Monolithic Power Systems, Inc.
MX ˙ BMV ˙ US6098391054
SecurityMX:MPWR / Monolithic Power Systems, Inc.
InstitutionVanguard Group Inc
Latest Disclosed Ownership5,939,946 shares
Ownership 12.40%
Vanguard Group Inc ownership in MPWR / Monolithic Power Systems, Inc.

2025-07-29 - Vanguard Group Inc has filed an SCHEDULE 13G/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 5,939,946 shares of Monolithic Power Systems, Inc. (MX:MPWR). This represents 12.4 percent ownership of the company. In their previous filing dated 2024-02-13 , Vanguard Group Inc had reported owning 5,464,066 shares, indicating an increase of 8.71 percent.

Institutional Ownership: 13D/G Filings

This table shows a history of the 13D/G filings made by the investor and/or investor group. Note that the share values in this table are not directly comparable to any numbers shown in the 13F table (if any).

File
Date		Effective
Date		Form Prev
Shares		 Latest
Shares		 ΔShares
(Percent)		 Ownership
(Percent)		 ΔOwnership
(Percent)
2025-07-29 2025-07-29 13G/A 5,464,066 5,939,946 8.71 12.40 8.77
2024-02-13 2024-02-13 13G/A 5,118,311 5,464,066 6.76 11.40 4.59
2023-02-09 2023-02-09 13G/A 4,794,054 5,118,311 6.76 10.90 4.81
2022-02-10 2022-02-10 13G/A 4,770,876 4,794,054 0.49 10.40 -0.57
2021-03-10 2021-03-10 13G/A 4,024,262 4,770,876 18.55 10.46 17.26
2021-02-10 2021-02-10 13G/A 3,838,037 4,024,262 4.85 8.92 1.02
2020-02-12 2020-02-12 13G/A 3,660,323 3,838,037 4.86 8.83 2.32
2019-02-11 2019-02-11 13G/A 3,378,642 3,660,323 8.34 8.63 6.15
2018-02-09 2018-02-09 13G/A 2,877,732 3,378,642 17.41 8.13 14.99
2017-02-10 2017-02-10 13G/A 2,731,287 2,877,732 5.36 7.07 2.32
2016-02-10 2016-02-10 13G/A 2,731,287 6.91
2015-02-11 2015-02-11 13G/A 2,473,498 6.38
2014-02-11 2014-02-11 13G/A 2,205,527 5.77
2013-02-12 2013-02-12 13G/A 1,975,506 5.56
2012-02-10 2012-02-10 13G 1,777,693 5.27

Important Note: One of the primary uses of the 13D/G filings is to evaluate the ability of a firm to control a company (ie, the "beneficial ownership"). To that end, firms are required to report not just direct holdings in companies, but indirect holdings that they control. For investment firms, these indirect holdings can include shares in funds they manage, advisory accounts, and in the case of activist campaigns, pledged votes. Therefore, share counts listed in 13D/G filings can differ significantly than share counts listed in 13F filings.

