Monolithic Power Systems, Inc.
MX ˙ BMV ˙ US6098391054
SecurityMX:MPWR / Monolithic Power Systems, Inc.
InstitutionD. E. Shaw & Co., Inc.
ManagerDE Shaw
Latest Disclosed Ownership1,217 shares
Latest Disclosed Value $ 1,330,607
D. E. Shaw & Co., Inc. ownership in MPWR / Monolithic Power Systems, Inc.

On May 15, 2026 - D. E. Shaw & Co., Inc. filed a 13F-HR form disclosing ownership of 1,217 shares of Monolithic Power Systems, Inc. (MX:MPWR) valued at $1,330,607 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,348 shares of Monolithic Power Systems, Inc.. This represents a change in shares of -9.72% during the quarter.

D. E. Shaw & Co., Inc. 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 0 of underlying shares valued at $0 USD and put options representing 25,000 of underlying shares valued at $27,333,750 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: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)
2026-05-15 2026-03-31 13F MONOLITHIC PWR SYS COM 609839105 1,217 -131 -9.72 1,331 8.93 0.0006
2026-02-17 2025-12-31 13F MONOLITHIC PWR SYS COM 609839105 1,348 -106 -7.29 1,222 -8.74 0.0007
2025-11-14 2025-09-30 13F MONOLITHIC PWR SYS COM 609839105 1,454 -3,973 -73.21 1,339 -66.29 0.0008
2025-08-14 2025-06-30 13F MONOLITHIC PWR SYS COM 609839105 5,427 -1,850 -25.42 3,969 -5.95 0.0028
2025-05-15 2025-03-31 13F MONOLITHIC PWR SYS COM 609839105 7,277 -5,029 -40.87 4,221 -42.04 0.0038
2025-02-14 2024-12-31 13F MONOLITHIC PWR SYS COM 609839105 12,306 -17,987 -59.38 7,281 -74.00 0.0053
2024-11-14 2024-09-30 13F MONOLITHIC PWR SYS COM 609839105 30,293 -10,394 -25.55 28,006 -16.23 0.0240
2024-08-14 2024-06-30 13F MONOLITHIC PWR SYS COM 609839105 40,687 -5,835 -12.54 33,432 6.08 0.0313
2024-05-15 2024-03-31 13F MONOLITHIC PWR SYS COM 609839105 46,522 19,108 69.70 31,515 82.25 0.0270
2024-02-14 2023-12-31 13F MONOLITHIC PWR SYS COM 609839105 27,414 5,319 24.07 17,292 69.41 0.0151
2023-11-14 2023-09-30 13F MONOLITHIC PWR SYS COM 609839105 22,095 -17,676 -44.44 10,208 -52.49 0.0107
2023-08-14 2023-06-30 13F MONOLITHIC PWR SYS COM 609839105 39,771 -81,762 -67.28 21,485 -64.68 0.0219
2023-05-15 2023-03-31 13F MONOLITHIC PWR SYS COM 609839105 121,533 -47,877 -28.26 60,832 1.55 0.0651
2023-02-14 2022-12-31 13F MONOLITHIC PWR SYS COM 609839105 169,410 117,253 224.81 59,905 216.05 0.0662
2022-11-14 2022-09-30 13F MONOLITHIC PWR SYS COM 609839105 52,157 52,157 18,954 0.0226
2022-08-15 2022-06-30 13F MONOLITHIC PWR SYS COM 609839105 0 -808 -100.00 0 -100.00
2022-05-16 2022-03-31 13F MONOLITHIC PWR SYS COM 609839105 808 -12,446 -93.90 392 -94.01 0.0004
2022-02-14 2021-12-31 13F MONOLITHIC PWR SYS COM 609839105 13,254 11,332 589.59 6,539 601.61 0.0054
2021-11-15 2021-09-30 13F MONOLITHIC PWR SYS COM 609839105 1,922 -35,357 -94.84 932 -93.31 0.0008
2021-08-16 2021-06-30 13F MONOLITHIC PWR SYS COM 609839105 37,279 -12,834 -25.61 13,922 -21.34 0.0120
2021-05-17 2021-03-31 13F MONOLITHIC PWR SYS COM 609839105 50,113 48,424 2,867.02 17,700 2,759.45 0.0171
2021-02-16 2020-12-31 13F MONOLITHIC PWR SYS COM 609839105 1,689 -24,190 -93.47 619 -91.45 0.0006
2020-11-16 2020-09-30 13F MONOLITHIC PWR SYS COM 609839105 25,879 22,723 719.99 7,236 867.38 0.0074
