X0306 4 2015-10-14 0 0001501989 CytomX Therapeutics, Inc. CTMX 0001538676 Canaan IX L.P. 285 RIVERSIDE AVENUE, SUITE 250 WESTPORT CT 06880 1 0 1 0 0001654586 Canaan Partners IX LLC 285 RIVERSIDE AVENUE, SUITE 250 WESTPORT CT 06880 1 0 1 0 Common Stock 2015-10-14 4 C 0 4884755 A 4884755 I See Footnote Series B-1 Redeemable Convertible Preferred Stock 2015-10-14 4 C 0 3566337 D Common Stock 3566337 0 I See Footnote Series C Redeemable Convertible Preferred Stock 2015-10-14 4 C 0 1318418 D Common Stock 1318418 0 I See Footnote Immediately prior to the issuer's initial public offering ("IPO") on October 14, 2015, each share of the issuer's Series B-1 convertible preferred stock, which has no expiration date, automatically converted into one (1) share of the issuer's Common Stock, for no additional consideration. The shares are held directly by Canaan IX L.P. (the "Canaan Fund"). The sole general partner of the Canaan Fund is Canaan Partners IX LLC ("Canaan IX", and together with the Canaan Fund, the "Canaan Entities"), and each may be deemed to have sole voting, investment and dispositive power with respect to the shares held by the Canaan Fund. Timothy Shannon, a non-managing member of Canaan IX, serves as representative of the Canaan Entities on the issuer's board of directors. Canaan IX disclaims Section 16 beneficial ownership of the securities held by the Canaan Fund, except to the extent of its pecuniary interest therein, if any. Immediately prior to the issuer's IPO on October 14, 2015, each share of the issuer's Series C convertible preferred stock, which has no expiration date, automatically converted into one (1) share of the issuer's Common Stock, for no additional consideration. EXHIBIT 99 Joint Filer Information filed herewith and Exhibit 24-Power of Attorney (incorporated herein by reference to the Power of Attorney filed as Exhibit 24 to the Form 3 by the Reporting Persons on October 7, 2015). Canaan IX L.P., By: Canaan Partners IX LLC, its general partner, By: /s/ Jaime Slocum, Attorney-in-Fact 2015-10-16 Canaan Partners IX LLC, By: /s/ Jaime Slocum, Attorney-in-Fact 2015-10-16