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.
For MONOLITHIC POWER SYSTEMS, INC. (MPWR), EVP & General Counsel Saria Tseng reported internal reallocations of common stock on August 31, 2026. 2,000 shares were transferred as a bona fide gift from her direct holdings to the C&T Family Irrevocable Trust, where she is a trustee, with no funds exchanged and no sale occurring. After the transfer she held 142,218 shares directly, 2,000 shares indirectly through the family trust, and 1,000 shares indirectly through the C&T Discovery Foundation.
MONOLITHIC POWER SYSTEMS, INC. (MPWR) reported insider activity by Interim CFO Robert W. Dean II. On 2026-08-24, he sold 32 shares of common stock in open-market transactions at a weighted average price of $1,297.72 per share to cover tax withholding obligations upon the vesting of restricted stock units. The sale prices ranged from $1,296.07 to $1,298.01. On the same date, he also disposed of 5 shares through a transfer from his direct holdings to an individual who is not an immediate family member sharing the same household; no funds were exchanged, no sale occurred, and he no longer retains any pecuniary interest in those shares. After these transactions, an additional 65 shares of common stock are reported as held indirectly, described as "Held by Parent & Daughter."
For MONOLITHIC POWER SYSTEMS, INC. (MPWR), director Chang Kuo Wei Herbert reported selling 50 shares of common stock on 2026-08-24 in a sale in open market or private transaction at $1,281.57 per share. After this transaction, he directly holds 515 shares of MPWR common stock.
MONOLITHIC POWER SYSTEMS, INC. (MPWR) officer Robert W. Dean II, Interim CFO, reported a small sale of 6 shares of common stock on 2026-08-17 at $1,413.64 per share. The footnote states the sale was made to cover tax withholding obligations upon the vesting of restricted stock units. After this transaction, he holds 7,126 shares directly and 65 shares indirectly held by Parent & Daughter.
Monolithic Power Systems, Inc. director Chang Kuo Wei Herbert reported selling 50 shares of common stock on 2026-08-11. The sale was a non-derivative transaction in the open market or a private transaction at a price of $1,420.00 per share, leaving him with 565 shares held directly.
Maurice Sciammas, EVP, WW Sales & Marketing of Monolithic Power Systems, reported an internal bona fide gift of 25,000 shares of common stock on 2026-08-04, moving them from direct ownership to two GRATs where he serves as trustee. No funds were exchanged and no sale occurred. Following the transfer he holds 126,644 shares directly and 36,062 shares indirectly through the GRATs, in addition to other indirect family trust holdings.
Monolithic Power Systems, Inc. reports that Interim CFO Robert W. Dean II sold 105 shares of Common Stock on 2026-08-05 at $1,344.27 per share in an open market or private transaction. After this sale, he holds 7,132 shares directly and 65 shares indirectly, held by Parent & Daughter.
Monolithic Power Systems executive Maurice Sciammas, EVP, WW Sales & Marketing, reported the sale of 30 shares of Common Stock on 2026-08-03 at $1343.9400 per share. The transaction was executed indirectly by the Clement Sciammas Trust under a Rule 10b5-1 trading plan adopted on 11/19/2025, leaving that trust with 1119 shares. Sciammas also reports 151644 shares held directly and additional indirect holdings across multiple family trusts and accounts.
DEAN ROBERT W II reported acquisition or exercise transactions in this Form 4 filing.
Monolithic Power Systems interim CFO Robert W. Dean II reported an equity award of 1,359 shares of common stock linked to market-based restricted stock units granted in 2023. The Compensation Committee certified achievement of the three-year performance goals on July 25, 2026, and the shares will vest in three equal annual installments from July 25, 2027 through July 25, 2029. Following this grant, Dean beneficially owns 7,237 shares directly and 65 shares indirectly held by a Parent & Daughter account.
Maurice Sciammas, EVP, WW Sales & Marketing of Monolithic Power Systems, reported selling 15,000 shares of common stock on July 15, 2026 in 18 transactions under a Rule 10b5-1 trading plan adopted on November 24, 2025. Footnotes state each line’s price is a weighted average of multiple trades, with underlying trade prices ranging from $1,311.45 to $1,406.04 per share. He also reports various indirect holdings through family trusts and related accounts.
