Masimo Corporation
US ˙ NasdaqGS ˙ US5747951003

SecurityMASI / Masimo Corporation
InstitutionDimensional Fund Advisors Lp
Latest Disclosed Ownership164,402 shares
Latest Disclosed Value $ 29,242,681
Dimensional Fund Advisors Lp reports 5.49% decrease in ownership of MASI / Masimo Corporation

On May 7, 2026 - Dimensional Fund Advisors Lp filed a 13F-HR form disclosing ownership of 164,402 shares of Masimo Corporation (US:MASI) valued at $29,242,184 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 173,950 shares of Masimo Corporation. This represents a change in shares of -5.49% during the quarter. The current value of the position is $29,391,790 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-07 2026-03-31 13F MASIMO COM 574795100 164,402 -9,548 -5.49 29,243 29.25 0.0013
2026-02-12 2025-12-31 13F MASIMO COM 574795100 173,950 -85,718 -33.01 22,625 -40.93 0.0047
2025-11-12 2025-09-30 13F MASIMO COM 574795100 259,668 -263,558 -50.37 38,298 -56.49 0.0082
2025-08-12 2025-06-30 13F MASIMO COM 574795100 523,226 -180,152 -25.61 88,020 -24.88 0.0204
2025-05-13 2025-03-31 13F MASIMO COM 574795100 703,378 55,658 8.59 117,172 9.43 0.0291
2025-02-13 2024-12-31 13F MASIMO COM 574795100 647,720 50,022 8.37 107,076 34.36 0.0257
2024-11-07 2024-09-30 13F MASIMO COM 574795100 597,698 72,104 13.72 79,691 20.38 0.0193
2024-08-09 2024-06-30 13F MASIMO COM 574795100 525,594 165,257 45.86 66,201 25.11 0.0173
2024-05-10 2024-03-31 13F MASIMO COM 574795100 360,337 58,849 19.52 52,915 49.74 0.0143
2024-02-07 2023-12-31 13F MASIMO COM 574795100 301,488 16,042 5.62 35,339 41.19 0.0103
2023-11-09 2023-09-30 13F MASIMO COM 574795100 285,446 29,997 11.74 25,029 -40.46 0.0082
2023-08-09 2023-06-30 13F MASIMO COM 574795100 255,449 17,574 7.39 42,036 -4.23 0.0134
2023-05-12 2023-03-31 13F MASIMO COM 574795100 237,875 9,213 4.03 43,893 132,906.06 0.0148
2023-02-09 2022-12-31 13F MASIMO COM 574795100 228,662 3,375 1.50 34 -99.90 0.0100
2022-11-10 2022-09-30 13F MASIMO COM 574795100 225,287 11,308 5.28 31,803 13.73 0.0122
2022-08-12 2022-06-30 13F MASIMO COM 574795100 213,979 -12,547 -5.54 27,964 -15.20 0.0100
2022-05-13 2022-03-31 13F MASIMO COM 574795100 226,526 8,501 3.90 32,977 -48.34 0.0102
2022-02-09 2021-12-31 13F MASIMO COM 574795100 218,025 -407 -0.19 63,838 7.96 0.0193
2021-11-12 2021-09-30 13F MASIMO COM 574795100 218,432 -15,099 -6.47 59,132 4.43 0.0190
2021-08-12 2021-06-30 13F MASIMO COM 574795100 233,531 -7,718 -3.20 56,626 2.21 0.0179
2021-05-14 2021-03-31 13F MASIMO COM 574795100 241,249 10,801 4.69 55,401 -10.42 0.0183
2021-03-08 2020-12-31 13F/A-2 MASIMO COM 574795100 230,448 -10,893 -4.51 61,847 8.57 0.0223
2021-02-11 2020-12-31 13F MASIMO COM 574795100 230,448 -10,893 61,847 22,335.8491
2020-11-12 2020-09-30 13F MASIMO COM 574795100 241,341 -11,492 -4.55 56,964 -1.15 0.0242
