Tweedy Browne's IONS Position Overview
Tweedy Browne (via Tweedy, Browne Co LLC) currently holds 2.46 M shares of Ionis Pharmaceuticals, Inc. (IONS) worth $195 M, representing 15.74% of the portfolio. First purchased in 2022-Q1, this medium-term investment has been held for 16 quarters.
Based on 13F filings, Tweedy Browne has maintained a strategic position in IONS, demonstrating sustained confidence in this investment. Largest addition occurred in Q4 2022, adding 818,148 shares. Largest reduction occurred in Q4 2025, reducing 436,286 shares.
Analysis based on 13F filings available since 2013 Q2
Tweedy Browne's Ionis Pharmaceuticals (IONS) Holding Value Over Time
Track share changes against reported price movement
Quarterly Ionis Pharmaceuticals (IONS) Trades by Tweedy Browne
| Report Date | Bought/Sold (Sh.) | % Change | Qtr. End Shares | Reported Price |
|---|---|---|---|---|
| Q4 2025 | -436,286 | Reduce 15.04% | 2.46 M | $79.11 |
| Q3 2025 | +9,268 | Add 0.32% | 2.9 M | $65.42 |
| Q2 2025 | -91,570 | Reduce 3.07% | 2.89 M | $39.51 |
| Q1 2025 | -265,345 | Reduce 8.17% | 2.98 M | $30.17 |
| Q4 2024 | -205,813 | Reduce 5.96% | 3.25 M | $34.96 |
| Q4 2023 | -55,497 | Reduce 1.58% | 3.45 M | $50.59 |
| Q3 2023 | -30,685 | Reduce 0.87% | 3.51 M | $45.36 |
| Q2 2023 | -188 | Reduce 0.01% | 3.54 M | $41.03 |
| Q1 2023 | -90 | Reduce 0.00% | 3.54 M | $35.74 |
| Q4 2022 | +818,148 | Add 30.05% | 3.54 M | $37.77 |
| Q3 2022 | -3,790 | Reduce 0.14% | 2.72 M | $44.23 |
| Q2 2022 | -198,324 | Reduce 6.78% | 2.73 M | $37.02 |
| Q1 2022 | +2.93 M | New Buy | 2.93 M | $37.04 |
Tweedy Browne's Ionis Pharmaceuticals Investment FAQs
Tweedy Browne first purchased Ionis Pharmaceuticals, Inc. (IONS) in Q1 2022, acquiring 2,925,102 shares, as reported in their 13F filing for that period. Note: Analysis reflects filings available since Q2 2013; earlier records may be incomplete.
Tweedy Browne has held Ionis Pharmaceuticals, Inc. (IONS) for 16 quarters since Q1 2022.
Tweedy Browne's largest addition to Ionis Pharmaceuticals, Inc. (IONS) was in Q1 2022, adding 2,925,102 shares worth $108.35 M.
According to the latest 13F filing for Q4 2025, Tweedy Browne's firm, Tweedy, Browne Co LLC, owns 2,464,930 shares of Ionis Pharmaceuticals, Inc. (IONS), valued at approximately $195 M.
As of the Q4 2025 filing, Ionis Pharmaceuticals, Inc. (IONS) represents approximately 15.74% of Tweedy Browne's publicly disclosed stock portfolio, making it one of their key holdings.
Tweedy Browne's peak holding in Ionis Pharmaceuticals, Inc. (IONS) was 3,541,136 shares, as reported at the end of Q4 2022.