As of November 10, 2026, Ionis Pharmaceuticals Inc. is a publicly traded company (Nasdaq: IONS); its largest reported holder is Capital World Investors, with 12.8% on Schedule 13G/A of May 14, 2026, then Vanguard (5.05%). The largest insider holding is Brett P. Monia, the chief executive and a director, with 242,760 shares (0.15% of shares outstanding), per Form 4 of September 2, 2026 (Schedule 13G/A, May 14, 2026).
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Is Ionis Pharmaceuticals Inc. a real, registered company?
- Ionis Pharmaceuticals Inc files with the SEC under CIK 874015 (its SEC filings).
- Its shares are listed under the ticker IONS on Nasdaq (SEC company record).
- Incorporated in California; business address in Carlsbad, California, as its SEC filings state.
- Court and bankruptcy records: see Before you sign or pay below.
Before you sign or pay
- Court and bankruptcy: No federal court case or bankruptcy filing found under IONIS PHARMACEUTICALS INC in our court records and SEC 8-K records (as of 2026-11-10).
- Leadership changes: the latest reported is Ludwig N. Hantson (Form 8-K filed 2026-06-08). Check you are dealing with the people now in charge.
- Ownership: 5%+ holders are reported on Schedule 13D or 13G; the latest names Capital World Investors (filed 2026-05-14).
Who are Ionis Pharmaceuticals Inc.'s owners and officers?
Ionis Pharmaceuticals Inc.: incorporated in California; business address in Carlsbad, California; industry Pharmaceutical Preparations (Form D, 2026-06-08).
| Report | Holder | Share |
|---|---|---|
| Schedule 13G/A, 2026-05-15 | T. Rowe Price Investment Management, Inc. | 3.7% |
| Schedule 13G/A, 2026-05-14 | Capital World Investors | 12.8% |
| Schedule 13G, 2026-04-30 | Vanguard Capital Management | 5.05% |
| Schedule 13G/A, 2026-03-27 | The Vanguard Group | 0% |
| Schedule 13G/A, 2026-02-17 | T. Rowe Price Investment Management, Inc. | 5.6% |
| Schedule 13G/A, 2026-01-07 | Capital World Investors | 11.1% |
| Schedule 13G/A, 2025-11-14 | T. Rowe Price Investment Management, Inc. | 8.3% |
| Schedule 13G/A, 2025-08-12 | Wellington Management Group LLP | 4.3% |
Questions about who owns Ionis Pharmaceuticals Inc.
Who owns Ionis Pharmaceuticals Inc.?
On this page, 2 holders' latest ownership filings report 5% or more of Ionis Pharmaceuticals Inc.: Capital World Investors (12.8%, Schedule 13G/A, filed 2026-05-14) and Vanguard Capital Management (5.05%, Schedule 13G, filed 2026-04-30).
Who are the largest shareholders of Ionis Pharmaceuticals Inc.?
By the share each holder's latest filing reports, the largest holders of Ionis Pharmaceuticals Inc. on this page are Capital World Investors (12.8%) and Vanguard Capital Management (5.05%).
When did Capital World Investors buy into Ionis Pharmaceuticals Inc.?
The filings give report dates, not purchase dates. The earliest filing from Capital World Investors on this page is the Schedule 13G/A, filed 2026-01-07, reporting 11.1%; its latest, Schedule 13G/A filed 2026-05-14, reports 12.8%. That earliest filing is itself an amendment, which updates an earlier report.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 8 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
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| Filed | Person | Role | Change | Effective |
|---|---|---|---|---|
| Form 8-K, 2026-06-08 | Ludwig N. Hantson | appointed | 2026-06-04 |
Which insiders own Ionis Pharmaceuticals Inc. shares?
Directors, officers and holders of 10% or more report their shares on Forms 3, 4 and 5. Each line is the latest such report, largest holding first.
- , the chief executive and a director: 242,760 shares (0.15% of shares outstanding) (Form 4, 2026-09-02).
- , a director: 161,303 shares (0.10% of shares outstanding), 161,233 held directly and 70 indirectly (Form 4, 2026-07-17).
- , the executive vice president and corp: 102,883 shares (0.06% of shares outstanding) (Form 4, 2026-09-02).
- , the chief financial officer and executive vice president: 82,660 shares (0.05% of shares outstanding) (Form 4, 2026-03-18).
- , a director: 78,298 shares (0.05% of shares outstanding), 54,298 held directly and 24,000 indirectly (Form 4, 2026-07-31).
Shares outstanding: 166,545,100 as of 2026-11-03, from the company's latest SEC cover page.
How much has Ionis Pharmaceuticals Inc. raised?
No fundraising or offering filing from Ionis Pharmaceuticals Inc. is on file with us.
Keep reading
More on Ionis Pharmaceuticals Inc. and the records around it.
Ionis Pharmaceuticals Inc. elsewhere on the record
- Leadership changes Jun 2026
Companies that share a holder
- Capital World Investors also filed stake reports on 125 other companies: New Fortress Energy Inc. (Oct 2026), Aura Minerals Inc. (Oct 2026), Skyworks Solutions, Inc. (Oct 2026)
- T. Rowe Price Investment Management, Inc. also filed stake reports on 167 other companies: CABALETTA BIO INC (Nov 2026), MADISON SQUARE GARDEN SPORTS CORP (Nov 2026), MSG RANGERS CORP (Nov 2026)
- Wellington Management Group LLP also filed stake reports on 240 other companies: Hub Group, Inc. (Oct 2026), Latham Group, Inc. (Oct 2026), Redwood Trust, Inc. (Oct 2026)
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