Monolithic Power Systems executive Maurice Sciammas, EVP of Worldwide Sales & Marketing, reported an open-market sale of 30 shares of Common Stock at $1,351.61 per share by the Clement Sciammas Trust on July 1, 2026. The transaction was carried out under a Rule 10b5-1 trading plan adopted on November 19, 2025, indicating it was pre-scheduled. After this sale, the Clement Sciammas Trust held 1,149 shares indirectly. The filing also lists Sciammas’s broader holdings, including 166,644 shares held directly and additional indirect positions in various family trusts, GRATs, and brokerage accounts.
MONOLITHIC POWER SYSTEMS INC EVP Maurice Sciammas reported a small preplanned insider sale through a family trust. A trust named Clement Sciammas Trust sold 30 shares of common stock at $1,533.95 per share in an open-market transaction made pursuant to a Rule 10b5-1 trading plan adopted on 11/19/2025. Following this sale, that trust held 1,179 shares indirectly, while Sciammas also reported 166,644 shares held directly, suggesting this was a minor, routine disposition relative to his overall reported holdings.
Monolithic Power Systems executive Maurice Sciammas reported a bona fide gift of 12,472 shares of Common Stock held through various Sciammas GRATs. The shares were distributed from these grantor retained annuity trusts to individuals who are not immediate family members sharing the same household.
No funds were exchanged and no sale of shares occurred in these distributions, so this is a non-cash transfer rather than a market trade. After the distributions, the GRATs and Sciammas no longer have any pecuniary interest in the gifted shares, while separate direct and indirect Common Stock holdings are reported, including 166,644 shares held directly and 12,625 shares held indirectly through various Sciammas GRATs.
Monolithic Power Systems' EVP & General Counsel, Saria Tseng, reported an open-market sale of company stock. On May 27, 2026, she sold 7,565 shares of Common Stock at a price of $1,700 per share, and now holds 144,218 shares directly.
The filing also shows an indirect holding of 1,000 shares attributed to the C&T Discovery Foundation, recorded as a holding entry rather than a new trade.
Monolithic Power Systems’ interim CFO Robert W. Dean II reported a small, tax-related share sale. On 2026-05-26, he sold 22 shares of common stock at a weighted average price of $1,649.56 per share to cover tax withholding obligations tied to vested restricted stock units. After this transaction, he directly held 5,878 common shares and indirectly held 65 additional shares through an account noted as held by parent and daughter. The filing indicates a routine tax-withholding event rather than a discretionary reduction of his ownership stake.
Monolithic Power Systems director Jeff Zhou sold 486 shares of Common Stock in an open-market sale at $1,680 per share. This transaction reduced his direct holdings to 3,800 shares after the sale, indicating a partial, not complete, trim of his position.
Monolithic Power Systems EVP & General Counsel Saria Tseng reported multiple share dispositions. On May 22, 2026, she completed an open-market sale of 5,000 shares of common stock at $1,586.43 per share, leaving 151,783 shares held directly afterward.
The filing also reports a bona fide gift transfer of 200 shares from her direct holdings to an individual who is not an immediate family member sharing the same household. The footnote states no funds were exchanged, no sale occurred, and she no longer retains any pecuniary interest in those shares.
In addition, the filing shows 1,000 shares of common stock held indirectly through the C&T Discovery Foundation.
Monolithic Power Systems CEO Michael Hsing sold 40,000 shares of common stock in open-market transactions. The Form 4 shows 13 separate sales on May 18, 2026, with reported prices including $1,467.62, $1,486.76 and $1,521.43 per share.
After these sales, Hsing directly holds 879,020 shares. He also has indirect holdings of 12,825 shares through the ZH Family 2020 Trust and 133,040 shares through the M Hsing 04 Trust. A footnote notes that the ending balance includes 29 shares acquired through the company’s qualified ESPP program.
MONOLITHIC POWER SYSTEMS INC interim CFO Robert W. Dean II reported a small share sale primarily for tax purposes. On vesting of restricted stock units, 4 shares of Common Stock were sold at $1,563.28 per share to cover tax withholding obligations, leaving him with 5,900 directly held shares. A separate entry shows 65 shares held indirectly as "Held by Parent & Daughter," which reflects additional family-related ownership.
Monolithic Power Systems executive Maurice Sciammas, EVP of Worldwide Sales & Marketing, reported open-market sales of 12,000 shares of common stock on May 15, 2026. The shares were sold in multiple transactions at prices generally ranging from about $1,550 to $1,586 per share.
The filing states these sales were made under a Rule 10b5-1 trading plan adopted on November 24, 2025, indicating they were pre-arranged. Following the transactions, Sciammas directly holds 166,644 shares of Monolithic Power Systems common stock, in addition to various indirect holdings through family trusts and related accounts.
