Ultragenyx annual meeting approves 2023 Incentive Plan and A&R ESPP; three directors re-elected

Proposal No. 3 – Approval of the A&R ESPP At the Annual Meeting, the Company’s stockholders approved the A&R ESPP. The votes on Proposal 3 were as follows: Votes For Votes Against Abstentions Broker Non-Votes 59,717,345 262,515 5,566 5,026,508

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 2026 Annual Meeting of Stockholders or until their successors are elected. The votes on Proposal 1 were as follows: Class I Director Nominees Votes For Votes Withheld Broker Non-Votes Emil D. Kakkis, M.D., Ph.D. 58,836,682 1,148,744 5,026,508 Shehnaaz Suliman, M.D. 55,707,622 4,277,804 5,026,508 Daniel G. Welch 52,266,359 7,719,067 5,026,508

Proposal No. 2 – Approval of the 2023 Plan At the Annual Meeting, the Company’s stockholders approved the 2023 Plan. The votes on Proposal 2 were as follows: Votes For Votes Against Abstentions Broker Non-Votes 41,971,776 18,008,590 5,060 5,026,508

Proposal No. 5 – 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 5 were as follows: Votes For Votes Against Abstentions Broker Non-Votes 56,684,278 3,204,523 96,625 5,026,508

Proposal No. 4 – 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, 2023. The votes on Proposal 4 were as follows: Votes For Votes Against Abstentions 63,986,340 934,903 90,691