As of November 7, 2026, 7 holders' latest Schedule 13D or 13G filings report owning 5% or more of Ultragenyx Pharmaceutical Inc. The largest reported stake is Vanguard Portfolio Management's, at 8.6%. 13 filings are on record since November 5, 2025 (Schedule 13G/A, October 30, 2026).
Who owns Ultragenyx Pharmaceutical Inc?
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Key facts
- · Reporting person: Vanguard Portfolio Management · Sole voting: 62,161 · Shared voting: 0 · Sole dispositive: 8,481,266 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-10-30
- · Reporting person: Madison Avenue International LP · Sole voting: 0 · Shared voting: 6,307,798 · Sole dispositive: 0 · Shared dispositive: 6,307,798 · SCHEDULE 13G, 2026-10-20
- · Reporting person: RTW Investments, LP · Sole voting: 0 · Shared voting: 7,796,895 · Sole dispositive: 0 · Shared dispositive: 7,796,895 · SCHEDULE 13G, 2026-08-14
- · Reporting person: AQR Capital Management, LLC · Sole voting: 0 · Shared voting: 6,398,809 · Sole dispositive: 0 · Shared dispositive: 6,560,809 · SCHEDULE 13G, 2026-08-13
- · Reporting person: State Street Corporation · Sole voting: 0 · Shared voting: 5,871,222 · Sole dispositive: 0 · Shared dispositive: 6,158,766 · SCHEDULE 13G, 2026-08-07
Ultragenyx Pharmaceutical Inc has 13 Schedule 13D or 13G filings on record since 2025-11-05. 7 holders' latest filing reports 5% or more of common stock. Each figure below is the holder's own, as filed, with the filing linked.
Layoffs on record: about 130 jobs, latest 2026-11-03 (layoff filings and notices).
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Vanguard Portfolio Management | 8.6% | 8,481,266 | SCHEDULE 13G/A, 2026-10-30 | 2026-09-30 |
| BlackRock, Inc. | 8.3% | 8,141,384 | SCHEDULE 13G/A, 2026-07-30 | 2026-06-30 |
| RTW Investments, LP | 7.9% | 7,796,895 | SCHEDULE 13G, 2026-08-14 | 2026-06-30 |
| AQR Capital Management, LLC | 6.66% | 6,560,809 | SCHEDULE 13G, 2026-08-13 | 2026-06-30 |
| Madison Avenue International LP | 6.4% | 6,307,798 | SCHEDULE 13G, 2026-10-20 | 2026-10-13 |
| State Street Corporation | 6.3% | 6,158,766 | SCHEDULE 13G, 2026-08-07 | 2026-06-30 |
| Vanguard Capital Management | 5.13% | 5,058,419 | SCHEDULE 13G, 2026-07-31 | 2026-06-30 |
| Fmr LLC | 3.5% | 3,347,890 | SCHEDULE 13G/A, 2026-02-05 | 2025-12-31 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-27 | 2026-03-13 |
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Keep reading
More on Ultragenyx Pharmaceutical Inc and the records around it.
Ultragenyx Pharmaceutical Inc elsewhere on the record
- Layoff notices Nov 2026
- Who owns it
Companies that share a holder
- Madison Avenue International LP also filed stake reports on 11 other companies: Graham Holdings Co (Aug 2026), STAAR SURGICAL CO (Aug 2026), Theravance Biopharma, Inc. (Aug 2026)
- RTW Investments, LP also filed stake reports on 43 other companies: CG Oncology, Inc. (Aug 2026), iRhythm Holdings, Inc. (Aug 2026), Kailera Therapeutics, Inc. (Aug 2026)
- AQR Capital Management, LLC also filed stake reports on 190 other companies: Bold Eagle Acquisition Corp. (Nov 2026), Centurion Acquisition Corp. (Aug 2026), FG Merger II Corp. n/k/a BOXABL Inc. (Aug 2026)
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What the Full Report on Ultragenyx Pharmaceutical Inc covers
The Short Answer
Which Company This Is
What They Do, And How The Money Works
Who Runs It, And How To Reach Them
The Money: Funding, Valuation, Runway
Who Pays Them, And Who They Are Up Against
Warning Bells
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| Vanguard Portfolio Management | 62,161 | 0 | 8,481,266 | 0 | SCHEDULE 13G/A, 2026-10-30 |
| BlackRock, Inc. | 7,991,763 | 0 | 8,141,384 | 0 | SCHEDULE 13G/A, 2026-07-30 |
