Form 4 for COLB COLUMBIA BANKING SYSTEM, INC.

Accepted 2026-08-18 16:50:51 ET · period of report 2026-08-14 · accession 0000887343-26-000174 · 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
D	2026-08-18 16:50	2026-08-14	COLB	Giem Judi	EVP CHRO	M - OptEx	$32.69	+2,393	2,393	New	+$78.2K
D	2026-08-18 16:50	2026-08-14	COLB	Giem Judi	EVP CHRO	F - Tax	$32.69	-643	1,750	-27%	-$21.0K
D	2026-08-18 16:50	2026-08-14	COLB	Giem Judi	EVP CHRO	M - OptEx	—	-2,393	13.1K	-15%	—

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	2026-08-14	M	A	2,393	$32.69	2,393	D	—	—
2	Common	Common Stock	2026-08-14	F	D	643	$32.69	1,750	D	—	—
3	Derivative	Restricted Stock Unit	2026-08-14	M	D	2,393	—	13,108	D	— · — to —	2,393 Common Stock	(F1) Restricted Stock Units convert into common stock on a one-for-one basis. On July 22, 2025, the reporting person was granted 7,179 Restricted Stock Units, which vest in three annual installments beginning on August 14, 2026. (F1) Restricted Stock Units convert into common stock on a one-for-one basis. On July 22, 2025, the reporting person was granted 7,179 Restricted Stock Units, which vest in three annual installments beginning on August 14, 2026. (F1) Restricted Stock Units convert into common stock on a one-for-one basis. On July 22, 2025, the reporting person was granted 7,179 Restricted Stock Units, which vest in three annual installments beginning on August 14, 2026. (F1) Restricted Stock Units convert into common stock on a one-for-one basis. On July 22, 2025, the reporting person was granted 7,179 Restricted Stock Units, which vest in three annual installments beginning on August 14, 2026.