Monolithic Power Systems, Inc.
US ˙ NasdaqGS ˙ US6098391054

SecurityMPWR / Monolithic Power Systems, Inc.
InstitutionLord, Abbett & Co. Llc
Latest Disclosed Ownership121,847 shares
Latest Disclosed Value $ 133,221
Lord, Abbett & Co. Llc reports 1,074.43% increase in ownership of MPWR / Monolithic Power Systems, Inc.

On May 14, 2026 - Lord, Abbett & Co. Llc filed a 13F-HR form disclosing ownership of 121,847 shares of Monolithic Power Systems, Inc. (US:MPWR) valued at $133,221,417 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 10,375 shares of Monolithic Power Systems, Inc.. This represents a change in shares of 1,074.43% during the quarter. The current value of the position is $180,461,499 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)
2026-05-14 2026-03-31 13F MONOLITHIC PWR SYS COM 609839105 121,847 111,472 1,074.43 133 1,377.78 0.4349
2026-02-13 2025-12-31 13F MONOLITHIC PWR SYS COM 609839105 10,375 -13,125 -55.85 9 -57.14 0.0288
2025-11-13 2025-09-30 13F MONOLITHIC PWR SYS COM 609839105 23,500 23,500 22 0.0644
2025-02-14 2024-12-31 13F Monolithic Power Systems COM 609839105 0 -125,515 -100.00 0 -100.00
2024-12-13 2024-09-30 13F/A-1 Monolithic Power Systems COM 609839105 125,515 -91,766 -42.23 116 -34.83 0.3693
2024-11-14 2024-09-30 13F Monolithic Power Systems COM 609839105 125,515 -91,766 116 0.3741
2024-10-07 2024-06-30 13F/A-1 Monolithic Power Systems COM 609839105 217,281 53,735 32.86 179 61.82 0.5841
2024-08-14 2024-06-30 13F Monolithic Power Systems COM 609839105 217,281 53,735 179 0.5963
2024-10-07 2024-03-31 13F/A-1 Monolithic Power Systems COM 609839105 163,546 -2,529 -1.52 111 5.77 0.3576
2024-05-09 2024-03-31 13F Monolithic Power Systems COM 609839105 163,546 -2,529 111 0.3641
2024-10-07 2023-12-31 13F/A-1 Monolithic Power Systems COM 609839105 166,075 63,136 61.33 105 121.28 0.3676
2024-02-12 2023-12-31 13F Monolithic Power Systems COM 609839105 166,075 63,136 105 0.3762
2024-10-07 2023-09-30 13F/A-1 Monolithic Power Systems COM 609839105 102,939 -53,923 -34.38 48 -44.05 0.1768
2023-11-13 2023-09-30 13F Monolithic Power Systems COM 609839105 102,939 -53,923 48 0.1782
2024-10-07 2023-06-30 13F/A-1 Monolithic Power Systems COM 609839105 156,862 -74,774 -32.28 85 -26.96 0.2917
2023-08-14 2023-06-30 13F Monolithic Power Systems COM 609839105 156,862 -74,774 85 0.2918
2024-10-07 2023-03-31 13F/A-1 Monolithic Power Systems COM 609839105 231,636 45,668 24.56 116 76.92 0.4180
2023-05-12 2023-03-31 13F Monolithic Power Systems COM 609839105 231,636 45,668 116 0.4187
2024-10-07 2022-12-31 13F/A-1 Monolithic Power Systems COM 609839105 185,968 -1,689 -0.90 66 -99.90 0.2350
2023-02-10 2022-12-31 13F Monolithic Power Systems COM 609839105 185,968 -1,689 66 0.2355
2022-11-14 2022-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 187,657 -147,575 -44.02 68,195 -47.03 0.2491
2022-08-12 2022-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 335,232 2,591 0.78 128,742 -20.31 0.4552
2022-05-13 2022-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 332,641 -2,004 -0.60 161,557 -2.14 0.4307
2022-02-11 2021-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 334,645 807 0.24 165,090 2.03 0.3761
2021-11-09 2021-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 333,838 -20,667 -5.83 161,805 22.22 0.3871
2021-08-11 2021-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 354,505 53,169 17.64 132,390 24.39 0.3192
2021-05-11 2021-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 301,336 -155,921 -34.10 106,435 -36.44 0.2712