MONOLITHIC POWER SYSTEMS INC executive Maurice Sciammas reported intra-family gifts of company common stock. On 2026-05-13, entities associated with him made two bona fide gift transfers totaling 3,126 shares, with 1,563 shares moved in each transaction.
The shares were transferred between three GRATs and the Sciammas Family Trust, all of which list him as a trustee. Footnotes state no funds were exchanged and no sale of shares occurred, meaning these are non-market, non-cash movements of existing holdings.
After these transfers, the Sciammas Family Trust held 51,023 shares and various Sciammas GRATs held 25,097 shares. Separately, Sciammas is shown with 178,644 shares held directly, plus additional indirect positions through several other family trusts and accounts.
MONOLITHIC POWER SYSTEMS INC interim CFO Robert W. Dean II reported a non-market share transfer. On 2026-05-13, a Form 4 shows an "other" transaction moving 2,156 shares of common stock from his direct holdings.
The filing states no funds were exchanged, no sale occurred, and he no longer has any pecuniary interest in the transferred shares, indicating a non-cash disposition. After this restructuring, he reports 5,904 common shares held directly and 65 shares held indirectly under "Held by Parent & Daughter."
Monolithic Power Systems director Eugen J. Elmiger sold 12,000 shares of Common Stock in open-market transactions. The trades occurred on May 6, 2026 across multiple price levels, with individual line items showing sale prices between $1,559.88 and $1,600.14 per share. Following these sales, Elmiger directly holds 5,402 shares of Monolithic Power Systems common stock.
Monolithic Power Systems EVP Deming Xiao reported sizable insider sales of common stock. On May 6, 2026, he executed open-market sales totaling 30,000 shares of MPWR common stock across four transactions at prices between $1,648.38 and $1,661.38 per share. Following these sales, Xiao directly holds 205,959 shares of common stock. The filing also reports indirect holdings of 4,336 shares held by the Christopher Chao Xiao Trust and 20,455 shares held by his spouse, reflecting additional exposure to the company’s stock. A footnote notes that the ending balance includes 27 shares acquired earlier through the company’s qualified employee stock purchase plan.
Monolithic Power Systems director Eileen Wynne sold shares in an open-market trade. On May 6, 2026, she sold 335 shares of Common Stock at an average price of $1,582.68 per share. After this sale, she directly held 1,007 shares of Monolithic Power Systems stock.
MONOLITHIC POWER SYSTEMS INC director Jeff Zhou sold 1,514 shares of Common Stock in open-market transactions. The sales occurred on May 5 and May 6, 2026, at prices between $1,574.48 and $1,650.00 per share. After these transactions, Zhou directly holds 4,286 shares of Monolithic Power Systems common stock.
Monolithic Power Systems EVP Maurice Sciammas reported an indirect open-market sale of 380 shares of common stock at $1,583.81 per share through the Rosalind Sciammas Brokerage Account on May 5, 2026, leaving 919 shares in that account. The filing also lists multiple indirect trust and GRAT holdings and shows a separate direct holding of 178,644 common shares as of the same date.
MONOLITHIC POWER SYSTEMS INC EVP Maurice Sciammas reported a small pre-planned stock sale by a family trust. On May 4, 2026, the Clement Sciammas Trust sold 30 shares of MPWR common stock at $1,588.73 per share in an open-market transaction.
After this sale, the Clement Sciammas Trust held 1,209 shares. The filing also shows other indirect holdings in various Sciammas family trusts and GRATs, and 178,644 shares held directly. The sale was executed under a Rule 10b5-1 trading plan adopted on November 19, 2025, indicating it was pre-arranged.
Monolithic Power Systems EVP & General Counsel Saria Tseng reported open-market sales of 8,963 shares of common stock on April 8, 2026 under a pre-arranged Rule 10b5-1 trading plan adopted on November 28, 2025. Sale prices included tranches at about $1,266.48 and $1,312.82 per share. After these transactions, she directly holds 156,983 shares and indirectly holds 1,000 shares through the C&T Discovery Foundation.
MONOLITHIC POWER SYSTEMS INC executive Saria Tseng sold 7,636 shares of Common Stock in open-market transactions. The EVP & General Counsel executed eight planned sales on April 6, 2026 under a Rule 10b5-1 trading plan adopted on November 28, 2025, at prices such as $1,139.96, $1,170.38 and $1,179.50 per share. After these trades, Tseng holds 169,022 shares directly and 1,000 shares indirectly through C&T Discovery Foundation.
