<SEC-DOCUMENT>0000887343-25-000138.txt : 20250331
<SEC-HEADER>0000887343-25-000138.hdr.sgml : 20250331
<ACCEPTANCE-DATETIME>20250331163531
ACCESSION NUMBER:		0000887343-25-000138
CONFORMED SUBMISSION TYPE:	11-K
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20241231
FILED AS OF DATE:		20250331
DATE AS OF CHANGE:		20250331

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			COLUMBIA BANKING SYSTEM, INC.
		CENTRAL INDEX KEY:			0000887343
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		ORGANIZATION NAME:           	02 Finance
		EIN:				911422237
		STATE OF INCORPORATION:			WA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		11-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-20288
		FILM NUMBER:		25793945

	BUSINESS ADDRESS:	
		STREET 1:		1301 A STREET
		CITY:			TACOMA
		STATE:			WA
		ZIP:			98402
		BUSINESS PHONE:		2533051900

	MAIL ADDRESS:	
		STREET 1:		1301 A STREET
		CITY:			TACOMA
		STATE:			WA
		ZIP:			98402

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	COLUMBIA BANKING SYSTEM INC
		DATE OF NAME CHANGE:	19930328
</SEC-HEADER>
<DOCUMENT>
<TYPE>11-K
<SEQUENCE>1
<FILENAME>colbespp11-k2024.htm
<DESCRIPTION>11-K
<TEXT>
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<title>Document</title></head><body><div id="i9f5f67b1cb70433aa6be437900f4dc65_1"></div><div style="min-height:36pt;width:100%"><div><font><br></font></div></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:120%">UNITED STATES</font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:120%">SECURITIES AND EXCHANGE COMMISSION</font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">Washington, D.C. 20549</font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">___________________________________________________</font></div><div style="margin-top:9pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#160;</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:18pt;font-weight:700;line-height:120%">FORM 11-K</font></div><div style="text-align:center;text-indent:-22.5pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">___________________________________________________</font></div><div style="margin-top:5pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(Mark One)</font><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:5.310%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:92.490%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Wingdings',sans-serif;font-size:12pt;font-weight:400;line-height:100%">x</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:100%">ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934</font></td></tr></table></div><div style="margin-top:3pt;text-align:center;text-indent:-22.5pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">For the fiscal year ended DECEMBER&#160;31, 2024 </font></div><div style="margin-top:3pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">OR</font><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:5.310%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:92.490%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:400;line-height:100%">&#91;   &#93;</font></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:100%">TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934</font></td></tr></table></div><div style="margin-top:3pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">For the transition period from &#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;to &#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;.</font></div><div style="margin-top:3pt;text-align:center"><font><br></font></div><div style="margin-top:3pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Commission File Number.....</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">000-20288</font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">___________________________________________________</font></div><div style="text-align:center"><font><br></font></div><div style="padding-left:20.25pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A.&#160;&#160;&#160;&#160;Full title of the plan and the address of the plan, if different from that of the issuer named below&#58;</font></div><div><font><br></font></div><div style="margin-bottom:5pt;margin-top:5pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">AMENDED AND RESTATED EMPLOYEE STOCK PURCHASE PLAN OF COLUMBIA BANKING SYSTEM, INC. </font></div><div><font><br></font></div><div style="padding-left:20.25pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">B.&#160;&#160;&#160;&#160;Name of issuer of the securities held pursuant to the plan and the address of its principal executive office&#58;</font></div><div><font><br></font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:14pt;font-weight:700;line-height:120%">Columbia Banking System, Inc.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%"> </font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">1301 A Street</font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">Tacoma, Washington 98402-4200 </font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font><br></font></div><div><font><br></font></div><div><font><br></font></div><div style="height:36pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="text-align:center"><font><br></font></div></div></div><div id="i9f5f67b1cb70433aa6be437900f4dc65_4"></div><hr style="page-break-after:always"><div style="min-height:144pt;width:100%"><div><font><br></font></div></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:14pt;font-weight:400;line-height:120%">Amended and Restated Employee Stock Purchase Plan of </font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:14pt;font-weight:400;line-height:120%">Columbia Banking System, Inc.</font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Financial Statements as of December 31, 2024 and 2023, and for the Years Ended December 31, 2024 and 2023,</font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">and Report of Independent Registered Public Accounting Firm</font></div><div style="text-align:center"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="text-align:right"><font><br></font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="text-align:center"><font><br></font></div></div></div><div id="i9f5f67b1cb70433aa6be437900f4dc65_7"></div><hr style="page-break-after:always"><div style="min-height:180pt;width:100%"><div><font><br></font></div></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">CONTENTS</font></div><div><font><br></font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:138%">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</font></div><div style="text-align:center"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:99.198%"><tr><td style="width:0.1%"></td><td style="width:2.384%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:88.560%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.446%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:6.010%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:138%">PAGE</font></div></td></tr><tr><td colspan="6" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:138%">REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM</font></div></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:center"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a