COLUMBIA BANKING SYSTEM, INC. (Form: 8-K, Received: 04/25/2024 16:33:58)

0000887343false00008873432024-04-252024-04-25

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

Pursuant to Section 13 or 15(d) of the Securities and Exchange Act of 1934

Date of Report: April 25, 2024

(Date of earliest event reported)

Columbia Banking System, Inc.

(Exact Name of Registrant as Specified in Its Charter)


Washington	000-20288	91-1422237
(State or Other Jurisdiction of Incorporation or Organization)	(Commission File Number)	(I.R.S. Employer Identification Number)

Tacoma, Washington 98402-2156

(address of Principal Executive Offices)(Zip Code)

(Registrant's Telephone Number, Including Area Code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

[ ☐ ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[ ☐ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[ ☐ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

[ ☐ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:


TITLE OF EACH CLASS	TRADING SYMBOL	NAME OF EXCHANGE
Common Stock, No Par Value	COLB	The NASDAQ Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company [ ☐ ]

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. [ ]


Item 2.02			Results of Operations and Financial Condition.

On April 25, 2024, Columbia Banking System, Inc. issued a press release announcing first quarter 2024 financial results. The release is attached hereto as Exhibit 99.1. The information included in the press release is considered to be "furnished" under the Securities Exchange Act of 1934, as amended (the "Exchange Act"). Columbia Banking System, Inc. will include final financial statements and additional analyses for the quarter ended March 31, 2024 as part of its quarterly report on Form 10-Q covering that period.


Item 7.01			Regulation FD Disclosure.

Columbia Banking System, Inc. is filing an investor slide presentation that it intends to review in conjunction with its earnings release conference call on April 25, 2024. The slides are included as Exhibit 99.2 to this report and shall not be deemed to be "filed" for the purposes of Section 18 of the Exchange Act, or otherwise subject to the liability of that section, and shall not be incorporated by reference into any registration statement or other document filed under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.


Item 9.01			Financial Statements and Exhibits.
(d)			EXHIBITS
			99.1 Press Release announcing first quarter 2024 financial results da t e d April 25, 2024
			99.2 First Quarter 2024 Investor Presentation
			104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.


			Columbia Banking System, Inc. (Registrant)

Dated: April 25, 2024			By: /s/ Ronald L. Farnsworth Ronald L. Farnsworth Executive Vice President/Chief Financial Officer


COLUMBIA BANKING SYSTEM, INC. REPORTS FIRST QUARTER 2024 RESULTS
$0.59	$0.65	$23.68	$16.03
Earnings per diluted common share	Operating earnings per diluted common share 1	Book value per common share	Tangible book value per common share 1


CEO Commentary
"Our first quarter results reflect early progress on our targeted actions to improve our financial performance and drive shareholder value,” said Clint Stein, President and CEO. "Enterprise-wide evaluations and targeted changes resulted in tighter expense control and stabilizing deposit costs in the latter part of the quarter. We will continue to exercise prudent expense management, and we expect to see the positive financial impact of near-term initiatives fully reflected in the fourth quarter's expense run rate. Longer-term initiatives will optimize our performance from a revenue, expense, and profitability standpoint. As an organization, Columbia remains laser-focused on regaining our placement as a top-quartile bank across financial metrics as we strive to drive long-term, consistent, repeatable performance."
–Clint Stein, President and CEO of Columbia Banking System, Inc.


1Q24 HIGHLIGHTS (COMPARED TO 4Q23)

Net Interest Income and NIM			•Net interest income decreased by $30 million on a linked-quarter basis due to higher deposit costs relative to the fourth quarter and lower income earned on investment securities given slower prepayment activity.
			•Net interest margin was 3.52%, down 26 basis points from the prior quarter given the full-quarter effect of deposit repricing and balance mix shift during the fourth quarter.

Non-Interest Income and Expense			•Non-interest income decreased by $15 million due to the quarterly fluctuation in cumulative non-merger fair value accounting and hedges. Excluding these items, non-interest income increased by $1 million.
			•Non-interest expense decreased by $50 million due to lower discretionary spend and the fourth quarter's larger FDIC special assessment.

Credit Quality			•Net charge-offs were 0.47% of average loans and leases (annualized), compared to 0.31% in the prior quarter.
			•Provision expense of $17 million compares to $55 million in the prior quarter.
			•Non-performing assets to total assets was 0.28%, compared to 0.22% as of December 31, 2023.

Capital			•Estimated total risk-based capital ratio of 12.0% and estimated common equity tier 1 risk-based capital ratio of 9.8%.
			•Declared a quarterly cash dividend of $0.36 per common share on February 9, 2024, which was paid March 11, 2024.

Notable Items			•Recalibrated the commercial CECL model to be more reflective of the post-merger loan portfolio after a full year operating as a combined organization.
			•Incurred $4 million in merger-related expense and $5 million in expense related to an FDIC special assessment.


1Q24 KEY FINANCIAL DATA

PERFORMANCE METRICS	1Q24		4Q23		1Q23
Return on average assets	0.96%		0.72%		(0.14)%
Return on average common equity	10.01%		7.90%		(1.70)%
Return on average tangible common equity 1	14.82%		12.19%		(2.09)%
Operating return on average assets 1	1.04%		0.89%		0.74%
Operating return on average common equity 1	10.89%		9.81%		8.66%
Operating return on average tangible common equity 1	16.12%		15.14%		10.64%
Net interest margin	3.52%		3.78%		4.08%
Efficiency ratio	60.57%		64.81%		79.71%
Operating efficiency ratio, as adjusted 1	56.97%		57.31%		52.84%

INCOME STATEMENT ($ in 000s, excl. per share data)	1Q24		4Q23		1Q23
Net interest income	$423,362		$453,623		$374,698
Provision for credit losses	$17,136		$54,909		$105,539
Non-interest income	$50,357		$65,533		$54,735
Non-interest expense	$287,516		$337,176		$342,818
Pre-provision net revenue 1	$186,203		$181,980		$86,615
Operating pre-provision net revenue 1	$200,684		$212,136		$195,730
Earnings per common share - diluted	$0.59		$0.45		($0.09)
Operating earnings per common share - diluted 1	$0.65		$0.56		$0.46
Dividends paid per share	$0.36		$0.36		$0.35

BALANCE SHEET	1Q24		4Q23		1Q23
Total assets	$52.2	B	$52.2	B	$54.0	B
Loans and leases	$37.6	B	$37.4	B	$37.1	B
Total deposits	$41.7	B	$41.6	B	$41.6	B
Book value per common share	$23.68		$23.95		$23.44
Tangible book value per share 1	$16.03		$16.12		$15.12

Jacquelynne "Jacque" Bohlen, SVP/Investor Relations Director, 503-727-4117, jacquebohlen@umpquabank.com

1 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 2

Organizational Update

Columbia Banking System, Inc. ("Columbia," "we," or "our") conducted an enterprise-wide evaluation of our operations during the first quarter of 2024. The full-scale review resulted in consolidated positions, simplified reporting and organizational structures, and an improved profitability outlook. These changes are expected to be carried out during the second and third quarters of 2024. Please refer to the Q1 2024 Earnings Presentation for additional details.

On February 28, 2023, Columbia completed its merger with Umpqua Holdings Corporation ("UHC"), combining the two premier banks in the Northwest to create one of the largest banks headquartered in the West (the "merger"). Columbia's financial results for any periods ended prior to February 28, 2023 reflect UHC results only on a standalone basis. In addition, Columbia's reported financial results for the first quarter of 2023 reflect UHC financial results only until the closing of the merger after the close of business on February 28, 2023. As a result of these two factors, Columbia's financial results for each of the quarters of 2023 and the year ended December 31, 2023 may not be directly comparable to prior reported periods. Under the reverse acquisition method of accounting, the assets and liabilities of Columbia as of February 28, 2023 ("historical Columbia") were recorded at their respective fair values.

Net interest income was $423 million for the first quarter of 2024, down $30 million from the prior quarter. The decline reflects higher deposit costs relative to the fourth quarter and lower income earned on investment securities given slower prepayment activity.

Columbia's net interest margin was 3.52% for the first quarter of 2024, down 26 basis points from 3.78% for the fourth quarter of 2023. The contraction was driven by higher average deposit costs, which increased at an accelerated pace through the fourth quarter and into January before stabilizing in the latter part of the first quarter. The cost of interest-bearing deposits increased 34 basis points on a linked-quarter basis to 2.88% for the first quarter of 2024, which compares to 2.90% for the month of March and 2.89% at March 31, 2024. "During the first quarter, we executed a comprehensive review related to how we evaluate and approve deposit pricing," commented Tory Nixon, President of Umpqua Bank. "This resulted in enhanced pricing visibility, which contributed to stability in interest-bearing core deposit rates."

The cost of interest-bearing liabilities benefited from the movement of $1.4 billion in FHLB Advances to the Federal Reserve's Bank Term Funding Program in January, lowering the cost of these funds by approximately 75 basis points. Columbia's cost of interest-bearing liabilities increased 23 basis points on a linked-quarter basis to 3.25% for the first quarter of 2024, which compares to 3.24% for both the month of March and at March 31, 2024. Please refer to the Q1 2024 Earnings Presentation for additional net interest margin change details and interest rate sensitivity information as well as to our non-GAAP disclosures in this press release for the impact of purchase accounting accretion and amortization on individual line items.

Non-interest income was $50 million for the first quarter of 2024, down $15 million from the prior quarter. The decline was driven by quarterly fluctuations in fair value adjustments and mortgage servicing rights ("MSR") hedging activity, which collectively resulted in a net fair value loss of $4 million in the first quarter compared to a net fair value gain of $13 million in the fourth quarter, as detailed in our non-GAAP disclosures. Excluding these items, non-interest income increased by $1 million from the prior quarter.

Non-interest Expense

Non-interest expense was $288 million for the first quarter of 2024, down $50 million from the prior quarter level. Excluding merger-related expense, exit and disposal costs, and accruals for the FDIC special assessment, non-interest expense was $277 million2, down $17 million from the prior quarter due to lower discretionary spending and other expense items compared to elevated expense items in the fourth quarter. Please refer to the Q1 2024 Earnings Presentation for additional expense details.

Total consolidated assets were $52.2 billion as of March 31, 2024, unchanged from December 31, 2023. Cash and cash equivalents was $2.2 billion as of March 31, 2024, also unchanged from December 31, 2023. Including secured off-balance sheet lines of credit, total available liquidity was $18.6 billion as of March 31, 2024, representing 36% of total assets, 45% of total deposits, and 138% of uninsured deposits. Available-for-sale securities, which are held on balance sheet at fair value, were $8.6 billion as of March 31, 2024, a decrease of $213 million relative to December 31, 2023 due to paydowns and a decline in the fair value of the portfolio. Please refer to the Q1 2024 Earnings Presentation for additional details related to our securities portfolio and liquidity position.

2 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 3

Gross loans and leases were $37.6 billion as of March 31, 2024, an increase of $200 million relative to December 31, 2023. Commercial line utilization and construction project activity were the primary contributors to the 2% annualized loan growth in the quarter. Higher commercial real estate ("CRE") term balances reflect projects that transitioned from construction to permanent financing. Excluding this shift, origination volume during the first quarter was centered in our commercial and owner-occupied CRE portfolios. Please refer to the Q1 2024 Earnings Presentation for additional details related to our loan portfolio, which include underwriting characteristics, the composition of our commercial portfolios, and disclosure related to our office portfolio.

Total deposits were $41.7 billion as of March 31, 2024, an increase of $99 million relative to December 31, 2023. Customer deposits drove the quarter's increase, enabling a slight reduction in brokered deposits and borrowings. "Our teams are focused on customer deposit generation to reduce wholesale funding sources that create a drag on our earnings power," stated Mr. Nixon. "While inflationary pressures and seasonal patterns affected deposit flows, the teams generated successful momentum through targeted campaigns focused on extraordinary products and service, not price." Please refer to the Q1 2024 Earnings Presentation for additional details related to deposit characteristics and flows.

The allowance for credit losses was $437 million, or 1.16% of loans and leases, as of March 31, 2024, compared to $464 million, or 1.24% of loans and leases, as of December 31, 2023. The provision for credit losses was $17 million for the first quarter of 2024, and it reflects credit migration trends, changes in the economic forecasts used in credit models, charge-off activity, and a change within our Current Expected Credit Losses ("CECL") methodology. During the first quarter, we recalibrated the commercial CECL model to be more reflective of the post-merger loan portfolio after a full year operating as a combined organization. We believe the recalibrated CECL model is more reflective of the quality of our underwriting and borrower profiles.

Net charge-offs were 0.47% of average loans and leases (annualized) for the first quarter of 2024, compared to 0.31% for the fourth quarter of 2023. Net charge-offs in the FinPac portfolio were $24 million in the first quarter, largely unchanged from the fourth quarter, and were up $14 million in the commercial portfolio from the prior quarter, with the increase centered in a single credit. Charge-off activity in other portfolios, inclusive of a small net recovery in the CRE portfolio, was at an insignificant level. As of March 31, 2024, non-performing assets were $144 million, or 0.28% of total assets, compared to $114 million, or 0.22% of total assets, as of December 31, 2023. The quarter's increase was driven primarily by migration in our SBA portfolio and an owner-occupied CRE property. Nonperforming assets as of March 31, 2024 included $43 million of government guarantees. Please refer to the Q1 2024 Earnings Presentation for additional details related to the allowance for credit losses and other credit trends.

Columbia's book value per common share was $23.68 as of March 31, 2024, compared to $23.95 as of December 31, 2023. The linked-quarter change primarily reflects a change in accumulated other comprehensive (loss) income ("AOCI") to $(426) million at March 31, 2024, compared to $(340) million at the prior quarter-end. The change in AOCI is due primarily to an increase in the tax-effected net unrealized loss on available-for-sale securities to $413 million as of March 31, 2024, compared to $322 million as of December 31, 2023. Tangible book value per common share3 was $16.03 as of March 31, 2024, compared to $16.12 as of December 31, 2023.

Columbia's estimated total risk-based capital ratio was 12.0% and its estimated common equity tier 1 risk-based capital ratio was 9.8% as of March 31, 2024, compared to 11.9% and 9.6%, respectively, as of December 31, 2023. Columbia remains above current “well-capitalized” regulatory minimums. "Our total risk-based capital ratio at the parent company is now at our long-term target of 12%," stated Ron Farnsworth, Chief Financial Officer of Columbia. "We expect continued organic earnings generation to drive all capital ratios above target levels over time, increasing our flexibility for capital return in the future." The regulatory capital ratios as of March 31, 2024 are estimates, pending completion and filing of Columbia's regulatory reports.

3 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 4

Earnings Presentation and Conference Call Information

Columbia's Q1 2024 Earnings Presentation provides additional disclosure. A copy will be available on our investor relations page: www.columbiabankingsystem.com.

Columbia will host its first quarter 2024 earnings conference call on April 25, 2024, at 2:00 p.m. PT (5:00 p.m. ET). During the call, Columbia's management will provide an update on recent activities and discuss its first quarter 2024 financial results. Participants may register for the call using the below link to receive dial-in details and their own unique PINs or join the audiocast. It is recommended you join 10 minutes prior to the start time.

Join the audiocast: https://edge.media-server.com/mmc/p/jc6j526v/

Access the replay through Columbia's investor relations page: www.columbiabankingsystem.com

About Columbia Banking System, Inc.

Columbia (Nasdaq: COLB) is headquartered in Tacoma, Washington and is the parent company of Umpqua Bank, an award-winning western U.S. regional bank based in Lake Oswego, Oregon. Umpqua Bank is the largest bank headquartered in the Northwest and one of the largest banks headquartered in the West with locations in Arizona, California, Colorado, Idaho, Nevada, Oregon, Utah, and Washington. With over $50 billion of assets, Umpqua Bank combines the resources, sophistication and expertise of a national bank with a commitment to deliver superior, personalized service. The bank supports consumers and businesses through a full suite of services, including retail and commercial banking; Small Business Administration lending; institutional and corporate banking; and equipment leasing. Umpqua Bank customers also have access to comprehensive investment and wealth management expertise as well as healthcare and private banking through Columbia Wealth Advisors and Columbia Trust Company, a division of Umpqua Bank. Learn more at www.columbiabankingsystem.com.