2020-08-14 2020-06-30 13F MONOLITHIC PWR SYS COM 609839105 3,156 -15,202 -82.81 748 -75.67 0.0009
2020-05-15 2020-03-31 13F MONOLITHIC PWR SYS COM 609839105 18,358 18,358 481.69 3,074 310.96 0.0048
2019-05-15 2019-03-31 13F MONOLITHIC PWR SYS COM 609839105 0 -16,592 -100.00 0 -100.00
2019-02-14 2018-12-31 13F MONOLITHIC PWR SYS COM 609839105 16,592 14,246 607.25 1,929 556.12 0.0027
2018-11-14 2018-09-30 13F MONOLITHIC PWR SYS COM 609839105 2,346 -67,256 -96.63 294 -96.84 0.0004
2018-08-14 2018-06-30 13F MONOLITHIC PWR SYS COM 609839105 69,602 64,880 1,373.99 9,304 1,600.91 0.0121
2018-05-15 2018-03-31 13F MONOLITHIC PWR SYS COM 609839105 4,722 151 3.30 547 6.42 0.0007
2018-02-14 2017-12-31 13F MONOLITHIC PWR SYS COM 609839105 4,571 -2,008 -30.52 514 -26.68 0.0007
2017-11-14 2017-09-30 13F MONOLITHIC PWR SYS COM 609839105 6,579 -1,071 -14.00 701 -4.88 0.0011
2017-08-14 2017-06-30 13F MONOLITHIC PWR SYS COM 609839105 7,650 -2,197 -22.31 737 -18.74 0.0012
2017-05-15 2017-03-31 13F MONOLITHIC PWR SYS COM 609839105 9,847 -28,359 -74.23 907 -71.02 0.0016
2017-02-14 2016-12-31 13F MONOLITHIC PWR SYS COM 609839105 38,206 -37,936 -49.82 3,130 -48.94 0.0053
2016-11-14 2016-09-30 13F MONOLITHIC PWR SYS COM 609839105 76,142 -14,753 -16.23 6,130 -1.29 0.0108
2016-08-15 2016-06-30 13F MONOLITHIC PWR SYS COM 609839105 90,895 -28,014 -23.56 6,210 -17.93 0.0115
2016-05-16 2016-03-31 13F MONOLITHIC PWR SYS COM 609839105 118,909 -2,963 -2.43 7,567 -2.54 0.0136
2016-02-16 2015-12-31 13F MONOLITHIC PWR SYS COM 609839105 121,872 17,574 16.85 7,764 45.39 0.0116
2015-11-16 2015-09-30 13F MONOLITHIC PWR SYS COM 609839105 104,298 -57,077 -35.37 5,340 -34.74 0.0079
2015-08-14 2015-06-30 13F MONOLITHIC PWR SYS COM 609839105 161,375 -42,815 -20.97 8,183 -23.89 0.0122
2015-05-15 2015-03-31 13F MONOLITHIC PWR SYS COM 609839105 204,190 8,773 4.49 10,751 10.61 0.0165
2015-02-17 2014-12-31 13F MONOLITHIC PWR SYS COM 609839105 195,417 -19,074 -8.89 9,720 2.88 0.0125
2014-11-14 2014-09-30 13F MONOLITHIC PWR SYS COM 609839105 214,491 18,405 9.39 9,448 13.78 0.0122
2014-08-14 2014-06-30 13F MONOLITHIC PWR SYS COM 609839105 196,086 -58,525 -22.99 8,304 -15.87 0.0113
2014-05-15 2014-03-31 13F MONOLITHIC PWR SYS COM 609839105 254,611 -5,228 -2.01 9,871 9.60 0.0141
2014-02-14 2013-12-31 13F MONOLITHIC PWR SYS COM 609839105 259,839 112,406 76.24 9,006 101.75 0.0123
2013-11-20 2013-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 147,433 20,234 15.91 4,464 45.55 0.0071
2013-11-14 2013-09-30 13F MONOLITHIC PWR SYS COM 609839105 147,433 4,464
2013-08-14 2013-06-30 13F MONOLITHIC PWR SYS COM 609839105 127,199 127,199 3,067 0.0058
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
(%)
2026-05-15 2026-03-31 13F MONOLITHIC PWR SYS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-17 2025-12-31 13F MONOLITHIC PWR SYS COM Call 500 -64.29 453 -64.83 n/a n/a n/a
2025-11-14 2025-09-30 13F MONOLITHIC PWR SYS COM Call 1,400 0.00 1,289 25.90 n/a n/a n/a
2025-08-14 2025-06-30 13F MONOLITHIC PWR SYS COM Call 1,400 0.00 1,024 26.14 n/a n/a n/a
2025-05-15 2025-03-31 13F MONOLITHIC PWR SYS COM Call 1,400 55.56 812 52.44 n/a n/a n/a
2025-02-14 2024-12-31 13F MONOLITHIC PWR SYS COM Call 900 533 n/a n/a n/a
