Monolithic Power Systems, Inc.
US ˙ NasdaqGS ˙ US6098391054

SecurityMPWR / Monolithic Power Systems, Inc.
InstitutionMorgan Stanley
Latest Disclosed Ownership656,367 shares
Latest Disclosed Value $ 717,641,962
Morgan Stanley reports 1.12% increase in ownership of MPWR / Monolithic Power Systems, Inc.

On May 15, 2026 - Morgan Stanley filed a 13F-HR form disclosing ownership of 656,367 shares of Monolithic Power Systems, Inc. (US:MPWR) valued at $717,638,859 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on May 27, 2026 disclosing 649,070 shares of Monolithic Power Systems, Inc.. This represents a change in shares of 1.12% during the quarter. The current value of the position is $1,109,188,030 USD.

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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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 656,367 7,297 1.12 717,642 21.99 0.0432
2026-05-27 2025-12-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 649,070 90,399 16.18 588,294 14.38 0.0351
2026-02-13 2025-12-31 13F MONOLITHIC PWR SYS COM 609839105 649,070 90,399 588,294 0.0351
2026-05-27 2025-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 558,671 -6,348 -1.12 514,337 24.46 0.0311
2025-11-14 2025-09-30 13F MONOLITHIC PWR SYS COM 609839105 558,671 -6,348 514,337 0.0311
2025-08-15 2025-06-30 13F MONOLITHIC PWR SYS COM 609839105 565,019 24,388 4.51 413,245 31.79 0.0269
2025-05-15 2025-03-31 13F MONOLITHIC PWR SYS COM 609839105 540,631 81,329 17.71 313,556 15.38 0.0224
2025-05-15 2024-12-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 459,302 14,410 3.24 271,770 -33.92 0.0190
2025-02-14 2024-12-31 13F MONOLITHIC PWR SYS COM 609839105 459,302 14,410 271,770 0.0190
2025-05-14 2024-09-30 13F/A-2 MONOLITHIC PWR SYS COM 609839105 444,892 25,896 6.18 411,304 19.47 0.0298
2025-02-14 2024-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 444,892 25,896 411,304 0.0298
2024-11-14 2024-09-30 13F MONOLITHIC PWR SYS COM 609839105 444,892 25,896 411,304 0.0298
2025-05-14 2024-06-30 13F/A-2 MONOLITHIC PWR SYS COM 609839105 418,996 -74,167 -15.04 344,283 3.05 0.0266
2024-10-17 2024-06-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 418,996 -74,167 344,283 0.0266
2024-08-14 2024-06-30 13F MONOLITHIC PWR SYS COM 609839105 418,996 -74,167 344,283 0.0266
2024-10-17 2024-03-31 13F/A-2 MONOLITHIC PWR SYS COM 609839105 493,163 80,854 19.61 334,080 28.45 0.0268
2024-08-16 2024-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 493,163 80,854 334,080 0.0031
2024-05-15 2024-03-31 13F MONOLITHIC PWR SYS COM 609839105 493,163 80,854 334,080 0.0268
2024-08-16 2023-12-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 412,309 13,340 3.34 260,078 41.10 0.0229
2024-02-13 2023-12-31 13F MONOLITHIC PWR SYS COM 609839105 412,309 13,340 260,078 0.0229
2023-11-15 2023-09-30 13F MONOLITHIC PWR SYS COM 609839105 398,969 47,671 13.57 184,325 -2.88 0.0187
2023-08-14 2023-06-30 13F MONOLITHIC PWR SYS COM 609839105 351,298 26,989 8.32 189,783 16.91 0.0187
2023-05-15 2023-03-31 13F MONOLITHIC PWR SYS COM 609839105 324,309 -58,101 -15.19 162,330 20.05 0.0174
2023-02-14 2022-12-31 13F MONOLITHIC PWR SYS COM 609839105 382,410 14,283 3.88 135,224 1.08 0.0154
2022-11-14 2022-09-30 13F MONOLITHIC PWR SYS COM 609839105 368,127 41,586 12.74 133,777 6.68 0.0182
2022-10-27 2022-06-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 326,541 221,827 211.84 125,405 146.58 0.0163
2022-08-15 2022-06-30 13F MONOLITHIC PWR SYS COM 609839105 326,541 221,827 125,405 0.0033
2022-10-27 2022-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 104,714 14,046 15.49 50,857 13.70 0.0069
2022-05-13 2022-03-31 13F MONOLITHIC PWR SYS COM 609839105 104,714 14,046 50,857 0.0069
2022-02-14 2021-12-31 13F MONOLITHIC PWR SYS COM 609839105 90,668 -33,614 -27.05 44,729 -25.75 0.0055
2021-11-15 2021-09-30 13F MONOLITHIC PWR SYS COM 609839105 124,282 50,341 68.08 60,238 118.16 0.0081
2021-08-23 2021-06-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 73,941 -2,028 -2.67 27,612 2.90 0.0036
