MONOLITHIC POWER SYSTEMS INC — Director's Dealing 2013

May 8, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MONOLITHIC POWER SYSTEMS INC (MPWR)
CIK: 0001280452
Period of Report: 2013-05-07

Reporting Person: Hsing Michael (Director, CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-05-07	Common Stock	S	2053.0	$24.24	Disposed	589966	Direct
2013-05-08	Common Stock	S	5054.0	$24.1013	Disposed	584912	Direct
2013-05-08	Common Stock	A	449.0	$0.0	Acquired	585361	Direct
2013-05-08	Common Stock	S	238.0	$24.1007	Disposed	585123	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	465566	Indirect
Common Stock	133040	Indirect
Common Stock	33000	Indirect
Common Stock	133040	Indirect

Footnotes

F1: Shares sold to pay tax obligations resulting from the vesting of restricted stock units.

F2: Equitable stock dividend adjustment approved by the Board of Director as a result of dividend Payment to shareholders on December 28, 2012. Stock dividends will release according to the same vesting schedule as the original grants.