Ionis Pharmaceuticals Inc
Ownership
Ownership Structure
Who owns Ionis Pharmaceuticals Inc (IONS)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 99.2% of the shares are freely tradable; institutional investors hold 107.3%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| FMR Inc | 14.78 | 24,556,637 | +2.0 | 03/31/2026 |
| Capital World Investors | 13.04 | 21,669,226 | +2.3 | 06/30/2026 |
| BlackRock Inc | 6.28 | 10,442,476 | -1.9 | 03/31/2026 |
| Vanguard Portfolio Management, LLC | 4.70 | 7,808,902 | +0.0 | 03/31/2026 |
| Wellington Management Company LLP | 4.60 | 7,651,415 | +19.7 | 06/30/2026 |
| Vanguard Capital Management, LLC | 4.28 | 7,118,330 | +0.0 | 03/31/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Fidelity Growth Compy Commingled Pl S | 6.78 | 11,275,122 | +0.4 | 07/31/2026 |
| Fidelity Growth Company Fund | 5.12 | 8,503,255 | +0.4 | 07/31/2026 |
| Capital Group Growth Fnd of Amer Comp | 4.61 | 7,668,655 | +0.0 | 06/30/2026 |
| American Funds Growth Fd of Amer A | 4.61 | 7,668,655 | +0.0 | 06/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Monia Brett P | Chief Executive Officer | 242,760 | 10,778,544 $ | Aug 31, 2026 | direct |
| Berthelsen Spencer R | Director | 161,233 | 7,158,745 $ | Jul 15, 2026 | direct |
| Birchler Brian | EVP, Corp and Development Ops | 102,883 | 4,568,005 $ | Aug 31, 2026 | direct |
| Bennett C Frank | EVP, Chief Scientific Officer | 60,128 | 2,669,683 $ | Jul 7, 2026 | both |
| O'neil Patrick R. | EVP CLO & General Counsel | 59,205 | 2,628,702 $ | Aug 31, 2026 | direct |
| Herman Joan E | Director | 51,306 | 2,277,986 $ | Jul 15, 2026 | direct |
| Hayden Michael R | Director | 24,000 | 1,065,600 $ | Jul 31, 2026 | indirect |
| Kordasiewicz Holly B. | EVP, Chief Development Officer | 22,096 | 981,062 $ | Jul 7, 2026 | direct |
| Diaz Allene M. | Director | 3,811 | 169,208 $ | Jul 7, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Aug 31, 2026 | Bennett C Frank | EVP, Chief Scientific Officer | Other | 110 | 51.31 | 5,644 |
| Aug 31, 2026 | O'neil Patrick R. | EVP CLO & General Counsel | Other | 63 | 51.31 | 3,232 |
| Aug 31, 2026 | Monia Brett P | Chief Executive Officer | Other | 98 | 51.31 | 5,028 |
| Aug 31, 2026 | Birchler Brian | EVP, Corp and Development Ops | Other | 58 | 51.31 | 2,976 |
| Jul 31, 2026 | Hayden Michael R | Director | Buy | 5,000 | 51.60 | 258,000 |
| Jul 30, 2026 | Hayden Michael R | Director | Buy | 15,000 | 53.38 | 800,700 |
| Jul 15, 2026 | Herman Joan E | Director | Other | 5,220 | 0.00 | – |
| Jul 15, 2026 | Berthelsen Spencer R | Director | Other | 5,220 | 0.00 | – |
| Jul 7, 2026 | Bennett C Frank | EVP, Chief Scientific Officer | Sell | 15,000 | 85.46 | 1,281,930 |
| Jul 7, 2026 | Bennett C Frank | EVP, Chief Scientific Officer | Other | 15,000 | 0.00 | – |
| Jul 7, 2026 | Bennett C Frank | EVP, Chief Scientific Officer | Sell | 5,536 | 83.58 | 462,693 |
| Jul 7, 2026 | Diaz Allene M. | Director | Sell | 10,111 | 85.42 | 863,637 |
| Jul 7, 2026 | Diaz Allene M. | Director | Other | 10,111 | 47.11 | 476,329 |
| Jul 7, 2026 | Kordasiewicz Holly B. | EVP, Chief Development Officer | Sell | 362 | 84.30 | 30,517 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: September 18, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.