🕵️ Monolithic Power Systems Inc ($MPWR)
SEC insider & ownership activity, last 12 months · CIK 1280452 · every row links its SEC filing
Over the last 12 months insiders sold $779.6M with no open-market buying against it. Michael Hsing sold $331.2M (Aug–May). 2 planned sales are pending, the largest $4.6M (Theodore Bernhard Blegen). One red-flag 8-K in the window: Restatement (4.02), Feb 26, 2026.
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Monthly net open-market insider flow, last 12 months (up = net buying)
Insider flow
0 buyers, $0 (0 lots) · 12 sellers, $779.6M (354 lots)
| Insider | Buys | Bought | Sells | Sold | Last |
|---|---|---|---|---|---|
| Michael Hsing | 0 | – | 92 | $331.2M | May 18, 2026 |
| Saria Tseng | 0 | – | 67 | $164.2M | May 27, 2026 |
| Deming Xiao | 0 | – | 6 | $107.6M | May 6, 2026 |
| Sciammas Maurice | 0 | – | 60 | $101.3M | Jul 15, 2026 |
| Theodore Bernhard Blegen | 0 | – | 93 | $44.9M | Feb 6, 2026 |
| Eugen J. Elmiger | 0 | – | 15 | $22.4M | May 6, 2026 |
| Jeff Zhou | 0 | – | 7 | $3.9M | May 26, 2026 |
| Victor Lee | 0 | – | 8 | $2.0M | Feb 9, 2026 |
| Carintia Martinez | 0 | – | 1 | $1.3M | Sep 18, 2025 |
| Eileen Wynne | 0 | – | 1 | $530K | May 6, 2026 |
| Kuo Wei Chang | 0 | – | 2 | $177K | Nov 25, 2025 |
| Robert W. Dean II | 0 | – | 2 | $43K | May 26, 2026 |
5%+ holders
| Holder | Stake | Class | Schedule | Event | |
|---|---|---|---|---|---|
| FMR LLC | 10.5% | 13G | Jul 8, 2026 | filing ↗ | |
| Abigail P. Johnson | 10.5% | 13G | Jul 8, 2026 | filing ↗ | |
| Blackrock, Inc. | 10.2% | 13G | Jan 8, 2026 | filing ↗ | |
| Vanguard Capital Management | 7.2% | 13G | Apr 30, 2026 | filing ↗ | |
| Invesco Ltd. | 5.2% | 13G | Jul 15, 2026 | filing ↗ | |
| Vanguard Portfolio Management | 5.1% | 13G | Apr 29, 2026 | filing ↗ |
Planned insider sales (Form 144)
| Seller | Planned | Approx. sale date | |
|---|---|---|---|
| Maurice Sciammas | $20.2M | Jul 15, 2026 | filing ↗ |
| Theodore Bernhard Blegen | $4.6M | Jun 1, 2026 | filing ↗ |
| Saria Tseng | $12.9M | May 27, 2026 | filing ↗ |
| Jeff Zhou | $816K | May 26, 2026 | filing ↗ |
| Robert W. Dean II | $36K | May 26, 2026 | filing ↗ |
| Saria Tseng | $7.9M | May 22, 2026 | filing ↗ |
| Michael Hsing | $59.3M | May 18, 2026 | filing ↗ |
| Robert W. Dean II | $6K | May 18, 2026 | filing ↗ |
| Maurice Sciammas | $18.7M | May 15, 2026 | filing ↗ |
| Eugen J. Elmiger | $19.8M | May 7, 2026 | filing ↗ |
| Deming Xiao | $49.6M | May 6, 2026 | filing ↗ |
| Jeff Zhou | $825K | May 6, 2026 | filing ↗ |
| Eileen Wynne | $530K | May 6, 2026 | filing ↗ |
| Rosalind Sciammas | $600K | May 5, 2026 | filing ↗ |
| Jeff Zhou | $1.6M | May 5, 2026 | filing ↗ |
| Theodore Bernhard Blegen | $4.6M | May 1, 2026 | filing ↗ |
| Saria Tseng | $11.7M | Apr 8, 2026 | filing ↗ |
| Saria Tseng | $8.9M | Apr 6, 2026 | filing ↗ |
| Saria Tseng | $1.6M | Apr 1, 2026 | filing ↗ |
