LYTIR

Company · MPWR

Monolithic Power Systems, Inc.

Name as listed on its exchange; filed with the SEC as MONOLITHIC POWER SYSTEMS, INC.

Nasdaq's symbol directory lists MPWR on Nasdaq as “Monolithic Power Systems, Inc. - Common Stock”.

In the 12 months to Nov 8, 2026: insiders sold on 9 occasions ($41.4M); 6 planned-sale notices; 1 filing by holders of 5% or more; 4 congressional trade disclosures; 3 company reports (Form 8-K, since May 26, 2026).

All insider filings at the SEC · Appeared in No. 10, No. 9, No. 8, No. 7, No. 6

Insider purchases and sales, by month (last 12 months)Insider purchases: $0 in total; Insider sales: $41.4M in total.Jul: Insider sales $656KAug: Insider sales $367KSep: Insider sales $40.3MDecJanFebMarAprMayJunJulAugSepOctNov
Insider purchases above the line: $0Insider sales below: $41.4M
Dollar value of open-market purchases and sales reported on SEC Form 4, by the month traded. Sales include pre-arranged 10b5-1 plan sales.

Insider trades · SEC Form 4

Those inside the hall

Open-market purchases and sales only. Legs one person filed for one day are combined.

Who traded

  1. Hsing Michael, CEO sold on 1 day all under a 10b5-1 plan latest Sep 28, 2026 sold $40.3M
  2. Sciammas Maurice, EVP, WW Sales & Marketing sold on 3 days all under a 10b5-1 plan latest Aug 3, 2026 sold $697K
  3. DEAN ROBERT W II, Interim CFO sold on 3 days latest Aug 24, 2026 sold $191K
  4. CHANG KUO WEI HERBERT sold on 2 days latest Aug 24, 2026 sold $135K
Every trade (9)
  1. SELLHsing Michael, CEO sold Sep 28, 2026 30,000 shares 8 legs combined 10b5-1 plan (scheduled) filing $40.3M
  2. SELLCHANG KUO WEI HERBERT sold Aug 24, 2026 50 shares filing $64K
  3. SELLDEAN ROBERT W II, Interim CFO sold Aug 24, 2026 32 shares filing $42K
  4. SELLDEAN ROBERT W II, Interim CFO sold Aug 17, 2026 6 shares filing $8K
  5. SELLCHANG KUO WEI HERBERT sold Aug 11, 2026 50 shares filing $71K
  6. SELLDEAN ROBERT W II, Interim CFO sold Aug 5, 2026 105 shares filing $141K
  7. SELLSciammas Maurice, EVP, WW Sales & Marketing sold Aug 3, 2026 30 shares 10b5-1 plan (scheduled) filing $40K
  8. SELLSciammas Maurice, EVP, WW Sales & Marketing sold Jul 15, 2026 440 shares 3 legs combined 10b5-1 plan (scheduled) filing $616K
  9. SELLSciammas Maurice, EVP, WW Sales & Marketing sold Jul 1, 2026 30 shares 10b5-1 plan (scheduled) filing $41K

Planned sales · SEC Form 144

Notice given

A Form 144 is filed before an insider sells restricted stock. It states an intent; the sale, if it happens, appears later on a Form 4. Every recent notice

  1. MICHAEL HSING filed Sep 28, 2026 Officer 30,000 shares planned sale date 09/28/2026 filing $40.3M
  2. DEAN ROBERT W II filed Aug 24, 2026 Officer 32 shares planned sale date 08/24/2026 filing $42K
  3. DEAN ROBERT W II filed Aug 17, 2026 Officer 6 shares planned sale date 08/17/2026 filing $8K
  4. Kuo Wei Chang filed Aug 11, 2026 Director 100 shares planned sale date 08/11/2026 filing $142K
  5. ROBERT DEAN filed Aug 5, 2026 Officer 105 shares planned sale date 08/05/2026 filing $141K
  6. MAURICE SCIAMMAS filed Jul 15, 2026 Officer 15,000 shares planned sale date 07/15/2026 filing $20.2M

Large holders · SEC Schedules 13D and 13G

Five percent and over

Anyone who comes to hold more than 5% of a company's voting shares must tell the SEC. A Schedule 13D is filed by a holder who may seek to influence the company; a 13G by one who states it is a passive investor. An amendment updates an earlier filing, and a stake reported as 0% means the holder says it has sold all, or nearly all, of its shares. Every recent 13D and 13G

  1. FMR LLC filed Nov 5, 2026 Schedule 13G/A passive 4,450,333 shares filing 9.1%

Congress · STOCK Act

The Althing

Periodic transaction reports. Amounts are the ranges members report; the trade date is when it happened, the report can come up to 45 days later.

  1. Byron Donalds (R-FL19): Sale Jun 5, 2026 reported Jul 15, 2026 one of 6 trades the member reported that day House Stocks (including ADRs) owner: spouse $1,001 - $15,000
  2. Byron Donalds (R-FL19): Sale Jun 5, 2026 reported Jul 15, 2026 one of 6 trades the member reported that day House Stocks (including ADRs) $1,001 - $15,000
  3. Markwayne Mullin (R-OK): Purchase Feb 4, 2026 reported Mar 2, 2026 one of 17 trades the member reported that day Senate Stock $15,001 - $50,000
  4. Markwayne Mullin (R-OK): Purchase Jan 5, 2026 reported Feb 4, 2026 one of 10 trades the member reported that day Senate Stock $15,001 - $50,000

Company reports · SEC Form 8-K

In its own words

Current reports the company filed with the SEC; most items are due within four business days of the event. Each line lists the report's items by the SEC's own titles; the filing says what happened. Reports collected since May 26, 2026; every 8-K at the SEC.

  1. Results of operations and financial condition; Departure or appointment of directors or officers filing Oct 29, 2026
  2. Other events filing Sep 10, 2026
  3. Results of operations and financial condition filing Jul 30, 2026

Sources: SEC EDGAR (Forms 4, 144 and 8-K) and STOCK Act periodic transaction reports. Filings can be late, amended or wrong at the source; see methodology.