Ultragenyx CFO Howard Horn sells 7,066 shares

The chief financial officer's sale was linked to required tax withholding from RSU vesting; the reported post-sale position was 89,229 shares.

Rhea-AI Filing Summary

Ultragenyx Pharmaceutical Inc. (RARE) Chief Financial Officer Howard Horn reported a direct sale of 7,066 shares on October 15, 2026, at $15.27 per share. The shares were sold to pay required tax withholdings due to RSU vesting. Horn reported 89,229 shares after the transaction; no Rule 10b5-1 plan is reported.

Insider Trade Summary

Net Seller: 7,066 shares

Net Sell 1 txn

Insider Horn Howard

Role Chief Financial Officer

Sold 7,066 shs ($108K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	7,066	$15.27	$108K

Holdings After Transaction: Common Stock — 89,229 shares (Direct)

Footnotes (2)

1. F1. Represents shares sold to pay required tax withholdings due to the vesting of RSUs.
2. F2. Includes previously reported shares of common stock underlying RSUs granted to the Reporting Person, which are subject to certain vesting conditions.

Key Figures

Shares sold: 7,066 shares Sale price: $15.27 per share Shares following transaction: 89,229 shares

3 metrics

Shares sold 7,066 shares October 15, 2026; sold to pay required tax withholdings due to RSU vesting

Sale price $15.27 per share October 15, 2026

Shares following transaction 89,229 shares Reported after the October 15, 2026 transaction

Key Terms

RSUs, vesting conditions, tax withholdings

3 terms

RSUs financial

"due to the vesting of RSUs"

RSUs, or restricted stock units, are a form of company shares given to employees as part of their compensation. They are typically awarded with certain restrictions, such as a waiting period before they can be fully owned or sold, similar to earning a gift that becomes fully yours over time. For investors, RSUs can impact a company's stock offerings and reflect how much the company relies on stock-based incentives to attract and retain talent.

vesting conditions financial

"subject to certain vesting conditions"

Vesting conditions are the rules that determine when someone earning company stock or stock options actually gains the right to keep or sell them, typically based on staying with the company for a set time or meeting performance targets. Think of it like keys that unlock gradually — some unlock by calendar date, others only after agreed milestones. Investors care because vesting shapes management incentives, the timing of share sales, and the number of shares that can enter the market, which can affect a company's valuation and ownership mix.

tax withholdings financial

"required tax withholdings due to the vesting of RSUs"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many shares did Ultragenyx (RARE) CFO Howard Horn sell?

Howard Horn, Ultragenyx's Chief Financial Officer, reported selling 7,066 shares on October 15, 2026, at $15.27 per share. The shares were sold to pay required tax withholdings due to RSU vesting; he reported 89,229 shares afterward. No Rule 10b5-1 plan is reported.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/19/2026 - 01:49 PM EDT Accepted by SEC EDGAR 10/19/2026 - 01:48 PM EDT Learn about SEC filing dates

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Horn Howard

(Last) (First) (Middle)

C/O ULTRAGENYX PHARMACEUTICAL INC.

60 LEVERONI COURT

(Street)

NOVATO CALIFORNIA 94949

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/15/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	10/15/2026		S		7,066(1)	D	$15.27	89,229(2)	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 sold to pay required tax withholdings due to the vesting of RSUs.

2. 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	10/19/2026
	** 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.
* Form 4: SEC 1474 (03-26)