Masimo Corporation
US ˙ NasdaqGS ˙ US5747951003

SecurityMASI / Masimo Corporation
InstitutionSimplex Trading, Llc
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Simplex Trading, Llc ownership in MASI / Masimo Corporation

On November 12, 2025 - Simplex Trading, Llc filed a 13F-HR form disclosing ownership of 0 shares of Masimo Corporation (US:MASI) valued at $0 USD as of September 30, 2025. The entity filed a previous 13F-HR on August 5, 2025 disclosing 98 shares of Masimo Corporation. The current value of the position is $0 USD.

Simplex 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 46,400 of underlying shares valued at $8,253,168 USD and put options representing 1,100 of underlying shares valued at $195,657 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.

Upgrade to unlock premium data and export to Excel .

Institutional Put/Call Ratios
(Premium Subscription Required)

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.

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)
2025-11-12 2025-09-30 13F MASIMO COM 574795100 0 -98 -100.00 0 0.0000
2025-08-05 2025-06-30 13F MASIMO COM 574795100 98 -2,240 -95.81 0 0.0000
2025-05-12 2025-03-31 13F MASIMO COM 574795100 2,338 1,513 183.39 0 0.0002
2025-02-11 2024-12-31 13F MASIMO COM 574795100 825 -11,704 -93.42 0 -100.00 0.0001
2024-11-08 2024-09-30 13F MASIMO COM 574795100 12,529 6,169 97.00 2 0.0010
2024-07-25 2024-06-30 13F MASIMO COM 574795100 6,360 765 13.67 1 0.0005
2024-04-25 2024-03-31 13F MASIMO COM 574795100 5,595 -9,051 -61.80 1 -100.00 0.0005
2024-02-02 2023-12-31 13F MASIMO COM 574795100 14,646 -36,043 -71.11 2 -75.00 0.0011
2023-11-01 2023-09-30 13F MASIMO COM 574795100 50,689 46,724 1,178.41 4 0.0035
2023-08-04 2023-06-30 13F MASIMO COM 574795100 3,965 630 18.89 1 0.0005
2023-04-27 2023-03-31 13F MASIMO COM 574795100 3,335 2,504 301.32 1 0.0005
2023-02-02 2022-12-31 13F MASIMO COM 574795100 831 -235 -22.05 0 -100.00 0.0001
2022-11-04 2022-09-30 13F MASIMO COM 574795100 1,066 1,066 150 0.0002
2022-05-02 2022-03-31 13F MASIMO COM 574795100 0 -124 -100.00 0 -100.00
2022-02-23 2021-12-31 13F/A-1 MASIMO COM 574795100 124 124 36 0.0000
2021-08-12 2021-06-30 13F MASIMO COM 574795100 0 -525 -100.00 0 -100.00
2021-04-26 2021-03-31 13F MASIMO COM 574795100 525 318 153.62 120 118.18 0.0002
2021-02-02 2020-12-31 13F MASIMO COM 574795100 207 207 -60.57 55 -54.17 0.0001
2020-10-14 2020-09-30 13F MASIMO COM 574795100 0 -2,664 -100.00 0 -100.00
2020-07-13 2020-06-30 13F MASIMO COM 574795100 2,664 -146 -5.20 607 22.13 0.0010
2020-04-29 2020-03-31 13F MASIMO COM 574795100 2,810 2,177 343.92 497 397.00 0.0009
