Ultragenyx CAO sells 1,283 shares of stock

Ultragenyx’s chief accounting officer sold a small block of shares under a Rule 10b5-1 plan and remains directly holding 67,863 shares, including unvested RSUs.

Available on EDGAR 09/15/2026 - 06:57 PM EDT Accepted by SEC EDGAR 09/15/2026 - 06:57 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Ultragenyx Pharmaceutical Inc. (RARE) senior vice president and chief accounting officer Theodore Alan Huizenga reported selling 1,283 shares of common stock on September 15, 2026, at $13.57 per share in an open-market or private transaction pursuant to a Rule 10b5-1 trading plan. Following this sale, he reported holding 67,863 shares directly, including shares underlying restricted stock units that remain subject to vesting conditions.

Insider Trade Summary 10b5-1

Net Seller: 1,283 shares

Net Sell 1 txn

Insider Huizenga Theodore Alan

Role SVP, Chief Accounting Officer

Sold 1,283 shs ($17K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1	1,283	$13.57	$17K

Holdings After Transaction: Common Stock — 67,863 shares (Direct)

Footnotes (1)

1. F1. 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: 1,283 shares Sale price: $13.57 per share Shares held after transaction: 67,863 shares +2 more

5 metrics

Shares sold 1,283 shares Common stock sale reported for September 15, 2026

Sale price $13.57 per share Price for the 1,283 common shares sold on September 15, 2026

Shares held after transaction 67,863 shares Direct holdings reported after the sale, including RSU-based shares

Net shares sold 1,283 shares Net buy/sell activity in this Form 4

Number of sell transactions 1 transaction Single reported sale of common stock

Key Terms

Rule 10b5-1 trading plan, restricted stock units, open market or private transaction

3 terms

Rule 10b5-1 trading plan regulatory

"transactions were made pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

restricted stock units financial

"shares of common stock underlying RSUs granted to the Reporting Person"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

open market or private transaction market

"Sale in open market or private transaction"

FAQ

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

What insider transaction did Ultragenyx (RARE) report for Theodore Alan Huizenga?

Ultragenyx reported that Theodore Alan Huizenga sold 1,283 shares of common stock on September 15, 2026, at $13.57 per share. The transaction was described as a sale in an open-market or private transaction under a Rule 10b5-1 trading plan.

How many Ultragenyx (RARE) shares does Theodore Alan Huizenga hold after this sale?

After the reported sale, Theodore Alan Huizenga directly holds 67,863 shares of Ultragenyx common stock. This amount includes previously reported shares underlying restricted stock units (RSUs) that are still subject to vesting conditions.

At what price were the Ultragenyx (RARE) shares sold in this Form 4 filing?

The 1,283 Ultragenyx common shares were sold at a price of $13.57 per share on September 15, 2026. The filing describes the transaction as a sale in an open-market or private transaction.

Was the Ultragenyx (RARE) insider sale made under a Rule 10b5-1 plan?

Yes. The filing indicates the transaction was conducted under a Rule 10b5-1 trading plan. Such plans are pre-arranged trading programs that allow insiders to sell shares according to predetermined instructions.

What is Theodore Alan Huizenga’s role at Ultragenyx (RARE)?

Theodore Alan Huizenga is identified as an officer of Ultragenyx, serving as Senior Vice President and Chief Accounting Officer. The reported transaction involves his holdings of Ultragenyx common stock.

Do Huizenga’s reported Ultragenyx (RARE) holdings include RSUs?

Yes. A footnote explains that his post-transaction total of 67,863 shares includes shares of common stock underlying RSUs previously granted to him, which are still subject to vesting conditions.

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

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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).

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^*

Huizenga Theodore Alan

(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)
	SVP, Chief Accounting Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/15/2026

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	09/15/2026		S		1,283	D	$13.57	67,863(1)	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. 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	09/15/2026
	** 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)