X0306 4 2020-12-08 1 0001671858 Silverback Therapeutics, Inc. SBTX 0001734820 Presidio Management Group XII, L.L.C. 1460 EL CAMINO REAL, SUITE100 MENLO PARK CA 94025 0 0 1 0 0001734819 U.S. Venture Partners XII, L.P. 1460 EL CAMINO REAL, SUITE 100 MENLO PARK CA 94025 0 0 1 0 0001754875 U.S. Venture Partners XII-A, L.P. 1460 EL CAMINO REAL, SUITE 100 MENLO PARK CA 94025 0 0 1 0 0001474322 Tansey Casey M 1460 EL CAMINO REAL, SUITE 100 MENLO PARK CA 94025 0 0 1 0 Common Stock 2020-12-08 4 C 0 1779969 A 1779969 I By U.S. Venture Partners XII, L.P. Common Stock 2020-12-08 4 C 0 289198 A 2069167 I By U.S. Venture Partners XII, L.P. Common Stock 2020-12-08 4 C 0 90335 A 90335 I By U.S. Venture Partners XII-A, L.P. Common Stock 2020-12-08 4 C 0 14677 A 105012 I By U.S. Venture Partners XII-A, L.P. Common Stock 2020-12-08 4 P 0 47619 21 A 47619 I Directly owned by Tansey Preferred Series B Stock 2020-12-08 4 C 0 6609027 0 D Common Stock 1779969 0 I By U.S. Venture Partners XII, L.P. Preferred Series B Stock 2020-12-08 4 C 0 335417 0 D Common Stock 90335 0 I By U.S. Venture Partners XII-A, L.P. Preferred Series C Stock 2020-12-08 4 C 0 1073793 0 D Common Stock 289198 0 I By U.S. Venture Partners XII, L.P. Preferred Series C Stock 2020-12-08 4 C 0 54496 0 D Common Stock 14677 0 I By U.S. Venture Partners XII-A, L.P. The shares were purchased in the Issuer's initial public offering. Series B and Series C Preferred Stock automatically converted into shares of the Issuer's Common Stock immediately upon the closing of the Issuer's imitial public offering, for no additional consideration at a rate of 1 share of Common Stock for each 3.713 shares of Preferred Stock, based on the conversion price currently in effect. The Preferred Stock had no expiration date. Presidio Management Group XII, L.L.C. ("PMG XII"), the general partner of each of U.S. Venture Partners XII, L.P. and U.S. Venture Partners XII-A, L.P. (together, the "USVP XII Funds"), has sole voting and dispositive power with respect to the shares held by the USVP XII. Casey Tansey is the sole managing partner of PMG XII and may be deemed to have voting and dispositive power over the reported securities held by the USVP XII Funds, and each of the foregoing persons disclaims beneficial ownership of such securities, except to the extent of any pecuniary interest therein. Dale Holladay, Attorney-in-Fact for each Reporting Person 2020-12-08