SEC Form 4 · accession 0001214659-26-008703
MONOLITHIC POWER SYSTEMS, INC. · MPWR
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
Maurice Sciammas
Officer — EVP, WW Sales & Marketing
Period of report
Jul 15, 2026
Accepted (ET)
Jul 17, 2026 · 5:43 pm EDT
Rule 10b5-1 plan
yes — trade under a plan
Issuer CIK
0001280452
Table I — non-derivative securities
| Security | Date | Code | Shares | Price | A/D | Owned after | D/I | Nature of ownership |
|---|---|---|---|---|---|---|---|---|
| Common StockF1,F2 | Jul 15, 2026 | S | 527 | $1,314.03 | D | 166,117 | D | |
| Common StockF1,F3 | Jul 15, 2026 | S | 274 | $1,318.42 | D | 165,843 | D | |
| Common StockF1,F4 | Jul 15, 2026 | S | 409 | $1,323.93 | D | 165,434 | D | |
| Common StockF1,F5 | Jul 15, 2026 | S | 464 | $1,329.30 | D | 164,970 | D | |
| Common StockF1,F6 | Jul 15, 2026 | S | 776 | $1,334.59 | D | 164,194 | D | |
| Common StockF1,F7 | Jul 15, 2026 | S | 1,460 | $1,339.59 | D | 162,734 | D | |
| Common StockF1,F8 | Jul 15, 2026 | S | 1,864 | $1,344.16 | D | 160,870 | D | |
| Common StockF1,F9 | Jul 15, 2026 | S | 1,506 | $1,348.91 | D | 159,364 | D | |
| Common StockF1,F10 | Jul 15, 2026 | S | 5,640 | $1,352.95 | D | 153,724 | D | |
| Common StockF1,F11 | Jul 15, 2026 | S | 50 | $1,359.36 | D | 153,674 | D | |
| Common StockF1,F12 | Jul 15, 2026 | S | 240 | $1,369.18 | D | 153,434 | D | |
| Common StockF1,F13 | Jul 15, 2026 | S | 472 | $1,375.47 | D | 152,962 | D | |
| Common StockF1,F14 | Jul 15, 2026 | S | 418 | $1,378.73 | D | 152,544 | D | |
| Common StockF1,F15 | Jul 15, 2026 | S | 410 | $1,384.11 | D | 152,134 | D | |
| Common StockF1,F16 | Jul 15, 2026 | S | 50 | $1,388.19 | D | 152,084 | D | |
| Common StockF1,F17 | Jul 15, 2026 | S | 213 | $1,396.16 | D | 151,871 | D | |
| Common StockF1,F18 | Jul 15, 2026 | S | 117 | $1,400.45 | D | 151,754 | D | |
| Common StockF1,F19 | Jul 15, 2026 | S | 110 | $1,405.71 | D | 151,644 | D | |
| Common Stock | holding | — | — | — | 1,699 | I | The Joseph Roger Sciammas 2020 Irrevocable Trust | |
| Common Stock | holding | — | — | — | 2,000 | I | Rosalind Sciammas Family 2021 Trust | |
| Common Stock | holding | — | — | — | 919 | I | Rosalind Sciammas Brokerage Account | |
| Common Stock | holding | — | — | — | 52,586 | I | Sciammas Family Trust | |
| Common Stock | holding | — | — | — | 11,062 | I | Various Sciammas GRATs | |
| Common Stock | holding | — | — | — | 1,699 | I | The Patrick Francis Sciammas 2020 Irrevocable Trust | |
| Common Stock | holding | — | — | — | 4,015 | I | By Sciammas Trust 2020 | |
| Common Stock | holding | — | — | — | 1,000 | I | Peter Rafferty and Eric Toothill 2021Trust | |
| Common Stock | holding | — | — | — | 1,699 | I | The Chloe Liliane Sciammas 2020 Irrevocable Trust | |
| Common Stock | holding | — | — | — | 1,149 | I | Clement Sciammas Trust | |
| Common Stock | holding | — | — | — | 5,000 | I | Clement Sciammas Family 2021 Trust |
Table II — derivative securities
No Table II lines on this filing.
Explanation of responses
- F1This transaction was made pursuant to a Rule 10b5-1 trading plan adopted on 11/24/2025.
- F10The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,352.13 to $1,357.03. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F11The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,357.88 to $1,362.57. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F12The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,366.15 to $1,371.04. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F13The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,371.23 to $1,376.20. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F14The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,376.51 to $1,381.11. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F15The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,381.79 to $1,386.22. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F16The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,388.18 to $1,388.22. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F17The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,393.94 to $1,398.92. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F18The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,398.97 to $1,400.85. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F19The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,404.25 to $1,406.04. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F2The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,311.45 to $1,316.40 The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F3The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,316.56 to $1,321.56. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F4The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,321.72 to $1,326.11. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F5The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,326.94 to $1,331.90. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F6The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,331.95 to $1,336.95. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F7The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,336.97 to $1,341.96. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F8The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,341.99 to $1,346.96. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.
- F9The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,347.09 to $1,352.00. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.