Christopher Merrywell - Feb 28, 2023 Form 4 Insider Report for COLUMBIA BANKING SYSTEM, INC. (COLB)

Role: EVP Chief Operating Officer
Signature: /s/ Andrea M. Newburn, Attorney-in-fact
Stock symbol: COLB
Transactions as of: Feb 28, 2023
Transactions value $: $0
Form type: 4
Date filed: 3/2/2023, 05:09 PM
Previous filing: Feb 23, 2023
Next filing: Mar 29, 2023

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	COLB	Common	Award	$0	+2K	+5.57%	$0.00	37.9K	Feb 28, 2023	Direct	F1
transaction	COLB	Common	Award	$0	+2K	+5.27%	$0.00	39.9K	Feb 28, 2023	Direct	F1
transaction	COLB	Common	Award	$0	+4.22K	+10.57%	$0.00	44.2K	Feb 28, 2023	Direct	F1
transaction	COLB	Common	Award	$0	+3.77K	+8.54%	$0.00	47.9K	Feb 28, 2023	Direct	F1

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

Explanation of Responses:

Id	Content
F1	At the effective time of the merger (the "Effective Time") of Cascade Merger Sub, Inc. ("Merger Sub"), a direct, wholly-owned subsidiary of the Issuer, with and into Umpqua Holdings Corporation ("Umpqua"), pursuant to that certain Agreement and Plan of Merger, dated as of October 11, 2021 (the "Merger Agreement"), by and among the Issuer, Umpqua and Merger Sub, each outstanding performance stock unit award of the Issuer granted under the Issuer's equity compensation plans was converted into a restricted stock unit award of the Issuer based on a level of performance determined in accordance with the Merger Agreement, with such awards continuing to vest after the Effective Time solely based on continued service.

Content

At the effective time of the merger (the "Effective Time") of Cascade Merger Sub, Inc. ("Merger Sub"), a direct, wholly-owned subsidiary of the Issuer, with and into Umpqua Holdings Corporation ("Umpqua"), pursuant to that certain Agreement and Plan of Merger, dated as of October 11, 2021 (the "Merger Agreement"), by and among the Issuer, Umpqua and Merger Sub, each outstanding performance stock unit award of the Issuer granted under the Issuer's equity compensation plans was converted into a restricted stock unit award of the Issuer based on a level of performance determined in accordance with the Merger Agreement, with such awards continuing to vest after the Effective Time solely based on continued service.