Every Form 4 that Monolithic Power Systems, Inc. (MPWR) has filed with the SEC in the last 12 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A Form 4 covers the transactions officers, directors and large holders report, so if you follow MPWR and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full MPWR filings page.
Monolithic Power Systems executive Deming Xiao reported a stock award tied to prior performance-based incentives. As EVP, Global Operations, he received 57,170 shares of common stock on February 3, 2026 at $0 per share, following the certification of performance-based restricted stock units granted in 2023. After this vesting, he beneficially owns 258,807 shares directly, plus 20,455 shares held indirectly by his spouse and 4,336 shares held indirectly through the Christopher Chao Xiao Trust.
Monolithic Power Systems EVP and CFO Theodore Blegen received 38,745 shares of common stock on February 3, 2026 through the vesting of previously granted performance-based restricted stock units. These shares were awarded at a price of $0 per share following certification of performance goals for a three-year period that began with a February 7, 2023 grant.
After this award, Blegen directly beneficially owned 104,078 shares of Monolithic Power Systems common stock. He also indirectly beneficially owned 5,331 shares held in an irrevocable trust for Sarah N. Blegen and another 5,331 shares held in an irrevocable trust for Theodore F. Blegen.
Monolithic Power Systems EVP & General Counsel Saria Tseng received 57,170 common shares on February 3, 2026 from previously granted performance-based restricted stock units. The company’s Compensation Committee certified that three-year performance goals were achieved, causing all units to fully vest and be released the same day at a price of $0 per share.
After this award, Tseng directly beneficially owned 223,501 shares of Monolithic Power Systems common stock and indirectly held 1,000 additional shares through C&T Discovery Foundation.
Monolithic Power Systems CEO Michael Hsing, who is also a director, reported the vesting of 136,825 shares of common stock on February 3, 2026. These shares came from performance-based restricted stock units granted on February 7, 2023 after a three-year performance period and were awarded at a price of $0 per share, subject to tax withholding.
After this award, Hsing directly beneficially owned 1,043,157 shares of common stock. In addition, indirect holdings totaled 133,040 shares through the M Hsing 04 Trust and 12,825 shares through the ZH Family 2020 Trust.
Monolithic Power Systems executive Maurice Sciammas reported a stock award tied to prior performance-based units. As EVP, WW Sales & Marketing, he received 57,170 shares of common stock on February 3, 2026, at a price of $0 after the company’s Compensation Committee certified performance goals for PSUs granted on February 7, 2023.
All 57,170 shares fully vested and were released the same day, bringing his directly held common stock to 201,500 shares. Additional indirect holdings are reported in various family trusts and accounts.
Monolithic Power Systems executive vice president and CFO Theodore Blegen reported multiple open‑market sales of common stock on February 2, 2026 under a pre‑arranged Rule 10b5‑1 trading plan. The trades involved small blocks of shares at weighted average prices ranging roughly from $1,110.14 to $1,139.54 per share. After these transactions, Blegen directly beneficially owned 65,333 common shares and indirectly held 5,331 shares in each of two irrevocable trusts for Sarah N. Blegen and Theodore F. Blegen.
Monolithic Power Systems executive Theodore Blegen, EVP and CFO, reported planned stock sales under a Rule 10b5-1 trading plan. On January 2, 2026, he sold multiple small blocks of Monolithic Power Systems common stock at prices between $927.61 and $946.62 per share, as disclosed across several transaction lines. These trades were executed pursuant to a Rule 10b5-1 plan adopted on February 26, 2025, which allows pre-arranged sales according to preset instructions.
Following these transactions, Blegen directly held 68,332 shares of common stock. The filing also shows indirect beneficial ownership of 5,331 shares held in an irrevocable trust for Sarah N. Blegen and another 5,331 shares held in an irrevocable trust for Theodore F. Blegen, reflecting additional trust-related holdings associated with the reporting person.
