---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-25-045035"
form_type: "8-K"
ticker: "MASI"
cik: "0000937556"
company_name: "MASIMO CORP"
filed_at: "2025-05-06T23:59:59+00:00"
generated_at: "2026-05-22T15:59:00.187014+00:00"
event_type: "cyber"
sentiment: "negative"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Masimo identifies unauthorized network activity on April 27; manufacturing and shipping operations impacted.

## Summary
- Discovered unauthorized activity on on-premise network on April 27, 2025; activated incident response and containment protocols.
- Certain manufacturing facilities operating at reduced levels; order processing and shipping temporarily disrupted.
- Company believes incident not affecting cloud-based systems; investigation ongoing with third-party experts and law enforcement.
- Full scope, nature, and impact not yet known; forward-looking statements cite potential legal, reputational, and financial risks.

## SEC filing metadata
- accession: 0001104659-25-045035
- form_type: 8-K
- ticker: MASI
- cik: 0000937556
- company_name: MASIMO CORP
- filed_at: 2025-05-06T23:59:59+00:00
- event_type: cyber
- sentiment: negative
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/937556/000110465925045035/0001104659-25-045035-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/937556/000110465925045035/tm2514064d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-25-045035
- JSON: https://secwatch.observer/filing/0001104659-25-045035.json
- Plain text: https://secwatch.observer/filing/0001104659-25-045035.txt

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