---
schema_version: "secwatch.filing_event.v1"
accession: "0000937556-25-000127"
form_type: "8-K"
ticker: "MASI"
cik: "0000937556"
company_name: "MASIMO CORP"
filed_at: "2025-08-19T23:59:59+00:00"
generated_at: "2026-05-17T11:42:33.969931+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.25
calibrated_materiality_score: 0.25
confidence: "high"
source: SEC EDGAR
---

# Director William Jellison resigns from Masimo board effective August 18, 2025

## Summary
- William Jellison resigned from the Board of Directors effective August 18, 2025.
- Resignation was not due to any disagreement with the company on operations, policies, or practices.
- Board Chairman Michelle Brennan thanked Jellison for his service during a transformative period.
- No replacement has been announced at this time.

## SEC filing metadata
- accession: 0000937556-25-000127
- form_type: 8-K
- ticker: MASI
- cik: 0000937556
- company_name: MASIMO CORP
- filed_at: 2025-08-19T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.25
- calibrated_materiality_score: 0.25
- confidence: high
- sec_items: 5.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/937556/000093755625000127/0000937556-25-000127-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/937556/000093755625000127/masi-20250818.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000937556-25-000127
- JSON: https://secwatch.observer/filing/0000937556-25-000127.json
- Plain text: https://secwatch.observer/filing/0000937556-25-000127.txt

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