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)
2026-01-29 2025-12-31 13F MONOLITHIC PWR SYS COM 609839105 6,034,394 -39,639 -0.65 5,469,333 -2.19 0.0793
2025-11-07 2025-09-30 13F MONOLITHIC PWR SYS COM 609839105 6,074,033 134,087 2.26 5,591,998 28.72 0.0837
2025-08-11 2025-06-30 13F MONOLITHIC PWR SYS COM 609839105 5,939,946 19,277 0.33 4,344,358 26.51 0.0703
2025-05-09 2025-03-31 13F MONOLITHIC PWR SYS COM 609839105 5,920,669 96,395 1.66 3,433,870 -0.36 0.0621
2025-02-11 2024-12-31 13F MONOLITHIC PWR SYS COM 609839105 5,824,274 74,046 1.29 3,446,223 -35.17 0.0600
2024-11-13 2024-09-30 13F MONOLITHIC PWR SYS COM 609839105 5,750,228 55,132 0.97 5,316,086 13.60 0.0952
2024-08-13 2024-06-30 13F MONOLITHIC PWR SYS COM 609839105 5,695,096 175,156 3.17 4,679,546 25.14 0.0899
2024-05-10 2024-03-31 13F MONOLITHIC PWR SYS COM 609839105 5,519,940 55,874 1.02 3,739,318 8.49 0.0741
2024-03-11 2023-12-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 5,464,066 90,589 1.69 3,446,624 38.83 0.0753
2024-02-14 2023-12-31 13F MONOLITHIC PWR SYS COM 609839105 5,464,066 90,589 3,446,624 0.0654
2023-12-18 2023-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 5,373,477 123,946 2.36 2,482,546 -12.46 0.0610
2023-11-14 2023-09-30 13F MONOLITHIC PWR SYS COM 609839105 5,373,477 123,946 2,482,546 0.0110
2023-08-14 2023-06-30 13F MONOLITHIC PWR SYS COM 609839105 5,249,531 101,846 1.98 2,835,954 10.06 0.0672
2023-07-14 2023-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 5,147,685 29,374 0.57 2,576,622 42.36 0.0656
2023-05-15 2023-03-31 13F MONOLITHIC PWR SYS COM 609839105 5,147,685 29,374 2,576,622 0.0656
2023-02-10 2022-12-31 13F MONOLITHIC PWR SYS COM 609839105 5,118,311 34,143 0.67 1,809,886 -2.04 0.0493
2022-11-14 2022-09-30 13F MONOLITHIC PWR SYS COM 609839105 5,084,168 130,675 2.64 1,847,587 -2.88 0.0543
2022-08-12 2022-06-30 13F MONOLITHIC PWR SYS COM 609839105 4,953,493 80,530 1.65 1,902,340 -19.62 0.0535
2022-05-13 2022-03-31 13F MONOLITHIC PWR SYS COM 609839105 4,872,963 78,909 1.65 2,366,701 0.07 0.0560
2022-02-14 2021-12-31 13F MONOLITHIC PWR SYS COM 609839105 4,794,054 21,742 0.46 2,365,050 2.25 0.0537
2021-11-12 2021-09-30 13F MONOLITHIC PWR SYS COM 609839105 4,772,312 -78,355 -1.62 2,313,044 27.69 0.0574
2021-08-13 2021-06-30 13F MONOLITHIC PWR SYS COM 609839105 4,850,667 25,957 0.54 1,811,481 6.30 0.0451
2021-05-14 2021-03-31 13F MONOLITHIC PWR SYS COM 609839105 4,824,710 800,448 19.89 1,704,135 15.63 0.0461
2021-02-12 2020-12-31 13F MONOLITHIC PWR SYS COM 609839105 4,024,262 157,592 4.08 1,473,805 36.32 0.0427
2020-11-16 2020-09-30 13F MONOLITHIC PWR SYS COM 609839105 3,866,670 -143,771 -3.58 1,081,159 13.75 0.0358
2020-08-14 2020-06-30 13F MONOLITHIC PWR SYS COM 609839105 4,010,441 78,686 2.00 950,475 44.36 0.0337
2020-05-15 2020-03-31 13F MONOLITHIC PWR SYS COM 609839105 3,931,755 93,718 2.44 658,411 -3.64 0.0281
2020-02-14 2019-12-31 13F MONOLITHIC PWR SYS COM 609839105 3,838,037 31,771 0.83 683,248 15.34 0.0233
2019-11-14 2019-09-30 13F MONOLITHIC PWR SYS COM 609839105 3,806,266 123,143 3.34 592,369 18.45 0.0220
