Masimo Corporation
MX ˙ BMV ˙ US5747951003
SecurityMX:MASI / Masimo Corporation
InstitutionWoodline Partners LP
Latest Disclosed Ownership153,234 shares
Latest Disclosed Value $ 27,255,732
Woodline Partners LP ownership in MASI / Masimo Corporation

On May 15, 2026 - Woodline Partners LP filed a 13F-HR/A form disclosing ownership of 153,234 shares of Masimo Corporation (MX:MASI) valued at $27,255,732 USD as of March 31, 2026. The entity filed a previous 13F-HR on November 14, 2025 disclosing 0 shares of Masimo Corporation.

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)
2026-05-15 2026-03-31 13F/A-1 MASIMO COM 574795100 153,234 153,234 27,256 0.1031
2026-05-15 2026-03-31 13F MASIMO COM 574795100 153,234 153,234 27,256 0.1030
2025-11-14 2025-09-30 13F MASIMO COM 574795100 0 -182,709 -100.00 0 -100.00
2025-08-14 2025-06-30 13F MASIMO COM 574795100 182,709 49,740 37.41 30,735 38.75 0.1624
2025-05-15 2025-03-31 13F MASIMO COM 574795100 132,969 81,784 159.78 22,153 161.84 0.1441
2025-02-14 2024-12-31 13F MASIMO COM 574795100 51,185 41,885 450.38 8,461 582.81 0.0572
2024-11-14 2024-09-30 13F MASIMO COM 574795100 9,300 -176,690 -95.00 1,240 -94.71 0.0104
2024-08-14 2024-06-30 13F MASIMO COM 574795100 185,990 132,844 249.96 23,424 200.14 0.2236
2024-05-15 2024-03-31 13F MASIMO COM 574795100 53,146 -229,129 -81.17 7,804 -76.41 0.0718
2024-02-14 2023-12-31 13F MASIMO COM 574795100 282,275 211,496 298.81 33,085 433.20 0.3598
2023-11-14 2023-09-30 13F MASIMO COM 574795100 70,779 70,779 6,206 0.0728
2023-05-15 2023-03-31 13F MASIMO COM 574795100 0 -80,516 -100.00 0 -100.00
2023-02-14 2022-12-31 13F MASIMO COM 574795100 80,516 63,017 360.12 11,912 382.27 0.1594
2022-11-14 2022-09-30 13F MASIMO COM 574795100 17,499 -25,537 -59.34 2,470 -56.08 0.0345
2022-08-15 2022-06-30 13F MASIMO COM 574795100 43,036 43,036 5,624 0.0867
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.