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 OF SECURITIES

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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(Print or Type Responses)
1. Name and Address of Reporting Person *
Horn Howard
  2. Issuer Name and Ticker or Trading Symbol
Ultragenyx Pharmaceutical Inc. [RARE] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chief Financial Officer
(Last)
(First)
(Middle)
C/O ULTRAGENYX PHARMACEUTICAL INC., 60 LEVERONI COURT		 3. Date of Earliest Transaction (Month/Day/Year)
03/01/2024
(Street)

NOVATO, CA 94949		 4. If Amendment, Date Original Filed (Month/Day/Year)
 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 (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 03/01/2024   A   19,400 (1) A $ 0 99,766 (2) D  

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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 (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 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
(Month/Day/Year) 		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) $ 53.69 03/01/2024   A   34,200     (3) 03/01/2034 Common Stock 34,200 $ 0 34,200 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Horn Howard
C/O ULTRAGENYX PHARMACEUTICAL INC.
60 LEVERONI COURT
NOVATO, CA 94949		       Chief Financial Officer  

Signatures

 /s/ Karah Parschauer, attorney-in-fact   03/05/2024
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) Award of Restricted Stock Units ("RSUs") under the Company's 2023 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
(2) Includes previously reported shares of common stock underlying RSUs granted to the Reporting Person, which are subject to certain vesting conditions. The amount of securities beneficially owned in column 5 reflects the correction of a typographical error in the Form 4 filed by the Reporting Person on October 10, 2023 (the "October 2023 Form 4"). The accurate number of securities beneficially owned by the Reporting Person in Column 5 of the October 2023 Form 4 is 80,366.
(3) 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.

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