MPWR
MONOLITHIC POWER SYSTEMS INC · Technology · Market cap $63.1B
Insiders sold $61.0M net in the last 90 days ·4 sellers, 0 buyers· 4 of 9 sales under Rule 10b5-1 plans· latest Form 4 filed Sep 30, 2026
Insider Buying
$0
reported purchases (SEC code P)
Insider Selling
$729.1M
reported sales (SEC code S)
Unique Insiders
11
in the rolling window
Latest filing
Sep 30, 2026
Hsing Michael
MONOLITHIC POWER SYSTEMS INC (MPWR) has 86 SEC Form 4 filings (351 transaction rows) in the rolling window, disclosed by 11 distinct insiders. Most recent filing: Sep 30, 2026.
Inside the rolling window, 11 insiders at MONOLITHIC POWER SYSTEMS INC reported no open-market purchases and 56 open-market sales totaling $729.1M. The most active filer is EVP, WW Sales & Marketing Sciammas Maurice with 14 filings. Insiders have net sold $253.6M over the trailing 6 months. The most recent open-market filing is a sale of 30,000 shares by CEO Hsing Michael, dated Sep 28, 2026, worth $40.3M.
- Industry:Semiconductors
- CEO:Michael R. Hsing
- Employees:4,501
- HQ:West Palm Beach, FL, US
- IPO:2004-11-19
| Source | |||||||
|---|---|---|---|---|---|---|---|
Hsing MichaelFirst in 4 months | CEO | Sale | 30,000 | $40.3M | Sep 30 | -4.7% | SEC ↗ |
| Interim CFO | Sale | 32 | $42K | Aug 26 | -1.6% | SEC ↗ | |
| Director | Sale | 50 | $64K | Aug 25 | -1.6% | SEC ↗ | |
| Interim CFO | Sale | 6 | $8K | Aug 20 | — | SEC ↗ | |
CHANG KUO WEI HERBERTFirst in 9 months | Director | Sale | 50 | $71K | Aug 13 | — | SEC ↗ |
| Interim CFO | Sale | 105 | $141K | Aug 6 | — | SEC ↗ | |
| EVP, WW Sales & Marketing | Sale | 30 | $40K | Aug 5 | — | SEC ↗ | |
| EVP, WW Sales & Marketing | Sale | 15,000 | $20.2M | Jul 17 | — | SEC ↗ | |
| EVP, WW Sales & Marketing | Sale | 30 | $41K | Jul 6 | — | SEC ↗ | |
| EVP, WW Sales & Marketing | Sale | 30 | $46K | Jun 3 | — | SEC ↗ | |
| EVP & General Counsel | Sale | 7,565 | $12.9M | May 29 | — | SEC ↗ | |
| Interim CFO | Sale | 22 | $36K | May 28 | — | SEC ↗ | |
| Director | Sale | 486 | $816K | May 27 | — | SEC ↗ | |
| EVP & General Counsel | Sale | 5,000 | $7.9M | May 27 | — | SEC ↗ | |
DEAN ROBERT W IIFirst filing | Interim CFO | Sale | 4 | $6K | May 20 | — | SEC ↗ |
Hsing MichaelFirst in 3 months | CEO | Sale | 40,000 | $59.3M | May 20 | — | SEC ↗ |
| EVP, WW Sales & Marketing | Sale | 12,000 | $18.7M | May 19 | — | SEC ↗ | |
Elmiger Eugen JFirst filing | Director | Sale | 12,000 | $19.0M | May 8 | — | SEC ↗ |
| EVP, Global Operations | Sale | 30,000 | $49.6M | May 8 | — | SEC ↗ | |
Wynne EileenFirst filing | Director | Sale | 335 | $530K | May 8 | — | SEC ↗ |
Zhou JeffFirst filing | Director | Sale | 1,014 | $1.6M | May 6 | — | SEC ↗ |
Zhou JeffFirst filing | Director | Sale | 500 | $825K | May 6 | — | SEC ↗ |
| EVP, WW Sales & Marketing | Sale | 380 | $602K | May 6 | — | SEC ↗ | |
| EVP, WW Sales & Marketing | Sale | 30 | $48K | May 6 | — | SEC ↗ | |
| EVP & General Counsel | Sale | 8,963 | $11.7M | Apr 10 | — | SEC ↗ |
Earnings: last 7 quarters
Congress trading MPWR 34 all-time
- RRep. Byron DonaldsSale$1,001 - $15,0002026-06-05
- RRep. Byron DonaldsSale$1,001 - $15,0002026-06-05
- RSen. Markwayne MullinPurchase$15,001 - $50,0002026-02-04
- DRep. Ro KhannaSale$1,001 - $15,0002026-01-29
- RSen. Markwayne MullinPurchase$15,001 - $50,0002026-01-05
- RSen. Markwayne MullinPurchase$15,001 - $50,0002026-01-05
STOCK Act disclosures are filed up to 45 days after the trade. Amount is a disclosed range, not an exact figure.
Frequently asked questions
How many SEC Form 4 insider filings does MPWR have?
MONOLITHIC POWER SYSTEMS INC (MPWR) has 86 SEC Form 4 filings (351 transaction rows) in the rolling 365-day window, disclosed by 11 distinct insiders. Most recent filing: Sep 30, 2026.
When was the most recent SEC Form 4 filing for MPWR?
The most recent Form 4 filing for MPWR on Tracefour is dated Sep 30, 2026.
Who is the most active insider at MPWR?
The most active SEC Form 4 filer at MPWR in the rolling window is EVP, WW Sales & Marketing Sciammas Maurice, with 14 filings.
What is the net insider flow at MPWR over the last 6 months?
Over the trailing 180 days, insiders at MPWR have net sold $253.6M based on SEC Form 4 disclosures.
What is the total insider buy and sell value at MPWR in the current window?
Inside the rolling window, insiders at MPWR bought $0 and sold $729.1M based on SEC Form 4 filings.
Can I get alerts for MPWR insider trading?
Yes. Tracefour sends a free email when a new SEC Form 4 purchase or sale is filed at MONOLITHIC POWER SYSTEMS INC (MPWR). Alerts are set per company from the page itself, there is no paid tier, and each email links to the original filing on SEC EDGAR.
Related companies
MONOLITHIC POWER SYSTEMS INC is in the Technology sector.