Masimo Corporation
US ˙ NasdaqGS ˙ US5747951003

SecurityMASI / Masimo Corporation
InstitutionQuantbot Technologies LP
Latest Disclosed Ownership27,425 shares
Latest Disclosed Value $ 4,878,085
Quantbot Technologies LP reports 51.82% decrease in ownership of MASI / Masimo Corporation

On May 13, 2026 - Quantbot Technologies LP filed a 13F-HR form disclosing ownership of 27,425 shares of Masimo Corporation (US:MASI) valued at $4,878,085 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 56,925 shares of Masimo Corporation. This represents a change in shares of -51.82% during the quarter. The current value of the position is $4,903,042 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)
2026-05-13 2026-03-31 13F MASIMO COM 574795100 27,425 -29,500 -51.82 4,878 -34.11 0.1996
2026-02-10 2025-12-31 13F MASIMO COM 574795100 56,925 56,925 7,404 0.2463
2025-11-12 2025-09-30 13F MASIMO COM 574795100 0 -509 -100.00 0 -100.00
2025-08-13 2025-06-30 13F MASIMO COM 574795100 509 509 86 0.0022
2023-11-07 2023-09-30 13F MASIMO COM 574795100 0 -317 -100.00 0 -100.00
2023-08-08 2023-06-30 13F MASIMO COM 574795100 317 317 52 0.0034
2023-02-13 2022-12-31 13F MASIMO COM 574795100 0 -7,025 -100.00 0 -100.00
2022-11-07 2022-09-30 13F MASIMO COM 574795100 7,025 7,025 991 0.0748
2022-08-09 2022-06-30 13F MASIMO COM 574795100 0 -37,776 -100.00 0 -100.00
2022-05-16 2022-03-31 13F MASIMO COM 574795100 37,776 34,128 935.53 5,497 414.70 0.4794
2022-02-11 2021-12-31 13F MASIMO COM 574795100 3,648 3,648 1,068 0.0866
2020-11-16 2020-09-30 13F MASIMO COM 574795100 0 -2,447 -100.00 0 -100.00
2020-08-13 2020-06-30 13F MASIMO COM 574795100 2,447 2,447 557 0.0736
2020-02-10 2019-12-31 13F MASIMO COM 574795100 0 -577 -100.00 0 -100.00
2019-11-12 2019-09-30 13F MASIMO COM 574795100 577 -452 -43.93 85 -44.44 0.0084
2019-08-13 2019-06-30 13F MASIMO COM 574795100 1,029 -2,895 -73.78 153 -71.77 0.0153
2019-05-13 2019-03-31 13F MASIMO COM 574795100 3,924 -2,747 -41.18 542 -24.30 0.0516
2019-02-13 2018-12-31 13F MASIMO COM 574795100 6,671 6,671 716 0.0701
2018-11-13 2018-09-30 13F MASIMO COM 574795100 0 -11,142 -100.00 0 -100.00
2018-08-13 2018-06-30 13F MASIMO COM 574795100 11,142 11,142 1,088 0.0741
2018-05-11 2018-03-31 13F MASIMO COM 574795100 0 -14,607 -100.00 0 -100.00
2018-02-12 2017-12-31 13F MASIMO COM 574795100 14,607 -15,395 -51.31 1,238 -52.31 0.1147
2017-11-07 2017-09-30 13F MASIMO COM 574795100 30,002 -4,036 -11.86 2,596 -16.34 0.2489
2017-08-11 2017-06-30 13F MASIMO COM 574795100 34,038 25,558 301.39 3,103 292.78 0.2923
2017-05-10 2017-03-31 13F MASIMO COM 574795100 8,480 8,480 790 0.0828
2017-02-09 2016-12-31 13F MASIMO COM 574795100 0 -4,641 -100.00 0 -100.00
2016-10-31 2016-09-30 13F MASIMO COM 574795100 4,641 1,679 56.68 276 78.06 0.0307
2016-08-02 2016-06-30 13F MASIMO COM 574795100 2,962 2,962 0.00 155 0.0165
2016-04-28 2016-03-31 13F MASIMO COM 574795100 0 0 0 0.0000
2015-10-22 2015-09-30 13F MASIMO COM 574795100 0 0 0 0.0000
2015-01-27 2014-12-31 13F MASIMO COM 574795100 0 -23,128 -100.00 0 -100.00
2014-10-15 2014-09-30 13F MASIMO COM 574795100 23,128 9,023 63.97 492 48.19 0.0677
2014-07-08 2014-06-30 13F MASIMO COM 574795100 14,105 11,407 422.79 332 354.79 0.0525
2014-05-21 2014-03-31 13F MASIMO COM 574795100 2,698 2,698 73 0.0172
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.