Monolithic Power Systems, Inc.
US ˙ NasdaqGS ˙ US6098391054

SecurityMPWR / Monolithic Power Systems, Inc.
InstitutionSimplex Trading, Llc
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Simplex Trading, Llc ownership in MPWR / Monolithic Power Systems, Inc.

On February 11, 2026 - Simplex Trading, Llc filed a 13F-HR form disclosing ownership of 0 shares of Monolithic Power Systems, Inc. (US:MPWR) valued at $0 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 12, 2025 disclosing 710 shares of Monolithic Power Systems, Inc.. The current value of the position is $0 USD.

Simplex Trading, Llc has a history of taking positions in derivatives of the underlying security (MPWR) in the form of stock options. The firm currently holds call options representing 2,900 of underlying shares valued at $3,170,715 USD and put options representing 2,300 of underlying shares valued at $2,514,704 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.

MPWR / Monolithic Power Systems, Inc. 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)
2026-02-11 2025-12-31 13F MONOLITHIC PWR SYS COM 609839105 0 -710 -100.00 0 0.0000
2025-11-12 2025-09-30 13F MONOLITHIC PWR SYS COM 609839105 710 370 108.82 1 0.0003
2025-08-05 2025-06-30 13F MONOLITHIC PWR SYS COM 609839105 340 -811 -70.46 0 0.0001
2025-05-12 2025-03-31 13F MONOLITHIC PWR SYS COM 609839105 1,151 1,151 1 0.0004
2024-02-02 2023-12-31 13F MONOLITHIC PWR SYS COM 609839105 0 -1,573 -100.00 0 0.0000
2023-11-01 2023-09-30 13F MONOLITHIC PWR SYS COM 609839105 1,573 -3,378 -68.23 1 -100.00 0.0006
2023-08-04 2023-06-30 13F MONOLITHIC PWR SYS COM 609839105 4,951 4,615 1,373.51 3 0.0022
2023-04-27 2023-03-31 13F MONOLITHIC PWR SYS COM 609839105 336 336 0 0.0001
2021-08-12 2021-06-30 13F MONOLITHIC PWR SYS COM 609839105 0 -44 -100.00 0 -100.00
2021-04-26 2021-03-31 13F MONOLITHIC PWR SYS COM 609839105 44 -2,305 -98.13 15 -98.26 0.0000
2021-02-02 2020-12-31 13F MONOLITHIC PWR SYS COM 609839105 2,349 2,349 5,238.64 860 5,633.33 0.0011
2020-04-28 2020-03-31 13F MONOLITHIC PWR SYS COM 609839105 0 -768 -100.00 0 -100.00
2020-02-05 2019-12-31 13F MONOLITHIC PWR SYS COM 609839105 768 768 136 0.0003
2019-10-15 2019-09-30 13F MONOLITHIC PWR SYS COM 609839105 0 -2,418 -100.00 0 -100.00
2019-07-26 2019-06-30 13F MONOLITHIC PWR SYS COM 609839105 2,418 2,418 328 0.0009
2018-10-23 2018-09-30 13F MONOLITHIC PWR SYS COM 609839105 0 -9 -100.00 0 -100.00
2018-07-30 2018-06-30 13F MONOLITHIC PWR SYS COM 609839105 9 -368 -97.61 1 -97.67 0.0000
2018-04-26 2018-03-31 13F MONOLITHIC PWR SYS COM 609839105 377 -537 -58.75 43 -57.84 0.0019
2018-01-10 2017-12-31 13F MONOLITHIC PWR SYS COM 609839105 914 914 142.44 102 137.21 0.0044
2017-10-25 2017-09-30 13F MONOLITHIC PWR SYS COM 609839105 0 -1,764 -100.00 0 -100.00
2017-07-12 2017-06-30 13F MONOLITHIC PWR SYS COM 609839105 1,764 1,764 170 0.0074
