Monolithic Power Systems, Inc.
MX ˙ BMV ˙ US6098391054
SecurityMX:MPWR / Monolithic Power Systems, Inc.
InstitutionNorthern Trust Corp
Latest Disclosed Ownership489,120 shares
Latest Disclosed Value $ 534,779,352
Northern Trust Corp reports 1.12% increase in ownership of MPWR / Monolithic Power Systems, Inc.

On May 14, 2026 - Northern Trust Corp filed a 13F-HR form disclosing ownership of 489,120 shares of Monolithic Power Systems, Inc. (MX:MPWR) valued at $534,779,352 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 483,700 shares of Monolithic Power Systems, Inc.. This represents a change in shares of 1.12% during the quarter.

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)
2026-05-14 2026-03-31 13F MONOLITHIC PWR SYS COM 609839105 489,120 5,420 1.12 534,779 21.98 0.0145
2026-02-17 2025-12-31 13F MONOLITHIC PWR SYS COM 609839105 483,700 -2,131 -0.44 438,406 -1.98 0.0559
2025-11-14 2025-09-30 13F MONOLITHIC PWR SYS COM 609839105 485,831 3,774 0.78 447,275 26.86 0.0572
2025-08-13 2025-06-30 13F MONOLITHIC PWR SYS COM 609839105 482,057 -16,459 -3.30 352,567 21.94 0.0485
2025-05-13 2025-03-31 13F MONOLITHIC PWR SYS COM 609839105 498,516 -10,777 -2.12 289,129 -4.05 0.0429
2025-02-14 2024-12-31 13F MONOLITHIC PWR SYS COM 609839105 509,293 94,414 22.76 301,349 -21.43 0.0427
2024-11-13 2024-09-30 13F MONOLITHIC PWR SYS COM 609839105 414,879 -17,318 -4.01 383,556 8.01 0.0628
2024-08-14 2024-06-30 13F MONOLITHIC PWR SYS COM 609839105 432,197 -11 -0.00 355,128 21.29 0.0598
2024-05-14 2024-03-31 13F MONOLITHIC PWR SYS COM 609839105 432,208 -13,899 -3.12 292,786 4.05 0.0506
2024-02-13 2023-12-31 13F MONOLITHIC PWR SYS COM 609839105 446,107 -13,670 -2.97 281,395 32.47 0.0509
2023-11-13 2023-09-30 13F MONOLITHIC PWR SYS COM 609839105 459,777 28,258 6.55 212,417 -8.88 0.0411
2023-08-11 2023-06-30 13F MONOLITHIC PWR SYS COM 609839105 431,519 -17,370 -3.87 233,120 3.75 0.0448
2023-05-15 2023-03-31 13F MONOLITHIC PWR SYS COM 609839105 448,889 3,871 0.87 224,687 42.78 0.0445
2023-02-13 2022-12-31 13F MONOLITHIC PWR SYS COM 609839105 445,018 -7,194 -1.59 157,363 -4.24 0.0330
2022-11-14 2022-09-30 13F MONOLITHIC PWR SYS COM 609839105 452,212 -690 -0.15 164,334 -5.52 0.0375
2022-08-12 2022-06-30 13F MONOLITHIC PWR SYS COM 609839105 452,902 8,756 1.97 173,932 -19.37 0.0373
2022-05-13 2022-03-31 13F MONOLITHIC PWR SYS COM 609839105 444,146 1,760 0.40 215,713 -1.16 0.0379
2022-02-08 2021-12-31 13F MONOLITHIC PWR SYS COM 609839105 442,386 -14,411 -3.15 218,242 -1.43 0.0358
2021-11-15 2021-09-30 13F MONOLITHIC PWR SYS COM 609839105 456,797 16,005 3.63 221,402 34.50 0.0392
2021-08-13 2021-06-30 13F MONOLITHIC PWR SYS COM 609839105 440,792 -2,458 -0.55 164,614 5.14 0.0290
2021-05-12 2021-03-31 13F MONOLITHIC PWR SYS COM 609839105 443,250 37,565 9.26 156,561 5.38 0.0291
2021-02-11 2020-12-31 13F MONOLITHIC PWR SYS COM 609839105 405,685 50,544 14.23 148,574 49.62 0.0289
2020-11-16 2020-09-30 13F MONOLITHIC PWR SYS COM 609839105 355,141 -9,340 -2.56 99,302 14.96 0.0218
2020-08-14 2020-06-30 13F MONOLITHIC PWR SYS COM 609839105 364,481 15,337 4.39 86,382 47.74 0.0205
