Monolithic Power SEC Filings

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, Inc. updated its corporate bylaws to make it easier for investors to call a special shareholder meeting. On November 19, 2025, the Board approved Amended and Restated Bylaws that lower the ownership threshold required to request a special meeting from at least 30% to at least 25% of the company’s outstanding voting capital stock.

The Board explains that it considered the 2025 annual meeting, where stockholders approved a non-binding proposal to set the threshold at 10%, along with feedback from a majority in interest of its top ten stockholders, who preferred a significantly higher threshold than 10%, and a review of peer practices. The full amended bylaws are filed as an exhibit and are effective immediately.

Monolithic Power Systems (MPWR)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)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.