Forward-Looking Statements

This press release includes forward-looking statements within the meaning of the "Safe-Harbor" provisions of the Private Securities Litigation Reform Act of 1995, which management believes are a benefit to shareholders. These statements are necessarily subject to risk and uncertainty and actual results could differ materially due to various risk factors, including those set forth from time to time in our filings with the Securities and Exchange Commission. You should not place undue reliance on forward-looking statements and we undertake no obligation to update any such statements. Forward-looking statements can be identified by words such as "anticipates," "intends," "plans," "seeks," "believes," "estimates," "expects," "target," "projects," "outlook," "forecast," "will," "may," "could," "should," "can" and similar references to future periods. In this press release we make forward-looking statements about strategic and growth initiatives and the result of such activity. Risks and uncertainties that could cause results to differ from forward-looking statements we make include, without limitation: current and future economic and market conditions, including the effects of declines in housing and commercial real estate prices, high unemployment rates, continued inflation and any recession or slowdown in economic growth particularly in the western United States; economic forecast variables that are either materially worse or better than end of quarter projections and deterioration in the economy that could result in increased loan and lease losses, especially those risks associated with concentrations in real estate related loans; our ability to effectively manage problem credits; the impact of bank failures or adverse developments at other banks on general investor sentiment regarding the liquidity and stability of banks; changes in interest rates that could significantly reduce net interest income and negatively affect asset yields and valuations and funding sources; changes in the scope and cost of FDIC insurance and other coverage; our ability to successfully implement efficiency and operational excellence initiatives; our ability to successfully develop and market new products and technology; changes in laws or regulations; any failure to realize the anticipated benefits of the merger when expected or at all; potential adverse reactions or changes to business or employee relationships, including those resulting from the completion of the merger and integration of the companies; the effect of geopolitical instability, including wars, conflicts and terrorist attacks; and natural disasters and other similar unexpected events outside of our control. We also caution that the amount and timing of any future common stock dividends or repurchases will depend on the earnings, cash requirements and financial condition of Columbia, market conditions, capital requirements, applicable law and regulations (including federal securities laws and federal banking regulations), and other factors deemed relevant by Columbia's Board of Directors, and may be subject to regulatory approval or conditions.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 5

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 6


Columbia Banking System, Inc.
Consolidated Statements of Operations
(Unaudited)
	Quarter Ended										% Change
($ in thousands, except per share data)	Mar 31, 2024		Dec 31, 2023		Sep 30, 2023		Jun 30, 2023		Mar 31, 2023		Seq. Quarter		Year over Year
Interest income:
Loans and leases	$	575,044	$	577,741	$	569,670	$	552,679	$	413,525	—	%	39	%
Interest and dividends on investments:
Taxable	75,017		78,010		80,066		79,036		39,729		(4)	%	89	%
Exempt from federal income tax	6,904		6,966		6,929		6,817		3,397		(1)	%	103	%
Dividends	3,707		4,862		4,941		2,581		719		(24)	%	416	%
Temporary investments and interest bearing deposits	23,553		24,055		34,407		34,616		18,581		(2)	%	27	%
Total interest income	684,225		691,634		696,013		675,729		475,951		(1)	%	44	%
Interest expense:
Deposits	198,435		170,659		126,974		100,408		63,613		16	%	212	%
Securities sold under agreement to repurchase and federal funds purchased	1,266		1,226		1,220		1,071		406		3	%	212	%
Borrowings	51,275		56,066		77,080		81,004		28,764		(9)	%	78	%
Junior and other subordinated debentures	9,887		10,060		9,864		9,271		8,470		(2)	%	17	%
Total interest expense	260,863		238,011		215,138		191,754		101,253		10	%	158	%
Net interest income	423,362		453,623		480,875		483,975		374,698		(7)	%	13	%
Provision for credit losses	17,136		54,909		36,737		16,014		105,539		(69)	%	(84)	%
Non-interest income:
Service charges on deposits	16,064		17,349		17,410		16,454		14,312		(7)	%	12	%
Card-based fees	13,183		14,593		15,674		13,435		11,561		(10)	%	14	%
Financial services and trust revenue	4,464		3,011		4,651		4,512		1,297		48	%	244	%
Residential mortgage banking revenue (loss), net	4,634		4,212		7,103		(2,342)		7,816		10	%	(41)	%
Gain on sale of debt securities, net	12		9		4		—		—		33	%	nm
(Loss) gain on equity securities, net	(1,565)		2,636		(2,055)		(697)		2,416		(159)	%	(165)	%
Gain on loan and lease sales, net	221		1,161		1,871		442		940		(81)	%	(76)	%
BOLI income	4,639		4,331		4,440		4,063		2,790		7	%	66	%
Other income (loss)	8,705		18,231		(5,117)		3,811		13,603		(52)	%	(36)	%
Total non-interest income	50,357		65,533		43,981		39,678		54,735		(23)	%	(8)	%
Non-interest expense:
Salaries and employee benefits	154,538		157,572		159,041		163,398		136,092		(2)	%	14	%
Occupancy and equipment, net	45,291		48,160		43,070		50,550		41,700		(6)	%	9	%
Intangible amortization	32,091		33,204		29,879		35,553		12,660		(3)	%	153	%
FDIC assessments	14,460		42,510		11,200		11,579		6,113		(66)	%	137	%
Merger-related expense	4,478		7,174		18,938		29,649		115,898		(38)	%	(96)	%
Other expenses	36,658		48,556		42,019		37,830		30,355		(25)	%	21	%
Total non-interest expense	287,516		337,176		304,147		328,559		342,818		(15)	%	(16)	%
Income (loss) before provision (benefit) for income taxes	169,067		127,071		183,972		179,080		(18,924)		33	%	nm
Provision (benefit) for income taxes	44,987		33,540		48,127		45,703		(4,886)		34	%	nm
Net income (loss)	$	124,080	$	93,531	$	135,845	$	133,377	$	(14,038)	33	%	nm

Weighted average basic shares outstanding	208,260		208,083		208,070		207,977		156,383		—	%	33	%
Weighted average diluted shares outstanding	208,956		208,739		208,645		208,545		156,383		—	%	34	%
Earnings (loss) per common share – basic	$	0.60	$	0.45	$	0.65	$	0.64	$	(0.09)	33	%	nm
Earnings (loss) per common share – diluted	$	0.59	$	0.45	$	0.65	$	0.64	$	(0.09)	31	%	nm

nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 7


Columbia Banking System, Inc. Consolidated Balance Sheets
(Unaudited)
											% Change
($ in thousands, except per share data)	Mar 31, 2024		Dec 31, 2023		Sep 30, 2023		Jun 30, 2023		Mar 31, 2023		Seq. Quarter		Year over Year
Assets:
Cash and due from banks	$	440,215	$	498,496	$	492,474	$	538,653	$	555,919	(12)	%	(21)	%
Interest-bearing cash and temporary investments	1,760,902		1,664,038		1,911,221		2,868,563		3,079,266		6	%	(43)	%
Investment securities:
Equity and other, at fair value	77,203		76,995		73,638		76,361		76,532		—	%	1	%
Available for sale, at fair value	8,616,545		8,829,870		8,503,986		8,998,428		9,249,600		(2)	%	(7)	%
Held to maturity, at amortized cost	2,247		2,300		2,344		2,388		2,432		(2)	%	(8)	%
Loans held for sale	47,201		30,715		60,313		183,633		49,338		54	%	(4)	%
Loans and leases	37,642,413		37,441,951		37,170,598		37,049,299		37,091,280		1	%	1	%
Allowance for credit losses on loans and leases	(414,344)		(440,871)		(416,560)		(404,603)		(417,464)		(6)	%	(1)	%
Net loans and leases	37,228,069		37,001,080		36,754,038		36,644,696		36,673,816		1	%	2	%
Restricted equity securities	116,274		179,274		168,524		258,524		246,525		(35)	%	(53)	%
Premises and equipment, net	336,869		338,970		337,855		368,698		375,190		(1)	%	(10)	%
Operating lease right-of-use assets	113,833		115,811		114,220		119,255		127,296		(2)	%	(11)	%
Goodwill	1,029,234		1,029,234		1,029,234		1,029,234		1,030,142		—	%	—	%
Other intangible assets, net	571,588		603,679		636,883		666,762		702,315		(5)	%	(19)	%
Residential mortgage servicing rights, at fair value	110,444		109,243		117,640		172,929		178,800		1	%	(38)	%
Bank-owned life insurance	682,293		680,948		648,232		643,727		641,922		—	%	6	%
Deferred tax asset, net	356,031		347,203		469,841		362,880		351,229		3	%	1	%
Other assets	735,058		665,740		673,372		657,365		653,904		10	%	12	%
Total assets	$	52,224,006	$	52,173,596	$	51,993,815	$	53,592,096	$	53,994,226	—	%	(3)	%
Liabilities:
Deposits
Non-interest-bearing	$	13,808,554	$	14,256,452	$	15,532,948	$	16,019,408	$	17,215,781	(3)	%	(20)	%
Interest-bearing	27,897,606		27,350,568		26,091,420		24,815,509		24,370,566		2	%	14	%
Total deposits	41,706,160		41,607,020		41,624,368		40,834,917		41,586,347		—	%	—	%
Securities sold under agreements to repurchase	213,573		252,119		258,383		294,914		271,047		(15)	%	(21)	%
Borrowings	3,900,000		3,950,000		3,985,000		6,250,000		5,950,000		(1)	%	(34)	%
Junior subordinated debentures, at fair value	309,544		316,440		331,545		312,872		297,721		(2)	%	4	%
Junior and other subordinated debentures, at amortized cost	107,838		107,895		107,952		108,009		108,066		—	%	—	%
Operating lease liabilities	129,240		130,576		129,845		132,099		140,648		(1)	%	(8)	%

Other liabilities	900,406		814,512		924,560		831,097		755,674		11	%	19	%
Total liabilities	47,266,761		47,178,562		47,361,653		48,763,908		49,109,503		—	%	(4)	%
Shareholders' equity:

Common stock	5,802,322		5,802,747		5,798,167		5,792,792		5,788,553		—	%	—	%
Accumulated deficit	(418,946)		(467,571)		(485,576)		(545,842)		(603,696)		(10)	%	(31)	%
Accumulated other comprehensive loss	(426,131)		(340,142)		(680,429)		(418,762)		(300,134)		25	%	42	%
Total shareholders' equity	4,957,245		4,995,034		4,632,162		4,828,188		4,884,723		(1)	%	1	%
Total liabilities and shareholders' equity	$	52,224,006	$	52,173,596	$	51,993,815	$	53,592,096	$	53,994,226	—	%	(3)	%

Common shares outstanding at period end	209,370		208,585		208,575		208,514		208,429		—	%	—	%

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 8


Columbia Banking System, Inc.
Financial Highlights
(Unaudited)
	Quarter Ended															% Change
	Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			Seq. Quarter		Year over Year
Per Common Share Data:
Dividends	$	0.36		$	0.36		$	0.36		$	0.36		$	0.35		—	%	3	%
Book value	$	23.68		$	23.95		$	22.21		$	23.16		$	23.44		(1)	%	1	%
Tangible book value (1)	$	16.03		$	16.12		$	14.22		$	15.02		$	15.12		(1)	%	6	%

Performance Ratios:
Efficiency ratio (2)	60.57		%	64.81		%	57.82		%	62.60		%	79.71		%	(4.24)		(19.14)
Non-interest expense to average assets (1)	2.22		%	2.58		%	2.28		%	2.46		%	3.53		%	(0.36)		(1.31)
Return on average assets ("ROAA")	0.96		%	0.72		%	1.02		%	1.00		%	(0.14)		%	0.24		1.10
Pre-provision net revenue ("PPNR") ROAA (1)	1.44		%	1.39		%	1.65		%	1.46		%	0.89		%	0.05		0.55
Return on average common equity	10.01		%	7.90		%	11.07		%	10.84		%	(1.70)		%	2.11		11.71
Return on average tangible common equity (1)	14.82		%	12.19		%	16.93		%	16.63		%	(2.09)		%	2.63		16.91

Performance Ratios - Operating: (1)
Operating efficiency ratio, as adjusted (1), (2), (5), (6)	56.97		%	57.31		%	51.26		%	54.04		%	52.84		%	(0.34)		4.13
Operating non-interest expense to average assets (1)	2.14		%	2.25		%	2.10		%	2.22		%	2.32		%	(0.11)		(0.18)
Operating ROAA (1), (5)	1.04		%	0.89		%	1.23		%	1.27		%	0.74		%	0.15		0.30
Operating PPNR ROAA (1), (5)	1.55		%	1.62		%	1.94		%	1.82		%	2.01		%	(0.07)		(0.46)
Operating return on average common equity (1), (5)	10.89		%	9.81		%	13.40		%	13.77		%	8.66		%	1.08		2.23
Operating return on average tangible common equity (1), (5)	16.12		%	15.14		%	20.48		%	21.13		%	10.64		%	0.98		5.48

Average Balance Sheet Yields, Rates, & Ratios:
Yield on loans and leases	6.13		%	6.13		%	6.08		%	5.95		%	5.55		%	—		0.58
Yield on earning assets (2)	5.69		%	5.75		%	5.65		%	5.48		%	5.19		%	(0.06)		0.50
Cost of interest bearing deposits	2.88		%	2.54		%	2.01		%	1.64		%	1.32		%	0.34		1.56
Cost of interest bearing liabilities	3.25		%	3.02		%	2.72		%	2.45		%	1.82		%	0.23		1.43
Cost of total deposits	1.92		%	1.63		%	1.23		%	0.99		%	0.80		%	0.29		1.12
Cost of total funding (3)	2.27		%	2.05		%	1.81		%	1.61		%	1.16		%	0.22		1.11
Net interest margin (2)	3.52		%	3.78		%	3.91		%	3.93		%	4.08		%	(0.26)		(0.56)
Average interest bearing cash / Average interest earning assets	3.56		%	3.64		%	5.17		%	5.47		%	4.33		%	(0.08)		(0.77)
Average loans and leases / Average interest earning assets	77.87		%	78.04		%	75.64		%	75.18		%	80.96		%	(0.17)		(3.09)
Average loans and leases / Average total deposits	90.41		%	89.91		%	90.63		%	90.98		%	93.01		%	0.50		(2.60)
Average non-interest bearing deposits / Average total deposits	33.29		%	35.88		%	38.55		%	40.05		%	39.55		%	(2.59)		(6.26)
Average total deposits / Average total funding (3)	90.09		%	90.02		%	86.66		%	85.59		%	91.36		%	0.07		(1.27)

Select Credit & Capital Ratios:
Non-performing loans and leases to total loans and leases	0.38		%	0.30		%	0.28		%	0.22		%	0.20		%	0.08		0.18
Non-performing assets to total assets	0.28		%	0.22		%	0.20		%	0.15		%	0.14		%	0.06		0.14
Allowance for credit losses to loans and leases	1.16		%	1.24		%	1.18		%	1.15		%	1.18		%	(0.08)		(0.02)
Total risk-based capital ratio (4)	12.0		%	11.9		%	11.6		%	11.3		%	10.9		%	0.10		1.10
Common equity tier 1 risk-based capital ratio (4)	9.8		%	9.6		%	9.5		%	9.2		%	8.9		%	0.20		0.90
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

(1) See GAAP to Non-GAAP Reconciliation.

(2) Tax-exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.

(3) Total funding = Total deposits + Total borrowings.

(4) Estimated holding company ratios.

(5) Non-interest expense adjustments were revised subsequent to the Company's reporting of its earnings results for the three months ended December 31, 2023. The revision includes adding the FDIC special assessment to the non-interest expense adjustments, which removes the special assessment from the Company's calculation of operating non-interest expense. The Company views the special assessment as an infrequent expense that is outside the control of the Company.