Monolithic Power Systems CEO and director Michael R. Hsing transferred 12,337 shares of common stock as a gift to a 501(c)(3) foundation on 12/09/2025. The company states that after the transfer he has no management or investment control and no pecuniary interest in those shares, and no funds were exchanged, so no sale occurred.
Following the transaction, Hsing beneficially owned 906,332 shares directly, plus 133,040 shares held indirectly through the M Hsing 04 Trust and 12,825 shares held indirectly through the ZH Family 2020 Trust.
Monolithic Power Systems Inc. (MPWR) director transaction reported. A company director reported the sale of 100 shares of Monolithic Power Systems common stock in an open market transaction. The sale took place at a price of $896.97 per share. After this transaction, the director reports beneficial ownership of 426 shares held directly.
Monolithic Power Systems (MPWR) executive Maurice Sciammas, EVP of Worldwide Sales & Marketing, reported a stock sale in a Form 4 filing. On 11/24/2025, he sold 3,976 shares of MPWR common stock at a price of $895.23 per share, coded as a sale transaction. After this trade, he directly owns 144,330 shares of common stock and also reports additional indirect holdings through multiple family trusts and related accounts, reflecting ongoing significant ownership in the company.
Monolithic Power Systems (MPWR) director reports small stock sale. A company director filed a Form 4 showing the sale of 100 shares of MPWR common stock on 11/21/2025 at a price of $873.97 per share, coded as a sale transaction ("S").
Following this trade, the director beneficially owns 526 shares of MPWR common stock in direct ownership. The filing is made by a single reporting person in the capacity of director and does not report any derivative securities activity.
Monolithic Power Systems (MPWR) reported insider activity by its EVP, WW Sales & Marketing, in a Form 4 filing. On 11/19/2025, the executive sold multiple blocks of common stock in open market transactions coded "S" for sales.
The reported trades covered relatively small share blocks at weighted average prices ranging from about $875.26 to $886.01, with detailed price ranges provided for each group of sales. After these transactions, the reporting person directly held 148,306 shares of MPWR common stock.
The filing also lists additional indirect beneficial ownership in various family trusts and related accounts, each holding smaller amounts of MPWR shares. The trades were reported as having been made under a Rule 10b5-1 trading arrangement, which is a pre-established plan for buying or selling stock.
Monolithic Power Systems (MPWR) executive vice president of worldwide sales and marketing Maurice Sciammas reported multiple open-market sales of common stock on 11/19/2025. Across a series of trades, he sold a total of 7,034 shares at weighted average prices reported between about $862 and $875 per share, with detailed price ranges noted for each trade.
After these transactions, Sciammas directly owned 176,272 shares of MPWR common stock and also had additional indirect holdings through various family trusts and accounts, including positions such as 49,460 shares in the Sciammas Family Trust and other named family and irrevocable trusts. The footnotes state that the reported prices are weighted averages and that full trade-by-trade price information is available upon request.
Monolithic Power Systems (MPWR) reported insider transactions by CEO and director Michael R. Hsing. On 11/12/2025, he executed multiple open‑market sales of common stock at disclosed weighted‑average prices, with per‑line price ranges provided.
Following the transactions, Hsing beneficially owns 918,669 shares directly. He also holds indirect positions of 133,040 shares via the M Hsing 04 Trust and 12,825 shares via the ZH Family 2020 Trust.
Monolithic Power Systems (MPWR) CEO and director Michael R. Hsing reported open-market sales of 40,000 shares of common stock on 11/11/2025 across multiple transactions. The filing lists weighted-average prices for each tranche, with disclosed price ranges from $952.05 to $967.17 for the respective trades. Following these sales, Hsing directly holds 955,669 shares.
The filing also shows indirect holdings of 133,040 shares by the M Hsing 04 Trust and 12,825 shares by the ZH Family 2020 Trust.
Monolithic Power Systems (MPWR) reported an insider transaction by its EVP, WW Sales & Marketing. On 11/05/2025, the reporting person sold 200 shares of common stock at $986.81 per share.
