HOUGEN ELIZABETH L

SEC source: 0001193125-26-390534 · ownership.xml · derivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 16,250

Underlying: Common Stock · 16,250 shares

Expires 2036-09-09

F1 · derivative.exercise_date: The shares subject to the option will vest in full on the earlier of September 10, 2027, or the date of the Issuer's 2027 annual stockholder meeting.

SEC source: 0001193125-26-385416 · ownership.xml · derivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,750

Underlying: Common Stock · 13,750 shares

Expires 2036-09-07

F1 · derivative.exercise_date: The shares subject to the option will vest in full on the earlier of September 8, 2027, or the date of the Issuer's 2027 annual stockholder meeting.

SEC source: 0000874015-26-000146 · edgardoc.xml · nonDerivative · entry 7

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 82,660

F1 · shares: Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on December 9, 2025.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $73.11 to $73.28 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.

SEC source: 0000874015-26-000146 · edgardoc.xml · derivative · entry 11

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 60,299 shares

Expires 2027-01-01

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-26-000146 · edgardoc.xml · derivative · entry 10

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 61,041 shares

Expires 2028-01-03

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-26-000146 · edgardoc.xml · derivative · entry 9

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 5,405

Underlying: Common Stock · 20,541 shares

Expires 2033-01-02

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-26-000146 · edgardoc.xml · derivative · entry 8

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 33,118 shares

Expires 2032-01-02

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-26-000146 · edgardoc.xml · nonDerivative · entry 6

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 92,832

F1 · shares: Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on December 9, 2025.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $72.71 to $72.88 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.

SEC source: 0000874015-26-000146 · edgardoc.xml · nonDerivative · entry 5

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 102,272

F1 · shares: Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on December 9, 2025.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $71.70 to $72.70 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.

SEC source: 0000874015-26-000146 · edgardoc.xml · nonDerivative · entry 4

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 307,880

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-26-000146 · edgardoc.xml · nonDerivative · entry 3

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 287,339

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-26-000146 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 254,221

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-26-000146 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 193,180

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-26-000098 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 132,881

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $83.11 to $83.32 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.

SEC source: 0000874015-26-000098 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 139,869

F1 · shares: Represents shares earned upon the vesting of performance-based restricted stock units ("PRSUs") for the performance period of the grant to the reporting person reported on January 18, 2023. The Compensation Committee certified achievement of the pre-established performance goal based on the Issuer's relative total shareholder return as compared to a peer group of companies at a level resulting in a vest of 167.27% of target shares. As reported at grant, the PRSUs could result in a payout of 0% to 200% based on actual achievement of the goal.

SEC source: 0000874015-26-000065 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 126,307

F2 · kind: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Restricted Stock Unit Agreement and Grant Notice.

F2 · shares: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Restricted Stock Unit Agreement and Grant Notice.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $75.18 to $75.26 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.

SEC source: 0000874015-26-000065 · edgardoc.xml · derivative · entry 5

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 68,825

Underlying: Common Stock · 12,885 shares

Expires not disclosed

F8 · security: Grant to reporting person of Restricted Stock Units under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan.

F6 · derivative.exercise_price: Each Restricted Stock Unit represents a contingent right to receive one share of Ionis common stock, or its equivalent cash value.

F7 · derivative.exercise_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

F7 · derivative.expiration_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

SEC source: 0000874015-26-000065 · edgardoc.xml · derivative · entry 4

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 55,940

Underlying: Common Stock · 28,729 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F6 · derivative.exercise_price: Each Restricted Stock Unit represents a contingent right to receive one share of Ionis common stock, or its equivalent cash value.

F7 · derivative.exercise_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

F7 · derivative.expiration_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

SEC source: 0000874015-26-000065 · edgardoc.xml · derivative · entry 3

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 120,995

Underlying: Common Stock · 34,360 shares

Expires not disclosed

F4 · security: Grant to reporting person of Performance Restricted Stock Units (PRSUs) under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan.

