Monolithic Power Systems, Inc.
MX ˙ BMV ˙ US6098391054
SecurityMX:MPWR / Monolithic Power Systems, Inc.
InstitutionJanus Henderson Group Plc
Latest Disclosed Ownership7,374 shares
Latest Disclosed Value $ 8,060,024
Janus Henderson Group Plc reports 1.77% increase in ownership of MPWR / Monolithic Power Systems, Inc.

On May 18, 2026 - Janus Henderson Group Plc filed a 13F-HR/A form disclosing ownership of 7,374 shares of Monolithic Power Systems, Inc. (MX:MPWR) valued at $8,060,024 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 7,246 shares of Monolithic Power Systems, Inc.. This represents a change in shares of 1.77% 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)
2026-05-18 2026-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 7,374 128 1.77 8,060 22.72 0.0014
2026-05-15 2026-03-31 13F MONOLITHIC PWR SYS COM 609839105 7,374 128 8,060 0.0015
2026-02-17 2025-12-31 13F MONOLITHIC PWR SYS COM 609839105 7,246 -120,492 -94.33 6,568 -94.41 0.0029
2025-11-14 2025-09-30 13F MONOLITHIC PWR SYS COM 609839105 127,738 309 0.24 117,502 26.11 0.0536
2025-08-14 2025-06-30 13F MONOLITHIC PWR SYS COM 609839105 127,429 21,816 20.66 93,173 52.10 0.0457
2025-05-15 2025-03-31 13F MONOLITHIC PWR SYS COM 609839105 105,613 99,668 1,676.50 61,256 1,640.72 0.0336
2025-02-14 2024-12-31 13F MONOLITHIC PWR SYS COM 609839105 5,945 -51 -0.85 3,519 -36.54 0.0018
2024-11-14 2024-09-30 13F MONOLITHIC PWR SYS COM 609839105 5,996 2,134 55.26 5,545 74.98 0.0028
2024-08-14 2024-06-30 13F MONOLITHIC PWR SYS COM 609839105 3,862 -1,137 -22.74 3,169 -6.35 0.0017
2024-05-15 2024-03-31 13F MONOLITHIC PWR SYS COM 609839105 4,999 2 0.04 3,384 7.36 0.0018
2024-02-14 2023-12-31 13F MONOLITHIC PWR SYS COM 609839105 4,997 -36 -0.72 3,153 35.57 0.0019
2023-11-14 2023-09-30 13F MONOLITHIC PWR SYS COM 609839105 5,033 -186 -3.56 2,325 -17.55 0.0015
2023-08-14 2023-06-30 13F MONOLITHIC PWR SYS COM 609839105 5,219 -558 -9.66 2,820 -2.42 0.0018
2023-05-15 2023-03-31 13F MONOLITHIC PWR SYS COM 609839105 5,777 1,167 25.31 2,890 77.30 0.0019
2023-02-14 2022-12-31 13F MONOLITHIC PWR SYS COM 609839105 4,610 1 0.02 1,630 -2.74 0.0012
2022-11-14 2022-09-30 13F MONOLITHIC PWR SYS COM 609839105 4,609 4 0.09 1,676 -5.26 0.0013
2022-08-15 2022-06-30 13F MONOLITHIC PWR SYS COM 609839105 4,605 -641 -12.22 1,769 -30.55 0.0012
2022-05-16 2022-03-31 13F MONOLITHIC PWR SYS COM 609839105 5,246 1,245 31.12 2,547 28.96 0.0012
2022-02-14 2021-12-31 13F MONOLITHIC PWR SYS COM 609839105 4,001 182 4.77 1,975 6.70 0.0008
2021-11-16 2021-09-30 13F MONOLITHIC PWR SYS COM 609839105 3,819 -159 -4.00 1,851 24.56 0.0008
2021-08-16 2021-06-30 13F MONOLITHIC PWR SYS COM 609839105 3,978 44 1.12 1,486 6.91 0.0006
2021-05-17 2021-03-31 13F MONOLITHIC PWR SYS COM 609839105 3,934 -3,406 -46.40 1,390 -48.29 0.0006
2021-02-16 2020-12-31 13F MONOLITHIC PWR SYS COM 609839105 7,340 -5,722 -43.81 2,688 -26.40 0.0012
2020-11-16 2020-09-30 13F MONOLITHIC PWR SYS COM 609839105 13,062 -2,393 -15.48 3,652 -0.30 0.0019
2020-08-14 2020-06-30 13F MONOLITHIC PWR SYS COM 609839105 15,455 7,855 103.36 3,663 187.75 0.0021
2020-05-14 2020-03-31 13F MONOLITHIC PWR SYS COM 609839105 7,600 -252,094 -97.07 1,273 -97.25 0.0009
2020-02-18 2019-12-31 13F MONOLITHIC PWR SYS COM 609839105 259,694 -2,628 -1.00 46,231 13.24 0.0237
2019-11-14 2019-09-30 13F MONOLITHIC PWR SYS COM 609839105 262,322 1,002 0.38 40,825 15.06 0.0221
2019-07-31 2019-06-30 13F MONOLITHIC PWR SYS COM 609839105 261,320 -1,625 -0.62 35,482 -0.40 0.0193
2019-04-30 2019-03-31 13F MONOLITHIC PWR SYS COM 609839105 262,945 3,055 1.18 35,626 17.92 0.0197
2019-02-06 2018-12-31 13F MONOLITHIC PWR SYS COM 609839105 259,890 -7,218 -2.70 30,212 -9.90 0.0193
2018-11-09 2018-09-30 13F MONOLITHIC PWR SYS COM 609839105 267,108 -1,584 -0.59 33,530 -6.64 0.0179
2018-08-10 2018-06-30 13F MONOLITHIC PWR SYS COM 609839105 268,692 15,237 6.01 35,916 22.40 0.0205
2018-05-14 2018-03-31 13F MONOLITHIC PWR SYS COM 609839105 253,455 27,541 12.19 29,342 15.59 0.0173
2018-03-12 2017-12-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 225,914 111,725 97.84 25,384 108.63 0.0156
2018-02-09 2017-12-31 13F MONOLITHIC PWR SYS COM 609839105 225,914 111,725 25,384
2017-11-14 2017-09-30 13F MONOLITHIC PWR SYS COM 609839105 114,189 -33,554 -22.71 12,167 -14.58 0.0078
2017-08-17 2017-06-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 147,743 68,089 85.48 14,243 94.15 0.0097
2017-08-14 2017-06-30 13F MONOLITHIC PWR SYS COM 609839105 147,743 68,089 14,243
2017-05-03 2017-03-31 13F MONOLITHIC PWR SYS COM 609839105 79,654 -2,338 -2.85 7,336 9.20 0.0515
2017-01-30 2016-12-31 13F MONOLITHIC PWR SYS COM 609839105 81,992 81,992 6,718 0.0495
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.