href="#i9f5f67b1cb70433aa6be437900f4dc65_10" style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline">1</a></font></div></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="6" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:138%">FINANCIAL STATEMENTS</font></div></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:138%">Statements of Net Assets Available for Benefits as of December&#160;31, 2024 and 2023</font></div></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:center"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a href="#i9f5f67b1cb70433aa6be437900f4dc65_13" style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline">2</a></font></div></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:138%">Statements of Changes in Net Assets Available for Benefits for the years ended December&#160;31, 2024 and 2023</font></div></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:center"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a href="#i9f5f67b1cb70433aa6be437900f4dc65_16" style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline">3</a></font></div></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:138%">Notes to Financial Statements </font></div></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:center"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a href="#i9f5f67b1cb70433aa6be437900f4dc65_19" style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline">4</a></font></div></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="6" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:100%">INDEX TO EXHIBITS</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:100%">EXHIBITS 23.1 - Consent of Independent Registered Public Accounting Firm</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:center"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a href="#i9f5f67b1cb70433aa6be437900f4dc65_34" style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline">6</a></font></div></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="6" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10.5pt;font-weight:400;line-height:100%">SIGNATURE</font></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:center"><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a href="#i9f5f67b1cb70433aa6be437900f4dc65_37" style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline">7</a></font></div></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr></table></div><div><font><br></font></div><div><font><br></font></div><div><font><br></font></div><div style="height:54pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div><font><br></font></div></div></div><div id="i9f5f67b1cb70433aa6be437900f4dc65_10"></div><hr style="page-break-after:always"><div style="min-height:108pt;width:100%"><div><font><br></font></div></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">Report of Independent Registered Public Accounting Firm</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">To the Plan Participants and Plan Administrator of the Amended and Restated Employee Stock Purchase Plan of Columbia Banking System, Inc.</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Opinion on the Financial Statements</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We have audited the accompanying statement of net assets available for benefits of the Amended and Restated Employee Stock Purchase Plan of Columbia Banking System, Inc. (&#34;the Plan&#34;) as of December&#160;31, 2024, the related statement of changes in net assets available for benefits for the year ended December&#160;31, 2024, and the related notes (collectively referred to as &#34;the financial statements&#34;). In our opinion, the financial statements present fairly, in all material respects, the net assets available for benefits of the Plan as of December&#160;31, 2024, and the changes in net assets available for benefits for the year ended December&#160;31, 2024, in conformity with accounting principles generally accepted in the United States of America (&#34;U.S.&#34;).</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Basis for Opinion</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">These financial statements are the responsibility of the Plan's management. Our responsibility is to express an opinion on the Plan's financial statements based on our audit. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (&#34;PCAOB&#34;) and are required to be independent with respect to the Plan in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Plan is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audit, we are required to obtain an understanding of internal control over financial reporting, but not for the purpose of expressing an opinion on the effectiveness of the Plan&#8217;s internal control over financial reporting. Accordingly, we express no such opinion.</font></div><div><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Our audit included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audit also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audit provides a reasonable basis for our opinion.</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#47;s&#47; Delap LLP</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We have served as the Plan's auditor since 2025.</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Lake Oswego, Oregon</font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">March&#160;31, 2025</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font><br></font></div><div style="height:81pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">1</font></div></div></div><div id="i9f5f67b1cb70433aa6be437900f4dc65_13"></div><hr style="page-break-after:always"><div style="min-height:36pt;width:100%"><div><font><br></font></div></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">AMENDED AND RESTATED EMPLOYEE STOCK PURCHASE PLAN OF COLUMBIA BANKING SYSTEM, INC.</font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:120%">STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS</font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:120%">AS OF DECEMBER 31, 2024 AND 2023</font></div><div><font><br></font></div><div style="text-align:center"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:99.839%"><tr><td style="width:1.0%"></td><td style="width:2.591%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:2.591%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:2.591%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:51.548%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:16.717%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.442%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:16.720%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="background-color:#083853;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;padding:0 1pt"></td><td colspan="9" style="background-color:#083853;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#ffffff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">December 31,</font></td></tr><tr><td colspan="12" style="background-color:#083853;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;border-top:1pt solid #dbdbdb;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#ffffff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">2024</font></td><td colspan="3" style="background-color:#083853;border-top:1pt solid #dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;border-top:1pt solid #dbdbdb;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#ffffff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">2023</font></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Unaudited</font></td></tr><tr><td colspan="9" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">ASSETS</font></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="9" style="background-color:#dbdbdb;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Plan cash held by Umpqua Bank</font></td><td style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,419,168&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total assets</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,419,168&#160;</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr style="height:12pt"><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;border-top:1pt solid #000;padding:0 1pt"></td></tr><tr><td colspan="12" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">LIABILITIES </font></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="9" style="background-color:#dbdbdb;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Payable to purchase shares</font></td><td style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,389,188&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="9" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Payable to participants and other</font></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">29,980&#160;</font></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total liabilities</font></td><td style="background-color:#dbdbdb;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,419,168&#160;</font></td><td style="background-color:#dbdbdb;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td style="background-color:#dbdbdb;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr style="height:14pt"><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000;padding:0 1pt"></td></tr><tr><td colspan="12" style="background-color:#dbdbdb;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">NET ASSETS AVAILABLE FOR BENEFITS</font></td><td style="background-color:#dbdbdb;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td style="background-color:#dbdbdb;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div><div><font><br></font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">See accompanying notes.</font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">2</font></div><div style="text-align:center"><font><br></font></div></div></div><div id="i9f5f67b1cb70433aa6be437900f4dc65_16"></div><hr style="page-break-after:always"><div style="min-height:36pt;width:100%"><div><font><br></font></div></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">AMENDED AND RESTATED EMPLOYEE STOCK PURCHASE PLAN OF COLUMBIA BANKING SYSTEM, INC. </font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:120%">STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS</font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:120%">YEARS ENDED DECEMBER 31, 2024 AND 2023</font></div><div><font><br></font></div><div><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:2.425%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:2.585%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:1.944%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:52.425%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:16.688%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.441%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:16.692%"></td><td style="width:0.1%"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#083853;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;padding:0 1pt"></td><td colspan="9" style="background-color:#083853;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#ffffff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">December 31,</font></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="12" style="background-color:#083853;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;border-top:1pt solid #dbdbdb;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#ffffff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">2024</font></td><td colspan="3" style="background-color:#083853;border-top:1pt solid #dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#083853;border-top:1pt solid #dbdbdb;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#ffffff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">2023</font></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:2px 1pt;text-align:center;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Unaudited</font></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="12" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">ADDITIONS</font></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt 0 19pt"></td><td colspan="9" style="background-color:#dbdbdb;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Participant contributions, net withdrawals</font></td><td style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,419,168&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#dbdbdb;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,185,163&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt 0 19pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total additions</font></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,419,168&#160;</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,185,163&#160;</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr style="height:12pt"><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="12" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">DEDUCTIONS</font></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt 0 13pt"></td><td colspan="9" style="background-color:#dbdbdb;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cost of shares purchased</font></td><td colspan="2" style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="2" style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,185,163&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:0 1pt 0 13pt"></td><td colspan="9" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Payable to purchase shares</font></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,389,188&#160;</font></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="9" style="background-color:#dbdbdb;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Payable to participants</font></td><td colspan="2" style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">29,980&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="2" style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total deductions</font></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,419,168&#160;</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,185,163&#160;</font></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr style="height:14pt"><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="3" style="background-color:#dbdbdb;border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="12" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">CHANGE IN NET ASSETS AVAILABLE FOR BENEFITS</font></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt 0 13pt"></td><td colspan="9" style="background-color:#dbdbdb;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net assets available for benefits beginning of year</font></td><td colspan="2" style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#dbdbdb;padding:0 1pt"></td><td colspan="2" style="background-color:#dbdbdb;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#dbdbdb;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:0 1pt 0 13pt"></td><td colspan="9" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net assets available for benefits end of year</font></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</font></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</font></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr></table></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">See accompanying notes.