| Theodore Bernhard Blegen | $3.3M | Apr 1, 2026 | filing ↗ |
| Saria Tseng | $25.9M | Mar 30, 2026 | filing ↗ |
| Sciammas Maurice | $131K | Mar 20, 2026 | filing ↗ |
| Theodore Bernhard Blegen | $3.3M | Mar 2, 2026 | filing ↗ |
| Michael Hsing | $38.7M | Feb 12, 2026 | filing ↗ |
| Michael Hsing | $39.2M | Feb 11, 2026 | filing ↗ |
| The Sciammas Trust DTD 06/08/2018 | $240K | Feb 10, 2026 | filing ↗ |
| Michael Hsing | $38.8M | Feb 10, 2026 | filing ↗ |
| Blegen Theodore | $1.2M | Feb 6, 2026 | filing ↗ |
| Sciammas Maurice | $1.5M | Feb 6, 2026 | filing ↗ |
| Tseng Saria | $1.5M | Feb 6, 2026 | filing ↗ |
| Hsing Michael | $3.6M | Feb 6, 2026 | filing ↗ |
| Xiao Deming | $1.5M | Feb 6, 2026 | filing ↗ |
| Blegen Theodore | $24.1M | Feb 4, 2026 | filing ↗ |
| Sciammas Maurice | $25.1M | Feb 4, 2026 | filing ↗ |
| Tseng Saria | $25.1M | Feb 4, 2026 | filing ↗ |
| Hsing Michael | $60.4M | Feb 4, 2026 | filing ↗ |
| Xiao Deming | $25.1M | Feb 4, 2026 | filing ↗ |
| Theodore Bernhard Blegen | $3.4M | Feb 2, 2026 | filing ↗ |
| Theodore Bernhard Blegen | $2.8M | Jan 2, 2026 | filing ↗ |
| Victor Lee | $1.9M | Dec 24, 2025 | filing ↗ |
| Bernie Blegen | $2.7M | Dec 1, 2025 | filing ↗ |
| Saria Tseng | $18.5M | Nov 26, 2025 | filing ↗ |
| Saria Tseng | $18.1M | Nov 25, 2025 | filing ↗ |
| Maurice Sciammas | $3.6M | Nov 24, 2025 | filing ↗ |
| Kuo Wei Chang | $169K | Nov 21, 2025 | filing ↗ |
| Maurice Sciammas | $30.8M | Nov 19, 2025 | filing ↗ |
| Michael Hsing | $29.0M | Nov 12, 2025 | filing ↗ |
| Hsing Michael | $6.7M | Nov 12, 2025 | filing ↗ |
| Michael Hsing | $38.3M | Nov 11, 2025 | filing ↗ |
| The Sciammas Trust DTD 06/08/2018 | $194K | Nov 5, 2025 | filing ↗ |
Material events (8-K)
| Item | Event date | |
|---|---|---|
| Shareholder vote (5.07) | Jun 11, 2026 | filing ↗ |
| Other events (8.01) | Jun 11, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Jun 11, 2026 | filing ↗ |
| Earnings (2.02) | Apr 30, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Apr 30, 2026 | filing ↗ |
| Restatement (4.02) | Feb 26, 2026 | filing ↗ |
| Earnings (2.02) | Feb 3, 2026 | filing ↗ |
| Officer/director changes (5.02) | Feb 3, 2026 | filing ↗ |
| Other events (8.01) | Feb 3, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Feb 3, 2026 | filing ↗ |
| Other events (8.01) | Dec 12, 2025 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Dec 12, 2025 | filing ↗ |
| Charter/bylaw changes (5.03) | Nov 19, 2025 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Nov 19, 2025 | filing ↗ |
| Earnings (2.02) | Oct 30, 2025 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Oct 30, 2025 | filing ↗ |
| Other events (8.01) | Sep 11, 2025 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Sep 11, 2025 | filing ↗ |
| Earnings (2.02) | Jul 31, 2025 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Jul 31, 2025 | filing ↗ |