Ultragenyx Pharmaceutical Inc.

Except for the factual statements made herein, information contained in this Current Report on Form 8-K consists of forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that involve risks, uncertainties and assumptions that are difficult to predict. Words such as “anticipates”, intends,” “expects,” “plans” and similar expressions, or the use of future tense, identify forward-looking statements, but their absence does not mean that a statement is not forward-looking. Such forward-looking statements are not guarantees of performance and actual actions or events could differ materially from those contained in such statements. These forward-looking statements include, but are not limited to, statements about the percentage reduction in organizational headcount; the timing of completion of the RIF; the Company’s expectations regarding the expected results and anticipated benefits of the Restructuring; and the Company’s estimates regarding the amount, timing and nature of the Restructuring charges. There can be no assurance that the Restructuring or the RIF will have the intended effect on the Company’s business plans and financial results, or that any anticipated charges and any anticipated cost savings associated with the Restructuring will achieve its intended benefits. In addition, the Company’s workforce reduction may be greater or less than anticipated and the workforce reduction may have an adverse impact on the Company’s business and results of operations. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of the Company in general, see the Company’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) on August 5, 2026 and its subsequent periodic reports filed with the SEC.

Item 9.01 Financial Statements and Exhibits.