X0609 4 2026-03-16 0 0000874015 IONIS PHARMACEUTICALS INC IONS 0001074773 HOUGEN ELIZABETH L 2855 GAZELLE COURT CARLSBAD CA 92010 0 1 0 0 EVP, Finance & CFO 1 Common Stock 2026-03-16 4 M 0 60299 60.89 A 193180 D Common Stock 2026-03-16 4 M 0 61041 56.78 A 254221 D Common Stock 2026-03-16 4 M 0 33118 32.6 A 287339 D Common Stock 2026-03-16 4 M 0 20541 37.58 A 307880 D Common Stock 2026-03-16 4 S 0 205608 72.381 D 102272 D Common Stock 2026-03-16 4 S 0 9440 72.765 D 92832 D Common Stock 2026-03-17 4 S 0 10172 73.207 D 82660 D Non-Qualified Stock Option (right to buy) 32.6 2026-03-16 4 M 0 33118 0.0 D 2023-01-03 2032-01-02 Common Stock 33118 0 D Non-Qualified Stock Option (right to buy) 37.58 2026-03-16 4 M 0 20541 0.0 D 2024-01-03 2033-01-02 Common Stock 20541 5405 D Non-Qualified Stock Option (right to buy) 56.78 2026-03-16 4 M 0 61041 0.0 D 2022-01-04 2028-01-03 Common Stock 61041 0 D Non-Qualified Stock Option (right to buy) 60.89 2026-03-16 4 M 0 60299 0.0 D 2021-01-02 2027-01-01 Common Stock 60299 0 D Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on December 9, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $71.70 to $72.70 inclusive. The reporting person undertakes to provide to Ionis Pharmaceuticals, Inc. any security holder of Ionis Pharmaceuticals, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (2) on this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $72.71 to $72.88 inclusive. The reporting person undertakes to provide to Ionis Pharmaceuticals, Inc. any security holder of Ionis Pharmaceuticals, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (3) on this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $73.11 to $73.28 inclusive. The reporting person undertakes to provide to Ionis Pharmaceuticals, Inc. any security holder of Ionis Pharmaceuticals, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (4) on this Form 4. By: Patrick R. O'Neil, attorney-in-fact For: Elizabeth L. Hougen 2026-03-18