Arbutus CFO exercises options at $3.49 and $4.39

The issuer withheld 206,637 shares otherwise issuable to satisfy the aggregate exercise prices.

Rhea-AI Filing Summary

Arbutus Biopharma Corp (ABUS) Chief Financial Officer Nguyen Tuan exercised options on September 18, 2026, for 265,625 common shares at an exercise price of $3.49 per share and 27,475 common shares at an exercise price of $4.39 per share. The issuer withheld 206,637 shares otherwise issuable upon the exercises to satisfy the aggregate exercise prices. The options represented rights to purchase 750,000 and 188,400 shares, respectively, and vest subject to continuous service.

Insider Trade Summary

293,100 shares exercised/converted

Exercise 5 txns

Insider Nguyen Tuan

Role Chief Financial Officer

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy) F2	265,625	$0.00	$0.00
Exercise	Stock Option (Right to Buy) F3	27,475	$0.00	$0.00
Exercise	Common Shares	265,625	$3.49	$927K
Exercise	Common Shares	27,475	$4.39	$121K
Exercise Price or Tax Liability	Common Shares F1	206,637	$5.07	$1.05M

Holdings After Transaction: Stock Option (Right to Buy) — 645,300 contracts (Direct); Common Shares — 159,963 shares (Direct)

Footnotes (3)

1. F1. The Reporting Person exercised options on September 18, 2026. The Issuer withheld an aggregate of 206,637 shares otherwise issuable upon the exercises to satisfy the aggregate exercise prices.
2. F2. The option, representing a right to purchase a total of 750,000 shares, vests over a four-year period, with 25% of the total shares subject to the option vesting on the 1st anniversary of the March 31, 2025 grant date and the remaining 75% vesting over the subsequent three-year period in substantially equal monthly installments at a rate of 1/48th of the total shares subject to the option each month, subject to the Reporting Person's continuous service as of each vesting date.
3. F3. The option, representing a right to purchase a total of 188,400 shares, vests over a four-year period, with 1/48th of the shares subject to the option vesting in substantially equal monthly installments measured from one month following the February 2, 2026 grant date, subject to the Reporting Person's continuous service as of each vesting date.

Key Figures

Common shares acquired on option exercise: 265,625 shares Common shares acquired on option exercise: 27,475 shares Shares withheld: 206,637 shares +2 more

5 metrics

Common shares acquired on option exercise 265,625 shares September 18, 2026; exercise price of $3.49 per share

Common shares acquired on option exercise 27,475 shares September 18, 2026; exercise price of $4.39 per share

Shares withheld 206,637 shares Withheld by the issuer to satisfy the aggregate exercise prices

Shares subject to option 750,000 shares Option granted March 31, 2025

Shares subject to option 188,400 shares Option granted February 2, 2026

Key Terms

Stock Option (Right to Buy), vesting date, substantially equal monthly installments

3 terms

Stock Option (Right to Buy) financial

"Stock Option (Right to Buy)"

vesting date financial

"as of each vesting date"

substantially equal monthly installments financial

"vesting over the subsequent three-year period in substantially equal monthly installments"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many ABUS shares did CFO Nguyen Tuan acquire?

Nguyen Tuan acquired 265,625 common shares at an exercise price of $3.49 per share and 27,475 common shares at an exercise price of $4.39 per share on September 18, 2026.

How many ABUS shares were withheld, and why?

The issuer withheld 206,637 shares otherwise issuable upon the exercises to satisfy the aggregate exercise prices.

How do Nguyen Tuan's options vest?

The option representing rights to purchase 750,000 shares vests 25% on the first anniversary of the March 31, 2025 grant date, with the remaining 75% vesting over the next three years in substantially equal monthly installments. The 188,400-share option vests in substantially equal monthly installments measured from one month after the February 2, 2026 grant date. Both schedules are subject to continuous service.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/23/2026 - 08:32 PM Accepted by SEC EDGAR 09/23/2026 - 08:31 PM Learn about SEC filing dates

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).

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^*

Nguyen Tuan

(Last) (First) (Middle)

C/O ARBUTUS BIOPHARMA CORPORATION

701 VETERANS CIRCLE

(Street)

WARMINSTER PENNSYLVANIA 18974

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Arbutus Biopharma Corp [ ABUS ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/18/2026

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 Shares	09/18/2026		M		265,625	A	$3.49	339,125	D
Common Shares	09/18/2026		M		27,475	A	$4.39	366,600	D
Common Shares	09/18/2026		F(1)		206,637	D	$5.07	159,963	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
Stock Option (Right to Buy)	$3.49	09/18/2026		M			265,625	(2)	03/31/2035	Common Shares	265,625	$0	484,375	D
Stock Option (Right to Buy)	$4.39	09/18/2026		M			27,475	(3)	02/02/2036	Common Shares	27,475	$0	160,925	D

Explanation of Responses:

1. The Reporting Person exercised options on September 18, 2026. The Issuer withheld an aggregate of 206,637 shares otherwise issuable upon the exercises to satisfy the aggregate exercise prices.

2. The option, representing a right to purchase a total of 750,000 shares, vests over a four-year period, with 25% of the total shares subject to the option vesting on the 1st anniversary of the March 31, 2025 grant date and the remaining 75% vesting over the subsequent three-year period in substantially equal monthly installments at a rate of 1/48th of the total shares subject to the option each month, subject to the Reporting Person's continuous service as of each vesting date.

3. The option, representing a right to purchase a total of 188,400 shares, vests over a four-year period, with 1/48th of the shares subject to the option vesting in substantially equal monthly installments measured from one month following the February 2, 2026 grant date, subject to the Reporting Person's continuous service as of each vesting date.

Remarks:

	/s/ Tuan Nguyen	09/23/2026
	** 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)