2020-02-05 2019-12-31 13F MASIMO COM 574795100 633 633 100 0.0002
2019-04-18 2019-03-31 13F MASIMO COM 574795100 0 -949 -100.00 0 -100.00
2019-01-16 2018-12-31 13F MASIMO COM 574795100 949 949 101 0.0003
2018-07-30 2018-06-30 13F MASIMO COM 574795100 0 -1,498 -100.00 0 -100.00
2018-04-26 2018-03-31 13F MASIMO COM 574795100 1,498 -778 -34.18 131 -32.12 0.0058
2018-01-10 2017-12-31 13F MASIMO COM 574795100 2,276 1,467 181.33 193 175.71 0.0083
2017-10-25 2017-09-30 13F MASIMO COM 574795100 809 -5,750 -87.67 70 -88.29 0.0029
2017-07-12 2017-06-30 13F MASIMO COM 574795100 6,559 593 9.94 598 7.55 0.0260
2017-04-21 2017-03-31 13F MASIMO COM 574795100 5,966 -1,879 -23.95 556 5.30 0.0241
2017-01-11 2016-12-31 13F MASIMO COM 574795100 7,845 7,553 2,586.64 528 3,005.88 0.0315
2016-10-07 2016-09-30 13F MASIMO COM 574795100 292 201 220.88 17 325.00 0.0012
2016-07-18 2016-06-30 13F MASIMO COM 574795100 91 91 -68.84 4 -76.47 0.0003
2016-01-20 2015-12-31 13F MASIMO COM 574795100 0 -1,311 -100.00 0 -100.00
2015-10-08 2015-09-30 13F MASIMO COM 574795100 1,311 1,311 50 0.0037
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
(%)
2026-05-14 2026-03-31 13F MASIMO CALL Call 46,400 8,253 n/a n/a n/a
2026-02-11 2025-12-31 13F MASIMO CALL Call 0 -100.00 0 n/a n/a n/a
2025-11-12 2025-09-30 13F MASIMO CALL Call 1,100 -21.43 0 n/a n/a n/a
2025-08-05 2025-06-30 13F MASIMO CALL Call 1,400 -48.15 0 n/a n/a n/a
2025-05-12 2025-03-31 13F MASIMO CALL Call 2,700 200.00 0 n/a n/a n/a
2025-02-11 2024-12-31 13F MASIMO CALL Call 900 -92.17 0 -100.00 n/a n/a n/a
2024-11-08 2024-09-30 13F MASIMO CALL Call 11,500 296.55 2 n/a n/a n/a
2024-07-25 2024-06-30 13F MASIMO CALL Call 2,900 -12.12 0 n/a n/a n/a
2024-04-25 2024-03-31 13F MASIMO CALL Call 3,300 -96.80 0 -100.00 n/a n/a n/a
2024-02-02 2023-12-31 13F MASIMO CALL Call 103,200 76.41 12 140.00 n/a n/a n/a
2023-11-01 2023-09-30 13F MASIMO CALL Call 58,500 3,800.00 5 n/a n/a n/a
2023-08-04 2023-06-30 13F MASIMO CALL Call 1,500 -77.61 0 -100.00 n/a n/a n/a
2023-04-27 2023-03-31 13F MASIMO CALL Call 6,700 219.05 1 n/a n/a n/a
2023-02-02 2022-12-31 13F MASIMO CALL Call 2,100 250.00 0 -100.00 n/a n/a n/a
2022-11-04 2022-09-30 13F MASIMO CALL Call 600 -45.45 84 -41.26 n/a n/a n/a
2022-08-03 2022-06-30 13F MASIMO CALL Call 1,100 -88.17 143 -89.43 n/a n/a n/a
2022-05-02 2022-03-31 13F MASIMO CALL Call 9,300 9,200.00 1,353 4,565.52 n/a n/a n/a
2022-02-23 2021-12-31 13F/A MASIMO CALL Call 100 -95.00 29 -94.18 n/a n/a n/a
2022-02-04 2021-12-31 13F MASIMO CALL Call 2,000 498 n/a n/a n/a
2021-10-28 2021-09-30 13F MASIMO CALL Call 2,000 5.26 498 8.26 n/a n/a n/a