| RTW Investments, LP | 0 | 7,796,895 | 0 | 7,796,895 | SCHEDULE 13G, 2026-08-14 |
| Roderick Wong | 0 | 7,796,895 | 0 | 7,796,895 | SCHEDULE 13G, 2026-08-14 |
| AQR Capital Management, LLC | 0 | 6,398,809 | 0 | 6,560,809 | SCHEDULE 13G, 2026-08-13 |
| AQR Capital Management Holdings, LLC | 0 | 6,398,809 | 0 | 6,560,809 | SCHEDULE 13G, 2026-08-13 |
| Madison Avenue International LP | 0 | 6,307,798 | 0 | 6,307,798 | SCHEDULE 13G, 2026-10-20 |
| Madison Avenue Partners, LP | 0 | 6,307,798 | 0 | 6,307,798 | SCHEDULE 13G, 2026-10-20 |
| EMAI Management, LLC | 0 | 6,307,798 | 0 | 6,307,798 | SCHEDULE 13G, 2026-10-20 |
| Madison Avenue GP, LLC | 0 | 6,307,798 | 0 | 6,307,798 | SCHEDULE 13G, 2026-10-20 |
| Caraway Jackson Investments LLC | 0 | 6,307,798 | 0 | 6,307,798 | SCHEDULE 13G, 2026-10-20 |
| Eli Samaha | 0 | 6,307,798 | 0 | 6,307,798 | SCHEDULE 13G, 2026-10-20 |
| State Street Corporation | 0 | 5,871,222 | 0 | 6,158,766 | SCHEDULE 13G, 2026-08-07 |
| Vanguard Capital Management | 761,928 | 0 | 5,058,419 | 0 | SCHEDULE 13G, 2026-07-31 |
The latest filing identifies Ultragenyx Pharmaceutical Inc by CUSIP 90400D108 and gives its principal executive office as 60 Leveroni Court, Novato, CA 94949 (SCHEDULE 13G/A, 2026-10-30).
What the percentages are based on
The following percentage is based on 98,588,873 Common Stock outstanding as of June 30, 2026, as disclosed in the Issuer's Quarterly Report on Form 10-Q, filed with the Securities and Exchange Commission on August 5, 2026. As of October 20, 2026, the Reporting Persons may be deemed to have beneficially owned approximately 6.4% of the outstanding Common Stock.Madison Avenue International LP, SCHEDULE 13G, 2026-10-20
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-11-05 | Fmr LLC | 8.3% | SCHEDULE 13G |
| 2026-02-05 | Fmr LLC | 3.5% | SCHEDULE 13G/A |
| 2026-03-27 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-04-29 | Vanguard Portfolio Management | 5.5% | SCHEDULE 13G |
| 2026-05-12 | State Street Corporation | 5.1% | SCHEDULE 13G |
| 2026-07-30 | BlackRock, Inc. | 8.3% | SCHEDULE 13G/A |
| 2026-07-31 | Vanguard Capital Management | 5.13% | SCHEDULE 13G |
| 2026-07-31 | Vanguard Portfolio Management | 6.95% | SCHEDULE 13G/A |
| 2026-08-07 | State Street Corporation | 6.3% | SCHEDULE 13G |
| 2026-08-13 | AQR Capital Management, LLC | 6.66% | SCHEDULE 13G |
| 2026-08-14 | RTW Investments, LP | 7.9% | SCHEDULE 13G |
| 2026-10-20 | Madison Avenue International LP | 6.4% | SCHEDULE 13G |
| 2026-10-30 | Vanguard Portfolio Management | 8.6% | SCHEDULE 13G/A |
Questions about who owns Ultragenyx Pharmaceutical Inc
Who owns Ultragenyx Pharmaceutical Inc?
On this page, 7 holders' latest ownership filings report 5% or more of Ultragenyx Pharmaceutical Inc: Vanguard Portfolio Management (8.6%, Schedule 13G/A, filed 2026-10-30), BlackRock, Inc. (8.3%, Schedule 13G/A, filed 2026-07-30), RTW Investments, LP (7.9%, Schedule 13G, filed 2026-08-14), AQR Capital Management, LLC (6.66%, Schedule 13G, filed 2026-08-13) and Madison Avenue International LP (6.4%, Schedule 13G, filed 2026-10-20); 2 more are listed above.
Who are the largest shareholders of Ultragenyx Pharmaceutical Inc?
By the share each holder's latest filing reports, the largest holders of Ultragenyx Pharmaceutical Inc on this page are Vanguard Portfolio Management (8.6%), BlackRock, Inc. (8.3%) and RTW Investments, LP (7.9%).
When did Vanguard Portfolio Management buy into Ultragenyx Pharmaceutical Inc?
The filings give report dates, not purchase dates. The earliest filing from Vanguard Portfolio Management on this page is the Schedule 13G, filed 2026-04-29, reporting 5.5%; its latest, Schedule 13G/A filed 2026-10-30, reports 8.6%.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 13 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.