(6) The operating efficiency ratio has been adjusted to remove B&O taxes and for a tax-equivalent adjustment to BOLI income. The Company views the adjusted operating efficiency ratio as a better representation of its efficiency ratio when compared to other banks as it normalizes for the tax treatment of the adjusted items. The adjustment re-aligns Columbia's calculation of its operating efficiency ratio with its pre-merger calculation.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 9


Columbia Banking System, Inc.
Loan & Lease Portfolio Balances and Mix
(Unaudited)
	Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			% Change
($ in thousands)	Amount			Amount			Amount			Amount			Amount			Seq. Quarter		Year over Year
Loans and leases:
Commercial real estate:
Non-owner occupied term, net	$	6,557,768		$	6,482,940		$	6,490,638		$	6,434,673		$	6,353,550		1	%	3	%
Owner occupied term, net	5,231,676			5,195,605			5,235,227			5,254,401			5,156,848			1	%	1	%
Multifamily, net	5,828,960			5,704,734			5,684,495			5,622,875			5,590,587			2	%	4	%
Construction & development, net	1,728,652			1,747,302			1,669,918			1,528,924			1,467,561			(1)	%	18	%
Residential development, net	284,117			323,899			354,922			388,641			440,667			(12)	%	(36)	%
Commercial:
Term, net	5,544,450			5,536,765			5,437,915			5,449,787			5,906,774			—	%	(6)	%
Lines of credit & other, net	2,491,557			2,430,127			2,353,548			2,268,790			2,184,762			3	%	14	%
Leases & equipment finance, net	1,706,759			1,729,512			1,728,991			1,740,037			1,746,267			(1)	%	(2)	%
Residential:
Mortgage, net	6,128,884			6,157,166			6,121,838			6,272,898			6,187,964			—	%	(1)	%
Home equity loans & lines, net	1,950,421			1,938,166			1,899,948			1,898,958			1,870,002			1	%	4	%
Consumer & other, net	189,169			195,735			193,158			189,315			186,298			(3)	%	2	%
Total loans and leases, net of deferred fees and costs	$	37,642,413		$	37,441,951		$	37,170,598		$	37,049,299		$	37,091,280		1	%	1	%

Loans and leases mix:
Commercial real estate:
Non-owner occupied term, net	17		%	17		%	17		%	17		%	16		%
Owner occupied term, net	14		%	14		%	14		%	14		%	14		%
Multifamily, net	15		%	15		%	15		%	15		%	15		%
Construction & development, net	5		%	5		%	4		%	4		%	4		%
Residential development, net	1		%	1		%	1		%	1		%	1		%
Commercial:
Term, net	15		%	15		%	15		%	15		%	16		%
Lines of credit & other, net	6		%	6		%	6		%	6		%	6		%
Leases & equipment finance, net	5		%	5		%	5		%	5		%	5		%
Residential:
Mortgage, net	16		%	16		%	17		%	17		%	17		%
Home equity loans & lines, net	5		%	5		%	5		%	5		%	5		%
Consumer & other, net	1		%	1		%	1		%	1		%	1		%
Total	100		%	100		%	100		%	100		%	100		%

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 10


Columbia Banking System, Inc.
Deposit Portfolio Balances and Mix
(Unaudited)
	Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			% Change
($ in thousands)	Amount			Amount			Amount			Amount			Amount			Seq. Quarter		Year over Year
Deposits:
Demand, non-interest bearing	$	13,808,554		$	14,256,452		$	15,532,948		$	16,019,408		$	17,215,781		(3)	%	(20)	%
Demand, interest bearing	8,095,211			8,044,432			6,898,831			6,300,082			5,900,462			1	%	37	%
Money market	10,822,498			10,324,454			10,349,217			10,115,908			10,681,422			5	%	1	%
Savings	2,640,060			2,754,113			3,018,706			3,171,714			3,469,112			(4)	%	(24)	%
Time	6,339,837			6,227,569			5,824,666			5,227,805			4,319,570			2	%	47	%
Total	$	41,706,160		$	41,607,020		$	41,624,368		$	40,834,917		$	41,586,347		—	%	—	%

Total core deposits (1)	$	37,436,569		$	37,423,402		$	37,597,830		$	37,639,368		$	39,155,298		—	%	(4)	%

Deposit mix:
Demand, non-interest bearing	33		%	34		%	37		%	39		%	41		%
Demand, interest bearing	20		%	19		%	17		%	15		%	14		%
Money market	26		%	25		%	25		%	25		%	26		%
Savings	6		%	7		%	7		%	8		%	9		%
Time	15		%	15		%	14		%	13		%	10		%
Total	100		%	100		%	100		%	100		%	100		%

(1) Core deposits are defined as total deposits less time deposits greater than $250,000 and all brokered deposits.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 11


	Columbia Banking System, Inc.
	Credit Quality – Non-performing Assets
	(Unaudited)
		Quarter Ended															% Change
($ in thousands)		Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			Seq. Quarter		Year over Year
Non-performing assets: (1)
Loans and leases on non-accrual status:
	Commercial real estate, net	$	39,736		$	28,689		$	26,053		$	10,994		$	15,612		39	%	155	%
	Commercial, net	58,960			45,682			44,341			39,316			42,301			29	%	39	%


	Total loans and leases on non-accrual status	98,696			74,371			70,394			50,310			57,913			33	%	70	%
Loans and leases past due 90+ days and accruing: (2)
	Commercial real estate, net	253			870			71			184			1			(71)	%	nm
	Commercial, net	10,733			8,232			8,606			7,720			151			30	%	nm
	Residential, net (2)	31,916			29,102			25,180			21,370			17,423			10	%	83	%
	Consumer & other, net	437			326			240			399			140			34	%	212	%
	Total loans and leases past due 90+ days and accruing	43,339			38,530			34,097			29,673			17,715			12	%	145	%
Total non-performing loans and leases (1), (2)		142,035			112,901			104,491			79,983			75,628			26	%	88	%
Other real estate owned		1,762			1,036			1,170			278			409			70	%	331	%
Total non-performing assets (1), (2)		$	143,797		$	113,937		$	105,661		$	80,261		$	76,037		26	%	89	%


Loans and leases past due 31-89 days		$	109,673		$	85,235		$	82,918		$	73,376		$	78,641		29	%	39	%
Loans and leases past due 31-89 days to total loans and leases		0.29		%	0.23		%	0.22		%	0.20		%	0.21		%	0.06		0.08
Non-performing loans and leases to total loans and leases (1), (2)		0.38		%	0.30		%	0.28		%	0.22		%	0.20		%	0.08		0.18
Non-performing assets to total assets (1), (2)		0.28		%	0.22		%	0.20		%	0.15		%	0.14		%	0.06		0.14

nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

(1) Non-accrual and 90+ days past due loans include government guarantees of $43.0 million, $31.6 million, $26.9 million, $26.6 million, and $24.4 million at March 31, 2024, December 31, 2023, September 30, 2023, June 30, 2023, and March 31, 2023, respectively.

(2) Excludes certain mortgage loans guaranteed by Ginnie Mae, which Columbia has the unilateral right to repurchase but has not done so, totaling $1.6 million, $1.0 million, $700,000, $1.6 million, and $5.4 million at March 31, 2024, December 31, 2023, September 30, 2023, June 30, 2023, and March 31, 2023, respectively.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 12


	Columbia Banking System, Inc.
	Credit Quality – Allowance for Credit Losses
	(Unaudited)
		Quarter Ended															% Change
($ in thousands)		Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			Seq. Quarter		Year over Year
Allowance for credit losses on loans and leases (ACLLL)
Balance, beginning of period		$	440,871		$	416,560		$	404,603		$	417,464		$	301,135		6	%	46	%
Initial ACL recorded for PCD loans acquired during the period		—			—			—			—			26,492			nm		(100)	%
Provision for credit losses on loans and leases (1)		17,476			53,183			35,082			15,216			106,498			(67)	%	(84)	%
Charge-offs
	Commercial real estate, net	(161)			(629)			—			(174)			—			(74)	%	nm
	Commercial, net	(47,232)			(31,949)			(26,629)			(32,036)			(19,248)			48	%	145	%
	Residential, net	(490)			(89)			(206)			(4)			(248)			451	%	98	%
	Consumer & other, net	(1,870)			(1,841)			(1,884)			(1,264)			(773)			2	%	142	%
	Total charge-offs	(49,753)			(34,508)			(28,719)			(33,478)			(20,269)			44	%	145	%
Recoveries
	Commercial real estate, net	358			35			31			209			58			nm		nm
	Commercial, net	4,732			4,414			4,901			4,511			3,058			7	%	55	%
	Residential, net	170			781			156			63			123			(78)	%	38	%
	Consumer & other, net	490			406			506			618			369			21	%	33	%
	Total recoveries	5,750			5,636			5,594			5,401			3,608			2	%	59	%
Net (charge-offs) recoveries
	Commercial real estate, net	197			(594)			31			35			58			nm		240	%
	Commercial, net	(42,500)			(27,535)			(21,728)			(27,525)			(16,190)			54	%	163	%
	Residential, net	(320)			692			(50)			59			(125)			(146)	%	156	%
	Consumer & other, net	(1,380)			(1,435)			(1,378)			(646)			(404)			(4)	%	242	%
	Total net charge-offs	(44,003)			(28,872)			(23,125)			(28,077)			(16,661)			52	%	164	%
Balance, end of period		$	414,344		$	440,871		$	416,560		$	404,603		$	417,464		(6)	%	(1)	%
Reserve for unfunded commitments
Balance, beginning of period		$	23,208		$	21,482		$	19,827		$	19,029		$	14,221		8	%	63	%
Initial ACL recorded for unfunded commitments acquired during the period		—			—			—			—			5,767			nm		(100)	%
(Recapture) provision for credit losses on unfunded commitments		(340)			1,726			1,655			798			(959)			(120)	%	(65)	%
Balance, end of period		22,868			23,208			21,482			19,827			19,029			(1)	%	20	%
Total Allowance for credit losses (ACL)		$	437,212		$	464,079		$	438,042		$	424,430		$	436,493		(6)	%	—	%

Net charge-offs to average loans and leases (annualized)		0.47		%	0.31		%	0.25		%	0.30		%	0.23		%	0.16		0.24
Recoveries to gross charge-offs		11.56		%	16.33		%	19.48		%	16.13		%	17.80		%	(4.77)		(6.24)
ACLLL to loans and leases		1.10		%	1.18		%	1.12		%	1.09		%	1.13		%	(0.08)		(0.03)
ACL to loans and leases		1.16		%	1.24		%	1.18		%	1.15		%	1.18		%	(0.08)		(0.02)

nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

(1) For the quarter ended March 31, 2023, the provision for credit losses on loans and leases includes $88.4 million initial provision related to non-PCD loans acquired during the period.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 13


Columbia Banking System, Inc.
Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates
(Unaudited)
	Quarter Ended
	March 31, 2024						December 31, 2023						March 31, 2023
($ in thousands)	Average Balance		Interest Income or Expense		Average Yields or Rates		Average Balance		Interest Income or Expense		Average Yields or Rates		Average Balance		Interest Income or Expense		Average Yields or Rates
INTEREST-EARNING ASSETS:
Loans held for sale	$	30,550	$	525	6.88	%	$	48,868	$	649	5.31	%	$	54,008	$	799	5.92	%
Loans and leases (1)	37,597,101		574,519		6.13	%	37,333,310		577,092		6.13	%	29,998,630		412,726		5.55	%
Taxable securities	8,081,003		78,724		3.90	%	7,903,053		82,872		4.19	%	4,960,966		40,448		3.26	%
Non-taxable securities (2)	851,342		7,886		3.71	%	809,551		8,073		3.99	%	437,020		4,068		3.72	%
Temporary investments and interest-bearing cash	1,720,791		23,553		5.51	%	1,743,447		24,055		5.47	%	1,605,081		18,581		4.69	%
Total interest-earning assets	48,280,787		$	685,207	5.69	%	47,838,229		$	692,741	5.75	%	37,055,705		$	476,622	5.19	%
Goodwill and other intangible assets	1,619,134						1,652,282						623,042
Other assets	2,184,052						2,341,845						1,747,228
Total assets	$	52,083,973					$	51,832,356					$	39,425,975
INTEREST-BEARING LIABILITIES:
Interest-bearing demand deposits	$	8,035,339	$	51,378	2.57	%	$	7,617,427	$	44,861	2.34	%	$	4,759,251	$	9,815	0.84	%
Money market deposits	10,612,073		72,497		2.75	%	10,276,894		61,055		2.36	%	8,845,784		32,238		1.48	%
Savings deposits	2,688,360		715		0.11	%	2,880,622		698		0.10	%	2,686,388		556		0.08	%
Time deposits	6,406,807		73,845		4.64	%	5,847,400		64,045		4.35	%	3,205,128		21,004		2.66	%
Total interest-bearing deposits	27,742,579		198,435		2.88	%	26,622,343		170,659		2.54	%	19,496,551		63,613		1.32	%
Repurchase agreements and federal funds purchased	231,667		1,266		2.20	%	245,989		1,226		1.98	%	281,032		406		0.59	%
Borrowings	3,920,879		51,275		5.26	%	3,918,261		56,066		5.68	%	2,352,715		28,764		4.96	%
Junior and other subordinated debentures	423,528		9,887		9.39	%	440,007		10,060		9.07	%	417,966		8,470		8.22	%
Total interest-bearing liabilities	32,318,653		$	260,863	3.25	%	31,226,600		$	238,011	3.02	%	22,548,264		$	101,253	1.82	%
Non-interest-bearing deposits	13,841,582						14,899,001						12,755,080
Other liabilities	937,863						1,011,019						772,870
Total liabilities	47,098,098						47,136,620						36,076,214
Common equity	4,985,875						4,695,736						3,349,761
Total liabilities and shareholders' equity	$	52,083,973					$	51,832,356					$	39,425,975
NET INTEREST INCOME (2)			$	424,344					$	454,730					$	375,369
NET INTEREST SPREAD					2.44	%					2.73	%					3.37	%
NET INTEREST INCOME TO EARNING ASSETS OR NET INTEREST MARGIN (1), (2)					3.52	%					3.78	%					4.08	%

(1)Non-accrual loans and leases are included in the average balance.

(2)Tax-exempt income has been adjusted to a tax equivalent basis at a 21% tax rate. The amount of such adjustment was an addition to recorded income of approximately $982,000 for the three months ended March 31, 2024, as compared to $1.1 million for the three months ended December 31, 2023 and $671,000 for the three months ended March 31, 2023.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 14


Columbia Banking System, Inc.
Residential Mortgage Banking Activity
(Unaudited)
	Quarter Ended															% Change
($ in thousands)	Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			Seq. Quarter		Year over Year
Residential mortgage banking revenue:
Origination and sale	$	2,920		$	2,686		$	2,442		$	3,166		$	3,587		9	%	(19)	%
Servicing	6,021			5,966			8,887			9,167			9,397			1	%	(36)	%
Change in fair value of MSR asset:
Changes due to collection/realization of expected cash flows over time	(3,153)			(3,215)			(4,801)			(4,797)			(4,881)			(2)	%	(35)	%
Changes due to valuation inputs or assumptions	3,117			(6,251)			5,308			(2,242)			(2,937)			nm		nm
MSR hedge (loss) gain	(4,271)			5,026			(4,733)			(7,636)			2,650			(185)	%	(261)	%
Total	$	4,634		$	4,212		$	7,103		$	(2,342)		$	7,816		10	%	(41)	%

Closed loan volume for-sale	$	86,903		$	87,033		$	103,333		$	119,476		$	131,726		—	%	(34)	%
Gain on sale margin	3.36		%	3.09		%	2.36		%	2.65		%	2.72		%	0.27		0.64

Residential mortgage servicing rights:
Balance, beginning of period	$	109,243		$	117,640		$	172,929		$	178,800		$	185,017		(7)	%	(41)	%
Additions for new MSR capitalized	1,237			920			1,658			1,168			1,601			34	%	(23)	%
Sale of MSR assets	—			149			(57,454)			—			—			(100)	%	nm
Change in fair value of MSR asset:
Changes due to collection/realization of expected cash flows over time	(3,153)			(3,215)			(4,801)			(4,797)			(4,881)			(2)	%	(35)	%
Changes due to valuation inputs or assumptions	3,117			(6,251)			5,308			(2,242)			(2,937)			nm		nm
Balance, end of period	$	110,444		$	109,243		$	117,640		$	172,929		$	178,800		1	%	(38)	%

Residential mortgage loans serviced for others	$	8,081,039		$	8,175,664		$	8,240,950		$	12,726,615		$	12,914,046		(1)	%	(37)	%
MSR as % of serviced portfolio	1.37		%	1.34		%	1.43		%	1.36		%	1.38		%	0.03		(0.01)

nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 15

Non-GAAP Financial Measures

In addition to results presented in accordance with generally accepted accounting principles in the United States of America ("GAAP"), this press release contains certain non-GAAP financial measures. The company believes presenting certain non-GAAP financial measures provides investors with information useful in understanding our financial performance, our performance trends, and our financial position. We utilize these measures for internal planning and forecasting purposes. We, as well as securities analysts, investors, and other interested parties, also use these measures to compare peer company operating performance. We believe that our presentation and discussion, together with the accompanying reconciliations, provides a complete understanding of factors and trends affecting our business and allows investors to view performance in a manner similar to management. These non-GAAP measures should not be considered a substitution for GAAP basis measures and results, and we strongly encourage investors to review our consolidated financial statements in their entirety and not to rely on any single financial measure. Because non-GAAP financial measures are not standardized, it may not be possible to compare these financial measures with other companies’ non-GAAP financial measures having the same or similar names.


Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation
(Unaudited)
		Quarter Ended															% Change
($ in thousands, except per share data)		Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			Seq. Quarter		Year over Year
Total shareholders' equity	a	$	4,957,245		$	4,995,034		$	4,632,162		$	4,828,188		$	4,884,723		(1)	%	1	%
Less: Goodwill		1,029,234			1,029,234			1,029,234			1,029,234			1,030,142			—	%	—	%
Less: Other intangible assets, net		571,588			603,679			636,883			666,762			702,315			(5)	%	(19)	%
Tangible common shareholders' equity	b	$	3,356,423		$	3,362,121		$	2,966,045		$	3,132,192		$	3,152,266		—	%	6	%



Total assets	c	$	52,224,006		$	52,173,596		$	51,993,815		$	53,592,096		$	53,994,226		—	%	(3)	%
Less: Goodwill		1,029,234			1,029,234			1,029,234			1,029,234			1,030,142			—	%	—	%
Less: Other intangible assets, net		571,588			603,679			636,883			666,762			702,315			(5)	%	(19)	%
Tangible assets	d	$	50,623,184		$	50,540,683		$	50,327,698		$	51,896,100		$	52,261,769		—	%	(3)	%
Common shares outstanding at period end	e	209,370			208,585			208,575			208,514			208,429			—	%	—	%

Total shareholders' equity to total assets ratio	a / c	9.49		%	9.57		%	8.91		%	9.01		%	9.05		%	(0.08)		0.44
Tangible common equity ratio	b / d	6.63		%	6.65		%	5.89		%	6.04		%	6.03		%	(0.02)		0.60

Book value per common share	a / e	$	23.68		$	23.95		$	22.21		$	23.16		$	23.44		(1)	%	1	%
Tangible book value per common share	b / e	$	16.03		$	16.12		$	14.22		$	15.02		$	15.12		(1)	%	6	%

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 16


Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
		Quarter Ended										% Change
($ in thousands)		Mar 31, 2024		Dec 31, 2023		Sep 30, 2023		Jun 30, 2023		Mar 31, 2023		Seq. Quarter		Year over Year
Non-Interest Income Adjustments
Gain on sale of debt securities, net		$	12	$	9	$	4	$	—	$	—	33	%	nm
(Loss) gain on equity securities, net		(1,565)		2,636		(2,055)		(697)		2,416		(159)	%	(165)	%
Gain (loss) on swap derivatives		1,197		(8,042)		5,700		1,288		(3,543)		nm		nm
Change in fair value of certain loans held for investment		(2,372)		19,354		(19,247)		(6,965)		9,488		(112)	%	(125)	%
Change in fair value of MSR due to valuation inputs or assumptions		3,116		(6,251)		5,308		(2,242)		(2,937)		nm		nm
MSR hedge (loss) gain		(4,271)		5,026		(4,733)		(7,636)		2,650		(185)	%	(261)	%
Total non-interest income adjustments	a	$	(3,883)	$	12,732	$	(15,023)	$	(16,252)	$	8,074	(130)	%	(148)	%

Non-Interest Expense Adjustments
Merger-related expense		$	4,478	$	7,174	$	18,938	$	29,649	$	115,898	(38)	%	(96)	%
Exit and disposal costs		1,272		2,791		4,017		2,119		1,291		(54)	%	(1)	%
FDIC special assessment (2)		4,848		32,923		—		—		—		(85)	%	nm
Total non-interest expense adjustments	b	$	10,598	$	42,888	$	22,955	$	31,768	$	117,189	(75)	%	(91)	%

Net interest income	c	$	423,362	$	453,623	$	480,875	$	483,975	$	374,698	(7)	%	13	%

Non-interest income (GAAP)	d	$	50,357	$	65,533	$	43,981	$	39,678	$	54,735	(23)	%	(8)	%
Less: Non-interest income adjustments	a	3,883		(12,732)		15,023		16,252		(8,074)		nm		nm
Operating non-interest income (non-GAAP)	e	$	54,240	$	52,801	$	59,004	$	55,930	$	46,661	3	%	16	%

Revenue (GAAP)	f=c+d	$	473,719	$	519,156	$	524,856	$	523,653	$	429,433	(9)	%	10	%
Operating revenue (non-GAAP)	g=c+e	$	477,602	$	506,424	$	539,879	$	539,905	$	421,359	(6)	%	13	%

Non-interest expense (GAAP)	h	$	287,516	$	337,176	$	304,147	$	328,559	$	342,818	(15)	%	(16)	%
Less: Non-interest expense adjustments	b	(10,598)		(42,888)		(22,955)		(31,768)		(117,189)		(75)	%	(91)	%
Operating non-interest expense (non-GAAP)	i	$	276,918	$	294,288	$	281,192	$	296,791	$	225,629	(6)	%	23	%

Net income (loss) (GAAP)	j	$	124,080	$	93,531	$	135,845	$	133,377	$	(14,038)	33	%	nm
Provision (benefit) for income taxes		44,987		33,540		48,127		45,703		(4,886)		34	%	nm
Income (loss) before provision for income taxes		169,067		127,071		183,972		179,080		(18,924)		33	%	nm
Provision for credit losses		17,136		54,909		36,737		16,014		105,539		(69)	%	(84)	%
Pre-provision net revenue (PPNR) (non-GAAP)	k	186,203		181,980		220,709		195,094		86,615		2	%	115	%
Less: Non-interest income adjustments	a	3,883		(12,732)		15,023		16,252		(8,074)		nm		nm
Add: Non-interest expense adjustments	b	10,598		42,888		22,955		31,768		117,189		(75)	%	(91)	%
Operating PPNR (non-GAAP)	l	$	200,684	$	212,136	$	258,687	$	243,114	$	195,730	(5)	%	3	%

Net income (loss) (GAAP)	j	$	124,080	$	93,531	$	135,845	$	133,377	$	(14,038)	33	%	nm
Less: Non-interest income adjustments	a	3,883		(12,732)		15,023		16,252		(8,074)		nm		nm
Add: Non-interest expense adjustments	b	10,598		42,888		22,955		31,768		117,189		(75)	%	(91)	%
Tax effect of adjustments		(3,620)		(7,539)		(9,482)		(11,981)		(23,565)		(52)	%	(85)	%
Operating net income (non-GAAP)	m	$	134,941	$	116,148	$	164,341	$	169,416	$	71,512	16	%	89	%

nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 17


Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
		Quarter Ended															% Change
($ in thousands, except per share data)		Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			Seq. Quarter		Year over Year
Average assets	n	$	52,083,973		$	51,832,356		$	53,011,361		$	53,540,574		$	39,425,975		—	%	32	%
Less: Average goodwill and other intangible assets, net		1,619,134			1,652,282			1,684,093			1,718,705			623,042			(2)	%	160	%
Average tangible assets	o	$	50,464,839		$	50,180,074		$	51,327,268		$	51,821,869		$	38,802,933		1	%	30	%

Average common shareholders' equity	p	$	4,985,875		$	4,695,736		$	4,866,975		$	4,935,239		$	3,349,761		6	%	49	%
Less: Average goodwill and other intangible assets, net		1,619,134			1,652,282			1,684,093			1,718,705			623,042			(2)	%	160	%
Average tangible common equity	q	$	3,366,741		$	3,043,454		$	3,182,882		$	3,216,534		$	2,726,719		11	%	23	%

Weighted average basic shares outstanding	r	208,260			208,083			208,070			207,977			156,383			—	%	33	%
Weighted average diluted shares outstanding	s	208,956			208,739			208,645			208,545			156,383			—	%	34	%

Select Per-Share & Performance Metrics
Earnings-per-share - basic	j / r	$	0.60		$	0.45		$	0.65		$	0.64		$	(0.09)		33	%	nm
Earnings-per-share - diluted	j / s	$	0.59		$	0.45		$	0.65		$	0.64		$	(0.09)		31	%	nm
Efficiency ratio (1)	h / f	60.57		%	64.81		%	57.82		%	62.60		%	79.71		%	(4.24)		(19.14)
Non-interest expense to average assets	h / n	2.22		%	2.58		%	2.28		%	2.46		%	3.53		%	(0.36)		(1.31)
Return on average assets	j / n	0.96		%	0.72		%	1.02		%	1.00		%	(0.14)		%	0.24		1.10
Return on average tangible assets	j / o	0.99		%	0.74		%	1.05		%	1.03		%	(0.15)		%	0.25		1.14
PPNR return on average assets	k / n	1.44		%	1.39		%	1.65		%	1.46		%	0.89		%	0.05		0.55
Return on average common equity	j / p	10.01		%	7.90		%	11.07		%	10.84		%	(1.70)		%	2.11		11.71
Return on average tangible common equity	j / q	14.82		%	12.19		%	16.93		%	16.63		%	(2.09)		%	2.63		16.91

Operating Per-Share & Performance Metrics
Operating earnings-per-share - basic (2)	m / r	$	0.65		$	0.56		$	0.79		$	0.81		$	0.46		16	%	41	%
Operating earnings-per-share - diluted (2)	m / s	$	0.65		$	0.56		$	0.79		$	0.81		$	0.46		16	%	41	%
Operating efficiency ratio, as adjusted (1), (2), (3)	u / y	56.97		%	57.31		%	51.26		%	54.04		%	52.84		%	(0.34)		4.13
Operating non-interest expense to average assets	i / n	2.14		%	2.25		%	2.10		%	2.22		%	2.32		%	(0.11)		(0.18)
Operating return on average assets (2)	m / n	1.04		%	0.89		%	1.23		%	1.27		%	0.74		%	0.15		0.30
Operating return on average tangible assets (2)	m / o	1.08		%	0.92		%	1.27		%	1.31		%	0.75		%	0.16		0.33
Operating PPNR return on average assets (2)	l / n	1.55		%	1.62		%	1.94		%	1.82		%	2.01		%	(0.07)		(0.46)
Operating return on average common equity (2)	m / p	10.89		%	9.81		%	13.40		%	13.77		%	8.66		%	1.08		2.23
Operating return on average tangible common equity (2)	m / q	16.12		%	15.14		%	20.48		%	21.13		%	10.64		%	0.98		5.48

nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "n/m."

(1) Tax-exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate and added to stated revenue for this calculation.

(2) Non-interest expense adjustments were revised subsequent to the Company's reporting of its earnings results for the three months ended December 31, 2023. The revision includes the FDIC special assessment in non-interest expense adjustments, which removes the special assessment from the Company's calculation of operating non-interest expense. The Company views the special assessment as an infrequent expense that is outside the control of the Company.

(3) The operating efficiency ratio has been adjusted to remove B&O taxes and for a tax-equivalent adjustment to BOLI income. The Company views the adjusted operating efficiency ratio as a better representation of its efficiency ratio when compared to other banks as it normalizes for the tax treatment of the adjusted items. The adjustment re-aligns Columbia's calculation of its operating efficiency ratio with its pre-merger calculation.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 18


Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
Operating Efficiency Ratio, as adjusted
(Unaudited)
		Quarter Ended															% Change
($ in thousands)		Mar 31, 2024			Dec 31, 2023			Sep 30, 2023			Jun 30, 2023			Mar 31, 2023			Seq. Quarter		Year over Year
Non-interest expense (GAAP)	h	$	287,516		$	337,176		$	304,147		$	328,559		$	342,818		(15)	%	(16)	%
Less: Non-interest expense adjustments	b	(10,598)			(42,888)			(22,955)			(31,768)			(117,189)			(75)	%	(91)	%
Operating non-interest expense (non-GAAP)	i	276,918			294,288			281,192			296,791			225,629			(6)	%	23	%
Less: B&O taxes	t	(3,223)			(2,727)			(3,275)			(3,647)			(2,129)			18	%	51	%
Operating non-interest expense, excluding B&O taxes (non-GAAP)	u	$	273,695		$	291,561		$	277,917		$	293,144		$	223,500		(6)	%	22	%




Net interest income (tax equivalent) (1)	v	$	424,344		$	454,730		$	482,031		$	485,168		$	375,369		(7)	%	13	%
Non-interest income (GAAP)	d	50,357			65,533			43,981			39,678			54,735			(23)	%	(8)	%
Add: BOLI tax equivalent adjustment (1)	w	1,809			1,182			1,178			1,360			957			53	%	89	%
Total Revenue, excluding BOLI tax equivalent adjustments (tax equivalent)	x	476,510			521,445			527,190			526,206			431,061			(9)	%	11	%
Less: Non-interest income adjustments	a	3,883			(12,732)			15,023			16,252			(8,074)			nm		nm
Total Adjusted Operating Revenue, excluding BOLI tax equivalent adjustments (tax equivalent) (non-GAAP)	y	$	480,393		$	508,713		$	542,213		$	542,458		$	422,987		(6)	%	14	%

Efficiency ratio (1)	h / f	60.57		%	64.81		%	57.82		%	62.60		%	79.71		%	(4.24)		(19.14)

Operating efficiency ratio, as adjusted (non-GAAP) (1), (2), (3)	u / y	56.97		%	57.31		%	51.26		%	54.04		%	52.84		%	(0.34)		4.13

nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

(1) Tax-exempt income has been adjusted to a taxable equivalent basis using a 21% tax rate and added to stated revenue for this calculation.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 19


Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
		Quarter Ended										% Change
($ in thousands)		Mar 31, 2024		Dec 31, 2023		Sep 30, 2023		Jun 30, 2023		Mar 31, 2023		Seq. Quarter		Year over Year
Loans and leases interest income	a	$	574,519	$	577,092	$	567,929	$	551,997	$	412,726	—	%	39	%
Less: Acquired loan accretion - rate related (2), (3)	b	23,482		26,914		28,963		30,548		11,832		(13)	%	98	%

Less: Acquired loan accretion - credit related (3)	c	5,119		5,430		6,370		7,100		3,806		(6)	%	34	%

Adjusted loans and leases interest income	d=a-b-c	$	545,918	$	544,748	$	532,596	$	514,349	$	397,088	—	%	37	%

Taxable securities interest income	e	$	78,724	$	82,872	$	85,007	$	81,617	$	40,448	(5)	%	95	%

Less: Acquired taxable securities accretion - rate related	f	31,527		34,290		39,219		34,801		15,356		(8)	%	105	%
Adjusted Taxable securities interest income	g=e-f	$	47,197	$	48,582	$	45,788	$	46,816	$	25,092	(3)	%	88	%

Non-taxable securities interest income (1)	h	$	7,886	$	8,073	$	8,085	$	8,010	$	4,068	(2)	%	94	%

Less: Acquired non-taxable securities accretion - rate related	i	2,270		2,309		2,288		2,274		901		(2)	%	152	%
Adjusted Taxable securities interest income (1)	j=h-i	$	5,616	$	5,764	$	5,797	$	5,736	$	3,167	(3)	%	77	%

Interest income (1)	k	$	685,207	$	692,741	$	697,169	$	676,922	$	476,622	(1)	%	44	%
Less: Acquired loan and securities accretion - rate related	l=b+f+i	57,279		63,513		70,470		67,623		28,089		(10)	%	104	%
Less: Acquired loan accretion - credit related	c	5,119		5,430		6,370		7,100		3,806		(6)	%	34	%
Adjusted interest income (1)	m=k-l-c	$	622,809	$	623,798	$	620,329	$	602,199	$	444,727	—	%	40	%

Interest-bearing deposits interest expense	n	$	198,435	$	170,659	$	126,974	$	100,408	$	63,613	16	%	212	%
Less: Acquired deposit accretion	o	—		(187)		(373)		(280)		(93)		nm		nm
Adjusted interest-bearing deposits interest expense	p=n-o	$	198,435	$	170,846	$	127,347	$	100,688	$	63,706	16	%	211	%

Interest expense	q	$	260,863	$	238,011	$	215,138	$	191,754	$	101,253	10	%	158	%
Less: Acquired interest-bearing liabilities accretion (2)	r	(57)		(244)		(430)		(337)		(150)		(77)	%	(62)	%
Adjusted interest expense	s=q-r	$	260,920	$	238,255	$	215,568	$	192,091	$	101,403	10	%	157	%

Net Interest Income (1)	t	$	424,344	$	454,730	$	482,031	$	485,168	$	375,369	(7)	%	13	%
Less: Acquired loan, securities, and interest-bearing liabilities accretion - rate related (3)	u=l-r	57,336		63,757		70,900		67,960		28,239		(10)	%	103	%
Less: Acquired loan accretion - credit related (3)	c	5,119		5,430		6,370		7,100		3,806		(6)	%	34	%
Adjusted net interest income (1)	v=t-u-c	$	361,889	$	385,543	$	404,761	$	410,108	$	343,324	(6)	%	5	%

Average loans and leases	aa	37,597,101		37,333,310		37,050,518		37,169,315		29,998,630		1	%	25	%
Average taxable securities	ab	8,081,003		7,903,053		8,356,165		8,656,147		4,960,966		2	%	63	%
Average non-taxable securities	ac	851,342		809,551		844,417		865,278		437,020		5	%	95	%
Average interest-earning assets	ad	48,280,787		47,838,229		48,981,105		49,442,518		37,055,705		1	%	30	%
Average interest-bearing deposits	ae	27,742,579		26,622,343		25,121,745		24,494,717		19,496,551		4	%	42	%
Average interest-bearing liabilities	af	32,318,653		31,226,600		31,413,978		31,372,416		22,548,264		3	%	43	%

nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

(1)Tax-exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.

