144 0001206369 XXXXXXXX LIVE 0000874015 IONIS PHARMACEUTICALS INC 000-19125 2855 GAZELLE COURT CARLSBAD CA 92010 7609319200 KLEIN JOSEPH III Director Common UBS Financial Services, Inc.

11 Madison Avenue 4th Floor New York NY 10010

28000 1680000.00 159391229 09/03/2024 NASDAQ COMMON 09/03/2024 Exercise of Stock Option Issuer N 28000 09/03/2024 Cash Y 9,334 shares represented in this filing are being sold under the 2011 Lucy S. Klein Trust, 9,333 shares are being sold under the 2011 Noah Z. Klein Trust and 9,333 shares are being sold under the 2011 Alexander J. Klein Trust. 09/03/2025 01/03/2024 /s/ UBS Financial Services Inc, as attorney-in-fact for Judith S Sandler