MONOLITHIC POWER SYSTEMS INC — Director's Dealing 2013

May 22, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MONOLITHIC POWER SYSTEMS INC (MPWR)
CIK: 0001280452
Period of Report: 2013-05-20

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-05-20	Common Stock	M	40000.0	$11.31	Acquired	151434	Direct
2013-05-20	Common Stock	S	40000.0	$24.2507	Disposed	111434	Direct
2013-05-20	Common Stock	M	1882.0	$11.31	Acquired	113316	Direct
2013-05-20	Common Stock	S	1882.0	$24.2507	Disposed	111434	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2013-05-20	Non-Qualified Stock Option (right to buy)	$11.31	M	1882.0	Disposed	2013-10-26	Common Stock (1882)	Direct
2013-05-20	Non-Qualified Stock Option (right to buy)	$11.85	M	40000.0	Disposed	2013-10-26	Common Stock (40000)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	44004	Indirect
Common Stock	14371	Indirect
Common Stock	14371	Indirect

Footnotes

F1: The expiration date for this grant was October 26, 2013.

F2: On December 11, 2012, the Company's Board declared a special cash dividend of $1.00 per common share, which was paid on December 28, 2012 to all shareholders of record as of the close of business on December 21, 2012. The Board approved a modification whereby each outstanding option as of December 28, 2012 was increased by a ratio of 1.0471 with a corresponding reduction in the exercise price.

F3: 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 $24.20 to $24.49. 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.