Brian Birchler - 29 Jan 2026 Form 4 Insider Report for IONIS PHARMACEUTICALS INC (IONS)

Role: EVP, Corp and Development Ops
Signature: By: Patrick R. O'Neil, attorney-in-fact For: Brian Birchler
Issuer symbol: IONS
Transactions as of: 29 Jan 2026
Net transactions value: -$513,048
Form type: 4
Filing time: 02 Feb 2026, 20:51:32 UTC
Previous filing: 20 Jan 2026
Next filing: 03 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Birchler Brian	EVP, Corp and Development Ops	2855 GAZELLE COURT, CARLSBAD	By: Patrick R. O'Neil, attorney-in-fact For: Brian Birchler	02 Feb 2026	0001970151

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	IONS	Common Stock	Award	$0	+11,991	+20%	$0.000000	72,426	29 Jan 2026	Direct	F1
transaction	IONS	Common Stock	Sale	$513,048	-6,179	-8.5%	$83.03	66,247	30 Jan 2026	Direct	F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Represents shares earned upon the vesting of performance-based restricted stock units ("PRSUs") for the performance period of the grant to the reporting person reported on January 18, 2023. The Compensation Committee certified achievement of the pre-established performance goal based on the Issuer's relative total shareholder return as compared to a peer group of companies at a level resulting in a vest of 167.27% of target shares. As reported at grant, the PRSUs could result in a payout of 0% to 200% based on actual achievement of the goal.
F2	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.00 to $83.08 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.

Content

Represents shares earned upon the vesting of performance-based restricted stock units ("PRSUs") for the performance period of the grant to the reporting person reported on January 18, 2023. The Compensation Committee certified achievement of the pre-established performance goal based on the Issuer's relative total shareholder return as compared to a peer group of companies at a level resulting in a vest of 167.27% of target shares. As reported at grant, the PRSUs could result in a payout of 0% to 200% based on actual achievement of the goal.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.00 to $83.08 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.