[Form 4] Ionis Pharmaceuticals, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Patrick O'Neil, EVP, CLO & General Counsel of Ionis Pharmaceuticals (IONS), filed a Form 4 reporting multiple transactions on September 2–3, 2025. The filing shows exercises of non-qualified stock options and contemporaneous sales executed under a Rule 10b5-1 trading plan adopted May 2, 2025. Reported option exercises include 13,050 shares at a $32.60 strike, 14,000 at $37.58, and 49,800 at $53.77. Reported sales under the 10b5-1 plan include 13,050 shares at a weighted average $54.5148, 65,475 shares at a weighted average $60.89, and 11,375 shares at a weighted average $61.42. The Form discloses the number of shares beneficially owned following each transaction line as reported in the filing.

Positive

• Sales executed under a Rule 10b5-1 trading plan, indicating transactions were pre-planned and reducing concerns about opportunistic insider trading
• Detailed disclosure of weighted-average sale prices and offer to provide per-trade details, enhancing transparency for shareholders

Negative

• Significant insider share sales (totaling tens of thousands of shares) reduced direct beneficial ownership as shown in the filing

Insights

Corporate Governance Expert

TL;DR: Insider exercised options and sold shares via a pre-established 10b5-1 plan; disclosure aligns with governance best practices.

The filing documents option exercises and large-volume sales executed pursuant to a Rule 10b5-1 plan adopted May 2, 2025, which provides a structured, pre-planned mechanism for insider dispositions and helps mitigate appearance of opportunistic trading. The report includes weighted-average sale prices and commitments to provide transaction-level details upon request, which supports transparency. No amendment or corrective disclosure is indicated.

Securities Analyst

TL;DR: Material share sales occurred but were executed under a trading plan; net change in beneficial ownership is reported per transaction lines.

The Form 4 shows multiple option exercises (strikes $32.60, $37.58, $53.77) followed by planned sales at weighted average prices in the mid-$50s to low-$60s. These transactions increased exercised share count while reducing direct holdings through sales under the 10b5-1 plan. The filing provides sufficient price ranges and offers to supply per-trade detail on request, enabling further analysis of proceeds and timing if needed.

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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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)
09/02/2025

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	09/02/2025		M		13,050	A	$32.6	70,180	D
Common Stock	09/02/2025		S		13,050(1)	D	$54.5148(2)	57,130	D
Common Stock	09/03/2025		M		14,000	A	$37.58	71,130	D
Common Stock	09/03/2025		S		65,475(3)	D	$60.89(4)	5,655	D
Common Stock	09/03/2025		M		13,050	A	$32.6	18,705	D
Common Stock	09/03/2025		S		11,375(3)	D	$61.42(5)	7,330	D
Common Stock	09/03/2025		M		49,800	A	$53.77	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)	$32.6	09/02/2025		M			13,050	01/03/2023	01/02/2032	Common Stock	13,050	$0.0	17,517	D
Non-Qualified Stock Option (right to buy)	$32.6	09/03/2025		M			13,050	01/03/2023	01/02/2032	Common Stock	13,050	$0.0	4,467	D
Non-Qualified Stock Option (right to buy)	$37.58	09/03/2025		M			14,000	01/03/2024	01/02/2033	Common Stock	14,000	$0.0	8,942	D
Non-Qualified Stock Option (right to buy)	$53.77	09/03/2025		M			49,800	01/02/2020	01/01/2026	Common Stock	49,800	$0.0	0	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 $54.50 to 54.59, 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) of this Form 4.

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

4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $60.3418 to $61.34 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 (4) on this Form 4.

5. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $61.35 to $61.48 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 (5)on this Form 4.

	Patrick O'Neil	09/04/2025
	** 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.
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FAQ

What transactions did Patrick O'Neil report on the Form 4 for IONS?

The Form 4 reports option exercises and sales on September 2–3, 2025, including exercises of 13,050, 14,000 and 49,800 option shares and sales of 13,050, 65,475 and 11,375 common shares under a 10b5-1 plan.

Were the sales by the insider part of a 10b5-1 trading plan?

Yes. The filing states the shares were sold pursuant to a Rule 10b5-1 trading plan adopted May 2, 2025.

What prices were reported for the insider sales in the Form 4?

Weighted-average prices reported are approximately $54.5148, $60.89, and $61.42 for the respective sale blocks; the filing gives specific price ranges and offers to provide per-trade breakdowns on request.

Did the filing disclose the option exercise strike prices?

Yes. The filing discloses option strike prices of $32.60, $37.58, and $53.77 for the exercised non-qualified stock options.

How can shareholders obtain more granular details about the individual sale prices?

The reporting person undertakes to provide Ionis, any security holder, or the SEC staff with full information regarding the number of shares sold at each separate price within the disclosed ranges upon request.