[Form 4] IONIS PHARMACEUTICALS INC Insider Trading Activity

Rhea-AI Filing Summary

IONIS PHARMACEUTICALS INC director Spencer R. Berthelsen reported an option exercise paired with a share sale. On June 1, 2026, he exercised a non-qualified stock option for 8,000 shares of common stock at $24.42 per share and then sold 8,000 shares in an open-market transaction at $75.67 per share. After these transactions, he directly held 156,013 shares of common stock. The filing also shows 70 shares held indirectly by his daughter, for which he disclaims beneficial ownership. The sale was executed under a Rule 10b5-1 Trading Plan adopted on September 12, 2025, indicating it was pre-arranged.

Insider Trade Summary 10b5-1

Net Seller: 8,000 shares ($605,360)

Net Sell 4 txns

Insider BERTHELSEN SPENCER R

Role null

Sold 8,000 shs ($605K)

Type	Security	Shares	Price	Value
Exercise	Non-Qualified Stock Option (right to buy)	8,000	$0.00	--
Exercise	Common Stock	8,000	$24.42	$195K
Sale	Common Stock	8,000	$75.67	$605K
holding	Common Stock	--	--	--

Holdings After Transaction: Non-Qualified Stock Option (right to buy) — 8,000 shares (Direct, null); Common Stock — 164,013 shares (Direct, null); Common Stock — 70 shares (Indirect, by Daughter)

Footnotes (1)

1. Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on September 12, 2025. The reporting person disclaims beneficial ownership of all securities held by his daughter, and this report should not be deemed an admission that the reporting person is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

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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
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).

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^*

BERTHELSEN SPENCER R

(Last) (First) (Middle)

2855 GAZELLE COURT

(Street)

CARLSBAD CALIFORNIA 92010

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
IONIS PHARMACEUTICALS INC [ IONS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/01/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	06/01/2026		M		8,000	A	$24.42	164,013	D
Common Stock	06/01/2026		S		8,000(1)	D	$75.67	156,013	D
Common Stock								70	I	by Daughter(2)

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)	$24.42	06/01/2026		M			8,000	07/01/2017	06/30/2026	Common Stock	8,000	$0.0	8,000	D

Explanation of Responses:

1. Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on September 12, 2025.

2. The reporting person disclaims beneficial ownership of all securities held by his daughter, and this report should not be deemed an admission that the reporting person is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

	Spencer R. Berthelsen	06/03/2026
	** 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.
* Form 4: SEC 1474 (03-26)