Monolithic Power Systems EVP & General Counsel Saria Tseng reported open-market sales of 1,400 shares of common stock on April 1, 2026. The trades occurred in multiple blocks at weighted average prices ranging from about $1,130.82 to $1,137.71 per share under a pre-arranged Rule 10b5-1 trading plan adopted on November 28, 2025. After these transactions, she directly holds 173,582 shares and has an additional 1,000 shares reported as indirectly held through C&T Discovery Foundation.
Monolithic Power Systems EVP Maurice Sciammas, through the Clement Sciammas Trust, sold 30 shares of common stock in an open-market transaction at $1,116.44 per share on April 1, 2026.
The trust held 1,239 shares after the sale as indirect ownership. Sciammas also held 178,644 shares directly, while other related trusts and accounts held additional indirect positions, including 49,460 shares in the Sciammas Family Trust and 26,660 shares in various Sciammas GRATs. The sale was made under a Rule 10b5-1 trading plan adopted on November 19, 2025.
Monolithic Power Systems EVP & General Counsel Saria Tseng reported selling a total of 25,674 shares of common stock in multiple open-market transactions on March 30, 2026. The weighted-average sale prices for these trades ranged from about $998 to $1,042 per share, as detailed in price-range footnotes.
The filing notes these transactions were executed under a pre-arranged Rule 10b5-1 trading plan adopted on November 28, 2025. After the sales, Tseng directly holds 174,982 shares and has an additional 1,000 shares held indirectly through the C&T Discovery Foundation.
Monolithic Power Systems EVP Maurice Sciammas reported an open-market sale of 30 shares of common stock on March 20, 2026. The sale was executed indirectly through the Clement Sciammas Trust at a weighted average price of $1,095.07 per share, with individual prices ranging from $1,094.79 to $1,095.19. Following the sale, the trust held 1,269 shares, while Sciammas also reported 178,644 shares held directly and additional indirect holdings through various family trusts and accounts. The transaction was carried out under a Rule 10b5-1 trading plan adopted on November 19, 2025.
Monolithic Power Systems CEO Michael Hsing reported a series of open-market sales of company common stock on February 12, 2026. The Form 4 shows multiple sale transactions at prices ranging from $1,155.71 to $1,217.12 per share, including 12,731 shares at $1,155.71 and 4,992 shares at $1,159.84.
After these sales, Hsing held 888,234 shares directly. He also had indirect beneficial ownership of 133,040 shares through the M Hsing 04 Trust and 12,825 shares through the ZH Family 2020 Trust. The filing notes the transactions were made under a Rule 10b5-1 trading plan adopted on August 28, 2025.
Monolithic Power Systems CEO and director Michael Hsing reported a series of open-market sales of MPWR common stock. On February 11, 2026, he executed multiple Rule 10b5-1 plan trades, with weighted average prices ranging from $1,158.71 to $1,202.28 per share.
Following these transactions, Hsing directly owned 921,234 shares of common stock. He also had indirect beneficial holdings of 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, EVP of Worldwide Sales & Marketing, reported an indirect open‑market sale of 200 shares of Common Stock on February 11, 2026. The shares were sold at $1,179.975 per share by the Clement Sciammas Trust, an entity associated with him.
After this sale, the Clement Sciammas Trust held 1,299 shares. The filing also shows other beneficial holdings, including 178,625 shares held directly and additional indirect positions through various Sciammas family trusts and brokerage accounts.
Monolithic Power Systems CEO Michael Hsing, who also serves as a director, sold a total of 34,000 shares of common stock on February 10, 2026 in a series of open-market transactions under a pre-arranged Rule 10b5-1 trading plan adopted on August 28, 2025. The reported weighted average sale prices on that date ranged from about $1,128.88 to $1,197.26 per share. Following these sales, Hsing directly owns 954,234 shares and indirectly holds 133,040 shares through the M Hsing 04 Trust and 12,825 shares through the ZH Family 2020 Trust.
Monolithic Power Systems director Victor K. Lee sold shares in a planned trade. On 02/09/2026, he executed an open‑market sale of 400 shares of common stock at $1,212.16 per share, and held 27,756 shares afterward. The sale was made under a pre‑arranged Rule 10b5‑1 trading plan adopted on 08/25/2025.