</font></div><div style="text-align:center"><font><br></font></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">3</font></div><div><font><br></font></div></div></div><div id="i9f5f67b1cb70433aa6be437900f4dc65_19"></div><hr style="page-break-after:always"><div style="min-height:67.5pt;width:100%"><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">AMENDED AND RESTATED EMPLOYEE STOCK PURCHASE PLAN OF COLUMBIA BANKING SYSTEM, INC.</font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:120%">NOTES TO FINANCIAL STATEMENTS </font></div><div><font><br></font></div><div><font><br></font></div><div><font><br></font></div></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Note 1 &#8211; DESCRIPTION OF THE PLAN AND ACCOUNTING POLICIES</font></div><div style="text-align:justify"><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">General - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Amended and Restated Employee Stock Purchase Plan of Columbia Banking System, Inc. (as amended, the &#34;Plan&#34;) is intended to provide eligible employees of Columbia Banking System, Inc. (the &#34;Company&#34;) who wish to become shareholders of the Company a convenient method of doing so. The Plan covers substantially all employees of the Company who are employed by the Company on any given enrollment date.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Accounting Principles - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States of America. </font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Plan Administration - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The administrator of the Plan (the &#34;Plan Administrator&#34;) is the Compensation Committee of the Board of Directors of the Company or other persons acting in this capacity pursuant to a delegation of authority from the Compensation Committee. The Plan is intended to meet the qualification standards of Section 423 of the Internal Revenue Code of 1986, pursuant to which the Plan is not subject to taxation. The Plan is not subject to the provisions of the Employee Retirement Income Security Act of 1974.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Contributions - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Plan participants (&#34;Participants&#34;) may make contributions to the Plan through payroll deductions for the purpose of purchasing the Company&#8217;s common stock, no par value (&#34;Shares&#34;). Participants can elect the amount of the payroll deduction as either a percentage of their compensation or a flat dollar amount per payroll date. Participant contributions are recorded in the period that the Participants&#8217; payroll deductions are made. Participant contributions are not subject to vesting and are therefore fully vested at all times. </font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Share Purchases - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Plan allows Participants to purchase Shares at 90% of the closing price reported on the exchange where the Shares are traded (&#34;Fair Market Value&#34;) on either the first or last trading day of each six-month offering period, whichever is lower. The Plan operates with consecutive offering periods commencing on the first trading day on or after January 1st and ending on June 30th, and with the second offering period commencing on the first trading day on or after July 1st and ending on December 31st. Shares are recorded as purchased on the settlement date, in the subsequent offering period, and are distributed to each Participant&#8217;s account by the stock transfer agent. </font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In 2024, the Plan had a single offering period from July 1st to December 31st, with no Shares purchased during 2024. In 2023, Participants purchased 58,440 Shares through the Plan, following the closing of the January 1st to June 30th 2023, offering period (unaudited). Effective May 2024, the Plan was amended to increase the authorized Shares available for purchase to 877,206. Under the Plan, there were 877,206 Shares reserved for future issuance as of December 31, 2024.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Withdrawals - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">If a Participant elects to withdraw from the Plan at any time prior to the first day of the last calendar month of a six-month offering period, or if a Participant&#8217;s employment has been terminated at any time, the Plan refunds any amounts withheld during that period back to the Participant. All such amounts are included in participant contributions, net of withdrawals on the Statements of Changes in Net Assets Available for Benefits. </font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A Participant's accumulated payroll deductions will be used to purchase the maximum allowable number of whole Shares that can be purchased with the amounts in the Participant's notional account. Excess Participant contributions for Participants purchasing the maximum number of Shares with contributions from an offering period will be refunded to the Participants in the following offering period. For Participants purchasing less than the maximum allowable number of Shares with contributions from an offering period, the excess contributions will be carried forward to the next offering period and aggregated with future contributions for the purpose of purchasing Shares.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Payable to Purchase Shares - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Payable to purchase Shares primarily represents cash contributed to the Plan in the last offering period of a calendar year that was used to purchase Shares in the first offering period of the next calendar year. Participants purchased 77,523 Shares through the Plan in January 2025 for $1,383,786 related to contributions from the last offering period of 2024. Payable to purchase Shares also includes excess contributions from Participants who purchased less than the maximum number of Shares with contributions from a previous offering period. These excess contributions were carried forward to the next offering period and will be aggregated with future contributions for the purpose of purchasing Shares. </font></div><div style="height:58.5pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4</font></div></div></div><hr style="page-break-after:always"><div style="min-height:67.5pt;width:100%"><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:12pt;font-weight:700;line-height:120%">AMENDED AND RESTATED EMPLOYEE STOCK PURCHASE PLAN OF COLUMBIA BANKING SYSTEM, INC.