Ultragenyx (RARE) executive reports stock grant and tax share surrender

Rhea-AI Filing Summary

Ultragenyx Pharmaceutical executive Dennis Karl Huang reported equity compensation activity involving company common stock. On March 1, 2026, he acquired 11,137 shares at a stated price of $0.00 per share through a grant/award, when previously granted performance stock units converted upon certification of a performance metric.

On March 2, 2026, he disposed of 999 shares at $23.39 per share, surrendering them back to Ultragenyx to cover required tax withholdings tied to restricted stock unit vesting. After these transactions, he directly owned 124,729 common shares.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Huang Dennis Karl

(Last) (First) (Middle)

C/O ULTRAGENYX PHARMACEUTICAL INC.

60 LEVERONI COURT

(Street)

NOVATO CA 94949

(City) (State) (Zip)

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)
	See Remarks

3. Date of Earliest Transaction (Month/Day/Year)
03/01/2026

4. If Amendment, Date of 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

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	03/01/2026		A		11,137(1)	A	$0	125,728	D
Common Stock	03/02/2026		F		999(2)	D	$23.39	124,729(3)	D

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 Securities Underlying Derivative Security (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: 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

Explanation of Responses:

1. Represents shares of common stock which previously granted performance stock units were converted on March 1, 2026 upon certification of the performance metric.

2. Represents shares surrendered to the Issuer by the Reporting Person to pay required tax withholdings due to the vesting of RSUs.

3. Includes previously reported shares of common stock underlying RSUs granted to the Reporting Person, which are subject to certain vesting conditions.

Remarks:

EVP, Chief Technical Operations Officer

	/s/ Karah Parschauer, attorney-in-fact	03/03/2026
	** Signature of Reporting Person	Date
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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transactions did Ultragenyx (RARE) executive Dennis Karl Huang report?

Dennis Karl Huang reported one stock award and one tax-withholding share surrender. He received 11,137 common shares on March 1, 2026, from a performance-based award and surrendered 999 shares on March 2, 2026, to cover tax withholdings on vested RSUs.

How many Ultragenyx (RARE) shares did Dennis Karl Huang acquire in the latest Form 4?

He acquired 11,137 shares of Ultragenyx common stock on March 1, 2026. These came from previously granted performance stock units that converted into shares upon certification of a performance metric, with a reported acquisition price of $0.00 per share as part of his equity compensation.

Why did Dennis Karl Huang surrender Ultragenyx (RARE) shares in this filing?

He surrendered 999 Ultragenyx shares on March 2, 2026, to pay required tax withholdings. The surrender related to the vesting of restricted stock units, using shares instead of cash to satisfy tax obligations owed in connection with that vesting event.

What is Dennis Karl Huang’s Ultragenyx (RARE) share ownership after these transactions?

After completing both the stock award and tax-withholding surrender, Dennis Karl Huang directly owns 124,729 Ultragenyx common shares. This figure reflects the 11,137-share grant added on March 1, 2026, and the 999 shares surrendered for taxes on March 2, 2026.

Were the Ultragenyx (RARE) insider transactions open-market buys or sales?

The transactions were equity compensation related, not open-market trades. One entry records a grant of 11,137 shares from converting performance stock units, and the other is a disposition of 999 shares surrendered back to Ultragenyx to cover tax withholdings from RSU vesting.