F5 · derivative.exercise_date: The PRSUs may vest at the end of the three-year performance period following the date of grant based on the Issuer's relative total shareholder return as compared to a peer group of companies. The number of PRSUs reported represents the maximum that may be earned, which is 200% of the target number. No number of PRSUs is guaranteed to vest and the actual number of PRSUs that will vest at the end of the performance period may be anywhere from zero to the amount stated.

F5 · derivative.expiration_date: The PRSUs may vest at the end of the three-year performance period following the date of grant based on the Issuer's relative total shareholder return as compared to a peer group of companies. The number of PRSUs reported represents the maximum that may be earned, which is 200% of the target number. No number of PRSUs is guaranteed to vest and the actual number of PRSUs that will vest at the end of the performance period may be anywhere from zero to the amount stated.

SEC source: 0000874015-26-000065 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 139,229

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Acquired pursuant to vesting and release of shares in accordance with Restricted Stock Unit awards.

F1 · shares: Acquired pursuant to vesting and release of shares in accordance with Restricted Stock Unit awards.

SEC source: 0000874015-26-000020 · edgardoc.xml · derivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,770

Underlying: Common Stock · 25,770 shares

Expires 2036-01-01

F1 · derivative.exercise_date: Grant on 01/02/2026 to reporting person of stock options under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan. Following this transaction, the option was exercisable as to 0 shares on 01/02/2026. 25% of the shares subject to the option will vest and become exercisable on 01/02/2027. Thereafter, the remaining shares subject to the option will vest and become exercisable in 36 equal monthly installments over the next 3 years.

SEC source: 0000874015-25-000238 · edgardoc.xml · derivative · entry 3

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 49,800 shares

Expires 2026-01-01

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-25-000238 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 110,500

F1 · shares: Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on January 13, 2024.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $65.00 to $65.52 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.

SEC source: 0000874015-25-000238 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 160,300

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0001415889-25-018277 · form4-06262025_040606.xml · derivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,750

Underlying: Common Stock · 13,750 shares

Expires 2035-06-23

F1 · derivative.exercise_date: The shares subject to the option will vest in full on the earlier of June 24, 2026, or the date of the Issuer's 2026 annual stockholder meeting.

SEC source: 0000874015-25-000077 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 110,500

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $32.00 to $32.81 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.

SEC source: 0000874015-25-000077 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 112,023

F1 · shares: Represents shares earned upon the vesting of performance-based restricted stock units ("PRSUs") for the final performance period of the grant to the reporting person reported on January 19, 2022. The Compensation Committee certified achievement of the pre-established performance goal based on the Issuer's relative total shareholder return as compared to a peer group of companies at a level resulting in a vest of 150% of target shares. As reported at grant, the PRSUs could result in a payout of 0% to 150% based on actual achievement of the goal.

SEC source: 0000874015-25-000060 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 107,885

F2 · kind: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Restricted Stock Unit Agreement and Grant Notice.

F2 · shares: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Restricted Stock Unit Agreement and Grant Notice.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $32.80 to $32.82 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.

SEC source: 0000874015-25-000060 · edgardoc.xml · derivative · entry 5

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 84,669

Underlying: Common Stock · 23,887 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F7 · derivative.exercise_price: Each Restricted Stock Unit represents a contingent right to receive one share of Ionis common stock, or its equivalent cash value.

F8 · derivative.exercise_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

F8 · derivative.expiration_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

SEC source: 0000874015-25-000060 · edgardoc.xml · derivative · entry 4

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 108,556

Underlying: Common Stock · 46,500 shares

Expires not disclosed

F6 · security: Grant to reporting person of Restricted Stock Units under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan.

F7 · derivative.exercise_price: Each Restricted Stock Unit represents a contingent right to receive one share of Ionis common stock, or its equivalent cash value.

F8 · derivative.exercise_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

F8 · derivative.expiration_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

SEC source: 0000874015-25-000060 · edgardoc.xml · derivative · entry 3

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 86,635

Underlying: Common Stock · 31,000 shares

Expires not disclosed

F4 · security: Grant to reporting person of Performance Restricted Stock Units (PRSUs) under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan.