2021-08-16 2021-06-30 13F MONOLITHIC PWR SYS COM 609839105 73,941 -2,028 27,612 0.0008
2021-05-17 2021-03-31 13F MONOLITHIC PWR SYS COM 609839105 75,969 24,957 48.92 26,833 43.62 0.0039
2021-02-16 2020-12-31 13F MONOLITHIC PWR SYS COM 609839105 51,012 21,691 73.98 18,683 127.87 0.0029
2020-11-13 2020-09-30 13F MONOLITHIC PWR SYS COM 609839105 29,321 1,404 5.03 8,199 23.89 0.0016
2020-08-14 2020-06-30 13F MONOLITHIC PWR SYS COM 609839105 27,917 -17,564 -38.62 6,618 -13.12 0.0015
2020-05-26 2020-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 45,481 -13,975 -23.50 7,617 -28.04 0.0021
2020-05-15 2020-03-31 13F MONOLITHIC PWR SYS COM 609839105 45,481 -13,975 7,617 585.1444
2020-02-14 2019-12-31 13F MONOLITHIC PWR SYS COM 609839105 59,456 28,085 89.53 10,585 116.77 0.0025
2019-11-14 2019-09-30 13F MONOLITHIC PWR SYS COM 609839105 31,371 933 3.07 4,883 18.15 0.0013
2019-08-14 2019-06-30 13F MONOLITHIC PWR SYS COM 609839105 30,438 -34,772 -53.32 4,133 -53.22 0.0011
2019-05-15 2019-03-31 13F MONOLITHIC PWR SYS COM 609839105 65,210 31,853 95.49 8,835 127.82 0.0025
2019-02-14 2018-12-31 13F MONOLITHIC PWR SYS COM 609839105 33,357 -70,255 -67.81 3,878 -70.19 0.0012
2019-04-23 2018-09-30 13F/A-2 MONOLITHIC PWR SYS COM 609839105 103,612 -29,300 -22.04 13,007 -26.79 0.0033
2018-11-20 2018-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 103,612 0 13,007 0.0033
2018-11-14 2018-09-30 13F MONOLITHIC PWR SYS COM 609839105 103,612 -29,300 13,007
2019-04-23 2018-06-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 132,912 -100,484 -43.05 17,767 -34.25 0.0048
2018-08-14 2018-06-30 13F MONOLITHIC PWR SYS COM 609839105 132,912 -100,484 17,767
2019-04-23 2018-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 233,396 10,019 4.49 27,020 7.65 0.0075
2018-05-14 2018-03-31 13F MONOLITHIC PWR SYS COM 609839105 233,396 10,019 27,020
2019-04-23 2017-12-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 223,377 15,994 7.71 25,099 13.59 0.0069
2018-02-14 2017-12-31 13F MONOLITHIC PWR SYS COM 609839105 223,377 15,994 25,099
2017-11-14 2017-09-30 13F MONOLITHIC PWR SYS COM 609839105 207,383 51,361 32.92 22,096 46.90 0.0066
2017-08-11 2017-06-30 13F MONOLITHIC PWR SYS COM 609839105 156,022 -18,207 -10.45 15,042 -6.26 0.0045
2017-05-22 2017-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 174,229 -55,368 -24.12 16,047 -14.69 0.0049
2017-05-12 2017-03-31 13F MONOLITHIC PWR SYS COM 609839105 174,229 16,047
2017-02-22 2016-12-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 229,597 97,275 73.51 18,810 76.60 0.0062
2017-02-13 2016-12-31 13F MONOLITHIC PWR SYS COM 609839105 229,597 18,810
2016-11-10 2016-09-30 13F MONOLITHIC PWR SYS COM 609839105 132,322 64,899 96.26 10,651 131.24 0.0036
2016-08-12 2016-06-30 13F MONOLITHIC PWR SYS COM 609839105 67,423 48,287 252.34 4,606 277.85 0.0017
2016-05-12 2016-03-31 13F MONOLITHIC PWR SYS COM 609839105 19,136 3,630 23.41 1,219 23.38 0.0005
2016-02-09 2015-12-31 13F MONOLITHIC PWR SYS COM 609839105 15,506 -3,139 -16.84 988 3.56 0.0004
2016-02-08 2015-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 18,645 -27,778 -59.84 954 -59.47 0.0004
2015-11-09 2015-09-30 13F MONOLITHIC PWR SYS COM 609839105 18,645 954
2015-08-12 2015-06-30 13F MONOLITHIC PWR SYS COM 609839105 46,423 7,886 20.46 2,354 16.02 0.0008
2015-05-14 2015-03-31 13F MONOLITHIC PWR SYS COM 609839105 38,537 -9,853 -20.36 2,029 -15.70 0.0007
2015-02-13 2014-12-31 13F MONOLITHIC PWR SYS COM 609839105 48,390 -45,021 -48.20 2,407 -41.51 0.0009
2014-12-16 2014-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 93,411 26,127 38.83 4,115 57.72 0.0016
2014-11-14 2014-09-30 13F MONOLITHIC PWR SYS COM 609839105 93,411 4,115
2014-05-13 2014-03-31 13F MONOLITHIC PWR SYS COM 609839105 67,284 62,653 1,352.90 2,609 1,530.63 0.0011
2014-02-13 2013-12-31 13F MONOLITHIC PWR SYS COM 609839105 4,631 -12,970 -73.69 160 -69.98 0.0001
2013-11-13 2013-09-30 13F MONOLITHIC POWER COM 609839105 17,601 8,476 92.89 533 142.27 0.0003
2013-08-08 2013-06-30 13F MONOLITHIC POWER COM 609839105 9,125 9,125 220 0.0001
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.