Monolithic Power Systems executive Deming Xiao reported a tax-related stock sale. As EVP, Global Operations, he sold 22,875 shares of common stock on February 6, 2026 at an average price of $1,171.1637 per share.
According to the filing, the sale was made to cover taxes due upon the release of restricted stock units under the company’s equity incentive plan. After this transaction, Xiao directly held 235,932 shares, with additional indirect holdings of 20,455 shares owned by his spouse and 4,336 shares held by the Christopher Chao Xiao Trust.
Monolithic Power Systems executive Saria Tseng reported selling 22,875 shares of common stock on February 6, 2026, at an average price of $1,171.1637 per share. The filing states these sales were made to cover taxes upon the release of restricted stock units under the company’s equity incentive plan.
After this transaction, Tseng beneficially owned 200,626 shares of Monolithic Power Systems common stock directly and 1,000 shares indirectly through C&T Discovery Foundation, according to the report.
Monolithic Power Systems executive Maurice Sciammas, EVP, WW Sales & Marketing, reported selling 22,875 shares of common stock on 02/06/2026 at $1,171.1637 per share. The sale, coded "S", was made to cover taxes due upon the release of restricted stock units, as required by the company’s equity incentive plan.
Following this tax-related sale, he directly holds 178,625 common shares and also has additional indirect holdings through various family trusts and brokerage accounts.
Monolithic Power Systems EVP and CFO Theodore Blegen sold 21,725 shares of common stock on February 6, 2026. The shares were sold at an average price of $1,171.1637 per share to cover taxes upon the release of restricted stock units under the company’s equity incentive plan.
After the sale, Blegen directly owned 82,353 shares of common stock and had indirect beneficial ownership of 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 CEO Michael Hsing reported a tax-related share sale. On 02/06/2026, he sold 54,923 shares of common stock at $1,171.1637 per share to cover taxes due upon the release of restricted stock units under the company’s equity incentive plan.
After this transaction, he held 988,234 shares directly. Additional indirect holdings were reported as 133,040 shares held by the M Hsing 04 Trust and 12,825 shares held by the ZH Family 2020 Trust.
Monolithic Power Systems director Eileen Wynne reported receiving an annual equity award in the form of restricted stock units. On February 3, 2026, she was granted 189 shares of common stock at a price of $0 per share, as part of the independent directors’ annual RSU grant program.
The RSU grant will vest one year after the grant date, conditioned on her continued service with the company. Following this award, she beneficially owned 1,342 shares of Monolithic Power Systems common stock in direct form.
Monolithic Power Systems director Jeff Zhou received an equity grant of 189 shares of common stock on February 3, 2026. These shares were awarded at a price of $0 per share as part of the company’s annual restricted stock unit grant to each independent director.
The RSU grant will vest one year after the grant date, conditioned on Mr. Zhou’s continued service with the company. Following this grant, he beneficially owns 5,800 shares of Monolithic Power Systems common stock in direct ownership.
Monolithic Power Systems director Herbert Kuo Wei Chang received an annual equity award in the form of restricted stock units. On February 3, 2026, he was granted 189 shares of common stock at a price of $0 per share, bringing his directly held total to 615 shares.
The award represents the company’s routine annual restricted stock unit grant to each independent director. These RSUs will vest one year after the grant date, as long as Chang continues to serve on the Board of Directors during that period.
Monolithic Power Systems director Eugen J. Elmiger reported an equity award from the company. On February 3, 2026, he acquired 189 shares of common stock at a stated price of $0, reflecting an annual restricted stock unit grant to each independent director.
After this grant, Elmiger directly owned 17,402 shares of Monolithic Power Systems common stock. The RSU grant will vest one year after the grant date, provided he continues to serve the company as an independent director.
Monolithic Power Systems director Victor K. Lee reported an equity award from the company. On February 3, 2026, he acquired 189 shares of common stock at $0.00 per share in connection with the Board-approved annual restricted stock unit grant to each independent director.
The footnote explains that this RSU grant will vest one year after the grant date, as long as the director continues to serve the company. After this grant, Lee beneficially owned 28,156 shares of Monolithic Power Systems common stock in total, held directly.
Monolithic Power Systems director Carintia Martinez reported an annual equity award in the form of restricted stock units. On February 3, 2026, she acquired 189 shares of common stock at $0 per share, bringing her directly held beneficial ownership to 1,067 shares.
The grant was part of the company’s regular annual restricted stock unit program for independent directors. According to the disclosure, this RSU award will vest one year after the grant date, provided she continues serving on the board during that period.