, the “A&R Bylaws”), effective as of such adoption date.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1447362/000144736225000099/0001447362-25-000099-index.htm

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