(2)Includes discount accretion related to UHC's 2014 acquisition of Sterling Financial Corporation.

(3)The cumulative fair value discount on historical Columbia loans was established as of February 28, 2023, and the allocation between the credit-related discount and the rate-related discount was established at that time. Our disclosure of credit-related and rate-related discount accretion is an estimate based on the relative allocation of these two items to the discount at the closing of the merger.

Columbia Banking System, Inc. Reports First Quarter 2024 Results

April 25, 2024

Page 20


Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
		Quarter Ended										% Change
($ in thousands)		Mar 31, 2024		Dec 31, 2023		Sep 30, 2023		Jun 30, 2023		Mar 31, 2023		Seq. Quarter	Year over Year
Average yield on loans and leases	a / aa	6.13	%	6.13	%	6.08	%	5.95	%	5.55	%	—	0.58

Less: Acquired loan accretion - rate related (2),(3)	b / aa	0.25	%	0.29	%	0.31	%	0.33	%	0.16	%	(0.04)	0.09

Less: Acquired loan accretion - credit related (3)	c / aa	0.05	%	0.06	%	0.07	%	0.08	%	0.05	%	(0.01)	—
Adjusted average yield on loans and leases	d / aa	5.83	%	5.78	%	5.70	%	5.54	%	5.34	%	0.05	0.49

Average yield on taxable securities	e / ab	3.90	%	4.19	%	4.07	%	3.77	%	3.26	%	(0.29)	0.64

Less: Acquired taxable securities accretion - rate related	f / ab	1.57	%	1.72	%	1.86	%	1.61	%	1.26	%	(0.15)	0.31
Adjusted average yield on taxable securities	g / ab	2.33	%	2.47	%	2.21	%	2.16	%	2.00	%	(0.14)	0.33

Average yield on non-taxable securities (1)	h / ac	3.71	%	3.99	%	3.83	%	3.70	%	3.72	%	(0.28)	(0.01)

Less: Acquired non-taxable securities accretion - rate related	i / ac	1.07	%	1.13	%	1.07	%	1.05	%	0.84	%	(0.06)	0.23
Adjusted yield on non-taxable securities (1)	j / ac	2.64	%	2.86	%	2.76	%	2.65	%	2.88	%	(0.22)	(0.24)

Average yield on interest-earning assets (1)	k / ad	5.69	%	5.75	%	5.65	%	5.48	%	5.19	%	(0.06)	0.50
Less: Acquired loan and securities accretion - rate related	l / ad	0.48	%	0.53	%	0.57	%	0.55	%	0.31	%	(0.05)	0.17
Less: Acquired loan accretion - credit related	c / ad	0.04	%	0.05	%	0.05	%	0.06	%	0.04	%	(0.01)	—
Adjusted average yield on interest-earning assets (1)	m / ad	5.17	%	5.17	%	5.03	%	4.87	%	4.84	%	—	0.33

Average rate on interest-bearing deposits	n / ae	2.88	%	2.54	%	2.01	%	1.64	%	1.32	%	0.34	1.56
Less: Acquired deposit accretion	o / ae	—	%	—	%	(0.01)	%	—	%	—	%	—	—
Adjusted average rate on interest-bearing deposits	p / ae	2.88	%	2.54	%	2.02	%	1.64	%	1.32	%	0.34	1.56

Average rate on interest-bearing liabilities	q / af	3.25	%	3.02	%	2.72	%	2.45	%	1.82	%	0.23	1.43
Less: Acquired interest-bearing liabilities accretion (2)	r / af	—	%	—	%	(0.01)	%	—	%	—	%	—	—
Adjusted average rate on interest-bearing liabilities	s / af	3.25	%	3.02	%	2.73	%	2.45	%	1.82	%	0.23	1.43

Net interest margin (1)	t / ad	3.52	%	3.78	%	3.91	%	3.93	%	4.08	%	(0.26)	(0.56)
Less: Acquired loan, securities, and interest-bearing liabilities accretion - rate related (3)	u / ad	0.48	%	0.53	%	0.58	%	0.55	%	0.31	%	(0.05)	0.17
Less: Acquired loan accretion - credit related (3)	c / ad	0.04	%	0.05	%	0.05	%	0.06	%	0.04	%	(0.01)	—
Adjusted net interest margin (1)	v / ad	3.00	%	3.20	%	3.28	%	3.32	%	3.73	%	(0.20)	(0.73)

(1)Tax-exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.

(2) Includes discount accretion related to UHC's 2014 acquisition of Sterling Financial Corporation.

1st Quarter 2024 Earnings Presentation April 25, 2024

Disclaimer FORWARD-LOOKING STATEMENTS This presentation includes forward-looking statements within the meaning of the "Safe-Harbor" provisions of the Private Securities Litigation Reform Act of 1995, which management believes are a benefit to shareholders. These statements are necessarily subject to risk and uncertainty and actual results could differ materially due to various risk factors, including those set forth from time to time in our filings with the Securities and Exchange Commission. You should not place undue reliance on forward-looking statements and we undertake no obligation to update any such statements. Forward-looking statements can be identified by words such as "anticipates," "intends," "plans," "seeks," "believes," "estimates," "expects," "target," "projects," "outlook," "forecast," "will," "may," "could," "should," "can" and similar references to future periods. In this press release we make forward- looking statements about strategic and growth initiatives and the result of such activity. Risks and uncertainties that could cause results to differ from forward-looking statements we make include, without limitation: current and future economic and market conditions, including the effects of declines in housing and commercial real estate prices, high unemployment rates, continued inflation and any recession or slowdown in economic growth particularly in the western United States; economic forecast variables that are either materially worse or better than end of quarter projections and deterioration in the economy that could result in increased loan and lease losses, especially those risks associated with concentrations in real estate related loans; our ability to effectively manage problem credits; the impact of bank failures or adverse developments at other banks on general investor sentiment regarding the liquidity and stability of banks; changes in interest rates that could significantly reduce net interest income and negatively affect asset yields and valuations and funding sources; changes in the scope and cost of FDIC insurance and other coverage; our ability to successfully implement efficiency and operational excellence initiatives; our ability to successfully develop and market new products and technology; changes in laws or regulations; any failure to realize the anticipated benefits of the merger when expected or at all; potential adverse reactions or changes to business or employee relationships, including those resulting from the completion of the merger and integration of the companies; the effect of geopolitical instability, including wars, conflicts and terrorist attacks; and natural disasters and other similar unexpected events outside of our control. We also caution that the amount and timing of any future common stock dividends or repurchases will depend on the earnings, cash requirements and financial condition of Columbia, market conditions, capital requirements, applicable law and regulations (including federal securities laws and federal banking regulations), and other factors deemed relevant by Columbia's Board of Directors, and may be subject to regulatory approval or conditions. NON-GAAP FINANCIAL MEASURES In addition to results presented in accordance with GAAP, this presentation contains certain non-GAAP financial measures. A reconciliation of GAAP to non-GAAP measures is included in the Appendix. We believe presenting certain non-GAAP financial measures provides investors with information useful in understanding our financial performance, our performance trends, and our financial position. We utilize these measures for internal planning and forecasting purposes. We, as well as securities analysts, investors, and other interested parties, also use these measures to compare peer company operating performance. We believe that our presentation and discussion, together with the accompanying reconciliations, provides a complete understanding of factors and trends affecting our business and allows investors to view performance in a manner similar to management. These non-GAAP measures should not be considered a substitution for GAAP basis measures and results, and we strongly encourage investors to review our consolidated financial statements in their entirety and not to rely on any single financial measure. Because non-GAAP financial measures are not standardized, it may not be possible to compare these financial measures with other companies’ non-GAAP financial measures having the same or similar names. REVERSE ACQUISITION METHOD OF ACCOUNTING On February 28, 2023, Columbia Banking System, Inc. ("Columbia," "we," or "our") completed its merger with Umpqua Holdings Corporation ("UHC"), combining the two premier banks in the Northwest to create one of the largest banks headquartered in the West (the "merger"). Columbia's financial results for any periods ended prior to February 28, 2023 reflect UHC results only on a standalone basis as the merger was treated as a reverse merger with UHC as the accounting acquirer. In addition, Columbia's reported financial results for the first quarter of 2023 reflect UHC financial results only until the closing of the merger after the close of business on February 28, 2023. As a result of these two factors, Columbia's financial results for each of the quarters of 2023 and the year ended December 31, 2023 may not be directly comparable to prior reported periods. Under the reverse acquisition method of accounting, the assets and liabilities of Columbia as of February 28, 2023 ("historical Columbia") were recorded at their respective fair values. 2

Columbia Banking System: A Franchise Like No Other 3 West-Focused Regional Powerhouse Business Bank of Choice ■ In-market, relationship-based commercial banking ■ Attractive footprint in high-growth markets ■ Full suite of deposit products and services with contemporary digital capabilities ■ Expertise in treasury management, foreign exchange, and global cash management ■ Expanding small business platform ■ Comprehensive and growing wealth advisory and trust businesses ■ Niche verticals include diverse agricultural, healthcare, tribal banking, and equipment finance Columbia at a Glance Co rp or at e Ticker COLB Headquarters Tacoma, Washington Offices ~300 in eight states Fi na nc ia ls a s of M ar ch 3 1, 2 02 4 Assets $52 billion Loans $37 billion Deposits $42 billion Common Equity Tier 1 Capital Ratio 9.8%(1) Total Capital Ratio 12.0%(1) (1) Regulatory capital ratios are estimates pending completion and filing of Columbia’s regulatory reports.

Why Columbia? 4 ■ Community banking at scale business model drives granular, low-cost core deposit base ■ Opportunity to gain share in California and growing metros in the West while increasing density in the Northwest ■ Solid capital generation supports long-term organic growth and return to shareholders ■ Strong credit quality supported by diversified, well-structured, and conservatively underwritten loan portfolio ■ Compelling culture with deep community ties that is reflected in our proven ability to attract and retain top banking talent ■ Scaled western franchise that is difficult to replicate provides scarcity value

Operating in Large, Attractive Western Markets 5 Foothold in the West(1) Northwest (population in millions) Seattle, WA Portland, OR California and Nevada Los Angeles, CA Sacramento, CA Other West Phoenix, AZ Denver, CO 4.1mm 2.5mm 12.9mm 2.4mm 5.1mm 3.0mm Top Regional Bank in the NW (WA, OR, ID)(1) Total Northwest Rank Bank (HQ State) Assets ($B) Deposits ($B) Mkt Shr 1 Bank of America (NC) $3,180 $62 17.3 % 2 U.S. Bancorp (MN) 663 51 14.4 % 3 JPMorgan (NY) 3,875 47 13.3 % 4 Wells Fargo (CA) 1,932 42 11.7 % 5 COLB (WA) 52 33 9.3 % 6 KeyCorp (OH) 188 18 5.0 % 7 WaFd (WA) 23 12 3.3 % 8 Banner Corp. (WA) 16 11 3.0 % 5th Largest Bank HQ’d in our Footprint(1) Total Eight-State Footprint Rank Bank (HQ State) Assets ($B) Deposits ($B) Mkt Shr 1 Wells Fargo (CA) $1,932 $459 16.7 % 2 Zions (UT) 87 61 2.2 % 3 Western Alliance (AZ) 71 51 1.9 % 4 East West (CA) 70 49 1.8 % 5 COLB (WA) 52 41 1.5 % 6 Banc of California (CA) 39 29 1.1 % 7 FirstBank (CO) 28 24 0.9 % 8 Cathay General (CA) 23 15 0.6 % Established Presence in Attractive Markets(1) ■ Our market share in the Northwest stands with large national and super regional banks, at over 9% ■ Our foothold in top western markets and scaled franchise provide us the opportunity to increase share in California, Arizona, Colorado, and Utah ■ Projected population growth of 3.2% over the next five years in our collective footprint exceeds the national average of 2.4% ■ Current household income in our footprint is 109% of the national average, and the five-year growth rate of 10.4% compares favorably to 10.1% nationally Boise, ID Salt Lake City, UT Las Vegas, NV 0.8mm 2.4mm 1.3mm (1) Population, household income, asset, deposit, and market share data sourced from S&P Global Market Intelligence. Assets as of December 31, 2023; deposits and market share as of June 30, 2023 and adjusted by S&P to include acquisitions announced or closed subsequent to that date.

Opportunity to Increase Density and Gain Share throughout Our Footprint 6 Expand Footprint in California Broaden Presence in Other Western MarketsImprove Density in the Northwest Population Deposits ($mm) COLB MSA(1) (000s) Market COLB Mkt Shr Seattle 4,107 $143,835 $7,561 5.2 % Portland 2,537 67,109 5,673 8.5 % Boise 835 16,886 189 1.1 % Spokane 605 12,868 3,040 23.6 % Population Deposits ($mm) COLB MSA(1) (000s) Market COLB Mkt Shr Phoenix 5,120 $166,520 Opportunity to add targeted retail locations to support existing commercial banking presence Denver 3,031 114,538 Salt Lake City 1,284 69,725 Las Vegas 2,368 78,063 Population Deposits ($mm) COLB MSA(1) (000s) Market COLB Mkt Shr Los Angeles 12,869 $684,438 $848 0.1 % Sacramento 2,440 94,707 1,934 2.0 % San Francisco 4,592 458,774 525 0.1 % San Diego 3,298 105,112 16 < 0.1% (1) Population, deposit, and market share data sourced from S&P Global Market Intelligence. Deposits and market share as of June 30, 2023 and adjusted by S&P to include acquisitions announced or closed subsequent to that date.

Performance Improvement: Near-Term Initiatives 7 1H 2024 Actions to Improve Operational Efficiency ■ Initiatives to improve operating efficiency throughout the organization are expected to result in a Q4 2024 core expense run rate of $965 million to $985 million annualized, which excludes CDI amortization and non-operating expense(1) ■ Closed five branches in January to fund the opening of new retail locations in existing commercial banking de novo markets ■ Actively managing and selectively reducing deposit offering rates ■ Continued evaluation of wholesale funding options to optimize rate while managing duration risk ■ Additional product bundling and marketing designed to drive higher levels of new customer acquisition ■ Modified underwriting and pricing for FinPac as well as rationalizing its cost structure in light of the current operating environment (1) Non-GAAP financial measure. A reconciliation of adjustments to the comparable GAAP measure is detailed in the “Non-GAAP Reconciliation” section of the Appendix.