Following the transaction, the report lists beneficial ownership positions, including 183,306 shares direct and 44,930 shares held indirectly in the Sciammas Family Trust, among various other family trusts and accounts.
Monolithic Power Systems (MPWR) executive Bernie Blegen, EVP and CFO, reported open-market sales of common stock on 11/03/2025 pursuant to a Rule 10b5-1 trading plan adopted on 2/26/2025.
The sales were executed in multiple small lots at weighted average prices, including $1,013.62, $1,019.49, and $1,038.41 per share. Following these transactions, Blegen beneficially owns 74,332 shares directly.
He also reports indirect holdings of 5,331 shares in the Irrevocable Trust FBO Sarah N. Blegen and 5,331 shares in the Irrevocable Trust FBO Theodore F. Blegen.
Monolithic Power Systems (MPWR) — Form 4 insider filing: CEO and Director Michael R. Hsing reported a Code F transaction on 10/30/2025. The filing shows 121,918 shares of common stock were withheld by the company at $1,096.63 per share to satisfy income tax obligations tied to the earnout and vesting of market-based RSUs granted in October 2022.
After the withholding, Hsing beneficially owns 995,669 shares directly. He also has indirect holdings of 133,040 shares through the M Hsing 04 Trust and 12,825 shares through the ZH Family 2020 Trust. Code F indicates a tax-withholding event rather than an open-market sale.
Monolithic Power Systems (MPWR) EVP and CFO Bernie Blegen reported a Form 4 transaction. On 10/30/2025, 48,298 shares of common stock were withheld at $1,096.63 per share to satisfy income taxes related to the earnout and vesting of market-based RSUs granted in October 2022.
Following the transaction, Blegen directly owned 77,332 shares. Indirect holdings include 5,331 shares in an irrevocable trust for Sarah N. Blegen and 5,331 shares in an irrevocable trust for Theodore F. Blegen.
Monolithic Power Systems (MPWR): Form 4 insider transaction
EVP & General Counsel Saria Tseng reported a Code F transaction on 10/30/2025, reflecting tax withholding related to the vesting of market-based RSUs granted in October 2022. The company withheld 54,543 shares of common stock at a price of $1,096.63 per share to satisfy income tax obligations.
Following this withholding, the reporting person directly beneficially owns 207,331 shares of MPWR common stock. Code F indicates shares were disposed of by the issuer solely to cover taxes upon award vesting.
Monolithic Power Systems (MPWR) insider filing: EVP, WW Sales & Marketing Maurice Sciammas reported a Form 4 for a tax-withholding transaction on 10/30/2025. The company withheld 54,543 shares of common stock at $1,096.63 to satisfy income tax obligations tied to the earnout and vesting of market‑based RSUs granted in October 2022.
After the transaction, he holds 183,306 shares directly. Additional indirect holdings are reported across various family trusts and accounts.
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) 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.
Monolithic Power Systems (MPWR) director Carintia Martinez reported a sale of common stock under a 10b5-1 plan. On 09/18/2025 the reporting person sold 1,400 shares of Monolithic Power Systems common stock for a price reported as $900. After the sale the reporting person beneficially owned 878 shares. The filing states the transaction was executed pursuant to a Rule 10b5-1 trading plan adopted on 11/27/2024 and the Form 4 was signed by an attorney-in-fact on 09/18/2025.
Saria Tseng, EVP & General Counsel of Monolithic Power Systems, reported a sale of 14,510 shares of the company's common stock on 09/18/2025 at a price of $914.45 per share. The filing notes the sale was made pursuant to a Rule 10b5-1 trading plan adopted on 08/30/2024. After the reported transaction, the filing shows beneficial ownership of 144,494 shares, which includes 27 shares acquired through the company's qualified ESPP on 02/17/2025. The form is signed by the reporting person and discloses the relationship to the issuer as an officer.