MONOLITHIC POWER SYSTEMS INC — Director's Dealing 2013

Feb 8, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MONOLITHIC POWER SYSTEMS INC (MPWR)
CIK: 0001280452
Period of Report: 2013-02-06

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-02-06	Common Stock	S	3534.0	$22.8888	Disposed	105476.0	Direct
2013-02-06	Common Stock	A	615.0	$0.0	Acquired	106091.0	Direct
2013-02-07	Common Stock	S	241.0	$22.7	Disposed	105850.0	Direct
2013-02-07	Common Stock	S	12240.0	$25.0047	Disposed	51764.0	Indirect
2013-02-08	Common Stock	S	7760.0	$25.0004	Disposed	44004.0	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	14371.0	Indirect
Common Stock	14371.0	Indirect

Footnotes

F1: 50% of the Performance Units are subject to vest on the first anniversay of the Grant Date and 50% of the Performance Units are subject to vest on the second anniversary of the Grant Date, provided that the Grantee continues to be a service provider on such dates.

F2: Shares sold to pay tax obligations resulting from the vesting of performance units (restricted stock units) originally granted on February 25, 2010. The Performance was met and the shares were released per board approval on February 5, 2013.

F3: 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.

F4: Shares sold to pay tax obligations resulting from the release of restricted stock units.

F5: In accordance with the reporting person's 10b5-1 trading plan.

F6: The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $25.00 to $25.06. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

F7: The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $25.00 to $25.01. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.