F5 · derivative.exercise_date: The PRSUs may vest at the end of the three-year performance period following the date of grant based on the Issuer's relative total shareholder return as compared to a peer group of companies. The number of PRSUs reported represents the maximum that may be earned, which is 200% of the target number. No number of PRSUs is guaranteed to vest and the actual number of PRSUs that will vest at the end of the performance period may be anywhere from zero to the amount stated.

F5 · derivative.expiration_date: The PRSUs may vest at the end of the three-year performance period following the date of grant based on the Issuer's relative total shareholder return as compared to a peer group of companies. The number of PRSUs reported represents the maximum that may be earned, which is 200% of the target number. No number of PRSUs is guaranteed to vest and the actual number of PRSUs that will vest at the end of the performance period may be anywhere from zero to the amount stated.

SEC source: 0000874015-25-000060 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 116,755

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Acquired pursuant to vesting and release of shares in accordance with Restricted Stock Unit awards.

F1 · shares: Acquired pursuant to vesting and release of shares in accordance with Restricted Stock Unit awards.

SEC source: 0000874015-25-000026 · edgardoc.xml · derivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 31,000

Underlying: Common Stock · 31,000 shares

Expires 2035-01-01

F1 · derivative.exercise_date: Grant on 01/02/2025 to reporting person of stock options under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan. Following this transaction, the option was exercisable as to 0 shares on 01/02/2025. 25% of the shares subject to the option will vest and become exercisable on 01/02/2026. Thereafter, the remaining shares subject to the option will vest and become exercisable in 36 equal monthly installments over the next 3 years.

SEC source: 0000874015-24-000106 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 92,905

F2 · shares: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Performance restricted Stock Unit Agreement and Grant Notice.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $49.53 to $49.55 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.

SEC source: 0000874015-24-000199 · primary_doc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 92,868

F1 · shares: The original Form 4 filed on February 2, 2024 reported 2,125 restricted stock units sold by the reporting person which has been revised by this amendment to reflect the actual amount of shares sold and beneficially owned by Ms. Hougen.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $49.53 to $49.55 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.

F1 · balance_after: The original Form 4 filed on February 2, 2024 reported 2,125 restricted stock units sold by the reporting person which has been revised by this amendment to reflect the actual amount of shares sold and beneficially owned by Ms. Hougen.

SEC source: 0000874015-24-000106 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 95,030

F1 · shares: Represents shares earned upon the vesting of performance-based restricted stock units ("PRSUs") for the second performance period of the grant to the reporting person reported on January 19, 2022. The Compensation Committee certified achievement of the pre-established performance goal based on the Issuer's relative total shareholder return as compared to a peer group of companies at a level resulting in a vest of 150% of target shares. As reported at grant, the PRSUs could result in a payout of 0% to 150% based on actual achievement of the goal.

SEC source: 0000874015-24-000075 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 90,890

F2 · kind: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Restricted Stock Unit Agreement and Grant Notice.

F2 · shares: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Restricted Stock Unit Agreement and Grant Notice.

F3 · price: The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.35 to $50.43, 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) of this Form 4.

SEC source: 0000874015-24-000075 · edgardoc.xml · derivative · entry 3

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 62,056

Underlying: Common Stock · 22,487 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F4 · derivative.exercise_price: Each Restricted Stock Unit represents a contingent right to receive one share of Ionis common stock, or its equivalent cash value.

F5 · derivative.exercise_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

F5 · derivative.expiration_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

SEC source: 0000874015-24-000075 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 99,573

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Acquired pursuant to vesting and release of shares in accordance with Restricted Stock Unit awards.

F1 · shares: Acquired pursuant to vesting and release of shares in accordance with Restricted Stock Unit awards.

SEC source: 0000874015-24-000054 · edgardoc.xml · derivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 84,543

Underlying: Common Stock · 32,400 shares

Expires not disclosed

F3 · security: Grant to reporting person of Restricted Stock Units under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan.

F4 · derivative.exercise_price: Each Restricted Stock Unit represents a contingent right to receive one share of Ionis common stock, or its equivalent cash value.

F5 · derivative.exercise_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

F5 · derivative.expiration_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

SEC source: 0000874015-24-000054 · edgardoc.xml · derivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 55,635

Underlying: Common Stock · 27,000 shares

Expires not disclosed

F1 · security: Grant to reporting person of Performance Restricted Stock Units (PRSUs) under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan.

