Company · Ownership research

MONOLITHIC POWER SYSTEMS INC MPWR

CIK 0001280452

Form 4 transactions dated Sep 1, 2023 to Sep 23, 2026, as reported to the SEC.

Insider trading Initial holdings Institutional holders

This page lists 30 of 42 rows; the complete set is available through the API.

Insider filings on file run through 2026-09-02.

Insider purchases & sales

Purchased: $0.00
Sold: $1.14B

Sep 1, 2023 – Sep 2, 2026
Available records · partial months are marked ·

202610 of 30 preview events · 42 available in 2026

Date	Insider	Activity	Trade value (USD)	% of prior holding
2026-08-24	DEAN ROBERT W II Interim CFO	Sale	$41.53K 32 shares sold	0.45% sold Direct holding	▾
2026-08-24	CHANG KUO WEI HERBERT Director	Sale	$64.08K 50 shares sold	8.85% sold Direct holding	▾
2026-08-17	DEAN ROBERT W II Interim CFO	Sale	$8.48K 6 shares sold	0.08% sold Direct holding	▾
2026-08-11	CHANG KUO WEI HERBERT Director	Sale	$71.00K 50 shares sold	8.13% sold Direct holding	▾
2026-08-05	DEAN ROBERT W II Interim CFO	Sale	$141.15K 105 shares sold	1.45% sold Direct holding	▾
2026-08-03	Sciammas Maurice EVP, WW Sales & Marketing	Sale10b5-1 footnote	$40.32K 30 shares sold	2.61% sold Trust holding	▾
2026-07-15	Sciammas Maurice EVP, WW Sales & Marketing	Sale10b5-1 footnote	$20.25M 15,000 shares sold	9.00% sold Direct holding	▾
2026-07-01	Sciammas Maurice EVP, WW Sales & Marketing	Sale10b5-1 footnote	$40.55K 30 shares sold	2.54% sold Trust holding	▾
2026-06-01	Sciammas Maurice EVP, WW Sales & Marketing	Sale10b5-1 footnote	$46.02K 30 shares sold	2.48% sold Trust holding	▾
2026-05-27	Tseng Saria EVP & General Counsel	Sale	$12.86M 7,565 shares sold	4.98% sold Direct holding	▾

Showing 30 / 42 record groups in 2026. The complete set is available through the API.

MONOLITHIC POWER SYSTEMS INC · MPWR

Follow the people behind the trades.

Sign in to look up the full history beyond 3 years, use advanced screening & filtering, download CSV, and reach other datasets through the Akkru API.

Download CSV
Earlier filings
Advanced screening & filtering
API & AI access

Already have an account?

＋ New accounts get free API credits to explore data beyond ownership filings.

For AI agents & developers

The initial HTML of this page carries its exact data as script#research-data (JSON): values, units, scope, preview limits and SEC sources. Read it directly, no script or API key needed; script#research-access says what needs an account. For the year shown, this page lists 30 of 42 purchase / sale groups and 22 of 22 other groups; the totals and the monthly series cover the whole window.

Without an account: the last 3 years, with the row caps stated on the page. A free account opens all history on file on these pages and the CSV of what a page shows. Rows beyond the caps and bulk retrieval go through the authenticated API / MCP.

MCP  https://api.akkrudata.ai/mcp

list_insider_transactions
{"ticker":"MPWR","transaction_code":["P","S"],"transaction_form_type":"4","page_size":20}

Connect to MCP with OAuth and follow the returned pagination. Credits and usage limits depend on the account.

MCP endpoint: https://api.akkrudata.ai/mcp
API / MCP documentation: /documents
llms.txt: /llms.txt

Sources, coverage & how to read this data

Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.

Non-cancelled, non-derivative purchase (P) and sale (S) rows dated inside the public window, as reported. Includes open-market and private transactions. Data after the latest filing is not asserted complete and is not zero-filled. A grouped event shares filing, transaction date, security, code, direction, ownership bucket and source. Derivative groups also match underlying security, exercise price, exercise/expiration dates and footnote references. Reported rows are retained; P/S price lots can be grouped. Post-transaction balances are never summed.