Performance Improvement: Longer-Term 8 ■ Our relationship-based lending verticals and a strong core deposit base remain the cornerstone of our franchise. ■ Past transactional lending and the wholesale sources that fund these assets have muted the balance sheet’s profitability, but they have not diluted the quality of our core franchise. ■ Current interest rates make outright asset sales unattractive given a lengthy payback period. However, longer term, a decline in rates will provide the flexibility to minimize or eliminate the drag on earnings.(1) Opportunity to Strategically Reposition Balance Sheet Over Time Assets Liabilities + Equity $4B Borrowings $3B Brokered Deposits $4B Multifamily $2B Single-Family $9B Securities $37B Relationship Lending & Other Core Banking Franchise $45B Core Deposit Franchise & Capital Opportunity to reduce transactional assets and liabilities Relationship banking supports strong core franchise value (1) While asset classes, like transactional loans within our multifamily and single-family portfolios, have been identified as potential sources for asset sales if interest rates were to decline, assets have not been identified for sale.

FINANCIAL HIGHLIGHTS

First Quarter 2024 Highlights (1) Non-GAAP financial measure. A reconciliation to the comparable GAAP measurement for each is provided in the Appendix of this slide presentation. (2) Regulatory capital ratios are estimates pending completion and filing of Columbia’s regulatory reports. 10 ■ Total risk-based capital ratio of 12.0%(2) as of March 31, 2024 reached our long-term internal target after increasing over 100 basis points since the merger closed in Q1 2023. ■ Conducted an enterprise-wide evaluation of our operations that resulted in consolidated positions, simplified reporting and organizational structures, and an improved profitability outlook. ■ Launched a targeted campaign in early February 2024 to generate new small business deposit accounts. The campaign runs through April 2024 and includes bundled solutions for customers without promotional pricing. Non-interest bearing deposits generated through March 31, 2024 were 25% of total new money to the bank. ■ Introduced a new platform for consumer online account openings to improve efficiency and enhance vendor support. ■ Named to Newsweek’s list of Most Trustworthy Companies in America. Reported Operating(1) $124 million $135 million Net Income Net Income $186 million $201 million Pre-Provision Net Revenue(1) Pre-Provision Net Revenue $0.59 $0.65 Earnings-per-Share - Diluted Earnings-per-Share - Diluted 0.96% 1.04% Return on Assets Return on Assets 1.44% 1.55% PPNR Return on Assets(1) PPNR Return on Assets 10.01% 10.89% Return on Equity Return on Equity 14.82% 16.12% Return on Tangible Common Equity(1) Return on Tangible Common Equity

Our Diversified Commercial Bank Business Model with a Strong Retail Network Supports our Granular, High-Quality Deposit Base Non-interest, 33% Demand, 20% Money Market, 26% Savings, 6% Time, 15% Enterprise-wide Deposit Composition 11 ■ Deposits were $42 billion as of March 31, 2024 and represented by a granular base that is diversified by business line, industry, and geography. Our average customer account balance is $35 thousand(1). ■ Our use of public and brokered deposits as a source of funding beyond term debt impacts the composition of our enterprise-wide deposit portfolio. Our customer deposit composition(1) is more illustrative of the quality of Columbia’s core deposit franchise. Our bankers’ activity is geared toward protecting the quality of our relationship-based franchise while generating net customer balance growth to reduce the need for non-core funding sources over time. Commercial, 27% Commercial - Small Business, 20% Consumer, 39% Brokered, 7% Public & Other, 7% Deposits by Category Customer Deposit Composition(1) Non-interest, 37% Demand, 19% Money Market, 27% Savings, 7% Time, 10% (1) Excludes all public, administrative, and brokered deposits, as detailed on the “Liquidity Overview” slide in the Appendix. Excluded balances accounted for 14% of total deposits as of March 31, 2024. This is a non-GAAP financial measure.

Available-for-Sale Securities Portfolio as of March 31, 2024 ($ in millions) Current Par Amortized Cost Unrealized Gains Unrealized Losses Fair Value % of Total AFS Portfolio Effective Duration Book Yield U.S. Treasuries $390 $380 $0 ($7) $373 4 % 2.1 3.56 % U.S. Agencies 1,156 1,172 $1 ($79) 1,095 13 % 4.0 2.79 % Mortgage-backed securities - residential agency 3,162 2,952 $0 ($293) 2,660 31 % 6.9 3.18 % Collateralized mortgage obligations(1) 1,343 1,255 $1 ($113) 1,144 13 % 5.8 3.37 % Obligations of states and political subdivisions 1,130 1,068 $9 ($25) 1,052 12 % 4.7 3.40 % Commercial mortgage-backed securities - agency 2,496 2,345 $1 ($51) 2,294 27 % 4.4 4.69 % Total available for sale securities $9,677 $9,172 $12 ($568) $8,617 5.3 3.58 % Percentage of Current Par 95% 0% (6%) 89% 12 Securities Portfolio Overview Note: Table may not foot due to rounding. (1) Portfolio includes $263 million in high-quality non-agency collateralized mortgage obligations (“CMO”) that were in a small unrealized loss position at March 31, 2024 (amortized cost of $264 million). The remaining $881 million of the portfolio is comprised primarily of residential agency CMOs. ■ The total available-for-sale (“AFS”) securities portfolio had a book yield of 3.58% and an effective duration of 5.3 as of March 31, 2024, compared to 3.59% and 5.4, respectively, as of December 31, 2023. ■ As of March 31, 2024, 16% of the AFS securities portfolio (by fair value) was in an unrealized gain position and had a weighted average book yield of 4.42%. The remaining 84% of the portfolio was in an unrealized loss position and had a weighted average book yield of 3.44%. Unrealized Gain, 16% Unrealized Loss, 84% Available-for-Sale Securities Portfolio Percentage at Gain / Loss as of March 31, 2024

Loan Roll Forward Activity $ in m ill io ns Three Months Ended March 31, 2024 $37,442 $— $772 ($74) ($342) ($176) $20 $37,642 Beginning Balance (12/31/2023) Merger New Originations Net Advances/ Payments Prepayments Payoffs or Sales Other¹ Ending Balance (3/31/2024) 13 (1) Other includes purchase accounting accretion and amortization. $ in m ill io ns Three Months Ended March 31, 2023 $26,156 $10,884 $756 ($132) ($452) ($177) $55 $37,091 Beginning Balance (12/31/2022) Merger New Originations Net Advances/ Payments Prepayments Payoffs or Sales Other¹ Ending Balance (3/31/2023)

Diversified, High Quality Loan and Lease Portfolio Note: Portfolio statistics and delinquencies as of March 31, 2024. Annualized net charge-off rates for Q1 2024. Loan-to-value (“LTV”), FICO, and debt service coverage (“DSC”) ratios are based on weighted averages for portfolios where data are available. LTV represents average LTV based on most recent appraisal against updated loan balance. Totals may not foot due to rounding. • Portfolio average loan size of $481,000 • 1Q24 average loan size of $540,000 • Portfolio average FICO of 761 and LTV of 62% • 1Q24 average FICO of 772 and LTV of 63% • Total delinquencies of 0.70% • Annualized net charge-off (recovery) rate of 0.02% Non-owner Occupied CRE • Portfolio average loan size of $1.7 million • 1Q24 average loan size of $1.5 million • Portfolio average LTV of 51% and DSC of 1.86 • 1Q24 average LTV of 49% and DSC of 1.41 • Total delinquencies of 0.13% • Annualized net charge-off (recovery) rate of 0.00% Commercial & Industrial • Portfolio average loan size of $706,000 • 1Q24 average loan size of $757,000 • Total delinquencies of 0.95% • Annualized net charge-off (recovery) rate of 0.94% Multifamily • Portfolio average loan size of $2.3 million • 1Q24 average loan size of $679,000 • Portfolio average LTV of 54% and DSC of 1.56 • 1Q24 average LTV of 65% and DSC of 1.28 • Total delinquencies of 0.00% • Annualized net charge-off (recovery) rate of 0.00% Owner Occupied CRE • Portfolio average loan size of $1.0 million • 1Q24 average loan size of $1.8 million • Portfolio average LTV of 55% • 1Q24 average LTV of 61% • Total delinquencies of 0.70% • Annualized net charge-off (recovery) rate of 0.00% Lease & Equipment Finance (FinPac) • Portfolio average loan & lease size of $42,000 • 1Q24 average loan & lease size of $59,000 • Portfolio average yield: ~10% • Total delinquencies of 4.29% • Annualized net charge-off (recovery) rate of 5.64% Puget Sound, 20% WA Other, 8% Portland Metro, 13% OR Other, 14% Bay Area, 7% Northern CA, 9% Southern CA, 15% Other, 14% Mortgage, 16% FinPac, 5% C&I, 21% Owner Occupied CRE, 14% Non-OO CRE, 17% Multifamily, 15% Other Loan Categories, 11% Portfolio Composition at March 31, 2024 Geographic Distribution at March 31, 2024 Mortgage 14

C&I and CRE Portfolio Composition Agriculture, 8.5% Contractors, 7.4% Finance/Insurance, 7.7% Manufacturing, 7.7% Professional, 4.4% Public Admin, 6.6% Rental & Leasing, 7.3% Retail, 2.4% Support Services, 4.3% Transportation/ Warehousing, 8.6% Wholesale, 6.3% Gaming, 5.6% Dentists, 7.3% Other Healthcare, 3.4% Other, 12.6% Office, 16.6% Multifamily, 33.4% Industrial, 15.7% Retail, 11.5% Special Purpose, 7.5% Hotel/Motel, 4.2% Other, 11.2% CRE Portfolio Composition(1) $17.6 Billion at March 31, 2024 C&I Portfolio Composition(1) $9.7 Billion at March 31, 2024 (1) C&I portfolio composition includes term, lines of credit & other, and leases & equipment finance balances. CRE portfolio composition includes non-owner occupied term and owner occupied term balances as well as multifamily balances. (2) Owner occupied and non-owner occupied disclosure relates to commercial real estate portfolio excluding multifamily loans. 44% Owner Occupied / 56% Non-Owner Occupied(2)Commercial Line Utilization was 35% at March 31, 2024 15

Office Portfolio Details Puget Sound, 22% WA Other, 5% Portland Metro, 12% OR Other, 15%Bay Area, 6% N. CA, 11% S. CA, 20% Other, 9% Office Portfolio Metrics at March 31, 2024 Average loan size $1.35 million Average LTV 56% DSC (non-owner occupied) 1.70x % with guaranty (by $ / by #) 85% / 84% Past due 30-89 days $0.5mm / 0.02% of office Nonaccrual $13.3mm / 0.44% of office Special mention $22.1mm / 0.73% of office Classified $60.1mm / 1.99% of office Number of Loans by Balance Geography 16 ■ Loans secured by office properties represented 8% of our total loan portfolio at March 31, 2024. ■ Our office portfolio is 39% owner occupied, 59% non-owner occupied, and 2% construction. Dental and other healthcare loans compose 15% of our office portfolio. ■ The average loan size in our office portfolio is $1.35 million, delinquencies are at a de minimis level, and the majority of our loans contain a guaranty. ■ Excluding floating rate loans, which have already repriced to prevailing rates, only 8% of our office portfolio reprices through 2025. Loans repricing in 2024 and 2025 have average balances of $0.8 million and $1.1 million, respectively. ■ Properties located in suburban markets secure the majority of our office portfolio as only 6% of non-owner occupied office loans are located in downtown core business districts. 1,746 441 71 38 7 6 <$1mm $1-5mm $5-10mm $10-20mm $20-30mm >$30mm 2024, 4% 2025, 4% 2026, 4% 2027 & After, 14% Fixed Rate¹, 67% Floating Rate, 7% Repricing Schedule (1) Loans with a swap component are displayed as a fixed rate loan if the swap maturity is equal to the maturity of the loan. If the swap matures prior to the loan, the loan is displayed as adjustable with the rate resetting at the time of the swap maturity. 2024, 4% 2025, 7% 2026, 6% 2027 & After, 83% Maturity Schedule , 19 8 9 6 7 1,666 5 68

Continued Strong Credit Quality Pr ov is io n Ex pe ns e ($ in m ill io ns ) Provision Expense, Net Charge-Offs to Average Loans, and Non-Performing Assets to Total Assets¹ $17.1 $16.0 $36.7 $54.9 $17.1 $88.4 0.23% 0.30% 0.25% 0.31% 0.47% 0.14% 0.15% 0.20% 0.22% 0.28% Provision Expense Initial Provision Net Charge-Offs / Avg. Loans Non Performing Assets / Total Assets Q1 2023 Q2 2023 Q3 2023 Q4 2023 Q1 2024 17 A CL ($ in m ill io ns ) A CL / Total Loans and Leases Allowance for Credit Losses $436 $424 $438 $464 $437 $107 $94 $86 $80 $74 1.18% 1.15% 1.18% 1.24% 1.16% ACL Credit Discount ACL to Total Loans and Leases ACL + Credit Discount to Total Loans and Leases Q1 2023 Q2 2023 Q3 2023 Q4 2023 Q1 2024 $105.5 (1) Q1 2023 provision expense of $105.5 million includes an initial provision of $88.4 million related to historical Columbia non-PCD loans. ■ The remaining credit discount on loans of $74 million as of March 31, 2024 provides an additional 20 basis points of loss absorption when added to the ACL of $437 million. ■ Charge-off activity in Q1 2024 remained concentrated in the trucking portfolio of the FinPac business and was further impacted by a single credit within the commercial portfolio. Net charge-offs were otherwise at an insignificant level during the quarter. ■ Trends in nonperforming loans are consistent with a gradual shift toward a standard credit environment following an extended period of outstanding credit quality. ■ Nonperforming loans of $142 million as of March 31, 2024 included $43 million of government guarantees. 1.46% 1.40% 1.41% 1.45% 1.36%

Robust ACL Coverage (1) Total includes reserve for unfunded commitments of $22.9 million and $23.2 million as of March 31, 2024 and December 31, 2023, respectively. 18 ■ Our reserve coverage by loan segment and for the overall loan and lease portfolio reflects our robust underwriting criteria and ongoing, routine portfolio monitoring activities. For example, we stress applicable variables, like interest rates, cash flows, and occupancy, at inception and loan review and limit borrower proceeds as a result. These factors contribute to lower LTVs and higher DSC ratios, which are taken into consideration in the estimation of our ACL. ■ The quarter’s provision expense of $17 million reflects credit migration trends, changes in the economic forecasts used in credit models, charge-off activity, and a change within our Current Expected Credit Losses ("CECL") methodology. We used components of Moody’s Analytics’ February 2024 baseline economic forecast to estimate our ACL as of March 31, 2024. ■ During the first quarter, we recalibrated the commercial CECL model to be more reflective of the post-merger loan portfolio after a full year operating as a combined organization. We believe the recalibrated model is more reflective of the quality of our underwriting and borrower profiles. Allowance for Credit Losses (“ACL”) by Loan Segment ($ in thousands) Commercial Lease & Equipment Commercial Real Estate Residential & Home Equity Consumer Total(1) Remaining Credit Discount on Loans Total ACL including Credit Discount on Loans(1) Balance as of December 31, 2023 $137,619 $115,043 $137,058 $64,944 $9,416 $464,080 $79,850 $543,930 Q1 2024 Net (Charge-offs) Recoveries (18,734) (23,766) 197 (320) (1,380) (44,003) Reserve Build (Release) (22,109) 20,593 22,049 (3,857) 459 17,135 Balance as of March 31, 2024 $96,776 $111,870 $159,304 $60,767 $8,495 $437,212 $74,098 $511,310 % of Loans and Leases Outstanding 1.20% 6.55% 0.81% 0.75% 4.49% 1.16% 1.36%