2024-11-14 2023-12-31 13F/A MONOLITHIC PWR SYS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-02-14 2023-12-31 13F MONOLITHIC PWR SYS COM Call 0 0 n/a n/a n/a
2023-11-14 2023-09-30 13F MONOLITHIC PWR SYS COM Call 20,000 9,240 n/a n/a n/a
2023-02-14 2022-12-31 13F MONOLITHIC PWR SYS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-11-14 2022-09-30 13F MONOLITHIC PWR SYS COM Call 10,100 0.00 3,670 -5.39 n/a n/a n/a
2022-08-15 2022-06-30 13F MONOLITHIC PWR SYS COM Call 10,100 0.00 3,879 -20.92 n/a n/a n/a
2022-05-16 2022-03-31 13F MONOLITHIC PWR SYS COM Call 10,100 -49.75 4,905 -50.53 n/a n/a n/a
2022-02-14 2021-12-31 13F MONOLITHIC PWR SYS COM Call 20,100 84.40 9,916 87.70 n/a n/a n/a
2021-11-15 2021-09-30 13F MONOLITHIC PWR SYS COM Call 10,900 5,283 n/a n/a n/a
2018-08-14 2018-06-30 13F MONOLITHIC PWR SYS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2018-05-15 2018-03-31 13F MONOLITHIC PWR SYS COM Call 22,900 -35.49 2,651 -33.54 n/a n/a n/a
2018-02-14 2017-12-31 13F MONOLITHIC PWR SYS COM Call 35,500 55.02 3,989 50.47 n/a n/a n/a
2015-05-15 2015-03-31 13F MONOLITHIC PWR SYS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-02-17 2014-12-31 13F MONOLITHIC PWR SYS COM Call 21,100 -37.01 1,050 -28.86 n/a n/a n/a
2014-11-14 2014-09-30 13F MONOLITHIC PWR SYS COM Call 33,500 170.16 1,476 181.14 n/a n/a n/a
2014-08-14 2014-06-30 13F MONOLITHIC PWR SYS COM Call 12,400 525 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
(%)
2026-05-15 2026-03-31 13F MONOLITHIC PWR SYS COM Put 25,000 -30.17 27,334 -15.76 n/a n/a n/a
2026-02-17 2025-12-31 13F MONOLITHIC PWR SYS COM Put 35,800 -16.36 32,448 -17.65 n/a n/a n/a
2025-11-14 2025-09-30 13F MONOLITHIC PWR SYS COM Put 42,800 -3.60 39,403 21.34 n/a n/a n/a
2025-08-14 2025-06-30 13F MONOLITHIC PWR SYS COM Put 44,400 7.51 32,473 35.57 n/a n/a n/a
2025-05-15 2025-03-31 13F MONOLITHIC PWR SYS COM Put 41,300 43.90 23,953 41.06 n/a n/a n/a
2025-02-14 2024-12-31 13F MONOLITHIC PWR SYS COM Put 28,700 -14.84 16,982 -45.50 n/a n/a n/a
2024-11-14 2024-09-30 13F MONOLITHIC PWR SYS COM Put 33,700 77.37 31,156 99.57 n/a n/a n/a
2024-08-14 2024-06-30 13F MONOLITHIC PWR SYS COM Put 19,000 0.00 15,612 21.30 n/a n/a n/a
2024-05-15 2024-03-31 13F MONOLITHIC PWR SYS COM Put 19,000 16.56 12,871 25.18 n/a n/a n/a
2024-02-14 2023-12-31 13F MONOLITHIC PWR SYS COM Put 16,300 3,160.00 10,282 4,350.65 n/a n/a n/a
2023-11-14 2023-09-30 13F MONOLITHIC PWR SYS COM Put 500 231 n/a n/a n/a
2022-11-14 2022-09-30 13F MONOLITHIC PWR SYS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-08-15 2022-06-30 13F MONOLITHIC PWR SYS COM Put 12,600 -70.28 4,839 -76.50 n/a n/a n/a
2022-05-16 2022-03-31 13F MONOLITHIC PWR SYS COM Put 42,400 244.72 20,593 239.37 n/a n/a n/a
2022-02-14 2021-12-31 13F MONOLITHIC PWR SYS COM Put 12,300 -28.07 6,068 -26.79 n/a n/a n/a
2021-11-15 2021-09-30 13F MONOLITHIC PWR SYS COM Put 17,100 71.00 8,288 121.90 n/a n/a n/a
2021-08-16 2021-06-30 13F MONOLITHIC PWR SYS COM Put 10,000 3,735 n/a n/a n/a
2018-08-14 2018-06-30 13F MONOLITHIC PWR SYS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-05-15 2018-03-31 13F MONOLITHIC PWR SYS COM Put 4,300 0.00 498 3.11 n/a n/a n/a
2018-02-14 2017-12-31 13F MONOLITHIC PWR SYS COM Put 4,300 483 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.