Ultragenyx (RARE) CFO nets stock award and sells 10,044 shares

Rhea-AI Filing Summary

Ultragenyx Pharmaceutical Inc. Chief Financial Officer Howard Horn reported a mix of stock awards and sales. On March 1, 2026, he acquired 6,143 shares of common stock at no cost when previously granted performance stock units converted after the performance metric was certified. On March 2–3, 2026, he sold a total of 10,044 shares in open-market transactions at prices around the low‑$20s per share, with some shares sold to cover required tax withholdings from restricted stock unit vesting. After these transactions, he directly owned 85,034 shares of Ultragenyx common stock.

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).

X

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^*

Horn Howard

(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)
	Chief Financial Officer

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		6,143(1)	A	$0	95,078	D
Common Stock	03/02/2026		S		5,290(2)	D	$22.8(3)	89,788	D
Common Stock	03/02/2026		S		3,119	D	$22.54	86,669	D
Common Stock	03/03/2026		S		1,635	D	$22.4	85,034(4)	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 sold to pay required tax withholdings due to the vesting of RSUs.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $22.54 to $23.11 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range

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

	/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).
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FAQ

What insider transactions did Ultragenyx (RARE) CFO Howard Horn report?

Howard Horn reported both a stock award and stock sales. He acquired 6,143 Ultragenyx common shares from performance stock units on March 1, 2026, then sold a total of 10,044 shares in open‑market transactions on March 2 and 3, 2026.

How many Ultragenyx (RARE) shares did the CFO sell and at what prices?

Howard Horn sold 10,044 Ultragenyx common shares. The reported open‑market sales occurred at prices including $22.40, $22.80 and $22.54 per share, with one sale footnote showing a weighted average price over a $22.54 to $23.11 range.

What stock award did Ultragenyx (RARE) grant to its CFO in this Form 4?

The CFO received 6,143 shares of Ultragenyx common stock at no cost. These shares came from previously granted performance stock units that converted on March 1, 2026, after certification that the applicable performance metric had been achieved.

Were any Ultragenyx (RARE) CFO share sales related to tax withholdings?

Yes. A footnote explains that some shares were sold to pay required tax withholdings. Those tax withholdings arose due to the vesting of restricted stock units, meaning part of the reported sales were to satisfy associated tax obligations rather than discretionary cash sales.

How many Ultragenyx (RARE) shares does the CFO own after these transactions?

After the reported award and subsequent sales, Howard Horn directly owned 85,034 shares of Ultragenyx common stock. This post‑transaction holding figure reflects the net result of the 6,143‑share performance unit conversion and the 10,044 shares sold in March 2026.