Capital Management 19 Regulatory Capital Ratios: Bank and Holding Company as of March 31, 2024 8.4% 10.6% 10.6% 11.7% 7.7% 9.8% 9.8% 12.0% Umpqua Bank Columbia Banking System Tier 1 Leverage CET1 Tier 1 Capital Total Risk-Based —% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% ■ Regulatory capital ratios declined during Q1 2023 as a result of the merger and the impact of rate-related asset discounts on capital. Our capital ratios have continued to increase on a quarterly basis post merger closing. ■ We expect to organically generate capital above what is required to support prudent growth and our regular dividend, with excess capital driving ratios higher and providing for longer-term flexibility for return to shareholders. Note: Umpqua Bank and Columbia Banking System, Inc. long-term capital ratio targets reflect a targeted excess level of capital above regulatory well-capitalized minimums inclusive of the capital conservation buffer (“CCB”) where applicable. The minimum capital ratios to be considered well capitalized inclusive of the CCB are 7.0%, 8.5%, and 10.5% for the common equity tier 1 (“CET1”) ratio, tier 1 capital ratio, and total risk-based capital ratio, respectively. The CCB does not apply to the tier 1 leverage ratio, which has a well-capitalized minimum level of 5.0%. All regulatory capital ratios as of March 31, 2024 are estimates pending completion and filing of Columbia’s and Umpqua Bank’s regulatory reports. Capital Ratios Continue to Trend Up Post Merger Closing 8.9% 9.2% 9.5% 9.6% 9.8% 10.9% 11.3% 11.6% 11.9% 12.0% COLB: CET1 Ratio COLB: Total RBC Ratio 3/31/2023 6/30/2023 9/30/2023 12/31/2023 03/31/2024 —% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 12% Long-Term Target 9% Long-Term Target 9% Long-Term Target 6.5% Long-Term Target

Net Interest Income and Net Interest Margin (1) Chart Abbreviations: “PAA” = purchase accounting accretion and amortization; “LHFI” = loans held for investment. $ in m ill io ns Net Interest Income and Net Interest Margin $375 $484 $481 $454 $423 4.08% 3.93% 3.91% 3.78% 3.52% Net Interest Income Net Interest Margin Q1 2023 Q2 2023 Q3 2023 Q4 2023 Q1 2024 $— $100 $200 $300 $400 $500 3.00% 3.50% 4.00% 4.50% 5.00% Net Interest Margin: Q4 2023 vs Q1 2024 3.78% 0.04% (0.03)% (0.05)% (0.25)% 0.03% 3.52% Q4 2023 Reported LHFI-ex PAA¹ LHFI-PAA¹ Invest- ments Deposits Term Debt Q1 2024 Reported 20 ■ The cost of interest-bearing deposits increased 34 basis points on a linked-quarter basis to 2.88% in Q1 2024, which compares to 2.90% for the month of March and 2.89% at March 31, 2024. A comprehensive review related to the evaluation and approval of deposit pricing resulted in enhanced pricing visibility that contributed to stability in interest-bearing core deposit rates in the latter half of the first quarter. ■ The cost of interest-bearing liabilities increased 23 basis points on a linked-quarter basis to 3.25% in Q4 2023, which compares to 3.24% for both the month of March and at March 31, 2024. ■ The net interest margin decreased 26 basis points on a linked quarter basis to 3.52%, which compares to 3.55% for the month of March. Pricing reductions on wholesale funding and stabilizing interest-bearing deposit costs contributed to a slight increase in net interest margin in the latter part of the first quarter. While the net interest margin’s performance in March is encouraging, it does not indicate a cycle floor was reached in the earlier part of the quarter.

Loan Maturities at March 31, 2024 <=6 7 to 12 13 to 24 25 to 36 37 to 60 61+ % of ($ in millions) Months(1) Months Months Months Months Months Total Total(2) Fixed $1,852 $252 $642 $904 $2,311 $9,304 $15,265 40 % Floating 1,785 1,121 1,384 958 1,446 4,827 11,521 30 % Adjustable 68 78 237 260 655 10,055 11,353 30 % Total $3,705 $1,451 $2,263 $2,122 $4,412 $24,186 $38,139 100 % Interest Rate Sensitivity Floors: Floating and Adjustable Rate Loans at March 31, 2024 ($ in millions) No Floor(3) At Floor(3) Above Floor(3) Total Floating $7,080 $36 $4,405 $11,521 Adjustable 1,718 52 9,583 11,353 Total $8,798 $88 $13,988 $22,874 % of Total 39% 1% 61% 100% 21 Note: Tables may not foot due to rounding. (1) Fixed rate loans that mature in six months or less include commercial tranche loans that reprice in a manner similar to floating rate loans. (2) Floating rate loans are indexed to prime (8% of the total loan portfolio) and 1-month underlying interest rates (23% of the total loan portfolio). When adjustable rate loans reprice, they are indexed to interest rates that span 1-month tenors to 10-year tenors as well as the prime rate; the most prevalent underlying index rates are 6-month tenors (16% of the total loan portfolio) and 5-year tenors (6% of the total loan portfolio). (3) Loans were grouped into three buckets: (1) No Floor: no contractual floor on the loan; (2) At Floor: current rate = floor; (3) Above Floor: current rate exceeds floor. The amount above the floor was based on the current margin plus the current index assuming the loan repriced on March 31, 2024. The adjustable loans may not reprice until well into the future, depending on the timing and size of interest rate changes. (4) Deposit and funding repricing beta data present combined company results as if historical Columbia and historical UHC were one company for all periods through December 31, 2022; subsequent time periods present data on a legal basis given the merger. The beta presentation is calculated in this manner for comparison purposes. (5) For the scenarios shown, the interest rate simulations assume a parallel and sustained shift in market interest rates ratably over a twelve-month period (ramp) or immediately (shock). The simulation repricing betas applied to interest-bearing deposits in the rising rate and declining rate scenarios are 56% and 55%, respectively, for March 31, 2024. Additional data related to interest rate simulations are available in Columbia’s Form 10-K for the fiscal year ended December 31, 2023. Deposit and Funding Repricing Betas During the Current Rising-Rate Cycle(4) Effective Fed Funds Rate (Daily Avg.) Cost of Combined Company(4) Three Months Ended Interest- Bearing Deposits Total Deposits Total Funding March 31, 2024 5.33% 2.88% 1.92% 2.27% December 31, 2023 5.33% 2.54% 1.63% 2.05% December 31, 2022 3.65% 0.62% 0.35% 0.51% December 31, 2021 0.08% 0.10% 0.05% 0.09% Variance: Peak (Peak Value less Q4 2021) +5.25% +2.78% +1.87% +2.18% Repricing Betas: Cycle-to-Date 53% 36% 42% Interest Rate Simulation Impact on Net Interest Income at March 31, 2024(5) Ramp Shock Year 1 Year 2 Year 1 Year 2 Up 200 basis points (0.3)% (1.5)% 0.5% 0.1% Up 100 basis points (0.1)% (0.7)% 0.3% 0.1% Down 100 basis points 0.0% 0.4% (0.5)% (0.5)% Down 200 basis points 0.1% 0.3% (0.7)% (1.4)% Down 300 basis points 0.3% 0.1% (0.9)% (2.7)%

Non-Interest Income Note: Tables may not foot due to rounding. Q1 2023 results include only one month of the combined company’s operations. (1) Other commercial product revenue includes swaps, syndication, and international banking revenue, which are captured in “other income” on the income statement. Other income statement line items, like card-based fees, include other sources of commercial product revenue. For the Quarter Ended ($ in millions) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 Service charges on deposits $16.1 $17.3 $17.4 $16.5 $14.3 Card-based fees 13.2 14.6 15.7 13.4 11.6 Financial services and trust revenue 4.5 3.0 4.7 4.5 1.3 Residential mortgage banking revenue, net 4.6 4.2 7.1 (2.3) 7.8 (Loss) gain on equity securities, net (1.6) 2.6 (2.1) (0.7) 2.4 Gain on loan and lease sales, net 0.2 1.2 1.9 0.4 0.9 BOLI income 4.6 4.3 4.4 4.1 2.8 Other income Other commercial product revenue(1) $2.3 $3.9 $3.0 $3.0 $1.4 Commercial servicing revenue 0.6 (0.2) 0.5 0.4 0.9 Loan-related fees 3.7 3.2 3.6 3.3 3.4 Change in fair value of certain loans held for investment (2.4) 19.4 (19.2) (7.0) 9.5 Misc. income 3.3 (0.1) 1.3 2.8 1.9 Swap derivative gain (loss) 1.2 (8.0) 5.7 1.3 (3.5) 22 Q1 2024 Highlights (compared to Q4 2023) ■ Financial services and trust revenue increased following a temporary decline in brokerage income during the fourth quarter due to the transition of Columbia Wealth Advisors to a new broker platform. ■ Higher interest rates in the first quarter compared to the fourth quarter drove fair value changes in certain loans held for investment and the swap derivative that collectively reduced non-interest income by $12 million compared to the fourth quarter. These items are captured in other income.

Non-Interest Expense 23 $ in m ill io ns Non-Interest Expense ("NIE") $342.8 $328.6 $304.1 $337.2 $287.5 $225.6 $296.8 $281.2 $294.3 $276.9 GAAP Non-Interest Expense Operating Non-Interest Expense¹ Q1 2023 Q2 2023 Q3 2023 Q4 2023 Q1 2024 ■ Non-interest expense in Q1 2024 declined $50 million from the prior quarter level. The decrease was driven in part by a decline in expense related to an FDIC special assessment to $5 million from $33 million in Q4 2023. ■ Operating non-interest expense(1) declined $17 million from the prior quarter due to lower discretionary spending and other expense items compared to elevated expense items in Q4 2023. ■ Conducted an enterprise-wide evaluation of our operations during Q1 2024. The full-scale review resulted in consolidated positions, simplified reporting and organizational structures, and an improved profitability outlook. These changes are expected to be carried out during Q2 2024 and Q3 2024 to achieve the Q4 2024 core expense run rate outlined earlier in this presentation. $ in m ill io ns Non-Interest Expense: Q4 2023 vs Q1 2024 $337.2 $(3.0) $(2.0) $(3.6) $(2.1) $(1.1) $(5.6) $(32.3) $287.5 Q4 2023 NIE Comp. Repairs & Maint. Marketing Legal, Title & Consult. CDI Amort. Misc. Other Non- operating¹ Q1 2024 NIE (1) Non-GAAP financial measure. A reconciliation to the comparable GAAP measurement is provided at the end of this slide presentation. Non-operating expense items include exit and disposal costs, merger-related expense, and an FDIC special assessment. These items are detailed in the “Non-GAAP Reconciliation” section of the Appendix. Non-interest expense adjustments were revised subsequent to the Company's reporting of its earnings results for the three months ended December 31, 2023. The revision includes the FDIC special assessment in non-interest expense adjustments, which removes the special assessment from the Company's calculation of operating non-interest expense. The Company views the special assessment as an infrequent expense that is outside the control of the Company.

APPENDIX

Summary Income Statements Note: Tables may not foot due to rounding. Q1 2023 results include only one month of the combined company’s operations and a related initial provision of $88 million. (1) Non-GAAP financial measure. A reconciliation to the comparable GAAP measurement is provided at the end of this slide presentation. For the Quarter Ended ($ in millions, except per-share data) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 Net interest income before provision $423.4 $453.6 $480.9 $484.0 $374.7 Provision for credit losses 17.1 54.9 36.7 16.0 105.5 Net interest income after provision 406.2 398.7 444.1 468.0 269.2 Non-interest income 50.4 65.5 44.0 39.7 54.7 Non-interest expense 287.5 337.2 304.1 328.6 342.8 Income (loss) before provision (benefit) for income taxes 169.1 127.1 184.0 179.1 (18.9) Provision (benefit) for income taxes 45.0 33.5 48.1 45.7 (4.9) Net income (loss) $124.1 $93.5 $135.8 $133.4 ($14.0) Earnings (loss) per share, diluted $0.59 $0.45 $0.65 $0.64 ($0.09) Non-interest expense, excluding merger-related expense(1) 283.0 330.0 285.2 298.9 226.9 Pre-provision net revenue(1) $186.2 $182.0 $220.7 $195.1 $86.6 Operating pre-provision net revenue(1) $200.7 $212.1 $258.7 $243.1 $195.7 Operating net income(1) $134.9 $116.1 $164.3 $169.4 $71.5 Operating earnings per share, diluted(1) $0.65 $0.56 $0.79 $0.81 $0.46 25 Q1 2024 Highlights (compared to Q4 2023) ■ Net interest income decreased by $30 million due to higher deposit costs and lower income earned on investment securities given slower prepayment speeds. ■ Non-interest income decreased by $15 million due to the quarterly fluctuation in cumulative non-merger fair value accounting and hedges. ■ Non-interest expense decreased by $50 million due to lower discretionary spend and the fourth quarter’s larger FDIC special assessment. ■ Provision expense relates to a number of factors discussed on the “Robust ACL Coverage” slide.

Summary Period-End Balance Sheets Note: Tables may not foot due to rounding. Q1 2023 results were impacted by the closing of the merger on February 28, 2023 and the addition of historical Columbia balances at fair value. (1) Non-GAAP financial measure. A reconciliation to the comparable GAAP measurement is provided in the appendix of this slide presentation. ($ in millions, except per-share data) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 ASSETS: Total assets $52,224.0 $52,173.6 $51,993.8 $53,592.1 $53,994.2 Interest bearing cash and temporary investments 1,760.9 1,664.0 1,911.2 2,868.6 3,079.3 Investment securities available for sale, fair value 8,616.5 8,829.9 8,504.0 8,998.4 9,249.6 Loans and leases, gross 37,642.4 37,442.0 37,170.6 37,049.3 37,091.3 Allowance for credit losses on loans and leases (414.3) (440.9) (416.6) (404.6) (417.5) Goodwill and other intangibles, net 1,600.8 1,632.9 1,666.1 1,696.0 1,732.5 LIABILITIES AND EQUITY: Deposits 41,706.2 41,607.0 41,624.4 40,834.9 41,586.3 Securities sold under agreements to repurchase 213.6 252.1 258.4 294.9 271.0 Borrowings 3,900.0 3,950.0 3,985.0 6,250.0 5,950.0 Total shareholders' equity 4,957.2 4,995.0 4,632.2 4,828.2 4,884.7 RATIOS AND PER-SHARE METRICS: Loan to deposit ratio 90.3% 90.0% 89.3% 90.7% 89.2% Book value per common share $23.68 $23.95 $22.21 $23.16 $23.44 Tangible book value per common share(1) $16.03 $16.12 $14.22 $15.02 $15.12 Common equity to assets ratio 9.5% 9.6% 8.9% 9.0% 9.0% Tangible common equity to tangible assets ratio(1) 6.6% 6.7% 5.9% 6.0% 6.0% 26 Q1 2024 Highlights (compared to Q4 2023) ■ Commercial line utilization and construction project activity were the primary contributors to the 2% annualized loan growth in Q1 2024. Origination volume was centered in our commercial and owner-occupied commercial real estate portfolios. ■ Deposit balances were up slightly from Q4 2023 due to net growth in customer balances. ■ Book value and tangible book value decreased 1.1% and 0.6%, respectively, as an increase in accumulated other comprehensive loss due to higher interest rates more than offset organic capital generation. Book value and tangible book value increased 1.0% and 6.0%, respectively from March 31, 2023 despite an increase in accumulated other comprehensive loss over the same period.

Liquidity Overview Total Available Liquidity at March 31, 2024 ($ in millions) Total off-balance sheet liquidity (available lines of credit): $13,015 Cash and equivalents, less reserve requirement 1,898 Excess bond collateral 3,719 Total available liquidity $18,632 TOTAL AVAILABLE LIQUIDITY AS A PERCENTAGE OF: Assets of $52.2 billion at March 31, 2024 36 % Deposits of $41.7 billion at March 31, 2024 45 % Uninsured deposits of $13.5 billion at March 31, 2024 138 % Total Off-Balance Sheet Liquidity Available at March 31, 2024 ($ in millions) Gross Availability Utilization Net Availability FHLB lines $11,965 $2,370 $9,596 Federal Reserve Discount Window 2,820 — 2,820 Federal Reserve Term Funding Program(1) 1,550 1,550 — Uncommitted lines of credit 600 — 600 Total off-balance sheet liquidity $16,935 $3,920 $13,015 27 ■ Net growth in total customer deposits enabled a slight reduction in brokered deposits and term debt in Q1 2024. ■ Contraction in small business deposits during Q1 2024 was partially offset by a targeted campaign launched in early February 2024 to generate new business. The campaign runs through April 2024 and includes bundled solutions for customers without promotional pricing. Select Balance Sheet Items Three Months Ended Sequential Quarter Change ($ in millions) Q1 2024 Q4 2023 Q1 2023 Q1 2024 Commercial deposits $11,207 $11,142 $11,355 $65 Small business deposits 8,103 8,400 8,619 (297) Consumer deposits 16,241 15,842 17,243 399 Total customer deposits 35,551 35,384 37,217 167 Public deposits - non-interest bearing 645 619 638 26 Public deposits - interest bearing 2,285 2,285 1,918 — Total public deposits 2,930 2,904 2,556 26 Administrative deposits 135 169 182 (34) Brokered deposits 3,090 3,150 1,631 (60) Total deposits $41,706 $41,607 $41,586 $99 Term debt $3,900 $3,950 $5,950 ($50) Cash & cash equivalents $2,201 $2,163 $3,635 $39 Available-for-sale securities $8,617 $8,830 $9,250 ($213) Loans and leases $37,642 $37,442 $37,091 $200 Note: Tables may not foot due to rounding. (1) The Federal Reserve’s Bank Term Funding Program was discontinued in March 2024. We present associated balances as they were outstanding on Columbia’s balance sheet as of March 31, 2024.

