Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
282 institutional managers reported holding RARE for the quarter ended Mar 31, 2026. Reported positions total over 95% of shares outstanding; the top 10 hold 44%. 52 opened new positions; 45 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| Vanguard Group | 10.32M | 10.26% | $216.0M | added +0.6% | 2014 Q1 |
| BlackRock | 7.30M | 7.26% | $152.7M | added +10.1% | 2014 Q1 |
| State Street | 5.02M | 4.99% | $105.0M | added +16.7% | 2014 Q2 |
| AQR Capital | 4.58M | 4.55% | $95.8M | added +236.5% | 2023 Q4 |
| RTW Investments, LP | 3.65M | 3.63% | $76.3M | added +21.6% | 2021 Q4 |
| Sands Capital | 3.21M | 3.19% | $67.2M | trimmed -7.8% | 2023 Q2 |
| Sofinnova Investments, INC. | 3.15M | 3.13% | $65.8M | added +3676.6% | 2025 Q4 |
| Wellington Management | 2.64M | 2.63% | $55.2M | added +7.3% | 2014 Q1 |
| Bellevue Group AG | 2.38M | 2.37% | $49.8M | added +92148.1% | 2025 Q4 |
| Assenagon Asset Management S.a. | 2.26M | 2.24% | $47.2M | added +1030.4% | 2021 Q3 |
| Two Sigma | 2.21M | 2.19% | $46.1M | added +420.2% | 2020 Q2 |
| Frontier Capital Management CO LLC | 2.19M | 2.18% | $45.8M | added +11.5% | 2025 Q2 |
| Citadel Advisors | 2.12M | 2.10% | $44.3M | trimmed -9.1% | 2014 Q1 |
| Geode Capital | 1.85M | 1.84% | $38.7M | added +0.6% | 2014 Q1 |
| Millennium Management | 1.77M | 1.76% | $37.1M | added +101.2% | 2019 Q3 |
| Gw&k Investment Management, LLC | 1.62M | 1.61% | $33.8M | added +17.5% | 2023 Q1 |
| Morgan Stanley | 1.50M | 1.49% | $31.4M | trimmed -17.8% | 2014 Q1 |
| Jacobs Levy Equity Management, INC | 1.43M | 1.42% | $29.9M | trimmed -18.2% | 2025 Q2 |
| Voloridge Investment Management | 1.43M | 1.42% | $29.8M | added +121.8% | 2025 Q3 |
| D. E. Shaw | 1.26M | 1.25% | $26.4M | added +265.8% | 2024 Q2 |
| Rock Springs Capital Management LP | 1.22M | 1.21% | $25.5M | trimmed -3.8% | 2014 Q1 |
| Jones Hill Capital LP (focused) | 1.17M | 1.16% | $24.4M | first filing | 2026 Q1 |
| Candriam S.c.a. | 1.10M | 1.09% | $22.9M | added +37.1% | 2020 Q4 |
| UBS | 1.06M | 1.05% | $22.1M | added +20.9% | 2014 Q2 |
| Bank OF America CORP /DE/ | 1.05M | 1.04% | $21.9M | trimmed -13.8% | 2014 Q1 |
| Qube Research & Technologies LTD | 914.8k | 0.91% | $19.1M | opened | 2026 Q1 |
| BNP Paribas Financial Markets | 908.9k | 0.90% | $19.0M | trimmed -67.6% | 2014 Q3 |
| Point72 | 893.3k | 0.89% | $18.7M | opened | 2020 Q3 |
| Eagle Health Investments LP (focused) | 884.1k | 0.88% | $18.5M | opened | 2024 Q1 |
| Catalio Capital Management, LP (focused) | 850.8k | 0.85% | $17.8M | added +423.4% | 2025 Q2 |
| Sphera Funds Management LTD. | 809.3k | 0.81% | $16.9M | added +169.2% | 2022 Q3 |
| T. Rowe Price | 804.1k | 0.80% | $16.8M | trimmed -48.3% | 2014 Q1 |
| Nuveen | 662.1k | 0.66% | $13.9M | trimmed -17.4% | 2019 Q1 |
| HRT Financial LP | 613.2k | 0.61% | $12.8M | added +22.2% | 2022 Q4 |
| Pictet Asset Management Holding SA | 603.6k | 0.60% | $12.6M | trimmed -51% | 2020 Q3 |
| Palo Alto Investors LP | 596.5k | 0.59% | $12.5M | added +29.3% | 2025 Q2 |
| Legal & General Group PLC | 590.3k | 0.59% | $12.3M | added +43.5% | 2014 Q3 |
| Renaissance Technologies | 561.7k | 0.56% | $11.8M | added +53.4% | 2024 Q3 |
| Charles Schwab Investment Management | 558.5k | 0.56% | $11.7M | trimmed -6.8% | 2014 Q1 |
| Northern Trust | 535.6k | 0.53% | $11.2M | added +1.7% | 2014 Q1 |
| Susquehanna International Group | 524.8k | 0.52% | $11.0M | added +244.5% | 2017 Q4 |
| Jump Financial | 504.1k | 0.50% | $10.5M | added +334.9% | 2024 Q2 |
| Connor, Clark & Lunn Investment Management LTD. | 500.9k | 0.50% | $10.5M | added +89.8% | 2022 Q2 |
| Schonfeld Strategic Advisors | 494.7k | 0.49% | $10.3M | trimmed -33.3% | 2023 Q4 |
| Ikarian Capital, LLC | 482.6k | 0.48% | $10.1M | added +3708.5% | 2025 Q4 |
| Adage Capital Partners GP, L.l.c. | 480.0k | 0.48% | $10.0M | added +71.4% | 2020 Q4 |
| Manufacturers Life Insurance Company, THE | 451.1k | 0.45% | $9.4M | added +36.2% | 2022 Q1 |
| Squarepoint Ops LLC | 444.5k | 0.44% | $9.3M | added +13.8% | 2022 Q1 |
| Algert Global LLC | 428.5k | 0.43% | $9.0M | added +95.5% | 2023 Q1 |
| Russell Investments Group, LTD. | 403.0k | 0.40% | $8.4M | trimmed -52.1% | 2016 Q4 |
Largest 50 of 282 shown; the full ranked, searchable register is at boothcheck.com/holders/RARE. Related filers are grouped using the filings' own included-manager declarations. Historically, several managers opening new positions in the same quarter said almost nothing about the quarter that followed (59,118 cases since 2013). A filed record, not a forecast. Nothing here is investment advice.