2021-02-09 2020-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 457,257 -19,793 -4.15 167,461 25.54 0.4423
2020-11-12 2020-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 477,050 -76,663 -13.85 133,388 1.64 0.4257
2020-08-14 2020-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 553,713 -18,443 -3.22 131,230 36.96 0.4592
2020-05-14 2020-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 572,156 197,077 52.54 95,813 43.49 0.4245
2020-02-14 2019-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 375,079 11,895 3.28 66,772 18.13 0.2227
2019-11-14 2019-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 363,184 234,919 183.15 56,522 224.54 0.1924
2019-08-14 2019-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 128,265 -63,264 -33.03 17,416 -32.89 0.0566
2019-05-15 2019-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 191,529 -28,968 -13.14 25,950 1.24 0.0864
2019-02-14 2018-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 220,497 -22,473 -9.25 25,633 -15.96 0.0936
2018-11-14 2018-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 242,970 -83,543 -25.59 30,500 -30.12 0.0845
2018-08-14 2018-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 326,513 -13,705 -4.03 43,645 10.81 0.1276
2018-05-15 2018-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 340,218 -27,816 -7.56 39,387 -4.75 0.1170
2018-02-14 2017-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 368,034 -33,197 -8.27 41,352 -3.27 0.1176
2017-11-14 2017-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 401,231 -30,994 -7.17 42,751 2.60 0.1248
2017-08-24 2017-06-30 13F/A-1 MONOLITHIC PWR SYS INC COM COM 609839105 432,225 -20,543 -4.54 41,666 -0.08 0.1238
2017-08-14 2017-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 432,225 -20,543 41,666
2017-05-15 2017-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 452,768 -45,538 -9.14 41,700 2.14 0.1248
2017-02-14 2016-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 498,306 64,301 14.82 40,826 16.86 0.1239
2016-11-10 2016-09-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 434,005 -31,891 -6.85 34,937 9.76 0.1065
2016-08-12 2016-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 465,896 879 0.19 31,830 7.56 0.0997
2016-05-16 2016-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 465,017 136,594 41.59 29,594 41.44 0.0931
2016-02-16 2015-12-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 328,423 328,423 0.00 20,924 0.0629
2015-08-14 2015-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 0 -471,363 -100.00 0 -100.00
2015-05-15 2015-03-31 13F MONOLITHIC PWR SYS INC COM COM 609839105 471,363 471,363 0.00 24,817 0.0628
2015-02-13 2014-12-31 13F Monolithic Power Systems COM 609839105 0 -117,639 -100.00 0 -100.00
2014-11-14 2014-09-30 13F Monolithic Power Systems COM 609839105 117,639 -35,320 -23.09 5,182 -20.01 0.0130
2014-08-20 2014-06-30 13F/A-1 MONOLITHIC PWR SYS INC COM COM 609839105 152,959 480 0.31 6,478 9.57 0.0147
2014-08-14 2014-06-30 13F MONOLITHIC PWR SYS INC COM COM 609839105 152,959 6,478
2014-05-15 2014-03-31 13F MONOLITHIC PWR SYS COM 609839105 152,479 -54,607 -26.37 5,912 -17.64 0.0135
2014-03-05 2013-12-31 13F/A-1 Monolithic Power Systems COM 609839105 207,086 12,452 6.40 7,178 21.78 0.0160
2014-02-14 2013-12-31 13F Monolithic Power Systems COM 609839105 207,086 7,178
2013-11-14 2013-09-30 13F Monolithic Power Systems COM 609839105 194,634 194,634 5,894 0.0136
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.