2017-04-21 2017-03-31 13F MONOLITHIC PWR SYS COM 609839105 0 -229 -100.00 0 -100.00
2017-01-11 2016-12-31 13F MONOLITHIC PWR SYS COM 609839105 229 -2,525 -91.68 18 -91.86 0.0011
2016-10-07 2016-09-30 13F MONOLITHIC PWR SYS COM 609839105 2,754 2,420 724.55 221 904.55 0.0150
2016-07-18 2016-06-30 13F MONOLITHIC PWR SYS COM 609839105 334 -1,522 -82.00 22 -81.36 0.0015
2016-04-14 2016-03-31 13F MONOLITHIC PWR SYS COM 609839105 1,856 444 31.44 118 32.58 0.0094
2016-01-20 2015-12-31 13F MONOLITHIC PWR SYS COM 609839105 1,412 539 61.74 89 102.27 0.0070
2015-10-08 2015-09-30 13F MONOLITHIC PWR SYS COM 609839105 873 873 -38.17 44 -50.56 0.0032
2015-07-08 2015-06-30 13F MONOLITHIC PWR SYS COM 609839105 0 -2,168 -100.00 0 -100.00
2015-04-21 2015-03-31 13F MONOLITHIC PWR SYS COM 609839105 2,168 2,168 114 0.0133
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 MONOLITHIC PWR SYS CALL Call 2,900 -49.12 3,171 -38.64 n/a n/a n/a
2026-02-11 2025-12-31 13F MONOLITHIC PWR SYS CALL Call 5,700 67.65 5,166 172,100.00 n/a n/a n/a
2025-11-12 2025-09-30 13F MONOLITHIC PWR SYS CALL Call 3,400 -33.33 3 0.00 n/a n/a n/a
2025-08-05 2025-06-30 13F MONOLITHIC PWR SYS CALL Call 5,100 -52.34 4 -50.00 n/a n/a n/a
2025-05-12 2025-03-31 13F MONOLITHIC PWR SYS CALL Call 10,700 16.30 6 20.00 n/a n/a n/a
2025-02-11 2024-12-31 13F MONOLITHIC PWR SYS CALL Call 9,200 70.37 5 25.00 n/a n/a n/a
2024-11-08 2024-09-30 13F MONOLITHIC PWR SYS CALL Call 5,400 -37.21 5 -42.86 n/a n/a n/a
2024-07-25 2024-06-30 13F MONOLITHIC PWR SYS CALL Call 8,600 -32.28 7 -12.50 n/a n/a n/a
2024-04-25 2024-03-31 13F MONOLITHIC PWR SYS CALL Call 12,700 5.83 9 14.29 n/a n/a n/a
2024-02-02 2023-12-31 13F MONOLITHIC PWR SYS CALL Call 12,000 -24.05 8 0.00 n/a n/a n/a
2023-11-01 2023-09-30 13F MONOLITHIC PWR SYS CALL Call 15,800 -50.47 7 -58.82 n/a n/a n/a
2023-08-04 2023-06-30 13F MONOLITHIC PWR SYS CALL Call 31,900 866.67 17 1,600.00 n/a n/a n/a
2023-04-27 2023-03-31 13F MONOLITHIC PWR SYS CALL Call 3,300 -45.00 2 -50.00 n/a n/a n/a
2023-02-02 2022-12-31 13F MONOLITHIC PWR SYS CALL Call 6,000 -55.22 2 -99.96 n/a n/a n/a
2022-11-04 2022-09-30 13F MONOLITHIC PWR SYS CALL Call 13,400 76.32 4,869 66.86 n/a n/a n/a
2022-08-03 2022-06-30 13F MONOLITHIC PWR SYS CALL Call 7,600 -31.53 2,918 -45.87 n/a n/a n/a
2022-05-02 2022-03-31 13F MONOLITHIC PWR SYS CALL Call 11,100 -31.48 5,391 -32.54 n/a n/a n/a
2022-02-23 2021-12-31 13F/A MONOLITHIC PWR SYS CALL Call 16,200 362.86 7,991 517.07 n/a n/a n/a
2022-02-04 2021-12-31 13F MONOLITHIC PWR SYS CALL Call 3,500 1,295 n/a n/a n/a
2021-10-28 2021-09-30 13F MONOLITHIC PWR SYS CALL Call 3,500 0.00 1,295 -0.92 n/a n/a n/a
2021-08-12 2021-06-30 13F MONOLITHIC PWR SYS CALL Call 3,500 18,321.05 1,307 94.78 n/a n/a n/a
2021-04-26 2021-03-31 13F MONOLITHIC PWR SYS CALL Call 19 -55.81 671 -57.37 n/a n/a n/a
