Latest Period
Q1 2026
Security Snapshot
MASIMO CORP - Common Stock, par value $0.001 per share (MASI) Institutional Ownership
CUSIP: 574795100
13F Institutional Holders and Ownership History from Q1 2014 to Q1 2026
Institutions Reporting
442
Shares (Excl. Options)
53,396,778
Price
$177.87
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- Security type / class
- Equity / Common Stock, par value $0.001 per share
- Symbol
- MASI on Nasdaq
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 53,396,778
- Total 13F value
- $9,471,814,935
- Portfolio coverage rank
- 0.02%
- Share change
- -2,427,820
- Value change
- -$56,971,024
- Number of holders
- 442
- Shares outstanding
- 52,065,574
- SEC-reported price per share
- $178.58
- Insider filing price
- $178.58
Latest holder snapshot
5 signals
Issuer context
Names, identifiers, and filing context for this profile.
3 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- MASI - MASIMO CORP - Common Stock, par value $0.001 per share is tracked under CUSIP 574795100.
- 442 institutions reported positions in Q1 2026.
- 6 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 390 to 442 between Q4 2025 and Q1 2026.
- SEC-reported value moved from $7,200,597,392 to $9,471,814,935.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 442 institutions filings for Q1 2026.
Security key
574795100
Latest holder period
Q1 2026
13F holders
442
13D/G owners
6
CIK / CUSIP context first
Open Q1 2026 holders
MASI full holder history
MASIMO CORP SEC filings
MASIMO CORP company facts
MASIMO CORP insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 574795100:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
6
Security
MASI
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| BlackRock, Inc. | 7.9% | $692,807,191 | 4,231,142 | BlackRock, Inc. | 31 Jan 2025 | |||
| KIANI JOE E | 6.5% | -38% | $652,671,750 | -$401,127,387 | 3,657,039 | -38% | Joe Kiani | 31 Mar 2026 |
| Pentwater Capital Management LP | 6.1% | $566,820,720 | 3,176,000 | Pentwater Capital Management LP | 31 Mar 2026 | |||
| BARCLAYS PLC | 5.5% | $516,181,999 | 2,892,262 | Barclays PLC | 31 Mar 2026 | |||
| FMR LLC | 4.5% | -70% | $317,340,559 | -$767,176,959 | 2,349,975 | -71% | FMR LLC | 27 Feb 2026 |
| BlackRock Portfolio Management LLC | 0.2% | -100% | $20,787,845 | -$759,403,692 | 116,871 | -97% | BlackRock Portfolio Management LLC | 31 Mar 2026 |
As of 31 Mar 2026, 442 institutional investors reported holding 53,396,778 shares of MASIMO CORP - Common Stock, par value $0.001 per share (MASI). This represents 103% of the company’s total 52,065,574 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
71%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| BlackRock, Inc. | 8.9% | 4,644,578 | -48% | 0.01% | $826,131,120 |
| Politan Capital Management LP | 8.8% | 4,589,648 | 0% | 83% | $816,360,690 |
| Pentwater Capital Management LP | 6.1% | 3,176,000 | 4% | $564,915,120 | |
| BARCLAYS PLC | 5.3% | 2,743,985 | +4602% | 0.17% | $488,072,611 |
| HBK INVESTMENTS L P | 4.9% | 2,576,109 | 5.8% | $458,212,508 | |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ | 4.5% | 2,342,790 | -12% | 0.15% | $416,692,672 |
| VANGUARD CAPITAL MANAGEMENT LLC | 3.9% | 2,050,045 | 0% | 0.01% | $364,641,504 |
