MPWR · Insider Trading

Monolithic Power Systems, Inc.

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Every open-market purchase and sale reported by MPWR officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.

Form 4 Filings

most recent

Open-Market Buys

code P

Sales

code S

Reporting Insiders

current holders

MPWR — Recent Form 4 Transactions (latest 2026-09-30)

Filed	Insider	Role	Type	Shares	Value
2026-09-30	Michael Hsing	CEO	Sell	−30,000	−$40.35M
2026-09-02	Saria Tseng	EVP & General Counsel	G	—	—
2026-08-26	Robert W Dean II	Interim CFO	MIXED	−37	−$41.53K
2026-08-25	Kuo Wei Herbert Chang	Director	Sell	−50	−$64.08K
2026-08-19	Robert W Dean II	Interim CFO	Sell	−6	−$8.48K
2026-08-13	Kuo Wei Herbert Chang	Director	Sell	−50	−$71.00K
2026-08-06	Robert W Dean II	Interim CFO	Sell	−105	−$141.15K
2026-08-06	Maurice Sciammas	EVP, WW Sales & Marketing	G	—	—
2026-08-06	Robert W Dean II	Interim CFO	Sell	−105	−$141.15K
2026-08-06	Maurice Sciammas	EVP, WW Sales & Marketing	G	—	—
2026-08-05	Maurice Sciammas	EVP, WW Sales & Marketing	Sell	−30	−$40.32K
2026-07-28	Robert W Dean II	Interim CFO	A	+1,359	—
2026-07-17	Maurice Sciammas	EVP, WW Sales & Marketing	Sell	−15,000	−$20.25M
2026-07-06	Maurice Sciammas	EVP, WW Sales & Marketing	Sell	−30	−$40.55K

MPWR — Current Insider Holders

Insider	Role	Shares Held	Value
Michael Hsing	CEO	978,587	$1.14B
Saria Tseng	EVP & General Counsel	143,218	$167.27M
Maurice Sciammas	EVP, WW Sales & Marketing	128,343	$149.90M
Robert W Dean II	Interim CFO	7,154	$8.36M
Kuo Wei Herbert Chang	Director	515	$601.48K

MPWR Insider Trading FAQ

Who are the insiders at MPWR?

5 officers, directors and 10%+ beneficial owners currently report holdings in MPWR via SEC Form 4.

Are MPWR insiders buying or selling?

Across the 14 most recent Form 4 filings for MPWR, 0 were open-market purchases (code P) and 9 were sales (code S). Sales frequently reflect scheduled 10b5-1 plans or tax withholding rather than a view on the stock.

How current is MPWR insider data?

Form 4 must be filed within two business days of the transaction, so this is close to real time. The most recent MPWR filing is dated 2026-09-30.

How to read Form 4 activity

Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.

Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.

Full filing history and per-insider positions are on the MPWR quote page; the site-wide leaderboard is on the insider transactions hub.