Ionis Pharmaceuticals (IONS) Held by Superinvestors
IONIS PHARMACEUTICALS INC (IONS) is currently held by 4 superinvestors tracked by InsiderSet, with a combined reported market value of approximately $249.29M based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026.
Tweedy, Browne Co All Funds (US) is currently the largest disclosed institutional shareholder of IONS tracked by InsiderSet, reporting ownership valued at approximately $180.81M in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $103.25M, representing an estimated loss of -42.89% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 100% of the total disclosed IONS value among the investors covered in this analysis. Major shareholders include Tweedy, Browne Co All Funds (US), Renaissance Technologies LLC, ARK Invest, and several other long-term asset managers with concentrated positions in IONIS PHARMACEUTICALS INC (IONS).
This page ranks the largest institutional IONS shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Tweedy, Browne Co All Funds (US) | B. Tweedy, Ch. Browne | 13.70% | 2,280,311 | $180,805,859 | $103,252,482 | -$77,553,377 | -42.89% |
| Renaissance Technologies LLC | Jim Simons | 0.06% | 559,414 | $44,355,936 | $25,330,266 | -$19,025,670 | -42.89% |
| ARK Invest | Cathie Wood | 0.15% | 300,770 | $23,848,064 | $13,618,866 | -$10,229,198 | -42.89% |
| Sequoia Financial Advisors | 0.00% | 3,567 | $282,828 | $161,514 | -$121,314 | -42.89% |
Frequently asked questions about IONS
Who are the largest superinvestors holding IONS?
The largest superinvestors holding IONS in the latest SEC Form 13F filings include Tweedy, Browne Co All Funds (US), Renaissance Technologies LLC, ARK Invest, and Sequoia Financial Advisors. InsiderSet ranks these superinvestors by their latest reported IONS position.
What does the IONS superinvestors page include?
This page tracks IONS positions reported by a curated group of notable institutional investors and fund managers through SEC Form 13F. IONIS PHARMACEUTICALS INC (IONS) on this page reflects disclosed 13F holdings among those superinvestors, not every institutional shareholder of the stock.
How many superinvestors hold IONS?
InsiderSet currently tracks 4 superinvestors reporting IONS holdings in the latest available 13F data. This is the curated set on this page, not the total number of institutions that own IONS.
How much IONS stock do superinvestors hold?
Superinvestors tracked by InsiderSet disclosed approximately $249.29M in IONS holdings for Q2 2026. This figure is reported 13F value as of the filing period, not necessarily today's market value, and it covers the curated superinvestors on this page rather than every institutional filer.
When were IONS superinvestor holdings last updated?
The latest IONS superinvestor holdings on InsiderSet are based on SEC Form 13F filings for the quarter ended June 30, 2026. Form 13F filings are generally reported after the quarter ends, so the holdings shown represent the latest publicly disclosed positions rather than real-time holdings.
Are superinvestor IONS holdings real-time?
No. Form 13F data is not real-time. It represents positions reported by these superinvestors as of the end of the reporting quarter. A superinvestor may have changed its IONS position after the reporting date.
Are superinvestors buying or selling IONS?
Buying and selling can be analyzed by comparing IONS positions across consecutive 13F reporting periods. InsiderSet's IONS Ownership Changes page shows institutions that increased, reduced, initiated, or exited positions based on reported 13F holdings. View IONS ownership changes.
How have superinvestor IONS holdings changed over time?
InsiderSet tracks IONS holdings among these superinvestors across multiple 13F reporting periods, so holder counts, reported value, and reported shares can be compared over time.