SEC FORM 4

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Tseng Saria

(Last)

(First)

(Middle)

79 GREAT OAKS BLVD

(Street)

SAN JOSE

95119

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
MONOLITHIC POWER SYSTEMS INC [ MPWR ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	VP & General Counsel

3. Date of Earliest Transaction (Month/Day/Year)
02/03/2015

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	02/03/2015⁽¹⁾		M⁽¹⁾		43,200⁽¹⁾	A	$0.00	204,378	D
Common Stock	03/18/2015⁽²⁾		M⁽²⁾		43,200⁽²⁾	A	$0.00	247,578	D
Common Stock								2,000	I	By Family Trust

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Performance Shares	⁽³⁾	02/03/2015⁽¹⁾		M⁽¹⁾			43,200⁽¹⁾	⁽³⁾	⁽³⁾	Common Stock	43,200	$0.00	86,400	D
Performance Shares	⁽³⁾	03/18/2015⁽²⁾		M⁽²⁾			43,200⁽²⁾	⁽³⁾	⁽³⁾	Common Stock	43,200	$0.00	43,200	D

Explanation of Responses:

1. Each performance share represents a contingent right to receive a restricted stock unit upon MPWR's common stock achieving a 20-day average closing price of $47.00 per share from January 1, 2014 through December 31, 2018 (the "Performance Period"). Credited performance units are still subject to an additional, quarterly, five-year time-based vesting schedule beginning January 1, 2019, subject to acceleration under certain circumstances..

2. Each performance share represents a contingent right to receive a restricted stock unit upon MPWR's common stock achieving a 20-day average closing price of $52.00 per share from January 1, 2014 through December 31, 2018 (the "Performance Period"). Credited performance units are still subject to an additional, quarterly, five-year time-based vesting schedule beginning January 1, 2019, subject to acceleration under certain circumstances.

3. Each performance unit will vest as follows: one share of MPWR common stock will be credited for each performance unit if the price of MPWR common stock achieves a 20-day average closing price of $40.00 per share from January 1, 2014 through December 31, 2018 (the "Performance Period"), and up to four additional shares will be credited for each performance unit if the 20-day average closing price reaches $43.00, $47.00, $52.00 and $56.00 (that is, one share per price level) during the Performance Period. Credited performance units are then subject to an additional, quarterly, five-year time-based vesting schedule beginning January 1, 2019, subject to acceleration under certain circumstances.

Remarks:

	/s/ Saria Tseng	03/20/2015
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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