X0206 3 2014-04-01 0 0001595974 RUBICON PROJECT, INC. RUBI 0001603810 Mandal Sumant C/O THE RUBICON PROJECT, INC. 12181 BLUFF CREEK DRIVE, 4TH FLOOR LOS ANGELES CA 90094 1 0 1 0 Class A Common Stock 324237 I See Footnote Class A Common Stock 5796 I See Footnote Series A Convertible Preferred Stock Class A Common Stock 3022962 I See Footnote Series A Convertible Preferred Stock Class A Common Stock 54038 I See Footnote Series B Convertible Preferred Stock Class A Common Stock 1946205 I See Footnote Series B Convertible Preferred Stock Class A Common Stock 34790 I See Footnote Series C Convertible Preferred Stock Class A Common Stock 348781 I See Footnote Series C Convertible Preferred Stock Class A Common Stock 6235 I See Footnote Series D Convertible Preferred Stock Class A Common Stock 547155 I See Footnote Series D Convertible Preferred Stock Class A Common Stock 9781 I See Footnote Pursuant to the Sixth Amended and Restated Certificate of Incorporation (the "A&R Charter") of The Rubicon Project, Inc. (the "Issuer") to be filed immediately prior to the completion of the Issuer's initial public offering, effective upon the filing of the A&R Charter each share of Class A Common Stock (including each share of Class A Common Stock issued upon the conversion of shares of the Company's Convertible Preferred Stock upon closing of the Issuer's initial public offering) will be automatically reclassified and converted into one share of a single class of Common Stock. These shares are held by Clearstone Venture Partners III-A, LP ("CVP-A"). The reporting person is a managing member of Clearstone Venture Management III, LLC, which is the general partner of CVP-A. The reporting person disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported shares for purposes of Section 16 or for any other purpose. These shares are held by Clearstone Venture Partners III-B, a Delaware Multiple Series LLC ("CVP-B"). The reporting person is a managing member of Clearstone Venture Management III, LLC, which is the managing member of CVP-B. The reporting person disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported shares for purposes of Section 16 or for any other purpose. Each share of Convertible Preferred Stock will automatically convert into 1/2 of a share of Class A Common Stock upon completion of the Issuer's initial public offering of its Common Stock. The Convertible Preferred Stock has no expiration date. Exhibit 24.1 - Power of Attorney. /s/ Jonathan Feldman, attorney-in-fact 2014-04-01