Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Hsing Michael
  2. Issuer Name and Ticker or Trading Symbol
MONOLITHIC POWER SYSTEMS INC [MPWR]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
CEO
(Last)
(First)
(Middle)
79 GREAT OAKS BLVD
3. Date of Earliest Transaction (Month/Day/Year)
12/14/2013
(Street)

SAN JOSE, CA 95119
4. If Amendment, Date 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
(City)
(State)
(Zip)
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)
Code V Amount (A) or (D) Price
Common Stock 07/22/2014(1)   M(1)   110,000 (1) A $ 0 506,549 D  
Common Stock 10/21/2014(2)   M(2)   110,000 (2) A $ 0 377,994 D  
Common Stock               465,566 I By Jointly w/Spouse
Common Stock               133,040 I By S. Hsing 04 Trust
Common Stock               29,000 I Hsing Fam Foundation
Common Stock               133,040 I by M Hsing 04 Trust

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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 Underlying Securities
(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 of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Performance Shares (3) (4) 12/14/2013   A(5)   550,000 (3)     (4)   (4) Common Stock 550,000 (5) $ 0 550,000 (5) D  
Performance Shares (4) 07/22/2014(1)   M(1)     110,000 (1)   (4)   (4) Common Stock 110,000 $ 0 440,000 D  
Performance Shares (4) 10/21/2014(2)   M(2)     110,000 (2)   (4)   (4) Common Stock 110,000 $ 0 330,000 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Hsing Michael
79 GREAT OAKS BLVD
SAN JOSE, CA 95119
  X     CEO  

Signatures

 By: Saria Tseng For: Michael Hsing   11/21/2014
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(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 $40.00 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 $43.00 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) The reporting person was granted 110,000 performance units on December 14, 2013. Each performance unit vests as stated: 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 (one share per price level) during the Performance Period. Credited performance units are subject to an additional, five-year, quarterly, time-based vesting schedule beginning January 1, 2019, subject to acceleration under certain circumstances. The derivative securities reported in columns 5 and 9 reflect the maximum payout achievable. If the Company does not achieve a price threshold within the Performance Period, 1/5 of the reported derivative securities will be forfeited.
(4) 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.
(5) No new grants are being reported by this amendment. This amendment merely increases the number of derivative securities originally reported in column 5 and 9 of Table II of the Form 4 filed with the SEC on December 18, 2013 to match the number of shares underlying the derivative security originally reported in column 7 of Table II. These changes are needed to allow the Company to utilize its existing Section 16 filing program to report the vesting of the performance units when the different price thresholds are achieved. The Company's existing filing program does not allow for the reporting of vesting of performance units that entitle a grantee to a potential payout under those units greater than 1x.

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