Form 4 for COLB COLUMBIA BANKING SYSTEM, INC.

Accepted 2026-01-22 00:00:00 ET · period of report 2026-01-20 · accession 0000887343-26-000013 · SEC index · Original document

Summary rows

Aggregated the way they appear in lists: one row per insider, transaction code and security table.

X	Filed	Traded	Ticker	Insider	Title	Type	Price	Qty	Owned	ΔOwn	Value
M	2026-01-22	2026-01-20	COLB	Stein Clint	COB, Pres, CEO, Dir	D - Sale to Iss	$0.00	-6,315	129.0K	-5%	$0
M	2026-01-22	2026-01-20	COLB	Stein Clint	COB, Pres, CEO, Dir	F - Tax	$28.35	-13.2K	131.8K	-9%	-$375.6K

Purchase Sale Sale after option exercise All abbreviations

#	Table	Security	Date	Code	A/D	Shares	Price	Owned after	Own	Exercise / expiry	Underlying	Footnotes
1	Common	Common Stock	2026-01-20	D	D	3,588	$0.00	139,373	D	—	—	(F1) Shares forfeited pursuant to the terms of the performance restricted stock units granted on February 21, 2023 and reported on the reporting person's Form 4 filed on February 21, 2023 (in accordance with Rule 16b-3(e)) due to the issuer's total shareholder return performance target not being met at target.
2	Common	Common Stock	2026-01-20	F	D	5,635	$28.35	123,396	D	—	—	(F2) Represents withholding of shares of common stock to satisfy the reporting person's tax withholding obligations in connection with the vesting of previously issued restricted stock units.
3	Common	Common Stock	2026-01-20	D	D	2,727	$0.00	129,031	D	—	—	(F3) Shares forfeited pursuant to the terms of the performance restricted stock units granted on March 14, 2023 and reported on the reporting person's Form 4 filed on March 15, 2023 (in accordance with Rule 16b-3(e)) due to the issuer's total shareholder return performance target not being met at target.
4	Common	Common Stock	2026-01-20	F	D	7,615	$28.35	131,758	D	—	—	(F2) Represents withholding of shares of common stock to satisfy the reporting person's tax withholding obligations in connection with the vesting of previously issued restricted stock units.