Masimo Corporation
MX ˙ BMV ˙ US5747951003
SecurityMX:MASI / Masimo Corporation
InstitutionWalleye Trading LLC
Latest Disclosed Ownership1,100 shares
Latest Disclosed Value $ 195,657
Walleye Trading LLC ownership in MASI / Masimo Corporation

On May 8, 2026 - Walleye Trading LLC filed a 13F-HR form disclosing ownership of 1,100 shares of Masimo Corporation (MX:MASI) valued at $195,657 USD as of March 31, 2026. The entity filed a previous 13F-HR on May 15, 2024 disclosing 0 shares of Masimo Corporation.

Walleye Trading LLC has a history of taking positions in derivatives of the underlying security (MASI) in the form of stock options. The firm currently holds call options representing 362,600 of underlying shares valued at $64,495,662 USD and put options representing 27,800 of underlying shares valued at $4,944,786 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MX:MASI / Masimo Corporation Historical Put/Call Ratio
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)
2026-05-08 2026-03-31 13F MASIMO COM 574795100 1,100 1,100 196 0.0003
2024-05-15 2024-03-31 13F MASIMO COM 574795100 0 -6,428 -100.00 0 -100.00
2024-02-14 2023-12-31 13F MASIMO COM 574795100 6,428 4,642 259.91 753 382.69 0.0016
2023-11-21 2023-09-30 13F/A-1 MASIMO COM 574795100 1,786 1,786 157 0.0004
2023-11-14 2023-09-30 13F MASIMO COM 574795100 1,786 1,786 157 0.0004
2023-05-15 2023-03-31 13F MASIMO COM 574795100 0 -1,107 -100.00 0 -100.00
2023-02-14 2022-12-31 13F MASIMO COM 574795100 1,107 517 87.63 164 96.39 0.0005
2022-11-14 2022-09-30 13F MASIMO COM 574795100 590 590 83 0.0003
2022-05-16 2022-03-31 13F MASIMO COM 574795100 0 -1,344 -100.00 0 -100.00
2022-02-14 2021-12-31 13F MASIMO COM 574795100 1,344 239 21.63 393 31.44 0.0013
2021-11-15 2021-09-30 13F MASIMO COM 574795100 1,105 470 74.02 299 94.16 0.0011
2021-08-16 2021-06-30 13F MASIMO COM 574795100 635 635 154 0.0006
2020-05-15 2020-03-31 13F MASIMO COM 574795100 0 -589 -100.00 0 -100.00
2020-02-14 2019-12-31 13F MASIMO COM 574795100 589 589 93 0.0006
2019-11-14 2019-09-30 13F MASIMO COM 574795100 0 -165 -100.00 0 -100.00
2019-08-14 2019-06-30 13F MASIMO COM 574795100 165 -2,291 -93.28 25 -92.65 0.0002
2019-05-15 2019-03-31 13F MASIMO COM 574795100 2,456 1,688 219.79 340 314.63 0.0026
2019-02-14 2018-12-31 13F MASIMO COM 574795100 768 768 -68.73 82 -75.88 0.0006
2016-11-14 2016-09-30 13F MASIMO COM 574795100 0 -6,976 -100.00 0 -100.00
2016-08-15 2016-06-30 13F MASIMO COM 574795100 6,976 6,776 3,388.00 366 4,475.00 0.0024
2016-05-16 2016-03-31 13F MASIMO COM 574795100 200 200 -97.13 8 -97.81 0.0001
2016-02-16 2015-12-31 13F MASIMO COM 574795100 0 -3,648 -100.00 0 -100.00
2015-11-16 2015-09-30 13F MASIMO COM 574795100 3,648 3,048 508.00 141 513.04 0.0013
2015-08-14 2015-06-30 13F MASIMO COM 574795100 600 600 23 0.0002
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-08 2026-03-31 13F MASIMO COM Call 362,600 64,496 n/a n/a n/a
2024-08-14 2024-06-30 13F MASIMO COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-05-15 2024-03-31 13F MASIMO COM Call 1,800 -56.10 264 -45.00 n/a n/a n/a
2024-02-14 2023-12-31 13F MASIMO COM Call 4,100 115.79 481 189.16 n/a n/a n/a
2023-11-21 2023-09-30 13F/A MASIMO COM Call 1,900 167 n/a n/a n/a
2023-11-14 2023-09-30 13F MASIMO COM Call 1,900 167 n/a n/a n/a
2023-05-15 2023-03-31 13F MASIMO COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-02-14 2022-12-31 13F MASIMO COM Call 2,600 0.00 385 4.63 n/a n/a n/a
2022-11-14 2022-09-30 13F MASIMO COM Call 2,600 367 n/a n/a n/a
2021-08-16 2021-06-30 13F MASIMO COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-05-17 2021-03-31 13F MASIMO COM Call 900 -18.18 207 -29.83 n/a n/a n/a
2021-02-16 2020-12-31 13F MASIMO COM Call 1,100 -72.50 295 -68.75 n/a n/a n/a
2020-11-16 2020-09-30 13F MASIMO COM Call 4,000 33.33 944 38.01 n/a n/a n/a
2020-08-14 2020-06-30 13F MASIMO COM Call 3,000 -25.00 684 -27.54 n/a n/a n/a
2020-05-15 2020-03-31 13F MASIMO COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-02-14 2019-12-31 13F MASIMO COM Call 100 16 n/a n/a n/a
2019-11-14 2019-09-30 13F MASIMO COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2019-08-14 2019-06-30 13F MASIMO COM Call 4,200 68.00 625 80.64 n/a n/a n/a
2019-05-15 2019-03-31 13F MASIMO COM Call 2,500 -63.77 346 -53.31 n/a n/a n/a
2019-02-14 2018-12-31 13F MASIMO COM Call 6,900 741 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-08 2026-03-31 13F MASIMO COM Put 27,800 4,945 n/a n/a n/a
2024-08-14 2024-06-30 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-05-15 2024-03-31 13F MASIMO COM Put 300 -93.02 44 -91.27 n/a n/a n/a
2024-02-14 2023-12-31 13F MASIMO COM Put 4,300 -47.56 504 -29.81 n/a n/a n/a
2023-11-21 2023-09-30 13F/A MASIMO COM Put 8,200 719 n/a n/a n/a
2023-11-14 2023-09-30 13F MASIMO COM Put 8,200 719 n/a n/a n/a
2022-02-14 2021-12-31 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-11-15 2021-09-30 13F MASIMO COM Put 500 -44.44 135 -38.07 n/a n/a n/a
2021-08-16 2021-06-30 13F MASIMO COM Put 900 218 n/a n/a n/a
2021-05-17 2021-03-31 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-02-16 2020-12-31 13F MASIMO COM Put 300 -62.50 81 -57.14 n/a n/a n/a
2020-11-16 2020-09-30 13F MASIMO COM Put 800 700.00 189 721.74 n/a n/a n/a
2020-08-14 2020-06-30 13F MASIMO COM Put 100 -87.50 23 -87.83 n/a n/a n/a
2020-05-15 2020-03-31 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-02-14 2019-12-31 13F MASIMO COM Put 700 111 n/a n/a n/a
2019-11-14 2019-09-30 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2019-08-14 2019-06-30 13F MASIMO COM Put 600 -94.59 89 -94.20 n/a n/a n/a
2019-05-15 2019-03-31 13F MASIMO COM Put 11,100 65.67 1,535 113.49 n/a n/a n/a
2019-02-14 2018-12-31 13F MASIMO COM Put 6,700 719 n/a n/a n/a
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.