Vanguard Portfolio Management discloses 5.5% stake in Ultragenyx (RARE)

Rhea-AI Filing Summary

Ultragenyx Pharmaceutical Inc reports a passive institutional holding disclosure. Vanguard Portfolio Management reported beneficial ownership of 5,410,208 shares of Common Stock, representing 5.50% of the class as of 03/31/2026. The filing lists 24,216 shares of sole voting power and sole dispositive power over 5,410,208 shares. The filing is signed by Vanguard's Head of Global Fund Administration on 04/29/2026.

Insights

Institutional Ownership Analyst

Vanguard holds a mid-single-digit stake in Ultragenyx, typical for large index managers.

Vanguard Portfolio Management reports beneficial ownership of 5,410,208 shares, or 5.50%, as of 03/31/2026. The filing attributes sole voting power for 24,216 shares and sole dispositive power for the full position.

Such Schedule 13G disclosures are routine for passive managers; subsequent filings will show any material changes in stake size or voting arrangements.

Governance & Proxy Specialist

Ownership above 5% can affect proxy vote tallies but does not imply activist intent here.

The filing states Vanguard exercises dispositive power across funds and managed accounts, consistent with institutional stewardship language. No other holder is reported with >5%.

Watch for any later amendments that change voting power or disclose activist intentions; timing of any voting alignment is not stated in the excerpt.

Key Figures

Shares beneficially owned: 5,410,208 shares Percent of class: 5.50% Sole voting power: 24,216 shares +2 more

5 metrics

Shares beneficially owned 5,410,208 shares as of 03/31/2026

Percent of class 5.50% of common stock as reported

Sole voting power 24,216 shares sole power to vote or direct the vote

Sole dispositive power 5,410,208 shares sole power to dispose or direct disposition

Filing type Schedule 13G beneficial ownership disclosure

Key Terms

Schedule 13G, Beneficial ownership, Dispositive power

3 terms

Schedule 13G regulatory

"Vanguard Portfolio Management filed a Schedule 13G reporting beneficial ownership"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

Beneficial ownership financial

"Amount beneficially owned: 5410208 (b) Percent of class: 5.5 %"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

Dispositive power governance

"Sole power to dispose or to direct the disposition of: 5410208"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

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

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Accepted by SEC EDGAR 04/29/2026 - 03:48 PM Learn about SEC filing dates

FAQ

What stake does Vanguard report in Ultragenyx (RARE)?

Vanguard Portfolio Management reports beneficial ownership of 5,410,208 shares, equal to 5.50% of Ultragenyx's common stock as of 03/31/2026. This is the position disclosed on the Schedule 13G filing.

Who holds voting and dispositive power for Vanguard's Ultragenyx stake?

Vanguard reports sole voting power for 24,216 shares and sole dispositive power for 5,410,208 shares. Affiliates and managed accounts are referenced in the filing's adviser disclosure.

Does the Schedule 13G indicate Vanguard is an activist investor in RARE?

No activist intent is stated in the excerpt. The filing describes standard institutional holding and dispositive arrangements; it does not state any plans to influence management or seek board representation.

What date does the ownership amount refer to in the filing?

The reported ownership is tied to 03/31/2026. The Schedule 13G shows the share count and percentage as of that date, with the filing signed on 04/29/2026.

Are other holders identified with more than 5% in the filing?

No other person is reported with an interest over 5%. The filing states that no one else is known to have more than a 5% interest in the securities reported by Vanguard Portfolio Management.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Ultragenyx Pharmaceutical Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

90400D108

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 90400D108

1

Names of Reporting Persons

Vanguard Portfolio Management

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 24,216.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 5,410,208.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,410,208.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.50 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Portfolio Management LLC and the following affiliates of Vanguard Portfolio Management LLC or business divisions of such affiliates: Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Portfolio Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Portfolio Management LLC, or business divisions of such subsidiaries whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Ultragenyx Pharmaceutical Inc
(b)	Address of issuer's principal executive offices: 60 Leveroni Court, Novato, CA, 94949
Item 2.
(a)	Name of person filing: Vanguard Portfolio Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 90400D108
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 5410208
(b)	Percent of class: 5.5 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 24216
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 5410208
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Vanguard Portfolio Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Vanguard Portfolio Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/29/2026