Ticker · CUSIP 609839105

MPWR

MONOLITHIC PWR SYS INC

Technology·Semiconductors

···Share

Holders (tracked)

Combined shares

3,139,526

Combined value

$2.85B

Last close

$1468.35

Quarter

2025Q4

Price is +62.0% vs the avg quarter-end implied price across tracked holders.

Price · 1Y$1468+948.72 (+182.58%)H $1468 · L $504.36 · Avg Vol 621K

Insider sellCongress buy

Tracked holders · last 8 quarters

+6 vs previous quarter over the last 8.

SEC event timeline

30 events

Tseng Saria · EVP & General Counsel
2026-04-08
Sold $709.2K @ $1266.48
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $457.3K @ $1270.29
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $307.1K @ $1279.55
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $154.5K @ $1287.12
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $516.8K @ $1292.08
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $1.04M @ $1302.52
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $1.67M @ $1308.30
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $5.57M @ $1312.82
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $1.11M @ $1319.25
Insider sell
Tseng Saria · EVP & General Counsel
2026-04-08
Sold $158.6K @ $1321.94
Insider sell
Ron Baron (Baron Capital / BAMCO) added2026-02-17
+17,031 shares · 2025Q4
Position
Ken Griffin (Citadel Advisors) trimmed2026-02-17
−249,237 shares · 2025Q4
Position
D.E. Shaw & Co. trimmed2026-02-17
−106 shares · 2025Q4
Position
AQR Capital Management added2026-02-17
+8,573 shares · 2025Q4
Position
Two Sigma Investments opened position2026-02-17
+2,000 shares · 2025Q4
Position
Izzy Englander (Millennium Mgmt) trimmed2026-02-17
−145,811 shares · 2025Q4
Position
Steve Cohen (Point72) added2026-02-17
+11,900 shares · 2025Q4
Position
T. Rowe Price added2026-02-17
+117,596 shares · 2025Q4
Position
Wellington Management trimmed2026-02-17
−68,168 shares · 2025Q4
Position
Jeremy Grantham (GMO) added2026-02-17
+79 shares · 2025Q4
Position
Paul Tudor Jones (Tudor Investment) opened position2026-02-17
+4,100 shares · 2025Q4
Position
Ray Dalio (Bridgewater Associates) opened position2026-02-13
+2,871 shares · 2025Q4
Position
Renaissance Technologies exited2026-02-12
−8,086 shares · 2025Q4
Position
Norges Bank (Norway SWF) opened position2026-02-10
+726,705 shares · 2025Q4
Position
Ken Fisher (Fisher Asset Mgmt) opened position2026-02-09
+238 shares · 2025Q4
Position
AQR Capital Management trimmed2025-11-14
−3,739 shares · 2025Q3
Position
Izzy Englander (Millennium Mgmt) added2025-11-14
+154,958 shares · 2025Q3
Position
D.E. Shaw & Co. trimmed2025-11-14
−3,973 shares · 2025Q3
Position
T. Rowe Price trimmed2025-11-14
−515,006 shares · 2025Q3
Position
Wellington Management trimmed2025-11-14
−250,213 shares · 2025Q3
Position

Insider activity

Last 30 days

Net (open-market)

−$11.70M

Buys

0 · $0

Sells

10 · $11.70M

Unique insiders

Date	Insider	Code	Shares	Price	Value
04-08	Tseng Saria EVP & General Counsel · Insider	S	560	$1266.48	$709.2K
04-08	Tseng Saria EVP & General Counsel · Insider	S	360	$1270.29	$457.3K
04-08	Tseng Saria EVP & General Counsel · Insider	S	240	$1279.55	$307.1K
04-08	Tseng Saria EVP & General Counsel · Insider	S	120	$1287.12	$154.5K
04-08	Tseng Saria EVP & General Counsel · Insider	S	400	$1292.08	$516.8K
04-08	Tseng Saria EVP & General Counsel · Insider	S	800	$1302.52	$1.04M
04-08	Tseng Saria EVP & General Counsel · Insider	S	1,279	$1308.30	$1.67M
04-08	Tseng Saria EVP & General Counsel · Insider	S	4,244	$1312.82	$5.57M
04-08	Tseng Saria EVP & General Counsel · Insider	S	840	$1319.25	$1.11M
04-08	Tseng Saria EVP & General Counsel · Insider	S	120	$1321.94	$158.6K

View full insider history for MPWR →

Follow-the-investor returns

If you'd copied each holder of MPWR…

Cost basis inferred from each manager's quarter-over-quarter position changes. Sorted by % return on the position they're still holding.

