X0609 4 2026-07-07 0 0000874015 IONIS PHARMACEUTICALS INC IONS 0001073387 BENNETT C FRANK false 2855 GAZELLE COURT CARLSBAD CA 92010 0 1 0 0 EVP, Chief Scientific Officer 1 Common Stock 2026-07-07 4 S 0 5536 83.579 D 75018 D Common Stock 2026-07-07 4 J 0 15000 0.0 A 15000 I by Trust Common Stock 2026-07-07 4 S 0 15000 85.462 D 0 I by Trust Restricted Stock Unit 0.0 2026-07-07 4 J 0 15000 0.0 D Common Stock 15000 12109 D Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on March 31, 2026. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.070 to $84.065 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. Represents a transfer of 15,000 shares of common stock from direct ownership to indirect ownership held by the Clarence Frank Bennett TTEE Bennett Living Trust Dated 3/12/2008, of which the reporting person is the co-trustee with spouse. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $85.015 to $85.730 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. Restricted Stock Unit vested on January 15, 2026. Upon vesting, the restricted stock unit was paid out in whole shares of Ionis common stock. By: Patrick R. O’Neil, attorney-in-fact For: C. Frank Bennett 2026-07-09