Monolithic Power Systems, Inc.
MX ˙ BMV ˙ US6098391054
SecurityMX:MPWR / Monolithic Power Systems, Inc.
InstitutionRhumbline Advisers
Latest Disclosed Ownership102,110 shares
Latest Disclosed Value $ 111,641,850
Rhumbline Advisers reports 2.05% decrease in ownership of MPWR / Monolithic Power Systems, Inc.

On May 12, 2026 - Rhumbline Advisers filed a 13F-HR form disclosing ownership of 102,110 shares of Monolithic Power Systems, Inc. (MX:MPWR) valued at $111,641,850 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 104,246 shares of Monolithic Power Systems, Inc.. This represents a change in shares of -2.05% 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)
2026-05-12 2026-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 102,110 -2,136 -2.05 111,642 18.16 0.0955
2026-02-13 2025-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 104,246 -3,182 -2.96 94,484 -4.47 0.0764
2025-11-06 2025-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 107,428 -9,666 -8.25 98,902 15.49 0.0794
2025-08-12 2025-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 117,094 627 0.54 85,640 26.78 0.0733
2025-05-29 2025-03-31 13F/A-1 MONOLITHIC PWR SYS INC COM COM 609839105 116,467 8,693 8.07 67,548 5.93 0.0632
2025-04-08 2025-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 116,467 8,693 67,548 0.0632
2025-05-29 2024-12-31 13F/A-1 MONOLITHIC PWR SYS INC COM COM 609839105 107,774 -1,896 -1.73 63,770 -37.10 0.0570
2025-01-30 2024-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 107,774 -1,896 63,770 0.0570
2024-11-12 2024-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 109,670 -5,163 -4.50 101,390 7.45 0.0915
2024-08-01 2024-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 114,833 2,246 1.99 94,356 23.72 0.0887
2024-05-09 2024-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 112,587 2,253 2.04 76,269 9.59 0.0732
2024-02-08 2023-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 110,334 -202 -0.18 69,596 36.28 0.0729
2023-11-09 2023-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 110,536 3,335 3.11 51,068 -11.82 0.0593
2023-08-08 2023-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 107,201 1,051 0.99 57,913 109,169.81 0.0649
2023-05-11 2023-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 106,150 5,230 5.18 53 -99.85 0.0656
2023-02-14 2022-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 100,920 2,599 2.64 35,686 -0.12 0.0480
2022-11-10 2022-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 98,321 1,778 1.84 35,730 -3.63 0.0532
2022-08-11 2022-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 96,543 7,122 7.96 37,076 -14.63 0.0541
2022-05-12 2022-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 89,421 -2,018 -2.21 43,430 -3.72 0.0559
2022-02-10 2021-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 91,439 2,209 2.48 45,110 4.31 0.0553
2021-11-12 2021-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 89,230 7,431 9.08 43,248 41.57 0.0585
2021-08-05 2021-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 81,799 -4,532 -5.25 30,548 0.18 0.0401
2021-05-06 2021-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 86,331 -43,700 -33.61 30,493 -35.97 0.0414
2021-02-10 2020-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 130,031 -2,891 -2.17 47,621 28.13 0.0657
2020-11-12 2020-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 132,922 -12,211 -8.41 37,166 8.05 0.0582
2020-08-13 2020-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 145,133 11,265 8.42 34,397 53.43 0.0574
2020-05-06 2020-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 133,868 -6,738 -4.79 22,418 -10.44 0.0470
2020-02-05 2019-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 140,606 -300 -0.21 25,031 14.15 0.0419
2019-10-23 2019-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 140,906 -220 -0.16 21,929 14.44 0.0401
2019-08-14 2019-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 141,126 6,911 5.15 19,162 5.37 0.0360
2019-05-01 2019-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 134,215 21,568 19.15 18,185 38.87 0.0352
2019-01-31 2018-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 112,647 28,117 33.26 13,095 23.41 0.0285
2018-11-07 2018-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 84,530 -2,434 -2.80 10,611 -8.71 0.0205
2018-08-06 2018-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 86,964 4,150 5.01 11,624 21.25 0.0234
2018-05-02 2018-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 82,814 -4,623 -5.29 9,587 -2.41 0.0200
2018-02-09 2017-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 87,437 -7,117 -7.53 9,824 -2.49 0.0200
2017-11-06 2017-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 94,554 11,307 13.58 10,075 25.55 0.0219
2017-08-02 2017-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 83,247 532 0.64 8,025 5.34 0.0183
2017-05-02 2017-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 82,715 2,494 3.11 7,618 15.90 0.0178
2017-01-27 2016-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 80,221 3,096 4.01 6,573 5.86 0.0167
2016-11-08 2016-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 77,125 22,566 41.36 6,209 66.60 0.0171
2016-08-11 2016-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 54,559 1,300 2.44 3,727 9.97 0.0110
2016-05-02 2016-03-31 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 53,259 -155 -0.29 3,389 -0.41 0.0105
2016-02-03 2015-12-31 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 53,414 3,580 7.18 3,403 33.35 0.0110
2015-11-04 2015-09-30 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 49,834 1,796 3.74 2,552 4.76 0.0087
2015-08-04 2015-06-30 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 48,038 -1,270 -2.58 2,436 -6.16 0.0078
2015-05-12 2015-03-31 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 49,308 5,625 12.88 2,596 19.47 0.0075
2015-02-06 2014-12-31 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 43,683 -1,010 -2.26 2,173 10.36 0.0063
2014-11-12 2014-09-30 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 44,693 400 0.90 1,969 4.96 0.0059
2014-08-06 2014-06-30 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 44,293 -313 -0.70 1,876 8.50 0.0055
2014-05-06 2014-03-31 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 44,606 -1,460 -3.17 1,729 8.27 0.0051
2014-02-03 2013-12-31 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 46,066 10 0.02 1,597 14.48 0.0047
2013-11-05 2013-09-30 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 46,056 -652 -1.40 1,395 23.89 0.0043
2013-08-07 2013-06-30 13F MONOLITHIC POWER SYSTEMS INC C COM 609839105 46,708 46,708 1,126 0.0036
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.