[Form 4] IONIS PHARMACEUTICALS INC Insider Trading Activity

Rhea-AI Filing Summary

Patrick R. O'Neil, Executive Vice President, Chief Legal Officer & General Counsel of Ionis Pharmaceuticals (IONS), reported option exercises and subsequent sales on September 29-30, 2025. The Form 4 shows Mr. O'Neil acquired 10,473 shares on 09/29/2025 and 14,827 shares on 09/30/2025 via exercise of non-qualified stock options with an exercise price of $56.78 per share. On the same dates he sold the exercised shares: 10,473 shares on 09/29/2025 at a weighted average price of $64.5417, and 14,827 shares on 09/30/2025 at a weighted average price of $64.6777. The sales were executed pursuant to a Rule 10b5-1 trading plan adopted May 2, 2025. Following these transactions, Mr. O'Neil beneficially owned 57,130 shares.

Positive

• Sales were executed under a disclosed Rule 10b5-1 trading plan, indicating pre-planned, compliant transactions
• Option exercises converted compensation into equity then liquidity, demonstrating routine realization of vested compensation
• Filing provides weighted-average prices and undertakes to supply per-trade details, which supports transparency

Negative

• Reporting person reduced holdings by selling 25,300 shares (10,473 on 09/29/2025 and 14,827 on 09/30/2025)
• Beneficial ownership decreased from prior totals to 57,130 shares following the reported transactions

Insights

Financial Analyst

TL;DR: Routine insider option exercises followed by plan-based sales; material size for insider but not necessarily company-changing.

The filing documents standard option exercises at an exercise price of $56.78 and contemporaneous sales under a 10b5-1 plan at weighted average prices of $64.5417 and $64.6777. Total shares exercised and sold equal 25,300 shares (10,473 and 14,827). These transactions crystallize compensation value and generate liquidity for the reporting person while leaving 57,130 shares beneficially owned. This is a transparent, pre-planned disposition rather than an ad-hoc sale; therefore it carries limited new information about company fundamentals.

Corporate Governance Expert

TL;DR: Transactions were executed under a disclosed 10b5-1 plan, indicating procedural compliance and pre-authorization.

The report explicitly states the sales were pursuant to a Rule 10b5-1 trading plan adopted May 2, 2025, and provides weighted-average price ranges for the multi-trade executions. The filing includes required explanations and undertakings to provide per-trade details if requested, which aligns with best-practice disclosure. From a governance perspective, these are routine, properly documented insider transactions without any disclosed irregularities.

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
Estimated average burden
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).

1. Name and Address of Reporting Person^*

O'NEIL PATRICK R.

(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 CLO & General Counsel

3. Date of Earliest Transaction (Month/Day/Year)
09/29/2025

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	09/29/2025		M		10,473	A	$56.78	67,603	D
Common Stock	09/29/2025		S		10,473(1)	D	$64.5417(2)	57,130	D
Common Stock	09/30/2025		M		14,827	A	$56.78	71,957	D
Common Stock	09/30/2025		S		14,827(1)	D	$64.6777(3)	57,130	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
Non-Qualified Stock Option (right to buy)	$56.78	09/29/2025		M			10,473	01/04/2022	01/03/2028	Common Stock	10,473	$0.0	45,030	D
Non-Qualified Stock Option (right to buy)	$56.78	09/30/2025		M			14,827	01/04/2022	01/03/2028	Common Stock	14,827	$0.0	30,203	D

Explanation of Responses:

1. Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on May 2, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $64.50 to $64.63 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 $64.50 to $64.945 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.

	Patrick R. O'Neil	09/30/2025
	** 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).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transactions did Patrick R. O'Neil report for IONS?

The Form 4 reports Mr. O'Neil exercised non-qualified stock options totaling 25,300 shares (10,473 on 09/29/2025 and 14,827 on 09/30/2025) and sold those same shares on the same dates.

Were the sales executed under a pre-arranged trading plan for IONS insider filings?

Yes. The sales were made pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on May 2, 2025.

At what prices were the IONS shares sold according to the Form 4?

The weighted-average sale prices were $64.5417 for the 09/29/2025 sales (range $64.50–$64.63) and $64.6777 for the 09/30/2025 sales (range $64.50–$64.945).

What was the exercise price of the options exercised by the IONS reporting person?

The non-qualified stock options had an exercise price of $56.78 per share.

How many IONS shares does Patrick R. O'Neil beneficially own after these transactions?

After the reported transactions, the Form 4 discloses that Mr. O'Neil beneficially owned 57,130 shares.