UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Ultragenyx Pharmaceutical Inc.

(Exact name of Registrant as Specified in Its Charter)

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

As reported below, at its Annual Meeting of Stockholders (the “Annual Meeting”) on May 14, 2026, the stockholders of Ultragenyx Pharmaceutical Inc. (“Ultragenyx” or the “Company”) approved the Third Amended and Restated 2023 Incentive Plan (the “Third A&R 2023 Plan”). The Third A&R 2023 Plan is described in more detail in Ultragenyx’s 2026 Proxy Statement (“Proxy Statement”), filed with the Securities and Exchange Commission (the “SEC”) on March 27, 2026.

The foregoing description and the description incorporated by reference from the Proxy Statement are qualified in their entirety by reference to the Third A&R 2023 Plan, a copy of which is filed as Exhibit 10.1 and is incorporated herein by reference.

Item 5.07 Submission of Matters to a Vote of Security Holders.

On May 14, 2026, the Company held its Annual Meeting. As of the record date of March 23, 2026, 98,317,221 shares of the Company’s common stock were outstanding and entitled to vote at the Annual Meeting. A total of 84,786,388 shares of the Company’s common stock were represented in person or by proxy at the Annual Meeting.

Proposal No. 1 – Election of Class I Directors

At the Annual Meeting, the Company’s stockholders elected the Class I director nominees below to the Company’s Board of Directors to hold office until the 2029 Annual Meeting of Stockholders or until their successors are elected. The votes on Proposal 1 were as follows:

Proposal No. 2 – Approval of the Third A&R 2023 Plan

At the Annual Meeting, the Company’s stockholders approved the Third A&R 2023 Plan. The votes on Proposal 2 were as follows:

Proposal No. 3 – Ratification of Selection of Independent Registered Accounting Firm

At the Annual Meeting, the Company’s stockholders ratified the selection of Ernst & Young LLP as the independent registered public accounting firm of the Company for its fiscal year ending December 31, 2026. The votes on Proposal 3 were as follows:

Proposal No. 4 – Advisory (Non-Binding) Vote to Approve Executive Compensation

At the Annual Meeting, the Company’s stockholders voted, on an advisory basis, in favor of a resolution approving the compensation the Company pays to its “named executive officers” as described in the Proxy Statement. The votes on Proposal 4 were as follows:

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.