Ultragenyx Reports Inducement Grant Under Nasdaq Listing Rule 5635(c)(4)

Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE), a biopharmaceutical company focused on the development and commercialization of novel therapies for rare and ultra-rare diseases, today reported the grant of 45,984 restricted stock units of the company’s common stock to 23 newly hired non-executive officers of the company. The awards were approved by the compensation committee of the company’s board of directors and granted under the Ultragenyx Employment Inducement Plan, with a grant date of August 16, 2026, as an inducement material to the new employees entering into employment with Ultragenyx in accordance with Nasdaq Listing Rule 5635(c)(4).

The restricted stock units vest over four years, with 25% of the underlying shares vesting on each anniversary of the grant date, subject to the employee being continuously employed by the company as of such vesting dates.

About Ultragenyx Pharmaceutical Inc. Ultragenyx is a biopharmaceutical company committed to bringing novel products to patients for the treatment of serious rare and ultrarare genetic diseases. The company has built a diverse portfolio of approved therapies and product candidates aimed at addressing diseases with high unmet medical need and clear biology for treatment, for which there are typically no approved therapies treating the underlying disease.

The company is led by a management team experienced in the development and commercialization of rare disease therapeutics. Ultragenyx’s strategy is predicated upon time- and cost-efficient drug development, with the goal of delivering safe and effective therapies to patients with the utmost urgency.

For more information on Ultragenyx, please visit the company's website at: www.ultragenyx.com .

Contact Ultragenyx Investors & Media Joshua Higa (415) 475-6370