Masimo Corporation
MX ˙ BMV ˙ US5747951003
SecurityMX:MASI / Masimo Corporation
InstitutionJane Street Group, Llc
Latest Disclosed Ownership1,215 shares
Latest Disclosed Value $ 216,112
Jane Street Group, Llc ownership in MASI / Masimo Corporation

On May 12, 2026 - Jane Street Group, Llc filed a 13F-HR form disclosing ownership of 1,215 shares of Masimo Corporation (MX:MASI) valued at $216,112 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 102,881 shares of Masimo Corporation. This represents a change in shares of -98.82% during the quarter.

Jane Street Group, 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 8,500 of underlying shares valued at $1,511,895 USD and put options representing 0 of underlying shares valued at $0 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)
2026-05-12 2026-03-31 13F MASIMO COM 574795100 1,215 -101,666 -98.82 216 -98.39 0.0000
2026-02-12 2025-12-31 13F MASIMO COM 574795100 102,881 102,881 13,381 0.0020
2025-11-14 2025-09-30 13F MASIMO COM 574795100 0 -1,872 -100.00 0 -100.00
2025-08-14 2025-06-30 13F MASIMO COM 574795100 1,872 -178 -8.68 315 -7.92 0.0001
2025-05-19 2025-03-31 13F/A-1 MASIMO COM 574795100 2,050 -28,437 -93.28 342 -93.23 0.0001
2025-05-14 2025-03-31 13F MASIMO COM 574795100 2,050 -28,437 342 0.0001
2025-02-14 2024-12-31 13F MASIMO COM 574795100 30,487 5,807 23.53 5,040 53.16 0.0011
2024-11-15 2024-09-30 13F MASIMO COM 574795100 24,680 -4,923 -16.63 3,291 -11.75 0.0007
2024-08-15 2024-06-30 13F MASIMO COM 574795100 29,603 5,239 21.50 3,728 4.22 0.0009
2024-05-16 2024-03-31 13F MASIMO COM 574795100 24,364 -62,142 -71.84 3,578 -64.72 0.0007
2024-02-15 2023-12-31 13F MASIMO COM 574795100 86,506 -90,109 -51.02 10,139 -34.52 0.0026
2023-11-15 2023-09-30 13F MASIMO COM 574795100 176,615 175,106 11,604.11 15,486 6,143.95 0.0050
2023-08-14 2023-06-30 13F MASIMO COM 574795100 1,509 -9,691 -86.53 248 -88.00 0.0001
2023-05-16 2023-03-31 13F MASIMO COM 574795100 11,200 -7,870 -41.27 2,067 -26.76 0.0008
2023-02-15 2022-12-31 13F MASIMO COM 574795100 19,070 -109,674 -85.19 2,821 -84.48 0.0013
2022-11-15 2022-09-30 13F MASIMO COM 574795100 128,744 113,682 754.76 18,173 823.42 0.0080
2022-08-16 2022-06-30 13F MASIMO COM 574795100 15,062 4,403 41.31 1,968 26.89 0.0008
2022-05-17 2022-03-31 13F MASIMO COM 574795100 10,659 5,405 102.87 1,551 0.85 0.0005
2022-02-15 2021-12-31 13F MASIMO COM 574795100 5,254 2,158 69.70 1,538 83.53 0.0005
2021-11-16 2021-09-30 13F MASIMO COM 574795100 3,096 -4,126 -57.13 838 -52.14 0.0003
2021-08-16 2021-06-30 13F MASIMO COM 574795100 7,222 -15,029 -67.54 1,751 -65.73 0.0007
2021-05-18 2021-03-31 13F MASIMO COM 574795100 22,251 12,225 121.93 5,110 89.89 0.0025
2021-02-17 2020-12-31 13F MASIMO COM 574795100 10,026 1,805 21.96 2,691 38.64 0.0014
2020-11-17 2020-09-30 13F MASIMO COM 574795100 8,221 2,769 50.79 1,941 56.15 0.0012
2020-08-17 2020-06-30 13F MASIMO COM 574795100 5,452 1,993 57.62 1,243 102.77 0.0009
2020-05-15 2020-03-31 13F MASIMO COM 574795100 3,459 780 29.12 613 44.92 0.0006
2020-02-14 2019-12-31 13F MASIMO COM 574795100 2,679 -104 -3.74 423 2.17 0.0006
2019-11-14 2019-09-30 13F MASIMO COM 574795100 2,783 2,783 414 0.0007
2019-08-14 2019-06-30 13F MASIMO COM 574795100 0 -2,295 -100.00 0 -100.00
2019-05-16 2019-03-31 13F MASIMO COM 574795100 2,295 2,295 317 0.0005
2019-02-14 2018-12-31 13F MASIMO COM 574795100 0 -11,917 -100.00 0 -100.00
2018-11-14 2018-09-30 13F MASIMO COM 574795100 11,917 -107,467 -90.02 1,484 -87.27 0.0029
2018-08-15 2018-06-30 13F MASIMO COM 574795100 119,384 115,447 2,932.36 11,658 3,269.36 0.0274
2018-05-15 2018-03-31 13F MASIMO COM 574795100 3,937 -4,090 -50.95 346 -49.19 0.0009
2018-02-15 2017-12-31 13F MASIMO COM 574795100 8,027 4,364 119.14 681 114.83 0.0020
2017-11-14 2017-09-30 13F MASIMO COM 574795100 3,663 -7,303 -66.60 317 -69.01 0.0010
2017-05-15 2017-03-31 13F MASIMO COM 574795100 10,966 -7,624 -41.01 1,023 -18.36 0.0046
