MONOLITHIC POWER SYSTEMS INC — Director's Dealing 2010

Apr 14, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MONOLITHIC POWER SYSTEMS INC (MPWR)
CIK: 0001280452
Period of Report: 2010-04-14

Reporting Person: Hsing Michael (Director, CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-04-14	Common Stock	M	30000	$5	Acquired	312842	Direct
2010-04-14	Common Stock	S	30000	$24.25	Disposed	282842	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-04-14	Non-Qualified Stock Option (right to buy)	$5	M	30000	Disposed	2014-01-13	Common Stock (30000)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	498566	Indirect
Common Stock	133040	Indirect
Common Stock	133040	Indirect

Footnotes

F1: In accordance with the reporting person's 10b5-1 trading plan.