F2 · derivative.exercise_date: The PRSUs may vest at the end of the three-year performance period following the date of grant based on the Issuer's relative total shareholder return as compared to a peer group of companies. The number of PRSUs reported represents the maximum that may be earned, which is 200% of the target number. No number of PRSUs is guaranteed to vest and the actual number of PRSUs that will vest at the end of the performance period may be anywhere from zero to the amount stated.

F2 · derivative.expiration_date: The PRSUs may vest at the end of the three-year performance period following the date of grant based on the Issuer's relative total shareholder return as compared to a peer group of companies. The number of PRSUs reported represents the maximum that may be earned, which is 200% of the target number. No number of PRSUs is guaranteed to vest and the actual number of PRSUs that will vest at the end of the performance period may be anywhere from zero to the amount stated.

SEC source: 0000874015-24-000022 · edgardoc.xml · derivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 43,200

Underlying: Common Stock · 43,200 shares

Expires 2034-01-01

F1 · derivative.exercise_date: Grant on 01/02/2024 to reporting person of stock options under the Ionis Pharmaceuticals, Inc. Amended and Restated 2011 Equity Incentive Plan. Following this transaction, the option was exercisable as to 0 shares on 01/02/2024. 25% of the shares subject to the option will vest and become exercisable on 01/02/2025. Thereafter, the remaining shares subject to the option will vest and become exercisable in 36 equal monthly installments over the next 3 years.

SEC source: 0000874015-24-000005 · edgardoc.xml · derivative · entry 3

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 45,225 shares

Expires 2024-01-02

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-24-000005 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 77,086

F1 · kind: Represents a "net exercise" of outstanding stock options. The reporting person received 1,427 shares of common stock on net exercise of option to purchase 45,225 shares of common stock. Pursuant to the terms of the Company's 2011 Equity Incentive Plan, the Company withheld 43,798 shares of common stock underlying the option for payment of the exercise price and tax withholdings using the closing stock price on December 28, 2023 of $50.50.

SEC source: 0000874015-24-000005 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 120,884

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0000874015-23-000113 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 75,659

F1 · kind: Reporting shares purchased under the Ionis Pharmaceuticals, Inc. Amended and Restated 2000 Employee Stock Purchase Plan on February 28, 2023. These shares may not be sold until August 28, 2023.

SEC source: 0000874015-23-000092 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 75,496

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.56 to $40.64 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.

SEC source: 0000874015-23-000092 · edgardoc.xml · nonDerivative · entry 1

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 77,575

F1 · shares: Represents shares earned upon the vesting of performance-based restricted stock units ("PRSUs") for the first performance period of the grant to the reporting person reported on January 19, 2022. The Compensation Committee certified achievement of the pre-established performance goal based on the Issuer's relative total shareholder return as compared to a peer group of companies at a level resulting in a vest of 150% of target shares. As reported at grant, the PRSUs could result in a payout of 0% to 150% based on actual achievement of the goal.

SEC source: 0000874015-23-000065 · edgardoc.xml · nonDerivative · entry 2

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 73,435

F2 · kind: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Restricted Stock Unit Agreement and Grant Notice.

F2 · shares: The sale was made pursuant to an automatic sale to cover the required tax withholding obligations pursuant to the 2011 Equity Incentive Plan Restricted Stock Unit Agreement and Grant Notice.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $39.29 to $39.77 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.

SEC source: 0000874015-23-000065 · edgardoc.xml · derivative · entry 3

HOUGEN ELIZABETH L · CIK 0001074773 · EVP, Finance & CFO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 52,143

Underlying: Common Stock · 23,154 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F4 · derivative.exercise_price: Each Restricted Stock Unit represents a contingent right to receive one share of Ionis common stock, or its equivalent cash value.

F5 · derivative.exercise_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.

F5 · derivative.expiration_date: Restricted Stock Units vest in four equal annual installments. Upon vesting, the restricted stock units will be paid out in whole shares of Ionis common stock or cash as may be determined by the Company.