2020-08-13 2020-06-30 13F MASIMO COM 574795100 252,833 -10,084 -3.84 57,629 23.74 0.0253
2020-05-14 2020-03-31 13F MASIMO COM 574795100 262,917 -31,971 -10.84 46,571 -0.09 0.0243
2020-02-14 2019-12-31 13F MASIMO COM 574795100 294,888 -16,863 -5.41 46,611 0.49 0.0170
2019-11-12 2019-09-30 13F MASIMO COM 574795100 311,751 -78,481 -20.11 46,382 -20.13 0.0180
2019-08-13 2019-06-30 13F MASIMO COM 574795100 390,232 -2,687 -0.68 58,070 6.88 0.0225
2019-08-12 2019-03-31 13F/A-2 MASIMO COM 574795100 392,919 45 0.01 54,330 28.80 0.0216
2019-05-10 2019-03-31 13F MASIMO COM 574795100 392,919 45 54,330
2019-02-26 2018-12-31 13F/A-1 MASIMO COM 574795100 392,874 -16,352 -4.00 42,181 -17.23 0.0191
2019-02-13 2018-12-31 13F MASIMO COM 574795100 392,874 -16,352 42,181
2018-11-13 2018-09-30 13F MASIMO COM 574795100 409,226 -8,349 -2.00 50,963 24.98 0.0194
2018-08-10 2018-06-30 13F MASIMO COM 574795100 417,575 -66,563 -13.75 40,778 -4.23 0.0163
2018-05-11 2018-03-31 13F MASIMO COM 574795100 484,138 -25,442 -4.99 42,580 -1.47 0.0177
2018-02-12 2017-12-31 13F MASIMO COM 574795100 509,580 -117,351 -18.72 43,214 -20.36 0.0179
2017-11-13 2017-09-30 13F MASIMO COM 574795100 626,931 -75,215 -10.71 54,264 -15.24 0.0237
2017-08-11 2017-06-30 13F MASIMO COM 574795100 702,146 -391,059 -35.77 64,022 -37.20 0.0296
2017-05-12 2017-03-31 13F MASIMO COM 574795100 1,093,205 -43,194 -3.80 101,953 33.11 0.0487
2017-02-09 2016-12-31 13F MASIMO COM 574795100 1,136,399 -11,957 -1.04 76,594 12.12 0.0383
2016-11-10 2016-09-30 13F MASIMO COM 574795100 1,148,356 15,562 1.37 68,314 14.84 0.0369
2016-08-09 2016-06-30 13F MASIMO COM 574795100 1,132,794 -38,486 -3.29 59,487 21.39 0.0342
2016-05-13 2016-03-31 13F MASIMO COM 574795100 1,171,280 -179,932 -13.32 49,004 -12.63 0.0293
2016-02-10 2015-12-31 13F MASIMO COM 574795100 1,351,212 76,849 6.03 56,090 14.15 0.0350
2015-11-13 2015-09-30 13F MASIMO COM 574795100 1,274,363 32,032 2.58 49,138 2.10 0.0323
2015-08-14 2015-06-30 13F MASIMO COM 574795100 1,242,331 76,693 6.58 48,128 25.20 0.0295
2015-05-14 2015-03-31 13F MASIMO COM 574795100 1,165,638 91,968 8.57 38,442 35.93 0.0243
2015-02-06 2014-12-31 13F MASIMO COM 574795100 1,073,670 109,557 11.36 28,281 37.85 0.0186
2014-11-13 2014-09-30 13F MASIMO COM 574795100 964,113 48,017 5.24 20,516 -5.11 0.0145
2014-08-08 2014-06-30 13F MASIMO COM 574795100 916,096 123,023 15.51 21,620 -0.18 0.0150
2014-05-14 2014-03-31 13F MASIMO COM 574795100 793,073 84,034 11.85 21,658 4.50 0.0162
2014-02-12 2013-12-31 13F MASIMO COM 574795100 709,039 60,283 9.29 20,725 19.92 0.0162
2013-11-13 2013-09-30 13F MASIMO COM 574795100 648,756 93,409 16.82 17,283 46.79 0.0150
2013-08-15 2013-06-30 13F MASIMO COM 574795100 555,347 555,347 11,774 0.0111
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.