[Form 4] IONIS PHARMACEUTICALS INC Insider Trading Activity

Rhea-AI Filing Summary

Ionis Pharmaceuticals (IONS) filed a Form 4 reporting an insider sale. EVP, Corp and Development Ops Brian Birchler sold 8,000 shares of common stock on 11/06/2025 under a pre-arranged Rule 10b5-1 trading plan adopted on August 12, 2024. The transaction was reported as a sale at a weighted average price of $76.1724, with individual trades executed between $76.00 and $76.32.

Following this transaction, Birchler beneficially owns 48,826 shares directly. The filing notes that detailed trade-by-trade pricing information within the range is available upon request.

Insider Trade Summary

Net Seller: 8,000 shares ($609,379)

Net Sell 1 txn

Insider Birchler Brian

Role EVP, Corp and Development Ops

Sold 8,000 shs ($609K)

Type	Security	Shares	Price	Value
Sale	Common Stock	8,000	$76.1724	$609K

Holdings After Transaction: Common Stock — 48,826 shares (Direct)

Footnotes (1)

1. Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on August 12, 2024. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $76.00 to $76.32 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.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Birchler Brian

(Last) (First) (Middle)

2855 GAZELLE COURT

(Street)

CARLSBAD CA 92010

(City) (State) (Zip)

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, Corp and Development Ops

3. Date of Earliest Transaction (Month/Day/Year)
11/06/2025

4. If Amendment, Date of 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

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	11/06/2025		S		8,000(1)	D	$76.1724(2)	48,826	D

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 Securities Underlying Derivative Security (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: 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

Explanation of Responses:

1. Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on August 12, 2024.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $76.00 to $76.32 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.

	By: Patrick R. O'Neil, attorney-in-fact For: Brian Birchler	11/07/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
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