2021-02-02 2020-12-31 13F MONOLITHIC PWR SYS CALL Call 43 616.67 1,574 842.51 n/a n/a n/a
2020-10-14 2020-09-30 13F MONOLITHIC PWR SYS CALL Call 6 -64.71 167 -58.46 n/a n/a n/a
2020-07-13 2020-06-30 13F MONOLITHIC PWR SYS CALL Call 17 325.00 402 509.09 n/a n/a n/a
2020-04-29 2020-03-31 13F MONOLITHIC PWR SYS CALL Call 4 -33.33 66 -37.74 n/a n/a n/a
2020-02-05 2019-12-31 13F MONOLITHIC PWR SYS CALL Call 6 -96.69 106 -96.24 n/a n/a n/a
2019-10-15 2019-09-30 13F MONOLITHIC PWR SYS CALL Call 181 18,000.00 2,816 21,561.54 n/a n/a n/a
2019-07-26 2019-06-30 13F MONOLITHIC PWR SYS CALL Call 1 -98.15 13 -98.22 n/a n/a n/a
2019-04-18 2019-03-31 13F MONOLITHIC PWR SYS CALL Call 54 5,300.00 731 5,523.08 n/a n/a n/a
2019-01-16 2018-12-31 13F MONOLITHIC PWR SYS CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2018-10-23 2018-09-30 13F MONOLITHIC PWR SYS CALL Call 6 -60.00 75 -62.50 n/a n/a n/a
2018-07-30 2018-06-30 13F MONOLITHIC PWR SYS CALL Call 15 1,400.00 200 166.67 n/a n/a n/a
2018-04-26 2018-03-31 13F MONOLITHIC PWR SYS CALL Call 1 -93.33 0 -100.00 n/a n/a n/a
2018-01-10 2017-12-31 13F MONOLITHIC PWR SYS CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2017-10-25 2017-09-30 13F MONOLITHIC PWR SYS CALL Call 23 91.67 4 n/a n/a n/a
2017-07-12 2017-06-30 13F MONOLITHIC PWR SYS CALL Call 12 -76.00 0 -100.00 n/a n/a n/a
2017-04-21 2017-03-31 13F MONOLITHIC PWR SYS CALL Call 50 194.12 17 466.67 n/a n/a n/a
2017-01-11 2016-12-31 13F MONOLITHIC PWR SYS CALL Call 17 -43.33 3 -57.14 n/a n/a n/a
2016-10-07 2016-09-30 13F MONOLITHIC PWR SYS CALL Call 30 -14.29 7 16.67 n/a n/a n/a
2016-07-18 2016-06-30 13F MONOLITHIC PWR SYS CALL Call 35 775.00 6 200.00 n/a n/a n/a
2016-04-14 2016-03-31 13F MONOLITHIC PWR SYS CALL Call 4 -88.57 2 -66.67 n/a n/a n/a
2015-04-21 2015-03-31 13F MONOLITHIC PWR SYS CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-03-04 2014-12-31 13F MONOLITHIC PWR SYS CALL Call 9 1 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 MONOLITHIC PWR SYS PUT Put 2,300 -58.93 2,515 -50.46 n/a n/a n/a
2026-02-11 2025-12-31 13F MONOLITHIC PWR SYS PUT Put 5,600 -37.08 5,076 63,337.50 n/a n/a n/a
2025-11-12 2025-09-30 13F MONOLITHIC PWR SYS PUT Put 8,900 58.93 8 100.00 n/a n/a n/a
2025-08-05 2025-06-30 13F MONOLITHIC PWR SYS PUT Put 5,600 -25.33 4 0.00 n/a n/a n/a
2025-05-12 2025-03-31 13F MONOLITHIC PWR SYS PUT Put 7,500 -64.95 4 -66.67 n/a n/a n/a
2025-02-11 2024-12-31 13F MONOLITHIC PWR SYS PUT Put 21,400 345.83 13 200.00 n/a n/a n/a
2024-11-08 2024-09-30 13F MONOLITHIC PWR SYS PUT Put 4,800 -71.43 4 -69.23 n/a n/a n/a
2024-07-25 2024-06-30 13F MONOLITHIC PWR SYS PUT Put 16,800 -42.07 14 -31.58 n/a n/a n/a
2024-04-25 2024-03-31 13F MONOLITHIC PWR SYS PUT Put 29,000 60.22 20 72.73 n/a n/a n/a
2024-02-02 2023-12-31 13F MONOLITHIC PWR SYS PUT Put 18,100 1.69 11 37.50 n/a n/a n/a
