Ultragenyx (RARE) CEO logs share award and tax-driven stock sale

Rhea-AI Filing Summary

Ultragenyx Pharmaceutical President & CEO Emil Kakkis reported equity compensation activity and a related tax sale. On March 1, 2026, previously granted performance stock units converted into 71,177 shares of common stock upon certification of performance metrics. On March 2, 2026, he sold 54,404 shares of common stock at a weighted average price of $22.80 per share to cover required tax withholdings from RSU vesting. After these transactions, he directly owned 658,994 shares and indirectly held 2,158,985 shares through the Emil Kakkis and Jenny Soriano Living Trust.

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^*

KAKKIS EMIL D

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President & CEO

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		71,177(1)	A	$0	712,908	D
Common Stock	03/02/2026		S		54,404(2)	D	$22.8(3)	658,994(4)(5)	D
Common Stock								2,158,985	I	By Emil Kakkis and Jenny Soriano Living Trust, dated June 18, 2009

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 metrics.

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 490 shares acquired under the Company's Amended and Restated Employee Stock Purchase Plan on April 30, 2025.

5. 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.
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FAQ

What insider transactions did Ultragenyx (RARE) CEO Emil Kakkis report?

Emil Kakkis reported a grant of 71,177 Ultragenyx common shares from performance stock units and a sale of 54,404 shares. The sale was to cover required tax withholdings triggered by the vesting of restricted stock units, according to the Form 4 footnotes.

At what price did the Ultragenyx (RARE) CEO sell shares in this Form 4?

The Form 4 lists a weighted average sale price of $22.80 per Ultragenyx share. Footnotes explain that sales occurred in multiple trades between $22.54 and $23.11, and that detailed trade-level pricing is available to shareholders or regulators upon request.

How many Ultragenyx (RARE) shares does CEO Emil Kakkis own after this filing?

After the reported transactions, Emil Kakkis directly owned 658,994 Ultragenyx common shares. The filing also shows indirect ownership of 2,158,985 shares held through the Emil Kakkis and Jenny Soriano Living Trust, dated June 18, 2009, reflecting additional beneficial holdings.

Why did the Ultragenyx (RARE) CEO sell 54,404 shares in this transaction?

The Form 4 footnotes state the 54,404 Ultragenyx shares were sold to pay required tax withholdings. These tax obligations arose from the vesting of restricted stock units, meaning the sale functioned as a withholding transaction rather than a discretionary open-market sale for portfolio rebalancing.

What is the nature of the 71,177 Ultragenyx (RARE) shares granted to the CEO?

The 71,177 Ultragenyx shares represent performance stock units that converted into common stock on March 1, 2026. Conversion occurred after certification that specified performance metrics were achieved, turning the prior performance-based award into vested, deliverable common shares for Emil Kakkis.

How are indirect Ultragenyx (RARE) holdings of the CEO structured?

The Form 4 shows 2,158,985 Ultragenyx shares held indirectly by the Emil Kakkis and Jenny Soriano Living Trust. This trust, dated June 18, 2009, holds the shares for estate or wealth-planning purposes, and the reporting person lists them as indirect beneficial ownership.