2019-08-14 2019-06-30 13F MONOLITHIC PWR SYS COM 609839105 3,683,123 105,831 2.96 500,094 3.18 0.0188
2019-05-15 2019-03-31 13F MONOLITHIC PWR SYS COM 609839105 3,577,292 -83,031 -2.27 484,688 13.91 0.0190
2019-02-14 2018-12-31 13F MONOLITHIC PWR SYS COM 609839105 3,660,323 106,795 3.01 425,513 -4.61 0.0191
2018-12-13 2018-09-30 13F/A-2 MONOLITHIC PWR SYS COM 609839105 3,553,528 208,362 6.23 446,074 -0.24 0.0174
2018-11-23 2018-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 3,553,528 0 446,074 0.0174
2018-11-14 2018-09-30 13F MONOLITHIC PWR SYS COM 609839105 3,553,528 208,362 446,074
2018-08-14 2018-06-30 13F MONOLITHIC PWR SYS COM 609839105 3,345,166 22,077 0.66 447,149 16.23 0.0187
2018-05-15 2018-03-31 13F MONOLITHIC PWR SYS COM 609839105 3,323,089 -55,553 -1.64 384,715 1.34 0.0168
2018-02-14 2017-12-31 13F MONOLITHIC PWR SYS COM 609839105 3,378,642 191,987 6.02 379,624 11.81 0.0166
2017-11-14 2017-09-30 13F MONOLITHIC PWR SYS COM 609839105 3,186,655 68,117 2.18 339,538 12.94 0.0159
2017-08-24 2017-06-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 3,118,538 85,754 2.83 300,627 7.63 0.0148
2017-08-11 2017-06-30 13F MONOLITHIC PWR SYS COM 609839105 3,118,538 85,754 300,627
2017-05-12 2017-03-31 13F MONOLITHIC PWR SYS COM 609839105 3,032,784 155,052 5.39 279,320 18.47 0.0144
2017-02-14 2016-12-31 13F MONOLITHIC PWR SYS COM 609839105 2,877,732 104,052 3.75 235,772 5.59 0.0132
2016-11-14 2016-09-30 13F MONOLITHIC PWR SYS COM 609839105 2,773,680 -151,223 -5.17 223,282 11.74 0.0131
2016-08-10 2016-06-30 13F MONOLITHIC PWR SYS COM 609839105 2,924,903 105,377 3.74 199,829 11.37 0.0124
2016-05-13 2016-03-31 13F MONOLITHIC PWR SYS COM 609839105 2,819,526 88,239 3.23 179,434 3.12 0.0116
2016-02-08 2015-12-31 13F MONOLITHIC PWR SYS COM 609839105 2,731,287 52,108 1.94 174,011 26.85 0.0117
2015-11-12 2015-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 2,679,179 61,805 2.36 137,174 3.35 0.0058
2015-11-12 2015-09-30 13F/A-1 MONOLITHIC PWR SYS COM 609839105 2,679,179 61,805 137,174 0.0058
2015-08-13 2015-06-30 13F MONOLITHIC PWR SYS COM 609839105 2,617,374 98,661 3.92 132,727 0.09 0.0090
2015-05-15 2015-03-31 13F/A-1 MONOLITHIC PWR SYS COM 609839105 2,518,713 45,215 1.83 132,610 7.78 0.0090
2015-05-14 2015-03-31 13F MONOLITHIC PWR SYS COM 609839105 2,518,713 132,610
2015-02-12 2014-12-31 13F MONOLITHIC PWR SYS COM 609839105 2,473,498 26,498 1.08 123,032 14.14 0.0089
2014-11-12 2014-09-30 13F MONOLITHIC PWR SYS COM 609839105 2,447,000 21,444 0.88 107,790 4.93 0.0084
2014-08-11 2014-06-30 13F MONOLITHIC PWR SYS COM 609839105 2,425,556 125,821 5.47 102,722 15.21 0.0081
2014-05-13 2014-03-31 13F MONOLITHIC PWR SYS COM 609839105 2,299,735 94,208 4.27 89,161 16.64 0.0075
2014-02-12 2013-12-31 13F MONOLITHIC PWR SYS COM 609839105 2,205,527 120,655 5.79 76,444 21.09 0.0067
2013-11-07 2013-09-30 13F MONOLITHIC PWR SYS COM 609839105 2,084,872 121,188 6.17 63,131 33.34 0.0062
2013-08-13 2013-06-30 13F MONOLITHIC PWR SYS COM 609839105 1,963,684 1,963,684 47,345 0.0050
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.