X0306 4/A 2019-03-01 2019-03-04 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 2019-03-01 4 A 0 20000 0.00 A 470473 D Common Stock 2019-03-05 4 S 0 2890 65.52 D 467583 D Common Stock 2559741 I By Emil Kakkis and Jenny Soriano Living Trust, dated June 18, 2009 Stock Option (Right to Buy) 67.55 2019-03-01 4 A 0 66000 0.00 A 2029-03-01 Common Stock 66000 66000 D Award of Restricted Stock Units ("RSUs") under the Company's 2014 Incentive Plan. The RSUs shall vest with respect to 1/4th of the underlying shares on each anniversary of the grant date, such that the RSUs are fully vested on the fourth anniversary of the grant date. Includes previously reported shares of common stock underlying RSUs granted to the Reporting Person, which are subject to certain vesting conditions. Represents shares sold to pay required tax withholdings due to the vesting of Restricted Stock Units. On the first anniversary of the grant date of the option (the "Option Anniversary Date"), 1/4th of the shares initially subject to the option shall vest; thereafter, 1/48th of the shares initially subject to the option shall vest on each month as measured from the Option Anniversary Date. This amendment is filed to (i) include one additional share in column 5 of Table 1 inadvertently left off of the Form 4 filed on April 19, 2018 that reported an acquisition of RSUs into which previously granted PSUs were converted, and (ii) change the transaction date, transaction code, share amounts, and sale price reported in the second row of Table I to reflect that shares were sold to cover taxes rather than withheld. No other changes were made to the information reported on the original Form 4 filed on March 4, 2019. /s/ Ruben A. Garcia, attorney-in-fact 2019-04-17