2020-05-14 2020-03-31 13F MONOLITHIC PWR SYS COM 609839105 349,144 12,608 3.75 58,468 -2.41 0.0168
2020-02-14 2019-12-31 13F MONOLITHIC PWR SYS COM 609839105 336,536 7,655 2.33 59,911 17.05 0.0134
2019-11-13 2019-09-30 13F MONOLITHIC PWR SYS COM 609839105 328,881 -3,670 -1.10 51,183 13.35 0.0123
2019-08-13 2019-06-30 13F MONOLITHIC PWR SYS COM 609839105 332,551 1,062 0.32 45,153 0.53 0.0107
2019-05-13 2019-03-31 13F MONOLITHIC PWR SYS COM 609839105 331,489 11,907 3.73 44,913 20.89 0.0111
2019-02-12 2018-12-31 13F MONOLITHIC PWR SYS COM 609839105 319,582 -1,122 -0.35 37,151 -7.72 0.0104
2018-11-14 2018-09-30 13F MONOLITHIC PWR SYS COM 609839105 320,704 -36,237 -10.15 40,259 -15.62 0.0099
2018-09-18 2018-06-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 356,941 -270,411 -43.10 47,712 -34.31 0.0121
2018-08-14 2018-06-30 13F MONOLITHIC PWR SYS COM 609839105 359,676 -267,676 48,077
2018-05-09 2018-03-31 13F MONOLITHIC PWR SYS COM 609839105 627,352 -2,667 -0.42 72,629 2.60 0.0189
2018-02-14 2017-12-31 13F MONOLITHIC PWR SYS COM 609839105 630,019 -25,089 -3.83 70,789 1.41 0.0179
2017-11-13 2017-09-30 13F MONOLITHIC PWR SYS COM 609839105 655,108 -10,322 -1.55 69,802 8.82 0.0182
2017-08-11 2017-06-30 13F MONOLITHIC PWR SYS COM 609839105 665,430 28,367 4.45 64,147 9.33 0.0179
2017-05-12 2017-03-31 13F MONOLITHIC PWR SYS COM 609839105 637,063 5,578 0.88 58,673 13.41 0.0169
2017-02-13 2016-12-31 13F MONOLITHIC PWR SYS COM 609839105 631,485 -136,401 -17.76 51,736 -16.31 0.0159
2016-11-09 2016-09-30 13F MONOLITHIC PWR SYS COM 609839105 767,886 125,588 19.55 61,815 40.87 0.0193
2016-08-12 2016-06-30 13F MONOLITHIC PWR SYS COM 609839105 642,298 40,730 6.77 43,882 19.79 0.0142
2016-08-19 2016-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 601,568 11,685 1.98 36,633 -2.52 0.0122
2016-05-13 2016-03-31 13F Monolithic Pwr Sys I COMM 609839105 601,568 38,283
2016-02-12 2015-12-31 13F Monolithic Pwr Sys I COMM 609839105 589,883 12,287 2.13 37,581 27.08 0.0125
2015-11-12 2015-09-30 13F MONOLITHIC PWR SYS COM 609839105 577,596 577,596 0.00 29,573 0.0099
2015-08-13 2015-06-30 13F Monolithic Pwr Sys I COMM 609839105 0 -566,086 -100.00 0 -100.00
2015-05-14 2015-03-31 13F Monolithic Pwr Sys I COMM 609839105 566,086 1,783 0.32 29,804 6.18 0.0090
2015-02-12 2014-12-31 13F Monolithic Pwr Sys I COM 609839105 564,303 -25,097 -4.26 28,068 8.11 0.0085
2014-11-13 2014-09-30 13F Monolithic Pwr Sys I COMM 609839105 589,400 111,362 23.30 25,963 28.24 0.0082
2014-08-14 2014-06-30 13F MONOLITHIC PWR SYS com 609839105 478,038 -147,465 -23.58 20,245 -16.52 0.0063
2014-05-14 2014-03-31 13F MONOLITHIC PWR SYS COMM 609839105 625,503 83,149 15.33 24,251 29.02 0.0076
2014-02-21 2013-12-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 542,354 -46,603 -7.91 18,797 5.40 0.0060
2014-02-12 2013-12-31 13F MONOLITHIC PWR SYS COM 609839105 542,354 18,797
2013-11-13 2013-09-30 13F MONOLITHIC PWR SYS COM 609839105 588,957 50,570 9.39 17,834 37.40 0.0063
2013-08-09 2013-06-30 13F MONOLITHIC PWR SYS COM 609839105 538,387 538,387 12,980 0.0047
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.