Insider Trading Arrangements

3 Months Ended

9 Months Ended

Sep. 30, 2025

Trading Arrangements, by Individual [Table]

Material Terms of Trading Arrangement [Text Block]

Item 5. Other Information

Certain of our executive officers and directors have entered into trading plans pursuant to Rule 10b5-1(c) of the Securities Exchange Act of 1934, as amended. A trading plan is a written document that pre-establishes the amounts, prices and dates (or formula for determining the amounts, prices and dates) of future purchases or sales of our common stock, including the sale of shares acquired pursuant to the Monolithic Power Systems, Inc. 2004 Employee Stock Purchase Plan, amended and restated, and upon vesting of RSUs.

The following table summarizes the adoption of trading plans intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) during the three months ended September 30, 2025:

Name and Title	Adoption Date	Plan Duration	Intended Sale Amount (in shares)
Victor K. Lee, Director	August 25, 2025	Through August 31, 2026	Up to 2,000
Michael Hsing, President, Chief Executive Officer and Director	August 28, 2025	Through August 31, 2026	Up to 100,000

The following table summarizes the termination of trading plans intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) during the three months ended September 30, 2025:

Name and Title		Termination Date		Original Plan Duration		Intended Sale Amount (in shares)		Sold Amount (in shares)
Deming Xiao, Executive Vice President, Global Operations		August 5, 2025		Through February 27, 2026		Up to 160,000		39,999

During the three months ended September 30, 2025, no trading plans intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) were modified, and no other written trading arrangements that are not intended to qualify for the Rule 10b5-1(c) affirmative defense were adopted, modified, or terminated.

Non-Rule 10b5-1 Arrangement Adopted [Flag]

false

Non-Rule 10b5-1 Arrangement Terminated [Flag]

false

Victor K Lee [Member]

Trading Arrangements, by Individual [Table]

Trading Arrangement, Securities Aggregate Available Amount

2,000

Rule 10b5-1 Arrangement Adopted [Flag]

true

Trading Arrangement, Individual Name

Victor K. Lee

MONOLITHIC POWER SYSTEMS INC 10-Q