[Form 4] IONIS PHARMACEUTICALS INC Insider Trading Activity

Rhea-AI Filing Summary

Insider transactions by Patrick R. O'Neil, EVP, CLO & General Counsel at Ionis Pharmaceuticals (IONS). On 10/06/2025 the reporting person exercised 10,200 non‑qualified stock options with an exercise price of $52.87 and immediately sold those shares under a Rule 10b5‑1 plan. The Form 4 reports two separate block sales that day: 10,200 shares sold at a weighted average price of $69.8872 and 3,241 shares sold at a weighted average price of $69.2651, reflecting multiple executions within disclosed price ranges.

Following these transactions the reporting person’s beneficial ownership of common stock declined from 67,330 shares to 53,889, and the number of options/derivative securities held after the activity is reported as 17,000 exercisable into common stock. The sales were made pursuant to a 10b5‑1 trading plan adopted on 05/02/2025, and the filer offers to provide transaction‑level price details on request.

Positive

• Sales executed under a Rule 10b5‑1 plan, indicating prearranged compliance with insider trading rules
• Options exercised and sold at prices above the exercise price (exercise $52.87 vs sales near $69.9), indicating realized option value

Negative

• Reported direct common stock ownership declined from 67,330 to 53,889 shares after the transactions
• Substantial share sales the same day as option exercise reduced insider ownership concentration, which may decrease insider stake alignment

Insights

Corporate Governance Analyst

TL;DR: Insider exercised options at $52.87 and sold shares under a 10b5‑1 plan, reducing holdings to 53,889 shares.

Exercising 10,200 options at an exercise price of $52.87 then selling those shares at weighted average prices near $69.9 indicates the reporting person monetized stock‑option value while complying with a prearranged trading plan. The Form 4 discloses two weighted‑average sale prices and notes the 10b5‑1 plan adoption date of 05/02/2025.

The main dependencies are the accuracy of the weighted‑average prices and the 10b5‑1 plan terms; the filer commits to provide per‑trade price details on request. Investors should note the decline in direct common stock from 67,330 to 53,889 shares and the remaining 17,000 options outstanding; monitor future Form 4s for additional option exercises or plan‑based sales.

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^*

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)
10/06/2025

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	10/06/2025		M		10,200	A	$52.87	67,330	D
Common Stock	10/06/2025		S		10,200(1)	D	$69.8872(2)	57,130	D
Common Stock	10/06/2025		S		3,241(1)	D	$69.2651(3)	53,889	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)	$52.87	10/06/2025		M			10,200	01/02/2025	01/01/2034	Common Stock	10,200	$0.0	17,000	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 $69.70 to $70.075 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 $69.1912 to $69.32 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 (3) on this Form 4.

	Patrick R. O'Neil	10/08/2025
	** 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 did Patrick R. O'Neil report on the Form 4 for IONS?

The filing reports exercise of 10,200 non‑qualified options at $52.87 on 10/06/2025 and subsequent sales of 10,200 shares at a weighted average of $69.8872 and 3,241 shares at a weighted average of $69.2651.

Were the sales part of a planned trading program for IONS insider?

Yes. The shares sold were pursuant to a Rule 10b5‑1 trading plan adopted on 05/02/2025, as disclosed in the Form 4.

How many shares did the reporting person own after the transactions?

Following the reported activity the reporting person beneficially owned 53,889 common shares and held 17,000 derivative securities exercisable into common stock.

What prices were the sold shares transacted at according to the Form 4?

The Form 4 reports weighted average sale prices of $69.8872 (range $69.70–$70.075) and $69.2651 (range $69.1912–$69.32), with per‑trade details available on request.

Did the filer offer additional disclosure or supporting details?

Yes. The reporting person stated they will provide full information on the number of shares sold at each separate price within the disclosed ranges to Ionis, any security holder, or the SEC staff upon request.