Sec Form 4 Filing - KAKKIS EMIL D @ Ultragenyx Pharmaceutical Inc. - 2023-03-01

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person KAKKIS EMIL D 2. Issuer Name and Ticker or Trading Symbol Ultragenyx Pharmaceutical Inc. [ RARE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) President & CEO (Last) (First) (Middle) C/O ULTRAGENYX PHARMACEUTICAL INC., 60 LEVERONI COURT 3. Date of Earliest Transaction (MM/DD/YY) 03/01/2023 (Street) NOVATO, CA94949 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 03/01/2023 A 8,716 ( 1 ) A $ 0 569,406 D Common Stock 03/01/2023 A 46,200 ( 2 ) A $ 0 615,606 D Common Stock 03/01/2023 F 16,140 ( 3 ) D $ 45.65 599,176 ( 4 ) ( 5 ) D Common Stock 2,263,985 I By Emil Kakkis and Jenny Soriano Living Trust, dated June 18, 200

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (Right to Buy) $ 45.65 03/01/2023 A 83,500 ( 6 ) 03/01/2033 Common Stock 83,500 $ 0 83,500 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other KAKKIS EMIL D C/O ULTRAGENYX PHARMACEUTICAL INC. 60 LEVERONI COURT NOVATO, CA94949 X President & CEO Signatures /s/ Karah Parschauer, attorney-in-fact 03/03/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents shares of common stock which previously granted performance stock units were converted on March 1, 2023 upon certification of the performance metric. ( 2 )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. ( 3 )Represents shares surrendered to the Issuer by the Reporting Person to pay required tax withholdings due to the vesting of RSUs. ( 4 )Includes previously reported shares of common stock underlying RSUs granted to the Reporting Person, which are subject to certain vesting conditions. ( 5 )Reflects transfer of directly owned shares of common stock from the Reporting Person to a trust indirectly held by the Reporting Person that have taken place since the most recent prior report on Form 4. ( 6 )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.

Remarks: This Form 4 corrects an error made in the Reporting Person's prior most recent Form 4 which reflected a sale that occurred from his individual account, rather than from his trust account. The amounts set forth in Table I, Column 6 of this Form 4 reflect the corrected amounts that are directly and indirectly beneficially owned by the Reporting Person.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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