X0306 4 2016-05-21 false 0001515673 Ultragenyx Pharmaceutical Inc. RARE 0001303811 Kassberg Thomas Richard C/O ULTRAGENYX PHARMACEUTICAL INC. 60 LEVERONI COURT NOVATO CA 94949 false true false false CBO & Senior Vice President Common Stock 2016-05-21 4 F false 414.00 64.01 D 69790.00 D Represents shares surrendered to the Issuer by the Reporting Person to pay required tax withholdings due upon vesting of Restricted Stock Units granted to the Reporting Person under the 2014 Incentive Plan of the Issuer. The shares surrendered were valued based on the closing price of the common stock of the Issuer on the vesting date. Includes previously reported shares of common stock underlying Restricted Stock Units granted to the Reporting Person, which are subject to certain vesting conditions. /s/ Shalini Sharp by power of attorney for Thomas Kassberg 2016-05-24