Frank Namdar - 18 Feb 2026 Form 4 Insider Report for COLUMBIA BANKING SYSTEM, INC. (COLB)

Role: EVP Chief Credit Officer
Signature: /s/ Andrea M. Newburn, Attorney-in-fact
Issuer symbol: COLB
Transactions as of: 18 Feb 2026
Net transactions value: +$249,982
Form type: 4
Filing time: 20 Feb 2026, 19:34:42 UTC
Previous filing: 18 Feb 2026
Next filing: 02 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Namdar Frank	EVP Chief Credit Officer	C/O COLUMBIA BANKING SYSTEM, INC., 1301 A STREET, TACOMA	/s/ Andrea M. Newburn, Attorney-in-fact	20 Feb 2026	0001759802

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	COLB	Restricted Stock Unit	Award	$249,982	+8,002	+95%	$31.24	16,460	18 Feb 2026	Common Stock	8,002		Direct	F1
holding	COLB	Deferred Compensation Phantom Stock						2,917	18 Feb 2026	Common	2,917		Deferred Compensation	F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Restricted stock units granted 02/18/2026. The grant will vest 33.33% per year over three years.
F2	The deferred compensation plan phantom stock was accrued under the Registrant's deferred compensation plan and will be paid in cash in accordance with the terms of the deferred compensation plan following end of the reporting person's employment with the Registrant.