COLUMBIA BANKING SYSTEM, INC. — Director's Dealing 2026

Mar 18, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: COLUMBIA BANKING SYSTEM, INC. (COLB)
CIK: 0000887343
Period of Report: 2026-03-13

Reporting Person: Moore Devine David (EVP Chief Marketing Officer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-03-13	Common Stock	M	940	$26.23	Acquired	22884	Direct
2026-03-13	Common Stock	F	376	$26.23	Disposed	22508	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2026-03-13	Restricted Stock Unit	$	M	940	Disposed		Common Stock (940)	Direct

Footnotes

F1: Restricted Stock Units convert into common stock on a one-for-one basis. On February 25, 2025, the reporting person was granted 2,819 Restricted Stock Units, which vest in three annual installments beginning on March 13, 2026.