Ranked by reported Q2 2026 13F market value
Share of total reported institutional value in IONS held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | FMR LLC | 24.6M | $1.95B | +0.3% | 14.822% | 0.08% |
| 2 | Capital World Investors | 21.7M | $1.72B | +2.3% | 13.039% | 0.20% |
| 3 | BlackRock, Inc. | 10.7M | $848.8M | +2.5% | 6.441% | 0.01% |
| 4 | VANGUARD PORTFOLIO MANAGEMENT LLC | 7.9M | $623.2M | +0.7% | 4.729% | 0.03% |
| 5 | WELLINGTON MANAGEMENT GROUP LLP | 7.7M | $606.7M | +19.7% | 4.604% | 0.10% |
| 6 | VANGUARD CAPITAL MANAGEMENT LLC | 7.2M | $571.8M | +1.3% | 4.340% | 0.01% |
| 7 | TWO SIGMA INVESTMENTS, LP | 6.3M | $495.7M | +6.7% | 3.762% | 0.36% |
| 8 | ROYAL BANK OF CANADA | 6.2M | $490.2M | +62.6% | 3.720% | 0.07% |
| 9 | STATE STREET CORP | 4.3M | $343.7M | +8.5% | 2.609% | 0.01% |
| 10 | GEODE CAPITAL MANAGEMENT, LLC | 3.6M | $294.8M | -10.1% | 2.157% | 0.02% |
| 11 | JPMORGAN CHASE & CO | 2.7M | $216.2M | +13.0% | 1.608% | 0.01% |
| 12 | Artisan Partners Limited Partnership | 2.6M | $209.3M | +28.3% | 1.589% | 0.33% |
| 13 | Tweedy, Browne Co LLC | 2.3M | $180.8M | +0.2% | 1.372% | 13.70% |
| 14 | Deep Track Capital, LP | 2.2M | $174.4M | +12.8% | 1.324% | 2.54% |
| 15 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 2.1M | $168.6M | +73.9% | 1.280% | 0.01% |
| 16 | GOLDMAN SACHS GROUP INC | 2.1M | $167.3M | +24.1% | 1.270% | 0.01% |
| 17 | BAKER BROS. ADVISORS LP | 2.0M | $162.4M | 0.0% | 1.232% | 0.81% |
| 18 | DEERFIELD MANAGEMENT COMPANY, L.P. | 2.0M | $157.0M | 0.0% | 1.191% | 1.64% |
| 19 | AMERICAN CENTURY COMPANIES INC | 1.9M | $154.4M | +17.0% | 1.172% | 0.07% |
| 20 | BARCLAYS PLC | 1.7M | $131.1M | +386.4% | 0.995% | 0.03% |
| 21 | FRANKLIN RESOURCES INC | 1.6M | $128.7M | +3.1% | 0.977% | 0.03% |
| 22 | CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 1.6M | $127.3M | +1.4% | 0.966% | 0.02% |
| 23 | JANE STREET GROUP, LLC | 1.6M | $127.1M | +110.8% | 0.964% | 0.01% |
| 24 | Pictet Asset Management Holding SA | 1.6M | $127.0M | +11.3% | 0.961% | 0.12% |
| 25 | UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AME | 1.5M | $115.3M | -1.4% | 0.875% | 0.02% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in IONS — a direct measure of their conviction.
Filings activity in IONS during Q2 2026, grouped by how each filer changed its position.
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q2 2026 | 521 | +5.0% | 112.51% | +6.90 pp | $14.09B | +14% |
| Q1 2026 | 496 | +0.2% | 105.61% | +1.88 pp | $12.36B | 1.0% |
| Q4 2025 | 495 | +14% | 103.73% | 21.56 pp | $12.49B | +22% |
| Q3 2025 | 435 | +20% | 125.29% | +19.16 pp | $10.26B | +77% |
| Q2 2025 | 362 | +7.7% | 106.13% | +3.80 pp | $5.78B | +36% |
| Q1 2025 | 336 | 3.2% | 102.33% | +2.08 pp | $4.24B | 12% |
| Q4 2024 | 347 | +2.4% | 100.25% | +2.08 pp | $4.80B | 11% |
| Q3 2024 | 339 | — | 98.17% | — | $5.39B | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying IONS stock.
Based on Q2 2026 13F filings, institutional ownership of Ionis Pharmaceuticals, Inc. stands at 112.5%, held across 521 reporting institutions.
FMR LLC is the largest reported institutional holder of IONS, with approximately 24,631,956 shares worth $1.95B as of Q2 2026.
Yes — 3 widely-followed marquee investors appear among the top 25 institutional holders of IONS, including TWO SIGMA INVESTMENTS, LP, SUSQUEHANNA INTERNATIONAL GROUP, LLP, JANE STREET GROUP, LLC.
Our composite Smart Money Score for IONS is 78 out of 100 (Bullish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
61 institutions opened new positions in IONS during Q2 2026, while 43 fully exited. 328 added to existing positions and 114 trimmed.
IONS institutional ownership rose by 6.90 percentage points quarter-over-quarter, with a net change of +25 holders.
The top 10 institutions account for 56.4% of all reported 13F value in IONS, and the top 25 account for 73.0%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Ionis Pharmaceuticals, Inc. (IONS) Institutional Ownership