RARE: Financial results

Item 2.02 Results of Operations and Financial Condition. On August 4, 2026, Ultragenyx Pharmaceutical Inc. (the “Company”) issued a press release announcing its financial results for the three months ended June 30, 2026 (the “ Press Release ”). A copy of the Press Release is furnished herewith as Exhibit 99.1 The information set forth under Item 2.02 and in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, except as shall be expressly set forth by specific reference in such filing. Item 9.01 Financial Statements and Exhibits. (d) Exhibits Exhibit No. Description 99.1 Press Release, dated August 4, 2026. 104 The cover page from the Company’s Current Report on Form 8-K dated August 4, 2026 formatted in Inline XBRL. 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. Ultragenyx Pharmaceutical Inc. Date: August 4, 2026 By: /s/Howard Horn Howard Horn Executive Vice President, Chief Financial Officer, Corporate Strategy