MONOLITHIC POWER SYSTEMS INC (MPWR) Insider Transactions
Over the last 12 months, 12 MONOLITHIC POWER SYSTEMS INC (MPWR) insiders filed 376 SEC Form 4 transactions — $0 in open-market purchases ( 0 distinct buyers) and $763.8M in open-market sales. 11% of all transactions were executed under a pre-scheduled Rule 10b5-1 trading plan.
- $0Open-market buys (1y)
- $763.8MOpen-market sells (1y)
- 12Distinct insiders
- 376Transactions filed
- 11%Under Rule 10b5-1 plan
- 2026-06-01Latest filing
Recent Form 4 Filings Most recent 50 of 376 (1-year window)
Each row is a single Form 4 filing event for MPWR, sourced directly from SEC EDGAR. The Type column classifies the SEC transaction code into Buy / Sell / Grant / Exercise / Other; the 10b5-1 badge marks trades executed under a pre-scheduled SEC Rule 10b5-1 plan.
| Date | Insider | Title | Type | SEC Code | Value | Shares | Price |
|---|---|---|---|---|---|---|---|
| 2026-06-01 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $46.0K | 30 | $1533.95 |
| 2026-05-29 | Sciammas Maurice | EVP, WW Sales & Marketing | Other | G | $0 | 12,472 | $0.00 |
| 2026-05-27 | Tseng Saria | EVP & General Counsel | Sell | S | $12.9M | 7,565 | $1700.00 |
| 2026-05-26 | Zhou Jeff | — | Sell | S | $816.5K | 486 | $1680.00 |
| 2026-05-26 | DEAN ROBERT W II | Interim CFO | Sell | S | $36.3K | 22 | $1649.56 |
| 2026-05-22 | Tseng Saria | EVP & General Counsel | Other | G | $0 | 200 | $0.00 |
| 2026-05-22 | Tseng Saria | EVP & General Counsel | Sell | S | $7.9M | 5,000 | $1586.43 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $5.0M | 3,424 | $1462.61 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $8.5M | 5,819 | $1467.62 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $7.4M | 5,049 | $1472.84 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $6.0M | 4,082 | $1476.96 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $8.5M | 5,737 | $1482.51 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $9.9M | 6,688 | $1486.76 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $1.3M | 862 | $1491.48 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $911.7K | 608 | $1499.46 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $4.4M | 2,929 | $1503.05 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $5.7M | 3,769 | $1507.70 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $833.7K | 551 | $1513.11 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $534.4K | 352 | $1518.15 |
| 2026-05-18 | Hsing Michael | CEO | Sell | S | $197.8K | 130 | $1521.43 |
| 2026-05-18 | DEAN ROBERT W II | Interim CFO | Sell | S | $6.3K | 4 | $1563.28 |
| 2026-05-15 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $5.8M | 3,741 | $1550.36 |
| 2026-05-15 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $2.7M | 1,717 | $1557.48 |
| 2026-05-15 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $3.1M | 2,010 | $1562.01 |
| 2026-05-15 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $3.2M | 2,020 | $1567.15 |
| 2026-05-15 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $2.1M | 1,312 | $1571.49 |
| 2026-05-15 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $1.1M | 703 | $1577.75 |
| 2026-05-15 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $707.2K | 447 | $1582.21 |
| 2026-05-15 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell 10b5-1 | S | $79.3K | 50 | $1585.51 |
| 2026-05-13 | Sciammas Maurice | EVP, WW Sales & Marketing | Other | G | $0 | 1,563 | $0.00 |
| 2026-05-13 | Sciammas Maurice | EVP, WW Sales & Marketing | Other | G | $0 | 1,563 | $0.00 |
| 2026-05-13 | DEAN ROBERT W II | Interim CFO | Other | J | $0 | 2,156 | $0.00 |
| 2026-05-06 | Zhou Jeff | — | Sell | S | $825.0K | 500 | $1650.00 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $499.2K | 320 | $1559.88 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $1.3M | 814 | $1566.36 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $1.7M | 1,078 | $1571.58 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $1.3M | 834 | $1575.57 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $3.0M | 1,879 | $1581.81 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $4.1M | 2,587 | $1586.81 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $2.2M | 1,355 | $1591.38 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $4.2M | 2,619 | $1596.42 |
| 2026-05-06 | Elmiger Eugen J | — | Sell | S | $822.5K | 514 | $1600.14 |
| 2026-05-06 | Xiao Deming | EVP, Global Operations | Sell | S | $5.5M | 3,329 | $1648.38 |
| 2026-05-06 | Xiao Deming | EVP, Global Operations | Sell | S | $23.4M | 14,167 | $1652.80 |
| 2026-05-06 | Xiao Deming | EVP, Global Operations | Sell | S | $19.2M | 11,597 | $1657.93 |
| 2026-05-06 | Xiao Deming | EVP, Global Operations | Sell | S | $1.5M | 907 | $1661.38 |
| 2026-05-06 | Wynne Eileen | — | Sell | S | $530.2K | 335 | $1582.68 |
| 2026-05-05 | Zhou Jeff | — | Sell | S | $809.3K | 514 | $1574.48 |
| 2026-05-05 | Zhou Jeff | — | Sell | S | $800.0K | 500 | $1600.00 |
| 2026-05-05 | Sciammas Maurice | EVP, WW Sales & Marketing | Sell | S | $601.8K | 380 | $1583.81 |
Showing the most recent 50 of 376 transactions. For the full 1-year history with sorting, filtering, and cross-ticker industry context, open the full insider transactions drilldown.
Methodology & FAQ
How We Track MPWR Insider Transactions
Form 4 disclosures are sourced directly from SEC EDGAR and re-ingested on every pipeline cycle. A complete description of transaction-code handling, the open-market vs grant distinction, and the Rule 10b5-1 plan-reference heuristic is documented in the Methodology.
What is an SEC Form 4 filing for MONOLITHIC POWER SYSTEMS INC?
Form 4 is a transaction-level disclosure that corporate insiders — officers, directors, and beneficial owners of more than 10% of a registered class of equity securities — must file with the SEC within two business days of any change in their beneficial ownership of MONOLITHIC POWER SYSTEMS INC (MPWR) shares.
What is a Rule 10b5-1 trading plan?
Rule 10b5-1 is an SEC rule that lets insiders schedule trades in advance under a written plan, providing an affirmative defense against insider-trading allegations as long as the plan was adopted in good faith and not while in possession of material non-public information. Form 4 rows marked "10b5-1" on this page indicate the underlying trade was executed under such a plan; rows without the badge are discretionary or did not reference a plan in the Form 4 footnotes.
How is "insider buying" different from a stock grant or option exercise?
An insider buy (SEC transaction code P) is an open-market purchase of MONOLITHIC POWER SYSTEMS INC (MPWR) stock executed at the prevailing market price using the insider's personal capital. Stock grants (code A) and option exercises (code M) are compensation events, not directional trades; they are tracked separately and excluded from the "conviction" signal because they are not discretionary purchases.
How recent is the data?
Form 4 transactions are typically reported within two business days of execution. Pactolio re-ingests the EDGAR feed on a nightly cycle and reflects new filings on the next ingest run, typically within 24 hours of EDGAR acceptance. The table on this page covers the most recent 1-year window.