Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Swayze Eric 2. Issuer Name and Ticker or Trading Symbol IONIS PHARMACEUTICALS INC [IONS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) EVP Research (Last) (First) (Middle) 2855 GAZELLE COURT 3. Date of Earliest Transaction (Month/Day/Year) 01/02/2026 (Street) CARLSBAD, CA 92010 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 01/02/2026 M 5,125 A $60.89 35,578 D Common Stock 01/02/2026 S 5,125(1) D $78.57(2) 30,453 D Common Stock 01/02/2026 M 18,338 A $60.89 48,791 D Common Stock 01/02/2026 S 18,338(1) D $79.27(3) 30,453 D Common Stock 256 I by Son

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Non-Qualified Stock Option (right to buy)

$60.89

01/02/2026

M

5,125

01/02/2021

01/01/2027

Common Stock

5,125

$ 0

22,403

D

Non-Qualified Stock Option (right to buy)

$60.89

01/02/2026

M

18,338

01/02/2020

01/01/2027

Common Stock

18,338

$ 0

4,065

D

Non-Qualified Stock Option (right to buy)

$79.67

01/02/2026

A

19,350

01/02/2027(4)

01/01/2036

Common Stock

19,350

$ 0

19,350

D

Non-Qualified Stock Option (right to buy)

$79.67

01/02/2026

A

150

01/02/2027(5)

01/01/2036

Common Stock

150

$ 0

150

I

by Son

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Swayze Eric 2855 GAZELLE COURT CARLSBAD, CA 92010			EVP Research

Signatures

By: Patrick R. O'Neil, attorney-in-fact For: Eric Swayze		01/05/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on August 14, 2024.
(2)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $78.155 to $78.88 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 (2) on this Form 4.
(3)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $78.88 to $79.70 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 (3) on this Form 4.
(4)	Grant on 01/02/2026 to reporting person of stock options under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan. Following this transaction, the option was exercisable as to 0 shares on 01/02/2026. 25% of the shares subject to the option will vest and become exercisable on 01/02/2027. Thereafter, the remaining shares subject to the option will vest and become exercisable in 36 equal monthly installments over the next 3 years.
(5)	Grant on 01/02/2026 to reporting person's son of stock options under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan. Following this transaction, the option was exercisable as to 0 shares on 01/02/2026. 25% of the shares subject to the option will vest and become exercisable on 01/02/2027. Thereafter, the remaining shares subject to the option will vest and become exercisable in 36 equal monthly installments over the next 3 years.

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