2017-02-15 2016-12-31 13F MASIMO COM 574795100 18,590 -6,210 -25.04 1,253 -15.05 0.0055
2016-11-14 2016-09-30 13F MASIMO COM 574795100 24,800 24,800 1,475 0.0071
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
(%)
2026-05-12 2026-03-31 13F MASIMO COM Call 8,500 203.57 1,512 315.11 n/a n/a n/a
2026-02-12 2025-12-31 13F MASIMO COM Call 2,800 -33.33 364 -41.20 n/a n/a n/a
2025-11-14 2025-09-30 13F MASIMO COM Call 4,200 44.83 620 27.10 n/a n/a n/a
2025-08-14 2025-06-30 13F MASIMO COM Call 2,900 488 n/a n/a n/a
2025-05-19 2025-03-31 13F/A MASIMO COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-05-14 2025-03-31 13F MASIMO COM Call 0 0 n/a n/a n/a
2025-02-14 2024-12-31 13F MASIMO COM Call 9,300 -67.48 1,537 -59.69 n/a n/a n/a
2024-11-15 2024-09-30 13F MASIMO COM Call 28,600 17.21 3,813 24.12 n/a n/a n/a
2024-08-15 2024-06-30 13F MASIMO COM Call 24,400 208.86 3,073 164.83 n/a n/a n/a
2024-05-16 2024-03-31 13F MASIMO COM Call 7,900 -88.98 1,160 -86.20 n/a n/a n/a
2024-02-15 2023-12-31 13F MASIMO COM Call 71,700 10.48 8,404 47.68 n/a n/a n/a
2023-11-15 2023-09-30 13F MASIMO COM Call 64,900 854.41 5,690 408.94 n/a n/a n/a
2023-08-14 2023-06-30 13F MASIMO COM Call 6,800 23.64 1,119 10.26 n/a n/a n/a
2023-05-16 2023-03-31 13F MASIMO COM Call 5,500 223.53 1,015 303.98 n/a n/a n/a
2023-02-15 2022-12-31 13F MASIMO COM Call 1,700 -85.95 252 -85.30 n/a n/a n/a
2022-11-15 2022-09-30 13F MASIMO COM Call 12,100 656.25 1,708 717.22 n/a n/a n/a
2022-08-16 2022-06-30 13F MASIMO COM Call 1,600 -94.27 209 -94.85 n/a n/a n/a
2022-05-17 2022-03-31 13F MASIMO COM Call 27,900 -77.82 4,061 -88.97 n/a n/a n/a
2022-02-15 2021-12-31 13F MASIMO COM Call 125,800 116.90 36,832 134.58 n/a n/a n/a
2021-11-16 2021-09-30 13F MASIMO COM Call 58,000 474.26 15,701 541.12 n/a n/a n/a
2021-08-16 2021-06-30 13F MASIMO COM Call 10,100 -84.77 2,449 -83.92 n/a n/a n/a
2021-05-18 2021-03-31 13F MASIMO COM Call 66,300 1,310.64 15,226 1,107.45 n/a n/a n/a
2021-02-17 2020-12-31 13F MASIMO COM Call 4,700 -87.26 1,261 -85.52 n/a n/a n/a
2020-11-17 2020-09-30 13F MASIMO COM Call 36,900 -55.81 8,711 -54.24 n/a n/a n/a
2020-08-17 2020-06-30 13F MASIMO COM Call 83,500 19,037 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
(%)
2026-05-12 2026-03-31 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-12 2025-12-31 13F MASIMO COM Put 7,300 386.67 949 329.41 n/a n/a n/a
2025-11-14 2025-09-30 13F MASIMO COM Put 1,500 221 n/a n/a n/a
2025-02-14 2024-12-31 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-11-15 2024-09-30 13F MASIMO COM Put 35,600 165.67 4,747 181.33 n/a n/a n/a
2024-08-15 2024-06-30 13F MASIMO COM Put 13,400 -12.99 1,688 -25.39 n/a n/a n/a
2024-05-16 2024-03-31 13F MASIMO COM Put 15,400 87.80 2,261 135.28 n/a n/a n/a
2024-02-15 2023-12-31 13F MASIMO COM Put 8,200 -82.99 961 -77.26 n/a n/a n/a
2023-11-15 2023-09-30 13F MASIMO COM Put 48,200 3,342.86 4,226 1,737.39 n/a n/a n/a
2023-08-14 2023-06-30 13F MASIMO COM Put 1,400 -12.50 230 -22.03 n/a n/a n/a
2023-05-16 2023-03-31 13F MASIMO COM Put 1,600 295 n/a n/a n/a
2022-11-14 2022-09-30 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-08-16 2022-06-30 13F MASIMO COM Put 2,300 43.75 301 29.18 n/a n/a n/a
2022-05-17 2022-03-31 13F MASIMO COM Put 1,600 -40.74 233 -70.54 n/a n/a n/a
2022-02-15 2021-12-31 13F MASIMO COM Put 2,700 791 n/a n/a n/a
2021-11-16 2021-09-30 13F MASIMO COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-08-16 2021-06-30 13F MASIMO COM Put 3,900 -15.22 946 -10.42 n/a n/a n/a
2021-05-18 2021-03-31 13F MASIMO COM Put 4,600 -55.77 1,056 -62.16 n/a n/a n/a
2021-02-17 2020-12-31 13F MASIMO COM Put 10,400 258.62 2,791 307.45 n/a n/a n/a
2020-11-17 2020-09-30 13F MASIMO COM Put 2,900 -82.32 685 -81.68 n/a n/a n/a
2020-08-17 2020-06-30 13F MASIMO COM Put 16,400 3,739 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.