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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1. Name and Address of Reporting Person * TAPPIN TODD L   2. Issuer Name and Ticker or Trading Symbol RUBICON PROJECT, INC. [RUBI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) CFO & COO (Last) (First) (Middle) C/O THE RUBICON PROJECT, INC., 12181 BLUFF CREEK DRIVE, 4TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 04/14/2016 (Street) LOS ANGELES, CA 90094 4. If Amendment, Date Original Filed(Month/Day/Year) 04/18/2016 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

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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

Stock Option (right to buy)

$ 7.8

04/14/2016(1)

M

113,485

(2)

02/01/2023

Common Stock

113,485

$ 0 (3)

260,377

D

Stock Option (right to buy)

$ 7.8

04/15/2016(4)

M

98,247

(2)

02/01/2023

Common Stock

98,247

$ 0 (3)

162,130

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
TAPPIN TODD L C/O THE RUBICON PROJECT, INC. 12181 BLUFF CREEK DRIVE, 4TH FLOOR LOS ANGELES, CA 90094			CFO & COO

Signatures

/s/ Jonathan Feldman, attorney-in-fact		05/17/2016
**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)	The Form 4 filed by the reporting person on April 18, 2016 is being amended to reflect the correct transaction date of April 14, 2016 for the exercise of 113,485 stock options rather than the April 15, 2016 date that was previously reported.
(2)	The option, representing a right to purchase a total of 593,650 shares, became exercisable with respect to 25% of the grant on January 28, 2014 and becomes exercisable with respect to the remainder in 36 equal installments each calendar month thereafter.
(3)	Granted as compensation for services.
(4)	The Form 4 filed by the reporting person on April 18, 2016 is being amended to reflect the correct transaction date of April 15, 2016 for the exercise of 98,247 stock options rather than the April 14, 2016 date that was previously reported.

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