Investor	First in	Cost basis	Return	Position value today
Two Sigma Investments	2016Q1	$448.05	+227.7%	$1.5M
Two Sigma Investments	2016Q1	$448.05	+227.7%	$1.5M
Ray Dalio (Bridgewater Associates)	2020Q3	$454.26	+223.2%	$4.2M
Wellington Management	2016Q1	$504.59	+191.0%	$565.0M
T. Rowe Price	2016Q1	$518.15	+183.4%	$2.48B
Ron Baron (Baron Capital / BAMCO)	2021Q2	$643.55	+128.2%	$95.8M
Paul Tudor Jones (Tudor Investment)	2018Q2	$648.97	+126.3%	$1.5M
Paul Tudor Jones (Tudor Investment)	2018Q2	$648.97	+126.3%	$1.5M
AQR Capital Management	2016Q1	$680.91	+115.6%	$68.0M
Steve Cohen (Point72)	2018Q4	$867.67	+69.2%	$10.4M
Steve Cohen (Point72)	2018Q4	$867.67	+69.2%	$10.4M
Ken Griffin (Citadel Advisors)	2016Q3	$897.21	+63.7%	$16.5M
Ken Griffin (Citadel Advisors)	2016Q3	$897.21	+63.7%	$16.5M
Ken Griffin (Citadel Advisors)	2016Q3	$897.21	+63.7%	$16.5M
Izzy Englander (Millennium Mgmt)	2017Q1	$905.77	+62.1%	$7.3M
Izzy Englander (Millennium Mgmt)	2017Q1	$905.77	+62.1%	$7.3M
Izzy Englander (Millennium Mgmt)	2017Q1	$905.77	+62.1%	$7.3M
D.E. Shaw & Co.	2016Q1	$906.47	+62.0%	$52.6M
D.E. Shaw & Co.	2016Q1	$906.47	+62.0%	$52.6M
D.E. Shaw & Co.	2016Q1	$906.47	+62.0%	$52.6M
Ken Fisher (Fisher Asset Mgmt)	2025Q4	$907.74	+61.8%	$349K
Jeremy Grantham (GMO)	2025Q3	$919.88	+59.6%	$2.2M
Norges Bank (Norway SWF)	2016Q1	$10415.92	-85.9%	$1.07B

Who moved on this name in 2025Q4

Position changes reported for the latest quarter, grouped by direction.

New positions5

Norges Bank (Norway SWF)
+726,705
$658.7M
Paul Tudor Jones (Tudor Investment)
+4,100
$3.7M
Ray Dalio (Bridgewater Associates)
+2,871
$2.6M
Two Sigma Investments
+2,000
$1.8M
Ken Fisher (Fisher Asset Mgmt)
+238
$216K

Added to5

Ron Baron (Baron Capital / BAMCO)
+17,031
$15.4M
Steve Cohen (Point72)
+11,900
$10.8M
AQR Capital Management
+8,573
$7.8M
T. Rowe Price
+117,596
$107K
Jeremy Grantham (GMO)
+79
$72K

Trimmed4

Ken Griffin (Citadel Advisors)
−249,237
$225.9M
Izzy Englander (Millennium Mgmt)
−145,811
$132.2M
Wellington Management
−68,168
$61.8M
D.E. Shaw & Co.
−106
$96K

Exited1

Renaissance Technologies
−8,086
$7.4M

Institutional ownership over time

Distinct super-investors holding this ticker · combined dollar value, by quarter.

Quarter	Holders	Shares	Combined value	Δ holders
2022Q1	17	9,883,839	$195.84B	—
2022Q2	18	9,336,465	$163.84B	+1
2022Q3	22	9,633,282	$3.51B	+4
2022Q4	19	10,750,997	$3.80B	-3
2023Q1	16	10,391,808	$5.20B	-3
2023Q2	15	9,660,742	$5.22B	-1
2023Q3	21	8,152,958	$3.77B	+6
2023Q4	14	8,379,687	$5.29B	-7
2024Q1	15	9,574,941	$6.49B	+1
2024Q2	18	9,733,705	$8.00B	+3
2024Q3	16	3,823,621	$3.53B	-2
2024Q4	17	3,003,163	$1.78B	+1
2025Q1	18	3,587,692	$2.08B	+1
2025Q2	17	3,687,615	$2.70B	-1
2025Q3	17	2,712,241	$2.50B	—
2025Q4	23	3,139,526	$2.85B	+6

