X0306 4 2019-05-06 0 0001515673 Ultragenyx Pharmaceutical Inc. RARE 0001603347 Huizenga Theodore Alan C/O ULTRAGENYX PHARMACEUTICAL INC. 60 LEVERONI COURT NOVATO CA 94949 0 1 0 0 VP, Controller and PAO Common Stock 2019-05-06 4 A 0 800 0.00 A 16574 D Represents restricted stock units (RSUs) into which previously granted performance stock units were converted on May 6, 2019 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. Includes 270 shares acquired under the Company's 2014 Employee Stock Purchase Plan on April 30, 2019. /s/ Karah Parschauer, attorney-in-fact 2019-05-07