X0306 4 2018-04-19 0 0001515673 Ultragenyx Pharmaceutical Inc. RARE 0001248093 KAKKIS EMIL D C/O ULTRAGENYX PHARMACEUTICAL INC. 60 LEVERONI COURT NOVATO CA 94949 1 1 0 0 President & CEO Common Stock 2018-04-19 4 A 0 3429 0.00 A 452384 D Common Stock 2559741 I By Emil Kakkis and Jenny Soriano Living Trust, dated June 18, 2009 Represents restricted stock units (RSUs) into which previously granted performance stock units were converted on April 19, 2018 upon certification of the applicable performance metric. Half of these RSUs will vest on the first anniversary of the certification date and the other half will vest on the second anniversary of the certification date. Includes previously reported shares of common stock underlying RSUs granted to the Reporting Person, which are subject to certain vesting conditions. /s/ Ruben A. Garcia, attorney-in-fact 2018-04-19