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*
MAYFIELD XII A DELAWARE L P

(Last) (First) (Middle)
2484 SAND HILL ROAD

(Street)
MENLO PARK CA 94025

(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
RUBICON PROJECT, INC. [ RUBI ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director X 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
02/26/2015
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
Form filed by One Reporting Person
X 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)
Code V Amount (A) or (D) Price
Common Stock 02/26/2015 S 144,833 D $19.1593(1) 3,844,539 D(3)(4)(5)
Common Stock 02/26/2015 S 2,240 D $19.1593(1) 59,451 I(3)(4)(5) By Mayfield Associates Fund XII
Common Stock 02/26/2015 S 2,240 D $19.1593(1) 59,451 I(3)(4)(5) By Mayfield Principals Fund XII
Common Stock 02/27/2015 S 89,640 D $18.9346(2) 3,754,899 D(3)(4)(5)
Common Stock 02/27/2015 S 1,386 D $18.9346(2) 58,065 I(3)(4)(5) By Mayfield Associates Fund XII
Common Stock 02/27/2015 S 1,386 D $18.9346(2) 58,065 I(3)(4)(5) By Mayfield Principals Fund XII
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)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
1. Name and Address of Reporting Person*
MAYFIELD XII A DELAWARE L P

(Last) (First) (Middle)
2484 SAND HILL ROAD

(Street)
MENLO PARK CA 94025

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
Mayfield XII Management, L.L.C.

(Last) (First) (Middle)
2484 SAND HILL ROAD

(Street)
MENLO PARK CA 94025

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) X Other (specify below)
See Explanation of Responses
1. Name and Address of Reporting Person*
MAYFIELD ASSOCIATES FUND XII

(Last) (First) (Middle)
2484 SAND HILL ROAD

(Street)
MENLO PARK CA 94025

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) X Other (specify below)
See Explanation of Responses
1. Name and Address of Reporting Person*
Mayfield Principals Fund XII

(Last) (First) (Middle)
2484 SAND HILL ROAD

(Street)
MENLO PARK CA 94025

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) X Other (specify below)
See Explanation of Responses
1. Name and Address of Reporting Person*
Beck James T

(Last) (First) (Middle)
2484 SAND HILL ROAD

(Street)
MENLO PARK CA 94025

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director 10% Owner
Officer (give title below) X Other (specify below)
See Explanation of Responses
1. Name and Address of Reporting Person*
Chaddha Navin

(Last) (First) (Middle)
2484 SAND HILL ROAD

(Street)
MENLO PARK CA 94025

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director 10% Owner
Officer (give title below) X Other (specify below)
See Explanation of Responses
1. Name and Address of Reporting Person*
VASAN ROBERT T

(Last) (First) (Middle)
2484 SAND HILL ROAD

(Street)
MENLO PARK CA 94025

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer
Director 10% Owner
Officer (give title below) X Other (specify below)
See Explanation of Responses
Explanation of Responses:
1. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $19.00 to $19.96, inclusive. The Reporting Persons undertake to provide to The Rubicon Project, Inc., any security holder of The Rubicon Project, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (1) to this Form 4.
2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $18.85 to $19.37, inclusive. The Reporting Persons undertake to provide to The Rubicon Project, Inc., any security holder of The Rubicon Project, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (2) to this Form 4.
3. Mayfield XII Management, L.L.C. ("MF XII Management") is the sole general partner of each of Mayfield XII, a Delaware Limited Partnership ("MF XII") and Mayfield Associates Fund XII, a Delaware Limited Partnership ("MF A XII"), and is the sole managing director of Mayfield Principals Fund XII, a Delaware Multiple Series LLC ("MF PF XII"), and in such capacity may be deemed to beneficially own the shares of common stock beneficially held by each of MF XII, MF A XII and MF PF XII. MF XII Management is managed by three managing directors, James T. Beck, Navin Chaddha and Robert T. Vasan, and all action by the managing directors relating to the voting or disposition of the shares of common stock beneficially held by each of MF XII, MF A XII and MF PF XII requires approval of a majority of the managing directors.
4. Each of James T. Beck, Navin Chaddha, and Robert T. Vasan, as the managing directors of MF XII Management, may be deemed to share beneficial ownership of the shares that are beneficially owned by MF XII Management, but each disclaims such beneficial ownership, except to the extent of his pecuniary interest therein.
5. The filing of this statement shall not be deemed an admission that, for the purposes of Section 16 of the Securities Act of 1934 or otherwise, the Reporting Persons are the beneficial owners of equity securities covered by this statement.
Remarks:
James T. Beck, Authorized Signatory for Mayfield XII Management, L.L.C., the sole General Partner of Mayfield XII, a Delaware Limited Partnership 03/02/2015
James T. Beck, Authorized Signatory for Mayfield XII Management, L.L.C. 03/02/2015
James T. Beck, Authorized Signatory for Mayfield XII Management, L.L.C., the sole General Partner of Mayfield Associates Fund XII, a Delaware Limited Partnership 03/02/2015
James T. Beck, Authorized Signatory for Mayfield XII Management, L.L.C., the Managing Director of Mayfield Principals Fund XII, a Delaware Multiple Series LLC 03/02/2015
James T. Beck 03/02/2015
James T. Beck, Attorney-In-Fact for Navin Chaddha 03/02/2015
James T. Beck, Attorney-In-Fact for Robert T. Vasan 03/02/2015
** 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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