Congress members trading this stock

Date	Member	Type	Amount range	Filing
2025-10-20	Michael Patrick Guest	Buy	$1K – $15K	PDF ↗
2025-04-08	Rob Bresnahan	Buy	$1K – $15K	PDF ↗
2025-01-13	Rob Bresnahan	Sell	$1K – $15K	PDF ↗

Who owns MPWR

23 super-investors · 2025Q4

Tracked stake

3.14M

Combined value

$2.85B

% of shares outstanding

—

shares-out unknown

Quarter action mix

New7Added6Trim10

#	Manager	Shares	Value	% of book	Last action	8Q trend
1	T. Rowe Price	1.69M	$1.53B	0.2%	Added+117.6K
2	Norges Bank Norway SWF	726.7K	$659M	0.1%	New+726.7K
3	Wellington Management	384.8K	$349M	0.1%	Trim−68.2K
4	Ron Baron Baron Capital / BAMCO	65.2K	$59M	0.2%	Added+17.0K
5	Ken Griffin Citadel Advisors	63.8K	$58M	0.0%	Trim−249.2K
6	AQR Capital Management	46.3K	$42M	0.0%	Added+8.6K
7	Ken Griffin Citadel Advisors	44.5K	$40M	0.0%	Trim−249.2K
8	D.E. Shaw & Co.	35.8K	$32M	0.0%	Trim−106
9	Izzy Englander Millennium Mgmt	24.7K	$22M	0.0%	Trim−145.8K
10	Ken Griffin Citadel Advisors	11.2K	$10M	0.0%	Trim−249.2K
11	Steve Cohen Point72	10.4K	$9M	0.0%	Added+11.9K
12	Izzy Englander Millennium Mgmt	10.1K	$9M	0.0%	Trim−145.8K
13	Steve Cohen Point72	7.1K	$6M	0.0%	Added+11.9K
14	Izzy Englander Millennium Mgmt	5.0K	$5M	0.0%	Trim−145.8K
15	Paul Tudor Jones Tudor Investment	3.1K	$3M	0.0%	New+4.1K
16	Ray Dalio Bridgewater Associates	2.9K	$3M	0.0%	New+2.9K
17	Jeremy Grantham GMO	1.5K	$1M	0.0%	Added+79
18	D.E. Shaw & Co.	1.3K	$1M	0.0%	Trim−106
19	Paul Tudor Jones Tudor Investment	1.0K	$906K	0.0%	New+4.1K
20	Two Sigma Investments	1.0K	$906K	0.0%	New+2.0K
21	Two Sigma Investments	1.0K	$906K	0.0%	New+2.0K
22	D.E. Shaw & Co.	500	$453K	0.0%	Trim−106
23	Ken Fisher Fisher Asset Mgmt	238	$216K	0.0%	New+238	—

Recent moves

20 transactions

ADDRon Baron (Baron Capital / BAMCO)
+17,031 · 2025Q4
ADDSteve Cohen (Point72)
+11,900 · 2025Q4
ADDT. Rowe Price
+117,596 · 2025Q4
ADDJeremy Grantham (GMO)
+79 · 2025Q4
TRIMD.E. Shaw & Co.
−106 · 2025Q4
ADDAQR Capital Management
+8,573 · 2025Q4
TRIMKen Griffin (Citadel Advisors)
−249,237 · 2025Q4
NEWTwo Sigma Investments
+2,000 · 2025Q4
TRIMWellington Management
−68,168 · 2025Q4
NEWPaul Tudor Jones (Tudor Investment)
+4,100 · 2025Q4
TRIMIzzy Englander (Millennium Mgmt)
−145,811 · 2025Q4
NEWRay Dalio (Bridgewater Associates)
+2,871 · 2025Q4
SOLDRenaissance Technologies
−8,086 · 2025Q4
NEWNorges Bank (Norway SWF)
+726,705 · 2025Q4
NEWKen Fisher (Fisher Asset Mgmt)
+238 · 2025Q4
ADDIzzy Englander (Millennium Mgmt)
+154,958 · 2025Q3
TRIMD.E. Shaw & Co.
−3,973 · 2025Q3
TRIMT. Rowe Price
−515,006 · 2025Q3
TRIMWellington Management
−250,213 · 2025Q3
TRIMRon Baron (Baron Capital / BAMCO)
−2,824 · 2025Q3

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