Quick Takeaways
- BlackRock Portfolio Management LLC filed SCHEDULE 13G/A for MASIMO CORPORATION Common Stock (MASI).
- Disclosed ownership: 8.2%.
- Date of event: 31 Dec 2025.
BlackRock Portfolio Management LLC - 31 Dec 2025 SCHEDULE 13G/A Report for MASIMO CORPORATION Common Stock (MASI)
- Filing Manager
- BlackRock Portfolio Management LLC
- Reporting Manager
- BlackRock Portfolio Management LLC
- Security
- MASIMO CORPORATION Common Stock
- Symbol
- MASI
- Shares outstanding
- 53,491,488 shares
- Disclosed Ownership
- 4,386,302 shares
- Ownership
- 8.2%
- Form type
- SCHEDULE 13G/A
- Filing time
- 21 Jan 2026, 12:26:46 UTC
- Date of event
- 31 Dec 2025
- Previous filing
- 04 Mar 2025
- SEC
- View on sec.gov
Quoteable Key Fact
"BlackRock Portfolio Management LLC disclosed 8.2% ownership in MASIMO CORPORATION Common Stock (MASI) on 31 Dec 2025."
What Changed
- Previous schedule filing date: 04 Mar 2025.
- Current filing was accepted on 21 Jan 2026, 12:26.
Why This Matters
- This page explains what this Schedule 13D/13G filing tells you before manager-level rows.
- You can verify ownership claims directly against the original SEC filing.
Official SEC Source
Backed by Schedule 13D/13G
Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.
See Original FilingReporting Managers (1)
| Name | Ownership | Shares Owned | sole voting power | shared voting power | Signature | Title | CIK |
|---|---|---|---|---|---|---|---|
| BlackRock Portfolio Management LLC | 8.2% | 4,386,302 | 4,290,570 | 0 | Spencer Fleming | Managing Director |