EX-99.1 2 colb-20250930ex991earnings.htm PRESS RELEASE ANNOUNCING THIRD QUARTER 2025 FINANCIAL RESULTS
EXHIBIT 99.1

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COLUMBIA BANKING SYSTEM, INC. REPORTS THIRD QUARTER 2025 RESULTS
$96 million |  | $204 million |  | $0.40 |  | $0.85
Net income |  | Operating net income 1 |  | Earnings per common share - diluted |  | Operating earnings per common share - diluted 1

0

CEO Commentary
“Our third quarter performance reflects meaningful progress and growing momentum,” said Clint Stein, President and CEO. “We closed our strategic acquisition of Pacific Premier, which completes our Western footprint and enhances our ability to generate top-quartile returns. While reported results were impacted by acquisition-related items, core profitability remained strong. Customer deposit growth supported balance sheet optimization, as we organically reduced transactional loans and non-core funding. Underscoring confidence in our strategy and an outlook for continued excess capital generation, our Board of Directors authorized a $700 million share repurchase program. As we integrate new capabilities and deepen both new and existing customer relationships, we remain focused on delivering consistent, repeatable performance while positioning the company for sustainable, relationship-driven growth and capital return to our shareholders."
–Clint Stein, President and CEO of Columbia Banking System, Inc.

3Q25 HIGHLIGHTS (COMPARED TO 2Q25) |
Net Interest Income and NIM | •Net interest income increased by $59 million from the prior quarter, due to one month operating as a combined company and a favorable shift into lower-cost funding sources. |
•Net interest margin was 3.84%, up 9 basis points from the prior quarter, due to an increase in customer deposits and corresponding reduction in higher-cost funding sources. The net interest margin was also impacted by one month operating as a combined company in the current period. |
Non-Interest Income and Expense | •Non-interest income increased by $12 million. Excluding the impact of fair value and hedges,1 non-interest income increased by $6 million, due to one month operating as a combined company. |
•Non-interest expense increased by $115 million, primarily due to merger and restructuring expense of $87 million and one month operating as a combined company. |
Credit Quality | •Net charge-offs were 0.22% of average loans and leases (annualized), compared to 0.31% in the prior quarter. |
•Provision expense was $70 million and driven by the acquisition of Pacific Premier. |
•Non-performing assets to total assets was 0.29%, compared to 0.35% as of June 30, 2025. |
Capital | •Estimated total risk-based capital ratio of 13.4% and estimated common equity tier 1 risk-based capital ratio of 11.6%. |
•Declared a quarterly cash dividend of $0.36 per common share on August 15, 2025, which was paid September 15, 2025. |
Notable Items | •Our third small business and retail campaign of 2026 is ongoing. Through mid-October, these campaigns have brought approximately $1.1 billion in new deposits to the bank. |
•Our Board of Directors authorized the repurchase of up to $700 million of common stock under a new repurchase plan. |

3Q25 KEY FINANCIAL DATA
PERFORMANCE METRICS | 3Q25 |  | 2Q25 |  | 3Q24
Return on average assets | 0.67% |  | 1.19% |  | 1.12%
Return on average common equity | 6.19% |  | 11.56% |  | 11.36%
Return on average tangible common equity 1 | 8.58% |  | 16.03% |  | 16.34%
Operating return on average assets 1 | 1.42% |  | 1.25% |  | 1.10%
Operating return on average common equity 1 | 13.15% |  | 12.16% |  | 11.15%
Operating return on average tangible common equity 1 | 18.24% |  | 16.85% |  | 16.04%
Net interest margin | 3.84% |  | 3.75% |  | 3.56%
Efficiency ratio | 67.29% |  | 54.29% |  | 54.56%
Operating efficiency ratio, as adjusted 1 | 52.32% |  | 51.79% |  | 53.89%
INCOME STATEMENT ($ in millions, excl. per share data) | 3Q25 |  | 2Q25 |  | 3Q24
Net interest income | $505 |  | $446 |  | $430
Provision for credit losses | $70 |  | $30 |  | $29
Non-interest income | $77 |  | $65 |  | $66
Non-interest expense | $393 |  | $278 |  | $271
Pre-provision net revenue 1 | $189 |  | $233 |  | $225
Operating pre-provision net revenue 1 | $270 |  | $242 |  | $221
Earnings per common share - diluted | $0.40 |  | $0.73 |  | $0.70
Operating earnings per common share - diluted 1 | $0.85 |  | $0.76 |  | $0.69
Dividends paid per share | $0.36 |  | $0.36 |  | $0.36
BALANCE SHEET | 3Q25 |  | 2Q25 |  | 3Q24
Total assets | $67.5 | B |  | $51.9 | B |  | $51.9 | B
Loans and leases | $48.5 | B |  | $37.6 | B |  | $37.5 | B
Deposits | $55.8 | B |  | $41.7 | B |  | $41.5 | B
Book value per common share | $26.04 |  | $25.41 |  | $25.17
Tangible book value per common share 1 | $18.57 |  | $18.47 |  | $17.81

