Masimo Corp
MASIDelisted Jun 10, 2026- Industry
- Electromedical & Electrotherapeutic Apparatus
- SEC CIK
- 0000937556
Masimo Corp was delisted on Jun 10, 2026; its insiders filed their last Form 4 on Jun 12, 2026; 451 institutions reported holding it in 13F filings for Q1 2026, worth $9.69B in total; Soros Fund Management was the only superinvestor holding it.
Holders of 5% or more of MASI
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Masimo Corp, largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Kiani Joe E | 13G/A | 10.30%5.90M shares | −0.80 ppfrom 11.10% | Apr 22, 20254 filings | Feb 13, 2026 | SEC |
| BlackRock Portfolio Management LLC | 13G/A | 8.20%4.39M shares | −2.10 ppfrom 10.30% | Mar 4, 20252 filings | Jan 21, 2026 | SEC |
| BlackRock, Inc. | 13G/A | 7.90%4.23M shares | – | Feb 7, 20251 filing | Feb 7, 2025 | SEC |
| Politan Capital Management LP | 13D/A | 6.20%4.59M shares | – | Feb 17, 20261 filing | Feb 17, 2026 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
11 Schedule 13D and 13G filings on Masimo Corp, newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Mar 27, 202610:33 AM ET | Vanguard Group Inc | 13G/A | 0.00%0 shares | –Below 5% | Mar 13, 2026 | SEC |
| Mar 6, 202610:05 AM ET | FMR LLCand 1 other | 13G/A | 4.50%2.35M shares | −10.50 ppfrom 15.00%Below 5% | Feb 27, 2026 | SEC |
| Feb 17, 20269:45 PM ET | Politan Capital Management LPand 3 others | 13D/A | 6.20%4.59M shares | – | Feb 16, 2026 | SEC |
| Feb 13, 20267:59 PM ET | Kiani Joe E | 13G/A | 10.30%5.90M shares | −0.80 ppfrom 11.10% | Dec 31, 2025 | SEC |
| Jan 21, 202612:26 PM ET | BlackRock Portfolio Management LLC | 13G/A | 8.20%4.39M shares | −2.10 ppfrom 10.30% | Dec 31, 2025 | SEC |
| Nov 12, 20258:00 PM ET | Kiani Joe E | 13G/A | 11.10%6.38M shares | −0.30 ppfrom 11.40% | Sep 30, 2025 | SEC |
| Aug 12, 20257:00 PM ET | Kiani Joe E | 13G/A | 11.40%6.58M shares | −1.80 ppfrom 13.20% | Jun 30, 2025 | SEC |
| Apr 22, 20258:01 PM ET | Kiani Joe E | 13G/A | 13.20%7.62M shares | – | Mar 31, 2025 | SEC |
| Mar 4, 202512:39 PM ET | BlackRock Portfolio Management LLC | 13G | 10.30%5.54M shares | New | Feb 28, 2025 | SEC |
| Feb 12, 20259:30 AM ET | FMR LLCand 1 other | 13G/A | 15.00%8.03M shares | – | Dec 31, 2024 | SEC |
| Feb 7, 20251:50 PM ET | BlackRock, Inc. | 13G/A | 7.90%4.23M shares | – | Jan 31, 2025 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Masimo Corp shares.
No Form 144 notices for Masimo Corp are on file.