Purchase Accounting Details (1) Table does not capture all assets and liabilities with an associated fair value discount or premium. Assets and liabilities not presented have a significantly smaller impact on income through the accretion or amortization of their discount or premium. (2) The cumulative fair value discount on historical Columbia loans was established as of February 28, 2023, and the allocation between the credit-related discount and the rate-related discount was established at that time. Our disclosure of credit-related and rate-related discount accretion is an estimate based on the relative allocation of these two items to the discount at the closing of the merger. Adjustment at Closing Remaining Balances at Select Purchase Accounting Items(1) February 28, 2023 December 31, 2023 March 31, 2024 Notes ITEMS TO ACCRETE THROUGH INTEREST INCOME: Available for sale securities - rate discount $(1,011) million $(565) million $(543) million While an adjustment to historical Columbia securities’ book value was $1.0 billion at the closing of the merger, the purchase discount that will accrete into interest income over time was $0.6 billion when previously existing purchase premiums and the discount associated with bonds sold as part of the Q1 2023 portfolio restructuring were eliminated. Loans - rate discount(2) $(618) million $(468) million $(444) million Total rate discount on loans and securities $(1,629) million $(1,033) million $(987) million Loans - credit mark(2) $(130) million $(80) million $(74) million Total discount on loans and securities $(1,759) million $(1,113) million $(1,061) million Fair value discounts are accreted into interest income using the effective interest method, which amortizes the discount over the life of the loan or security. ITEM TO AMORTIZE THROUGH NON-INTEREST EXPENSE: Core deposit intangible $710 million $603 million $571 million CDI amortizes through non-interest expense over 10 years using the sum-of-the-years-digits method. 28

Non-GAAP Reconciliation: Tangible Capital ($ in thousands, except per-share data) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 Total shareholders' equity a $4,957,245 $4,995,034 $4,632,162 $4,828,188 $4,884,723 Less: Goodwill 1,029,234 1,029,234 1,029,234 1,029,234 1,030,142 Less: Other intangible assets, net 571,588 603,679 636,883 666,762 702,315 Tangible common shareholders’ equity b 3,356,423 3,362,121 2,966,045 3,132,192 3,152,266 Total assets c $52,224,006 $52,173,596 $51,993,815 $53,592,096 $53,994,226 Less: Goodwill 1,029,234 1,029,234 1,029,234 1,029,234 1,030,142 Less: Other intangible assets, net 571,588 603,679 636,883 666,762 702,315 Tangible assets d $50,623,184 $50,540,683 $50,327,698 $51,896,100 $52,261,769 Common shares outstanding at period end e 209,370 208,585 208,575 208,514 208,429 Total shareholders' equity to total assets ratio a / c 9.49 % 9.57 % 8.91 % 9.01 % 9.05 % Tangible common equity to tangible assets ratio b / d 6.63 % 6.65 % 5.89 % 6.04 % 6.03 % Book value per common share a / e $23.68 $23.95 $22.21 $23.16 $23.44 Tangible book value per common share b / e $16.03 $16.12 $14.22 $15.02 $15.12 29

Non-GAAP Reconciliation: Adjustments and Average Balances For the Quarter Ended ($ in thousands) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 Non-Interest Income Adjustments Gain on sale of debt securities, net $ 12 $ 9 $ 4 $ — $ — (Loss) gain on equity securities, net (1,565) 2,636 (2,055) (697) 2,416 Gain (loss) on swap derivatives 1,197 (8,042) 5,700 1,288 (3,543) Change in fair value of certain loans held for investment (2,372) 19,354 (19,247) (6,965) 9,488 Change in fair value of MSR due to valuation inputs or assumptions 3,116 (6,251) 5,308 (2,242) (2,937) MSR hedge (loss) gain (4,271) 5,026 (4,733) (7,636) 2,650 Total non-interest income adjustments a $ (3,883) $ 12,732 $ (15,023) $ (16,252) $ 8,074 Non-Interest Expense Adjustments Merger-related expense $ 4,478 $ 7,174 $ 18,938 $ 29,649 $ 115,898 Exit and disposal costs 1,272 2,791 4,017 2,119 1,291 FDIC special assessment(1) 4,848 32,923 — — — Total non-interest expense adjustments b $ 10,598 $ 42,888 $ 22,955 $ 31,768 $ 117,189 Average Assets n $ 52,083,973 $ 51,832,356 $ 53,011,361 $ 53,540,574 $ 39,425,975 Less: Average goodwill and other intangible assets, net 1,619,134 1,652,282 1,684,093 1,718,705 623,042 Average tangible assets o $ 50,464,839 $ 50,180,074 $ 51,327,268 $ 51,821,869 $ 38,802,933 Average common shareholders’ equity p $ 4,985,875 $ 4,695,736 $ 4,866,975 $ 4,935,239 $ 3,349,761 Less: Average goodwill and other intangible assets, net 1,619,134 1,652,282 1,684,093 1,718,705 623,042 Average tangible common equity q $ 3,366,741 $ 3,043,454 $ 3,182,882 $ 3,216,534 $ 2,726,719 Weighted average basic shares outstanding r 208,260 208,083 208,070 207,977 156,383 Weighted average diluted shares outstanding s 208,956 208,739 208,645 208,545 156,383 30 (1) Non-interest expense adjustments were revised subsequent to the Company's reporting of its earnings results for the three months ended December 31, 2023. The revision includes the FDIC special assessment in non-interest expense adjustments, which removes the special assessment from the Company's calculation of operating non-interest expense. The Company views the special assessment as an infrequent expense that is outside the control of the Company.

Non-GAAP Reconciliation: Income Statements For the Quarter Ended ($ in thousands) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 Net interest income c $ 423,362 $ 453,623 $ 480,875 $ 483,975 $ 374,698 Non-interest income (GAAP) d $ 50,357 $ 65,533 $ 43,981 $ 39,678 $ 54,735 Less: Non-interest income adjustments a 3,883 (12,732) 15,023 16,252 (8,074) Operating non-interest income (non-GAAP) e $ 54,240 $ 52,801 $ 59,004 $ 55,930 $ 46,661 Revenue (GAAP) f=c+d $ 473,719 $ 519,156 $ 524,856 $ 523,653 $ 429,433 Operating revenue (non-GAAP) g=c+e $ 477,602 $ 506,424 $ 539,879 $ 539,905 $ 421,359 Non-interest expense (GAAP) h $ 287,516 $ 337,176 $ 304,147 $ 328,559 $ 342,818 Less: Non-interest expense adjustments b (10,598) (42,888) (22,955) (31,768) (117,189) Operating non-interest expense (non-GAAP) i $ 276,918 $ 294,288 $ 281,192 $ 296,791 $ 225,629 Net income (loss) (GAAP) j $ 124,080 $ 93,531 $ 135,845 $ 133,377 $ (14,038) Provision (benefit) for income taxes 44,987 33,540 48,127 45,703 (4,886) Income (loss) before provision for income taxes 169,067 127,071 183,972 179,080 (18,924) Provision for credit losses 17,136 54,909 36,737 16,014 105,539 Pre-provision net revenue (PPNR) (non-GAAP) k 186,203 181,980 220,709 195,094 86,615 Less: Non-interest income adjustments a 3,883 (12,732) 15,023 16,252 (8,074) Add: Non-interest expense adjustments b 10,598 42,888 22,955 31,768 117,189 Operating PPNR (non-GAAP) l $ 200,684 $ 212,136 $ 258,687 $ 243,114 $ 195,730 Net income (GAAP) j $ 124,080 $ 93,531 $ 135,845 $ 133,377 $ (14,038) Less: Non-interest income adjustments a 3,883 (12,732) 15,023 16,252 (8,074) Add: Non-interest expense adjustments b 10,598 42,888 22,955 31,768 117,189 Tax effect of adjustments (3,620) (7,539) (9,482) (11,981) (23,565) Operating net income (non-GAAP) m $ 134,941 $ 116,148 $ 164,341 $ 169,416 $ 71,512 31

Non-GAAP Reconciliation: Earnings Per-Share and Performance Metrics For the Quarter Ended ($ in thousands, except per-share data) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 Select Per-Share & Performance Metrics Earnings per share - basic j/r $ 0.60 $ 0.45 $ 0.65 $ 0.64 $ (0.09) Earnings per share - diluted j/s $ 0.59 $ 0.45 $ 0.65 $ 0.64 $ (0.09) Efficiency ratio(1) h/f 60.57 % 64.81 % 57.82 % 62.60 % 79.71 % Non-interest expense to average assets h/n 2.22 % 2.58 % 2.28 % 2.46 % 3.53 % Return on average assets j/n 0.96 % 0.72 % 1.02 % 1.00 % (0.14) % Return on average tangible assets j/o 0.99 % 0.74 % 1.05 % 1.03 % (0.15) % PPNR return on average assets k/n 1.44 % 1.39 % 1.65 % 1.46 % 0.89 % Return on average common equity j/p 10.01 % 7.90 % 11.07 % 10.84 % (1.70) % Return on average tangible common equity j/q 14.82 % 12.19 % 16.93 % 16.63 % (2.09) % Operating Per-Share & Performance Metrics Operating earnings per share - basic(2) m/r $ 0.65 $ 0.56 $ 0.79 $ 0.81 $ 0.46 Operating earnings per share - diluted(2) m/s $ 0.65 $ 0.56 $ 0.79 $ 0.81 $ 0.46 Operating efficiency ratio, as adjusted(1), (2), (3) u/y 56.97 % 57.31 % 51.26 % 54.04 % 52.84 % Operating non-interest expense to average assets i/n 2.14 % 2.25 % 2.10 % 2.22 % 2.32 % Operating return on average assets(2) m/n 1.04 % 0.89 % 1.23 % 1.27 % 0.74 % Operating return on average tangible assets(2) m/o 1.08 % 0.92 % 1.27 % 1.31 % 0.75 % Operating PPNR return on average assets(2) l/n 1.55 % 1.62 % 1.94 % 1.82 % 2.01 % Operating return on average common equity(2) m/p 10.89 % 9.81 % 13.40 % 13.77 % 8.66 % Operating return on average tangible common equity(2) m/q 16.12 % 15.14 % 20.48 % 21.13 % 10.64 % (1) Tax-exempt income has been adjusted to a taxable equivalent basis using a 21% tax rate and added to stated revenue for this calculation. (2) Non-interest expense adjustments were revised subsequent to the Company's reporting of its earnings results for the three months ended December 31, 2023. The revision includes the FDIC special assessment in non-interest expense adjustments, which removes the special assessment from the Company's calculation of operating non-interest expense. The Company views the special assessment as an infrequent expense that is outside the control of the Company. (3) The operating efficiency ratio has been adjusted to remove B&O taxes and for a tax-equivalent adjustment to BOLI income. The Company views the adjusted operating efficiency ratio as a better representation of its efficiency ratio when compared to other banks as it normalizes for the tax treatment of the adjusted items. The adjustment re-aligns Columbia's calculation of its operating efficiency ratio with its pre-merger calculation. 32

Non-GAAP Reconciliation: Operating Efficiency Ratio, as Adjusted 33 For the Quarter Ended ($ in thousands) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 Non-interest expense (GAAP) h $287,516 $337,176 $304,147 $328,559 $342,818 Less: Non-interest expense adjustments b (10,598) (42,888) (22,955) (31,768) (117,189) Operating non-interest expense (non-GAAP) i 276,918 294,288 281,192 296,791 225,629 Less: B&O taxes t (3,223) (2,727) (3,275) (3,647) (2,129) Operating non-interest expense, excluding B&O taxes (non-GAAP) u $273,695 $291,561 $277,917 $293,144 $223,500 Non-interest income (tax equivalent)(1) v $424,344 $454,730 $482,031 $485,168 $375,369 Non-interest income (GAAP) d 50,357 65,533 43,981 39,678 54,735 Add: BOLI tax equivalent adjustment(1) w 1,809 1,182 1,178 1,360 957 Total Revenue, excluding BOLI tax equivalent adjustments (tax equivalent) x 476,510 521,445 527,190 526,206 431,061 Less: non-interest income adjustments a 3,883 (12,732) 15,023 16,252 (8,074) Total Adjusted operating revenue, excluding BOLI tax equivalent adjustments (tax equivalent) (non-GAAP) y $480,393 $508,713 $542,213 $542,458 $422,987 Efficiency ratio(1) h/f 60.57 % 64.81 % 57.82 % 62.60 % 79.71 % Operating efficieny ratio, as adjusted (non-GAAP)(1), (2), (3) u/y 56.97 % 57.31 % 51.26 % 54.04 % 52.84 % (1) Tax-exempt income has been adjusted to a taxable equivalent basis using a 21% tax rate and added to stated revenue for this calculation. (2) Non-interest expense adjustments were revised subsequent to the Company's reporting of its earnings results for the three months ended December 31, 2023. The revision includes the FDIC special assessment in non-interest expense adjustments, which removes the special assessment from the Company's calculation of operating non-interest expense. The Company views the special assessment as an infrequent expense that is outside the control of the Company. (3) The operating efficiency ratio has been adjusted to remove B&O taxes and for a tax-equivalent adjustment to BOLI income. The Company views the adjusted operating efficiency ratio as a better representation of its efficiency ratio when compared to other banks as it normalizes for the tax treatment of the adjusted items. The adjustment re-aligns Columbia's calculation of its operating efficiency ratio with its pre-merger calculation.

Non-GAAP Reconciliation: Net Interest Income & Net Interest Margin (1) The cumulative fair value discount on historical Columbia loans was established as of February 28, 2023, and the allocation between the credit-related discount and the rate-related discount was established at that time. Our disclosure of credit-related and rate-related discount accretion is an estimate based on the relative allocation of these two items to the discount at the closing of the merger. (2) Tax-exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate. 34 For the Quarter Ended ($ in thousands) Q1 2024 Q4 2023 Q3 2023 Q2 2023 Q1 2023 Net interest income a $424,344 $454,730 $482,031 $485,168 $375,369 Less: Acquired loan accretion - credit related(1) b 5,119 5,430 6,370 7,100 3,806 Net Interest Income, excluding credit PAA(1) c 419,225 449,300 475,661 478,068 371,563 Less: Acquired rate-related accretion(1) d 57,336 63,757 70,900 67,960 28,239 Adjusted net interest income(1) e $361,889 $385,543 $404,761 $410,108 $343,324 Average interest-earning assets f $48,280,787 $47,838,229 $48,981,105 $49,442,518 $37,055,705 Net interest margin(2) a / f 3.52 % 3.78 % 3.91 % 3.93 % 4.08 % Less: Acquired loan accretion - credit related(1) b / f 0.04 % 0.05 % 0.05 % 0.06 % 0.04 % Net Interest margin, excluding credit PAA(1), (2) c / f 3.48 % 3.73 % 3.86 % 3.87 % 4.04 % Less: Acquired rate-related accretion(1) d / f 0.48 % 0.53 % 0.58 % 0.55 % 0.31 % Adjusted net interest margin(1), (2) e / f 3.00 % 3.20 % 3.28 % 3.32 % 3.73 %


			TABLE INDEX
						Page
			Consolidated Statements of Operations			6
			Consolidated Balance Sheets			7
			Financial Highlights			8
			Loan & Lease Portfolio Balances and Mix			9
			Deposit Portfolio Balances and Mix			10
			Credit Quality - Non-performing Assets			11
			Credit Quality - Allowance for Credit Losses			12
			Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates			13
			Residential Mortgage Banking Activity			14
			GAAP to Non-GAAP Reconciliation			15