2021-08-12 2021-06-30 13F MASIMO CALL Call 1,900 9,900.00 460 5.50 n/a n/a n/a
2021-04-26 2021-03-31 13F MASIMO CALL Call 19 -24.00 436 -34.93 n/a n/a n/a
2021-02-02 2020-12-31 13F MASIMO CALL Call 25 -30.56 670 -21.08 n/a n/a n/a
2020-10-14 2020-09-30 13F MASIMO CALL Call 36 -56.10 849 -54.57 n/a n/a n/a
2020-07-13 2020-06-30 13F MASIMO CALL Call 82 1,950.00 1,869 2,570.00 n/a n/a n/a
2020-04-29 2020-03-31 13F MASIMO CALL Call 4 -71.43 70 -68.33 n/a n/a n/a
2020-02-05 2019-12-31 13F MASIMO CALL Call 14 -85.86 221 -85.00 n/a n/a n/a
2019-10-15 2019-09-30 13F MASIMO CALL Call 99 -59.43 1,473 -59.43 n/a n/a n/a
2019-07-26 2019-06-30 13F MASIMO CALL Call 244 -38.38 3,631 -33.68 n/a n/a n/a
2019-04-18 2019-03-31 13F MASIMO CALL Call 396 1,880.00 5,475 2,458.41 n/a n/a n/a
2019-01-16 2018-12-31 13F MASIMO CALL Call 20 -45.95 214 -53.48 n/a n/a n/a
2018-10-23 2018-09-30 13F MASIMO CALL Call 37 516.67 460 693.10 n/a n/a n/a
2018-07-30 2018-06-30 13F MASIMO CALL Call 6 -14.29 58 2,800.00 n/a n/a n/a
2018-04-26 2018-03-31 13F MASIMO CALL Call 7 -70.83 2 0.00 n/a n/a n/a
2018-01-10 2017-12-31 13F MASIMO CALL Call 24 0.00 2 -71.43 n/a n/a n/a
2017-10-25 2017-09-30 13F MASIMO CALL Call 24 -74.47 7 -81.58 n/a n/a n/a
2017-07-12 2017-06-30 13F MASIMO CALL Call 94 291.67 38 533.33 n/a n/a n/a
2017-04-21 2017-03-31 13F MASIMO CALL Call 24 -74.47 6 -84.21 n/a n/a n/a
2017-01-11 2016-12-31 13F MASIMO CALL Call 0 -100.00 0 n/a n/a n/a
2016-10-07 2016-09-30 13F MASIMO CALL Call 3 200.00 0 n/a n/a n/a
2016-07-18 2016-06-30 13F MASIMO CALL Call 1 -95.00 0 -100.00 n/a n/a n/a
2016-04-14 2016-03-31 13F MASIMO CALL Call 20 1,900.00 6 n/a n/a n/a
2016-01-20 2015-12-31 13F MASIMO CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-10-08 2015-09-30 13F MASIMO CALL Call 20 -75.90 1 -97.30 n/a n/a n/a
2015-07-08 2015-06-30 13F MASIMO CALL Call 83 315.00 37 3,600.00 n/a n/a n/a
2015-04-21 2015-03-31 13F MASIMO CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-03-04 2014-12-31 13F MASIMO CALL Call 19 5 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
(%)
2026-05-14 2026-03-31 13F MASIMO PUT Put 1,100 196 n/a n/a n/a
2026-02-11 2025-12-31 13F MASIMO PUT Put 0 -100.00 0 n/a n/a n/a
2025-11-12 2025-09-30 13F MASIMO PUT Put 1,000 233.33 0 n/a n/a n/a
2025-08-05 2025-06-30 13F MASIMO PUT Put 300 -96.05 0 -100.00 n/a n/a n/a
2025-05-12 2025-03-31 13F MASIMO PUT Put 7,600 -27.62 1 0.00 n/a n/a n/a
2025-02-11 2024-12-31 13F MASIMO PUT Put 10,500 -78.53 2 -83.33 n/a n/a n/a
2024-11-08 2024-09-30 13F MASIMO PUT Put 48,900 526.92 7 n/a n/a n/a