2023-11-01 2023-09-30 13F MONOLITHIC PWR SYS PUT Put 17,800 44.72 8 33.33 n/a n/a n/a
2023-08-04 2023-06-30 13F MONOLITHIC PWR SYS PUT Put 12,300 6.03 7 20.00 n/a n/a n/a
2023-04-27 2023-03-31 13F MONOLITHIC PWR SYS PUT Put 11,600 93.33 6 150.00 n/a n/a n/a
2023-02-02 2022-12-31 13F MONOLITHIC PWR SYS PUT Put 6,000 252.94 2 -99.68 n/a n/a n/a
2022-11-04 2022-09-30 13F MONOLITHIC PWR SYS PUT Put 1,700 -80.00 617 -81.10 n/a n/a n/a
2022-08-03 2022-06-30 13F MONOLITHIC PWR SYS PUT Put 8,500 -50.58 3,264 -60.92 n/a n/a n/a
2022-05-02 2022-03-31 13F MONOLITHIC PWR SYS PUT Put 17,200 2,357.14 8,353 2,321.16 n/a n/a n/a
2022-02-23 2021-12-31 13F/A MONOLITHIC PWR SYS PUT Put 700 -79.41 345 -72.58 n/a n/a n/a
2022-02-04 2021-12-31 13F MONOLITHIC PWR SYS PUT Put 3,400 1,258 n/a n/a n/a
2021-10-28 2021-09-30 13F MONOLITHIC PWR SYS PUT Put 3,400 0.00 1,258 -0.87 n/a n/a n/a
2021-08-12 2021-06-30 13F MONOLITHIC PWR SYS PUT Put 3,400 8,192.68 1,269 -12.36 n/a n/a n/a
2021-04-26 2021-03-31 13F MONOLITHIC PWR SYS PUT Put 41 4,000.00 1,448 3,922.22 n/a n/a n/a
2021-02-02 2020-12-31 13F MONOLITHIC PWR SYS PUT Put 1 0.00 36 33.33 n/a n/a n/a
2020-10-14 2020-09-30 13F MONOLITHIC PWR SYS PUT Put 1 -96.00 27 -95.44 n/a n/a n/a
2020-07-13 2020-06-30 13F MONOLITHIC PWR SYS PUT Put 25 -21.88 592 10.65 n/a n/a n/a
2020-04-29 2020-03-31 13F MONOLITHIC PWR SYS PUT Put 32 -21.95 535 -26.61 n/a n/a n/a
2020-02-05 2019-12-31 13F MONOLITHIC PWR SYS PUT Put 41 -48.75 729 -41.45 n/a n/a n/a
2019-10-15 2019-09-30 13F MONOLITHIC PWR SYS PUT Put 80 142.42 1,245 177.90 n/a n/a n/a
2019-07-26 2019-06-30 13F MONOLITHIC PWR SYS PUT Put 33 -88.38 448 -88.35 n/a n/a n/a
2019-04-18 2019-03-31 13F MONOLITHIC PWR SYS PUT Put 284 667.57 3,847 794.65 n/a n/a n/a
2019-01-16 2018-12-31 13F MONOLITHIC PWR SYS PUT Put 37 -53.75 430 -57.17 n/a n/a n/a
2018-10-23 2018-09-30 13F MONOLITHIC PWR SYS PUT Put 80 -31.62 1,004 -35.76 n/a n/a n/a
2018-07-30 2018-06-30 13F MONOLITHIC PWR SYS PUT Put 117 11,600.00 1,563 55.68 n/a n/a n/a
2018-04-26 2018-03-31 13F MONOLITHIC PWR SYS PUT Put 1 -99.15 0 -100.00 n/a n/a n/a
2018-01-10 2017-12-31 13F MONOLITHIC PWR SYS PUT Put 0 -100.00 0 n/a n/a n/a
2017-10-25 2017-09-30 13F MONOLITHIC PWR SYS PUT Put 3 -94.74 0 -100.00 n/a n/a n/a
2017-07-12 2017-06-30 13F MONOLITHIC PWR SYS PUT Put 57 128.00 8 100.00 n/a n/a n/a
2017-04-21 2017-03-31 13F MONOLITHIC PWR SYS PUT Put 25 25.00 4 0.00 n/a n/a n/a
2017-01-11 2016-12-31 13F MONOLITHIC PWR SYS PUT Put 20 -64.29 4 -20.00 n/a n/a n/a
2016-10-07 2016-09-30 13F MONOLITHIC PWR SYS PUT Put 56 -15.15 5 -54.55 n/a n/a n/a
2016-07-18 2016-06-30 13F MONOLITHIC PWR SYS PUT Put 66 -30.53 11 -50.00 n/a n/a n/a
2016-04-14 2016-03-31 13F MONOLITHIC PWR SYS PUT Put 95 375.00 22 2,100.00 n/a n/a n/a
2016-01-20 2015-12-31 13F MONOLITHIC PWR SYS PUT Put 20 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.