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Monolithic Power Systems (MPWR) reported an insider tax-withholding transaction by its EVP, Global Operations. On 10/30/2025, the officer had 54,543 shares of common stock withheld at $1,096.63 per share (Form 4 code F) to cover income taxes tied to the earnout and vesting of market-based RSUs granted in October 2022.
After the transaction, the reporting person beneficially owns 201,637 shares directly, plus 20,455 shares held by a spouse and 4,336 shares held by the Christopher Chao Xiao Trust.
Monolithic Power Systems (MPWR) furnished an update on its latest results. The company filed a Form 8‑K to furnish, under Item 2.02, a press release and earnings commentary for the quarter ended September 30, 2025. These materials are provided as Exhibits 99.1 and 99.2 and are furnished, not filed, under the Exchange Act.
MPWR’s common stock trades on the NASDAQ Global Select Market under the symbol MPWR. The company notes it operates across the US, Europe, and Asia and does not maintain a single headquarters; addresses are included to satisfy SEC requirements.
Monolithic Power Systems (MPWR) disclosed an insider equity award. On October 25, 2025, EVP & General Counsel acquired 135,520 common shares at $0 upon certification of performance criteria for previously granted market-based RSUs (MSUs). The MSUs were granted on October 25, 2022 and tied to five stock price targets and relative TSR over a three-year period. All awarded shares fully vested on October 25, 2025.
Following the transaction, the reporting person beneficially owned 261,874 shares, held directly.
Monolithic Power Systems (MPWR) filed a Form 4 showing its EVP and CFO received 87,690 shares of common stock on October 25, 2025. The shares were awarded at $0 upon certification and approval of performance goals tied to market-based RSUs granted on October 25, 2022; all shares fully vested on October 25, 2025.
Following the award, the reporting person beneficially owns 125,630 shares directly. In addition, 5,331 shares are held indirectly in an Irrevocable Trust FBO Theodore F. Blegen and 5,331 shares are held indirectly in an Irrevocable Trust FBO Sarah N. Blegen.
Monolithic Power Systems (MPWR) disclosed an insider equity vesting: CEO and Director Michael R. Hsing was awarded 302,920 shares of common stock on October 25, 2025 at $0 per share after the Compensation Committee certified performance for previously granted market-based RSUs.
The MSUs, granted on October 25, 2022, were tied to five stock price targets and relative total stockholder return over a three-year period; all awarded shares fully vested on October 25, 2025.
Following the transaction, Hsing beneficially owned 1,117,587 shares directly, plus 133,040 held indirectly by the M Hsing 04 Trust and 12,825 held indirectly by the ZH Family 2020 Trust.
Monolithic Power Systems (MPWR) executive Deming Xiao, EVP, Global Operations, reported the acquisition of 135,520 shares of common stock on October 25, 2025 at $0 per share. The shares were awarded upon certification of performance for market-based restricted stock units (MSUs) granted on October 25, 2022, tied to five stock price targets and relative total stockholder return over a three-year period; all shares vested on October 25, 2025.
Following the transaction, the filing shows 256,180 shares beneficially owned directly, plus 20,455 shares indirectly by spouse and 4,336 shares indirectly by the Christopher Chao Xiao Trust.
Monolithic Power Systems (MPWR) reported an insider transaction for EVP, WW Sales & Marketing, Maurice Sciammas. On October 25, 2025, the Compensation Committee certified the performance of previously granted market-based RSUs, resulting in an award of 135,520 shares. All awarded shares fully vested on the same date at a reported price of $0.
Following the transaction, Sciammas beneficially owns 237,849 shares directly. The ending balance includes 4 shares acquired on August 15, 2025 through the company’s ESPP. The filing also lists multiple indirect holdings across family trusts and accounts.
Monolithic Power Systems (MPWR) reported an insider transaction by its EVP & General Counsel. On 10/24/2025, the reporting person sold 1,300 shares of common stock at a price of $1,087.62 per share under transaction code “S.” Following the sale, the filer beneficially owned 126,354 shares, held directly. The filing notes the trade was made pursuant to a Rule 10b5-1 trading plan adopted on 8/30/2024.
Monolithic Power Systems (MPWR) executive Saria Tseng, EVP & General Counsel, reported open-market sales of common stock under a Rule 10b5-1 plan. On 10/15/2025, she sold 14,028 shares at $1,016.18. On 10/16/2025, she sold 1,499 shares at $1,021.26 and 1,313 shares at $1,030.81. Following these transactions, her beneficial ownership decreased to 127,654 shares. The trading plan was adopted on 8/30/2024.
Monolithic Power Systems (MPWR) Form 4 reports multiple open-market sales by EVP and CFO Theodore Blegen executed on 10/01/2025 under a Rule 10b5-1 trading plan adopted 02/26/2025. The schedule shows a sequence of sales at weighted-average prices ranging from $902.61 to $917.17 per share across separate blocks, reducing Mr. Blegen's direct holdings from earlier reported balances down to 37,940 shares held directly. The filing also discloses indirect ownership of 5,331 shares in an irrevocable trust for Theodore F. Blegen and 5,331 shares in an irrevocable trust for Sarah N. Blegen. The form is signed by an attorney-in-fact.