2024-07-25 2024-06-30 13F MASIMO PUT Put 7,800 -52.15 1 -100.00 n/a n/a n/a
2024-04-25 2024-03-31 13F MASIMO PUT Put 16,300 -63.29 2 -60.00 n/a n/a n/a
2024-02-02 2023-12-31 13F MASIMO PUT Put 44,400 -21.97 5 25.00 n/a n/a n/a
2023-11-01 2023-09-30 13F MASIMO PUT Put 56,900 1,932.14 5 n/a n/a n/a
2023-08-04 2023-06-30 13F MASIMO PUT Put 2,800 180.00 0 n/a n/a n/a
2023-04-27 2023-03-31 13F MASIMO PUT Put 1,000 400.00 0 n/a n/a n/a
2023-02-02 2022-12-31 13F MASIMO PUT Put 200 0.00 0 -100.00 n/a n/a n/a
2022-11-04 2022-09-30 13F MASIMO PUT Put 200 -81.82 28 -80.42 n/a n/a n/a
2022-08-03 2022-06-30 13F MASIMO PUT Put 1,100 10.00 143 -1.38 n/a n/a n/a
2022-05-02 2022-03-31 13F MASIMO PUT Put 1,000 -83.05 145 -90.13 n/a n/a n/a
2022-02-04 2021-12-31 13F MASIMO PUT Put 5,900 0.00 1,469 0.00 n/a n/a n/a
2021-10-28 2021-09-30 13F MASIMO PUT Put 5,900 0.00 1,469 2.73 n/a n/a n/a
2021-08-12 2021-06-30 13F MASIMO PUT Put 5,900 294,900.00 1,430 3,077.78 n/a n/a n/a
2021-04-26 2021-03-31 13F MASIMO PUT Put 2 -98.91 45 -99.08 n/a n/a n/a
2021-02-02 2020-12-31 13F MASIMO PUT Put 183 916.67 4,911 1,058.25 n/a n/a n/a
2020-10-14 2020-09-30 13F MASIMO PUT Put 18 -75.00 424 -74.16 n/a n/a n/a
2020-07-13 2020-06-30 13F MASIMO PUT Put 72 63.64 1,641 110.65 n/a n/a n/a
2020-04-29 2020-03-31 13F MASIMO PUT Put 44 -38.89 779 -31.55 n/a n/a n/a
2020-02-05 2019-12-31 13F MASIMO PUT Put 72 188.00 1,138 206.74 n/a n/a n/a
2019-10-15 2019-09-30 13F MASIMO PUT Put 25 -86.91 371 -86.95 n/a n/a n/a
2019-07-26 2019-06-30 13F MASIMO PUT Put 191 -60.29 2,842 -57.27 n/a n/a n/a
2019-04-18 2019-03-31 13F MASIMO PUT Put 481 23,950.00 6,651 31,571.43 n/a n/a n/a
2019-01-16 2018-12-31 13F MASIMO PUT Put 2 -66.67 21 -71.62 n/a n/a n/a
2018-10-23 2018-09-30 13F MASIMO PUT Put 6 -75.00 74 -68.38 n/a n/a n/a
2018-07-30 2018-06-30 13F MASIMO PUT Put 24 -11.11 234 11,600.00 n/a n/a n/a
2018-04-26 2018-03-31 13F MASIMO PUT Put 27 107.69 2 -99.15 n/a n/a n/a
2018-01-10 2017-12-31 13F MASIMO PUT Put 13 -43.48 0 -100.00 n/a n/a n/a
2017-10-25 2017-09-30 13F MASIMO PUT Put 23 -83.21 1 -99.21 n/a n/a n/a
2017-07-12 2017-06-30 13F MASIMO PUT Put 137 341.94 126 4,100.00 n/a n/a n/a
2017-04-21 2017-03-31 13F MASIMO PUT Put 31 3,000.00 3 -97.62 n/a n/a n/a
2017-01-11 2016-12-31 13F MASIMO PUT Put 1 -96.77 0 -100.00 n/a n/a n/a
2016-10-07 2016-09-30 13F MASIMO PUT Put 31 1,450.00 2 100.00 n/a n/a n/a
2016-07-18 2016-06-30 13F MASIMO PUT Put 2 -93.55 1 -50.00 n/a n/a n/a
2015-04-21 2015-03-31 13F MASIMO PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2015-03-04 2014-12-31 13F MASIMO PUT Put 10 1 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.