</font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:120%">NOTES TO FINANCIAL STATEMENTS </font></div><div><font><br></font></div><div><font><br></font></div><div><font><br></font></div></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Payable to Participants - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Payable to participants represents cash in Participant accounts that was contributed to the Plan in amounts greater than the cost of the maximum number of Shares allowed to be purchased during the year. All such amounts will be refunded to Participants from the Plan in the following offering period and are therefore not included in Net Assets Available for Benefits in the accompanying financial statements.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Limitations - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Participants are prohibited from purchasing Shares with an aggregate Fair Market Value in excess of $25,000 in any calendar year. Employees owning equity securities of the Company, including rights, options, warrants, or other securities convertible into Shares upon exercise, representing 5% or more of the total combined voting power or value of all classes of the Company's stock are not permitted to purchase Shares under the Plan.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Administrative Expenses - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">All Plan administrative expenses are paid by the Company and are not reflected in the accompanying financial statements.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Termination - </font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Although it has not expressed any intention to do so, the Company has the right to terminate the Plan at any time. In the event of a dissolution, merger, or acquisition of the Company, the Company may permit a Participant to purchase Shares to the extent of accumulated payroll deduction funds in the Participant&#8217;s account. In the event of a termination of the Plan, the assets will be returned to the Participants.</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Note 2 &#8211; PLAN ASSETS</font></div><div style="text-align:justify"><font><br></font></div><div style="text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Plan&#8217;s cash is maintained by the Company on behalf of the Plan.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> </font></div><div style="height:58.5pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">5</font></div></div></div><div id="i9f5f67b1cb70433aa6be437900f4dc65_34"></div><hr style="page-break-after:always"><div style="min-height:36pt;width:100%"><div><font><br></font></div></div><div style="-sec-extract:summary;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:174%">INDEX TO EXHIBITS</font></div><div style="text-align:center"><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:174%;text-decoration:underline">Exhibit No.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:174%">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:174%;text-decoration:underline">Description</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:400;line-height:174%">    23.1</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:174%">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</font><font style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:174%;text-decoration:underline"><a href="colbesppex23111-kconsent20.htm" style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:174%;text-decoration:underline">Consent of Independent Registered Public Accounting Firm</a></font></div><div><font><br></font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> </font></div><div style="height:36pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="-sec-extract:summary;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">6</font></div></div></div><div id="i9f5f67b1cb70433aa6be437900f4dc65_37"></div><hr style="page-break-after:always"><div style="min-height:36pt;width:100%"><div><font><br></font></div></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:700;line-height:120%">SIGNATURES</font></div><div><font><br></font></div><div style="margin-bottom:5pt;margin-top:5pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Pursuant to the requirements of the Securities and Exchange Act of 1934, the Plan Administrator has duly caused this annual report to be signed on its behalf by the undersigned hereunto duly authorized.</font></div><div><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:30.150%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:7.393%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:59.157%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Amended and Restated Employee Stock Purchase Plan of Columbia Banking System, Inc.</font></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Date&#58;  March&#160;31, 2025</font></div></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#160;&#47;s&#47; Lisa M. White</font></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Lisa M. White</font></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Executive Vice President, Corporate Controller and Principal Accounting Officer</font></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr></table></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:400;line-height:120%">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:400;line-height:120%">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</font></div><div><font><br></font></div><div style="height:36pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">7</font></div></div></div></body></html>
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</DOCUMENT>
<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>2
<FILENAME>colbesppex23111-kconsent20.htm
<DESCRIPTION>CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
<TEXT>
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<title>Document</title></head><body><div id="if94e9556f38b43a4b62d05049ea0ae30_1"></div><div style="min-height:42.75pt;width:100%"><div><font><br></font></div></div><div><font><br></font></div><div style="text-align:right"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Exhibit 23.1 </font></div><div style="text-align:right"><font><br></font></div><div style="text-align:center"><font><br></font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:115%">CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:112%">We consent to the incorporation by reference in Registration Statement Nos. 333-273424, 333-270191, 333-160371, 333-225955, 333-279235, 333-279237 and 333-279238 on Form S-8 and Registration Statement No. 333-283985 on Form S-3 of Columbia Banking System, Inc. of our report dated March 31, 2025, relating to the financial statements of the Amended and Restated Employee Stock Purchase Plan of Columbia Banking System, Inc. appearing in this Annual Report on Form 11-K for the year ended December 31, 2024.</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%">&#47;s&#47; Delap LLP</font></div><div><font><br></font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%">Lake Oswego, Oregon</font></div><div><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%">March 31, 2025</font></div><div style="margin-bottom:5pt;margin-top:5pt"><font><br></font></div><div><font><br></font></div><div style="height:42.75pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div><font><br></font></div></div></div></body></html>
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</SEC-DOCUMENT>
