ULTRAGENYX PHARMACEUTICAL IN (RARE) — Institutional Holders & Hedge Fund Ownership
ULTRAGENYX PHARMACEUTICAL IN (RARE) institutional ownership: 3 hedge funds and institutional investors, holding 4.9M shares ($101.7M), as of Q1 2026, per SEC Form 13F-HR filings.
ULTRAGENYX PHARMACEUTICAL IN (RARE) appears in the 13F portfolios of dozens of professional money managers each quarter; the aggregated filings surface top buyers, top sellers, and conviction-weighted holders for RARE. Pactolio aggregates these SEC Form 13F-HR filings into one view: top institutional holders, biggest QoQ buyers and sellers, and consolidated ownership changes for RARE.
The top RARE shareholders by portfolio weight are Jones Hill (5.23%), RTW Investments (0.76%), and Tetragon Financial Group (0.16%). In Q1 2026, Jones Hill made the largest position increase (+5.23%).
Top 3 Institutional Holders of ULTRAGENYX PHARMACEUTICAL IN (RARE) — Q1 2026
| # | Fund | Shares | Market Value | Portfolio Weight |
|---|---|---|---|---|
| 1 | Jones Hill | 1,165,557 | $24.4M | 5.23% |
| 2 | RTW Investments | 3,648,795 | $76.4M | 0.76% |
| 3 | Tetragon Financial Group | 39,473 | $827K | 0.16% |
- 3Hedge funds holding
- 4,853,825Shares held (disclosed)
- $101.7M13F market value
- 0.76%Median portfolio weight
Ownership History
Quarter-by-quarter share count, market value, and portfolio conviction weight (up to 5 of the heaviest weight-by-portfolio funds) of RARE. Sourced from 13F filings; reflects long equity positions only.
Quarter-over-Quarter ActivityQ1 2026
The biggest weight-increase and weight-decrease changes among funds that hold RARE. Deltas compare the selected filing to the previous reporting quarter.
Top buyers
- Jones Hill+5.23% · +1,165,557 shares
- Tetragon Financial Group+0.16% · +39,473 shares
- RTW Investments+0.07% · +648,656 shares
Top sellers
- Baker Bros. Advisors-0.37% · -2,772,692 shares
Ownership Statistics
- Funds holding
- 3
- Median weight
- 0.76%
- Largest holder
- Jones Hill · 5.23%
- Smallest holder
- Tetragon Financial Group · 0.16%
- Shares held
- 4,853,825 (-919,006)
All Institutional HoldersSortable · searchable
All institutional investors (Max 50) holding RARE in the selected quarter. Click a fund name to drill into its full 13F portfolio.
| 1 | Jones Hill | 1,165,557 | $24.4M | 5.23% |
| 2 | RTW Investments | 3,648,795 | $76.4M | 0.76% |
| 3 | Tetragon Financial Group | 39,473 | $827.0K | 0.16% |
Methodology & FAQ
Methodology: How We Track RARE Institutional Holdings
Our data is systematically aggregated directly from quarterly Form 13F-HR disclosures submitted to the U.S. Securities and Exchange Commission (SEC).
- Who Must File (Reporting Threshold): This dataset includes filings from U.S. institutional investment managers, hedge funds, mutual funds, university endowments, and family offices managing at least $100 million in Section 13(f) securities (including equities, options, convertibles, ETFs, and warrants).
- What is Included (Data Scope): We capture long positions in Section 13(f) securities for ULTRAGENYX PHARMACEUTICAL IN (RARE). By SEC regulation, 13F filings do not require the disclosure of short positions, non-U.S. holdings, or OTC derivatives. Listed options are excluded from portfolio weight calculations to ensure comparability across filers.
- Portfolio Weight Explained (Metric Definition): “Portfolio Weight” shows how much of a fund's total reported 13F portfolio value (excluding listed options) is allocated to RARE on the specific reporting date.
- How to Use This Data (Interpretation): Quarter-over-quarter changes in shares and portfolio weight reflect a combination of active trading and market price movements. These are descriptive metrics of fund allocation, not explicit buy or sell signals.
How do you measure hedge fund conviction and institutional concentration in RARE?
We evaluate fund conviction by looking at portfolio weight rather than just absolute share count. By tracking how the largest holders —such as Jones Hill , RTW Investments , and Tetragon Financial Group as of Q1 2026— change their position sizing quarter-over-quarter, we help investors distinguish between deliberate position sizing changes and passive mark-to-market drift.
Does the RARE ownership data include short interest or options?
SEC Form 13F mandates the disclosure of long positions in Section 13(f) securities, which includes equities and listed options (put and call contracts), but excludes short interest, swaps, and OTC derivatives by regulatory design. On this platform, listed options are excluded from portfolio weight calculations to ensure comparability across filers.
Are family offices and university endowments included in this RARE data?
Yes. In addition to traditional hedge funds and large asset managers, any institutional entity exercising investment discretion over at least $100 million in Section 13(f) securities must file a Form 13F. This explicitly includes single-family offices and university endowments. If a qualifying family office or endowment holds RARE stock, their allocation is systematically aggregated alongside traditional fund data.
When is the institutional ownership data updated, and is there a reporting lag?
Institutional investment managers are required to file their Form 13F within 45 days after the end of a calendar quarter (the standard “T+45” window). Our platform re-ingests new filings from the SEC EDGAR database on a nightly cycle, typically within 24–48 hours of publication, providing a point-in-time snapshot of reported consensus positioning for RARE as of each filing date.