Investor Contact
Jacquelynne "Jacque" Bohlen, SVP/Investor Relations Director, 503-727-4100, jacquebohlen@columbiabank.com
1 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 2
Acquisition and Branding Update
Columbia Banking System, Inc. ("Columbia," the "Company," "we," or "our") closed its acquisition of Pacific Premier Bancorp, Inc. ("Pacific Premier") on August 31, 2025, elevating Columbia's deposit market share to a top-10 position in Southern California. The acquisition completes our Western footprint and strengthens our presence as a leading financial institution in the western United States. Our integration efforts are progressing smoothly, and we remain on track to integrate systems in the first quarter of 2026.
Columbia Bank began serving customers under its unified name and brand effective September 1, 2025. The strategic transition streamlines our identity across all business lines, including Columbia Wealth Advisors, Columbia Trust Company, Columbia Private Bank, and Columbia Private Trust, making it easier for customers to recognize and engage with the full breadth of our services.
Share Repurchase Authorization Announcement
Columbia’s Board of Directors has authorized the repurchase of up to $700 million of common stock under a new repurchase plan. COLB common share repurchases may be executed in the open market or through privately negotiated transactions, including under Rule 10b5-1 plans. The timing and exact amount of common share repurchases will be at the discretion of senior management and subject to various factors, including, without limitation, Columbia’s capital position, financial performance, market conditions, and regulatory considerations. The repurchase program does not obligate Columbia to purchase any particular number of shares. The authorization will expire on November 30, 2026, but may be suspended, terminated or modified by the Board at any time.
“Our excess capital position as of September 30, 2025 supports the return of additional capital to our shareholders through share repurchases,” commented Mr. Stein. “In addition, we expect to produce exceptional profitability, which will result in meaningful capital generation over the coming quarters. Even as we expand our capital return platform, we are continuing to drive organic growth as we optimize the balance sheet, in line with our commitment to enhancing long-term shareholder value.”
Net Interest Income
Net interest income was $505 million for the third quarter of 2025, up $59 million from the prior quarter. The increase largely reflects the impact of one month operating as a combined company in the current period. Lower interest expense due to a favorable shift in Columbia's funding mix also contributed to the increase.
Columbia's net interest margin was 3.84% for the third quarter of 2025, up 9 basis points from the second quarter of 2025. Net interest margin benefited from lower funding costs, due to an increase in customer deposits and corresponding reduction in higher-cost funding sources. The net interest margin was also impacted by one month operating as a combined company in the current period.
The cost of interest-bearing deposits decreased 9 basis points from the prior quarter to 2.43% for the third quarter of 2025, compared to 2.29% for the month of September and 2.20% as of September 30, 2025, reflecting our proactive management of deposit rates ahead of and following the 25-basis point reduction in the federal funds rate in mid-September and a reduction in higher-cost brokered deposits during the month. The cost of interest-bearing deposits in September also benefited from the amortization of a premium related to Pacific Premier's time deposits, which will continue through December 31, 2025 at an equivalent monthly amount. The amortization contributed $4 million to net interest income during September, and favorably impacted deposit rates. Excluding this impact, the cost of interest-bearing deposits was 2.41% for the month of September and 2.32% as of September 30, 2025.
Columbia's cost of interest-bearing liabilities decreased 13 basis points from the prior quarter to 2.65% for the third quarter of 2025, compared to 2.47% for the month of September and 2.39% as of September 30, 2025. Excluding the previously discussed premium amortization, the cost of interest-bearing liabilities was 2.58% for the month of September and 2.50% as of September 30, 2025. We expect the premium to be fully amortized by December 31, 2025. Please refer to the Q3 2025 Earnings Presentation for additional net interest margin change details and interest rate sensitivity information.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 3
Non-interest Income
Non-interest income was $77 million for the third quarter of 2025, up $12 million from the prior quarter. The increase was driven by quarterly changes in fair value adjustments and mortgage servicing rights ("MSR") hedging activity, due to interest rate fluctuations during the quarter, collectively resulting in a net fair value gain of $5 million in the third quarter compared to a net fair value loss of $1 million in the second quarter, as detailed in our non-GAAP disclosures. Excluding these items, non-interest income was up $6 million 2 between periods, due to one month operating as a combined company.
Non-interest Expense
Non-interest expense was $393 million for the third quarter of 2025, up $115 million from the prior quarter, due to higher merger expense and one month operating as a combined company. Excluding merger and restructuring expense and a $1 million reversal of prior FDIC assessment expense, non-interest expense was $307 million 2, up $37 million from the prior quarter, as Pacific Premier contributed $34 million to the quarter's run rate. Other miscellaneous expenses also trended higher as we reinvest prior cost savings into our franchise. Please refer to the Q3 2025 Earnings Presentation for additional expense details.
