MONOLITHIC POWER SYSTEMS INC — Director's Dealing 2014

May 6, 2014

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MONOLITHIC POWER SYSTEMS INC (MPWR)
CIK: 0001280452
Period of Report: 2014-05-02

Reporting Person: Tseng Saria (VP & General Counsel)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2014-05-02	Common Stock	S	1350.0	$36.7695	Disposed	58497	Direct
2014-05-02	Common Stock	S	1148.0	$36.7136	Disposed	57349	Direct
2014-05-02	Common Stock	S	53.0	$36.51	Disposed	57296	Direct
2014-05-05	Common Stock	S	463.0	$36.2501	Disposed	56833	Direct
2014-05-05	Common Stock	S	23.0	$36.25	Disposed	56810	Direct
2014-05-05	Common Stock	S	724.0	$36.2501	Disposed	56086	Direct
2014-05-05	Common Stock	S	430.0	$36.5544	Disposed	55656	Direct
2014-05-05	Common Stock	S	5056.0	$36.6799	Disposed	50600	Direct
2014-05-06	Common Stock	S	701.0	$36.4106	Disposed	49899	Direct
2014-05-06	Common Stock	S	644.0	$36.6193	Disposed	49255	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	2000	Indirect

Footnotes

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

F2: In accordance with the reporting person's 10b5-1 trading plan.

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 $36.56 to $36.91. 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.

F4: 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 $36.18 to $36.89. 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.

F5: 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 $36.23 to $37.12. 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.

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 $36.49 to $36.73. 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.