Monolithic Power Systems (MPWR) CEO Michael Hsing Sells 30,000 Shares

What Happened

• Michael Hsing, CEO and director of Monolithic Power Systems (MPWR), reported sales of 30,000 shares in open-market transactions on September 28, 2026, generating approximately $40.35 million in proceeds. Individual tranches reported: 596, 2,121, 1,111, 2,949, 5,783, 6,343, 10,967 and 130 shares at per-share prices ranging roughly from $1,323.31 to $1,356.94 (weighted amounts reported per line).

Key Details

• Transaction date: 2026-09-28; Form 4 filed: 2026-09-30 (filed within the typical two-business-day reporting window).
• Total shares sold: 30,000; total proceeds: ~$40,349,046.
• Price range: roughly $1,323–$1,357 per share; weighted-average prices are reported by tranche (footnotes provide exact ranges for each line).
• Footnotes: F1 — sales were made pursuant to a Rule 10b5-1 trading plan adopted 05/29/2026; other footnotes (F3–F10) disclose weighted-average price ranges and availability of per-price breakdown on request. F2 notes the ending balance referenced in the filing includes 1 share acquired 08/17/2026 via the company ESPP.
• Transaction code: S = Sale.

Context

• These were planned, open-market sales under a 10b5-1 plan, which typically reflect pre-arranged trading schedules rather than ad hoc decisions; such sales are generally considered routine insider liquidity rather than a direct signal of a change in insider sentiment. Purchases generally carry more informational weight for investors.