MONOLITHIC POWER SYSTEMS INC — Director's Dealing 2010

Feb 10, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MONOLITHIC POWER SYSTEMS INC (MPWR)
CIK: 0001280452
Period of Report: 2010-02-09

Reporting Person: Sciammas Maurice (Sr. V.P.of Sales and Marketing)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-02-09	Common Stock	S	524	$20.2	Disposed	42878	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	95934	Indirect
Common Stock	24671	Indirect
Common Stock	24671	Indirect

Footnotes

F1: Shares sold to pay tax obligations resulting from the vesting of performance units (restricted stock units) originally granted on February 8, 2008.

F2: Shares held by Sciammas Family Living Trust, Maurice Sciammas and Christina Sciammas, Trustees

F3: Shares held by Christina Sciammas 2004 Trust, Christina Sciammas and Maurice Sciammas, Trustees

F4: Shares held by Maurice Sciammas 2004 Trust, Maurice Sciammas and Christina Sciammas, Trustees