Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
419 institutional managers reported holding ARWR for the quarter ended Mar 31, 2026. Together they hold about 84% of shares outstanding; the top 10 hold 51%. 95 opened new positions; 69 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| BlackRock | 18.16M | 12.75% | $1.14B | trimmed -14.8% | ≤2013 |
| Vanguard Group | 14.36M | 10.09% | $900.7M | trimmed -6.1% | ≤2013 |
| Avoro Capital Advisors LLC (focused) | 10.70M | 7.51% | $670.9M | added +0.7% | 2023 Q2 |
| FMR (Fidelity) | 7.27M | 5.10% | $455.7M | added +11.4% | 2018 Q3 |
| State Street | 6.50M | 4.56% | $407.3M | added +1.4% | 2015 Q4 |
| Geode Capital | 4.28M | 3.00% | $268.3M | added +31.1% | ≤2013 |
| Fred Alger Management, LLC | 3.34M | 2.35% | $209.6M | added +82.4% | 2025 Q3 |
| Invesco | 3.28M | 2.30% | $205.7M | added +498.9% | 2018 Q2 |
| UBS | 2.67M | 1.87% | $167.3M | added +18.7% | ≤2013 |
| Vestal Point Capital, LP | 2.27M | 1.60% | $142.7M | added +152.8% | 2025 Q4 |
| Baker Bros. Advisors LP | 1.99M | 1.40% | $125.0M | trimmed -8.4% | 2025 Q2 |
| Goldman Sachs | 1.74M | 1.22% | $109.1M | added +3.7% | 2013 Q3 |
| Northern Trust | 1.66M | 1.16% | $103.8M | added +23% | 2013 Q3 |
| Siren, L.l.c. | 1.62M | 1.13% | $101.3M | added +7.7% | 2024 Q3 |
| Deerfield Management Company, L.p. | 1.57M | 1.10% | $98.7M | trimmed -14.2% | 2025 Q3 |
| Janus Henderson | 1.44M | 1.01% | $90.1M | added +12.2% | 2020 Q2 |
| Pictet Asset Management Holding SA | 1.27M | 0.89% | $79.8M | added +23.8% | 2020 Q3 |
| Charles Schwab Investment Management | 1.19M | 0.84% | $74.7M | trimmed -11.9% | 2014 Q1 |
| Driehaus Capital Management LLC | 1.19M | 0.84% | $74.6M | trimmed -32.7% | 2025 Q3 |
| D. E. Shaw | 1.18M | 0.83% | $74.2M | added +710.5% | 2025 Q3 |
| Fisher Investments | 1.11M | 0.78% | $69.8M | trimmed -15.1% | 2024 Q2 |
| Bank OF America CORP /DE/ | 1.06M | 0.75% | $66.7M | added +71.1% | ≤2013 |
| Hood River Capital Management LLC | 1.06M | 0.74% | $66.2M | opened | 2026 Q1 |
| T. Rowe Price | 1.04M | 0.73% | $65.4M | added +24.4% | 2015 Q4 |
| Renaissance Technologies | 1.04M | 0.73% | $65.0M | opened | 2026 Q1 |
| Morgan Stanley | 960.5k | 0.67% | $60.2M | trimmed -34.9% | 2013 Q3 |
| BNY Mellon | 960.1k | 0.67% | $60.2M | added +8.1% | 2013 Q4 |
| Connor, Clark & Lunn Investment Management LTD. | 837.0k | 0.59% | $52.5M | added +26.2% | 2025 Q3 |
| Western Financial CORP/CA | 820.2k | 0.58% | $51.4M | unchanged | 2022 Q4 |
| Voya Investment Management LLC | 656.1k | 0.46% | $41.1M | added +55.2% | 2018 Q2 |
| BNP Paribas Financial Markets | 652.8k | 0.46% | $40.9M | added +1449.5% | 2014 Q1 |
| American Century Companies INC | 651.5k | 0.46% | $40.9M | added +8315.7% | 2025 Q4 |
| Dimensional Fund Advisors | 608.5k | 0.43% | $38.2M | added +312.8% | 2019 Q3 |
| Arrowstreet Capital | 587.1k | 0.41% | $36.8M | trimmed -71.9% | 2025 Q2 |
| RTW Investments, LP | 585.7k | 0.41% | $36.7M | unchanged | 2025 Q4 |
| Summit Partners Public Asset Management, LLC | 540.1k | 0.38% | $33.9M | added +14.9% | 2025 Q4 |
| Nuveen | 499.8k | 0.35% | $31.3M | added +73.2% | 2019 Q2 |
| Principal Financial Group INC | 490.1k | 0.34% | $30.7M | trimmed -31.5% | 2018 Q2 |
| Alyeska Investment Group | 472.9k | 0.33% | $29.7M | added +26% | 2025 Q4 |
| Franklin Resources | 462.7k | 0.33% | $29.0M | added +331% | 2024 Q1 |
| Panagora Asset Management INC | 461.2k | 0.32% | $28.9M | added +1182.7% | 2025 Q4 |
| Rhumbline Advisers | 404.4k | 0.28% | $25.4M | added +14.8% | 2018 Q2 |
| Susquehanna International Group | 378.8k | 0.27% | $23.8M | added +1210.3% | 2018 Q4 |
| Eventide Asset Management, LLC | 370.0k | 0.26% | $23.2M | unchanged | 2025 Q4 |
| Privium Fund Management B.v. | 366.9k | 0.26% | $23.0M | trimmed -7.9% | 2021 Q4 |
| Aberdeen Group plc | 364.0k | 0.26% | $22.8M | added +27.2% | 2024 Q2 |
| CPP Investment Board | 325.7k | 0.23% | $20.4M | added +1038.8% | 2025 Q4 |
| Lord, Abbett & CO. LLC | 312.8k | 0.22% | $19.6M | opened | 2026 Q1 |
| Nordea Investment Management AB | 306.4k | 0.21% | $19.2M | trimmed -5.5% | 2021 Q1 |
| Integral Health Asset Management, LLC | 300.0k | 0.21% | $18.8M | added +200% | 2024 Q4 |
Largest 50 of 419 shown; the full ranked, searchable register is at boothcheck.com/holders/ARWR. 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.