| VANGUARD PORTFOLIO MANAGEMENT LLC | 3.9% | 2,006,861 | 0% | 0.02% | $356,960,366 |
| FMR LLC | 2.8% | 1,450,823 | -82% | 0.01% | $258,057,947 |
| STATE STREET CORP | 2.8% | 1,437,724 | +1.6% | 0.01% | $255,727,968 |
| MILLENNIUM MANAGEMENT LLC | 1.9% | 988,853 | +426% | 0.13% | $175,887,283 |
| GOLDMAN SACHS GROUP INC | 1.9% | 984,192 | +55% | 0.02% | $175,058,231 |
| GEODE CAPITAL MANAGEMENT, LLC | 1.8% | 956,736 | +0.29% | 0.01% | $170,210,661 |
| AQR CAPITAL MANAGEMENT LLC | 1.6% | 831,966 | -24% | 0.07% | $147,399,452 |
| Balyasny Asset Management L.P. | 1.5% | 770,986 | 0.27% | $137,135,280 | |
| MORGAN STANLEY | 1.4% | 752,417 | -18% | 0.01% | $133,832,703 |
| JPMORGAN CHASE & CO | 1.1% | 572,645 | +386% | 0.01% | $101,541,410 |
| CITIGROUP INC | 1% | 533,388 | +340% | 0.06% | $94,873,724 |
| SG Americas Securities, LLC | 1% | 522,824 | +3082% | 0.1% | $92,995,000 |
| FIL Ltd | 0.93% | 482,000 | 0.07% | $85,733,340 | |
| First Trust Capital Management L.P. | 0.92% | 479,403 | 4.5% | $85,271,412 | |
| HSBC HOLDINGS PLC | 0.91% | 473,434 | 0.05% | $84,266,518 | |
| UBS Group AG | 0.9% | 468,257 | -22% | 0.01% | $83,288,873 |
| ALLIANCEBERNSTEIN L.P. | 0.87% | 455,354 | +740% | 0.02% | $59,223,341 |
| Magnetar Financial LLC | 0.82% | 427,081 | +7729% | 0.77% | $75,964,897 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
49
Latest
Q1 2026
Rows shown
1-25 of 49
| Period | 13F Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 53,396,778 | $9,471,814,935 | -$56,971,024 | $177.87 | 442 |
| 2025 Q4 | 55,356,007 | $7,200,597,392 | -$130,410,541 | $130.06 | 390 |
| 2025 Q3 | 56,175,682 | $8,285,636,420 | -$242,029,720 | $147.55 | 354 |
| 2025 Q2 | 57,531,263 | $9,678,040,277 | +$566,298,917 | $168.22 | 375 |
| 2025 Q1 | 54,245,883 | $9,034,866,757 | +$448,557,462 | $166.60 | 389 |
| 2024 Q4 | 51,411,548 | $8,501,447,911 | +$221,294,182 | $165.30 | 362 |
| 2024 Q3 | 50,430,653 | $6,717,968,664 | +$195,557,848 | $133.33 | 357 |
| 2024 Q2 | 49,545,428 | $6,238,873,009 | -$289,595,358 | $125.94 | 350 |
| 2024 Q1 | 51,603,603 | $7,578,656,800 | +$54,858,314 | $146.85 | 330 |
| 2023 Q4 | 50,338,512 | $5,900,007,837 | +$429,947,280 | $117.21 | 333 |
| 2023 Q3 | 47,611,421 | $4,174,934,463 | -$49,427,852 | $87.68 | 349 |
| 2023 Q2 | 45,905,078 | $7,556,450,399 | +$147,455,979 | $164.55 | 406 |
| 2023 Q1 | 44,980,748 | $8,299,415,764 | +$131,407,346 | $184.54 | 422 |
| 2022 Q4 | 44,446,198 | $6,576,885,382 | -$261,109,381 | $147.95 | 399 |
| 2022 Q3 | 46,357,468 | $6,545,831,305 | +$305,043,460 | $141.16 | 405 |
| 2022 Q2 | 44,331,887 | $5,805,221,289 | -$135,171,216 | $130.67 | 394 |
| 2022 Q1 | 45,258,877 | $6,588,554,196 | -$700,651,716 | $145.54 | 435 |
| 2021 Q4 | 46,324,863 | $13,546,650,154 | -$6,634,536 | $292.78 | 502 |
| 2021 Q3 | 46,260,495 | $12,512,067,827 | +$159,621,988 | $270.71 | 457 |
| 2021 Q2 | 45,755,768 | $11,088,901,374 | +$303,542,126 | $242.45 | 447 |
| 2021 Q1 | 45,034,445 | $10,334,233,469 | -$154,653,705 | $229.66 | 469 |
| 2020 Q4 | 46,134,675 | $12,367,769,029 | +$118,456,546 | $268.38 | 480 |
| 2020 Q3 | 45,513,746 | $10,736,770,297 | -$426,567 | $236.06 | 449 |
| 2020 Q2 | 45,565,863 | $10,382,684,886 | -$45,339,410 | $227.99 | 467 |
| 2020 Q1 | 45,927,274 | $8,139,877,716 | +$51,831,017 | $177.12 | 394 |