Balance Sheet
Total consolidated assets were $67.5 billion as of September 30, 2025, up from $51.9 billion as of June 30, 2025, due to the addition of Pacific Premier, partially offset by balance sheet optimization activity in the quarter. Cash and cash equivalents were $2.3 billion as of September 30, 2025, up from $1.9 billion as of June 30, 2025. Including secured off-balance sheet lines of credit, total available liquidity was $26.7 billion as of September 30, 2025, representing 40% of total assets, 48% of total deposits, and 130% of uninsured deposits. Available-for-sale securities, which are held on balance sheet at fair value, were $11.0 billion as of September 30, 2025, an increase of $2.4 billion relative to June 30, 2025, as securities acquired from Pacific Premier and an increase in the fair value of the portfolio was partially offset by net sales during the quarter. Please refer to the Q3 2025 Earnings Presentation for additional details related to our securities portfolio and liquidity position.
Gross loans and leases were $48.5 billion as of September 30, 2025, an increase of $10.8 billion relative to June 30, 2025, due to the addition of Pacific Premier, partially offset by run-off in commercial development and transactional loans, as well as the transfer of $282 million in residential real estate loans to the held-for-sale portfolio. Excluding these factors, the loan portfolio was essentially unchanged between June 30, 2025 and September 30, 2025. "Our teams continue to focus on new client acquisition and relationship-building, contributing to the 19% increase in new loan originations for the current quarter compared to the prior quarter," commented Chris Merrywell, President of Columbia Bank. "We continue to prioritize balance sheet optimization and profitability, as we reduce our exposure to non-relationship loans." Please refer to the Q3 2025 Earnings Presentation for additional details related to our loan portfolio, which include underwriting characteristics, the composition of our commercial portfolios, and disclosure related to transactional loans.
Total deposits were $55.8 billion as of September 30, 2025, an increase of $14.0 billion relative to June 30, 2025, due to the addition of Pacific Premier and organic growth in customer deposits, partially offset by lower brokered deposits. "Customer deposit growth approached $800 million organically during the quarter, reflecting new customer activity and a seasonal lift in balances," stated Mr. Merrywell. "Our focus on relationship banking directly contributed to new deposit generation in the quarter, which reduced our reliance on wholesale funding sources." Brokered deposits and borrowings were $4.8 billion as of September 30, 2025, a decrease of $1.9 billion relative to June 30, 2025. Please refer to the Q3 2025 Earnings Presentation for additional details related to deposit characteristics and flows.
Credit Quality
The allowance for credit losses ("ACL") was $492 million, or 1.01% of loans and leases, as of September 30, 2025, compared to $439 million, or 1.17% as of June 30, 2025. The $53 million increase in the ACL includes the addition of $5 million related to Pacific Premier purchased credit deteriorated ("PCD") loans, which was booked at acquisition closing and did not affect the income statement. The provision for credit losses was $70 million for the third quarter of 2025 and includes an initial provision for acquired non-PCD loans and unfunded commitments and a recalibration of our models to incorporate historical Pacific Premier data into our ACL assumptions, where applicable. Excluding these items, our provision expense was $0 for the third quarter of 2025 2.
2 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 4
Net charge-offs were 0.22% of average loans and leases (annualized) for the third quarter of 2025, compared to 0.31% for the second quarter of 2025. Net charge-offs in the FinPac portfolio were $16 million in the third quarter, compared to $14 million in the second quarter. Net charge-offs excluding the FinPac portfolio were $6 million in the third quarter, compared to $15 million in the second quarter. Non-performing assets were $199 million, or 0.29% of total assets, as of September 30, 2025, compared to $180 million, or 0.35% of total assets, as of June 30, 2025. Please refer to the Q3 2025 Earnings Presentation for additional details related to the allowance for credit losses and other credit trends.
Capital
Columbia's book value per common share was $26.04 as of September 30, 2025, compared to $25.41 as of June 30, 2025. The increase reflects common shares issued and exchanged as a result of the acquisition, net capital generation from operations, and a favorable change in accumulated other comprehensive (loss) income ("AOCI") to $(268) million as of September 30, 2025, compared to $(333) million as of the prior quarter-end. The change in AOCI is due primarily to a decrease in the tax-effected net unrealized loss on available-for-sale securities to $240 million as of September 30, 2025, compared to $311 million as of June 30, 2025. Tangible book value per common share 3 was $18.57 as of September 30, 2025, compared to $18.47 as of June 30, 2025. The items discussed above offset 1.7% tangible book value dilution as a result of the Pacific Premier acquisition, resulting in net tangible book value expansion during the quarter.
Columbia's estimated total risk-based capital ratio was 13.4% and its estimated common equity tier 1 risk-based capital ratio was 11.6% as of September 30, 2025, compared to 13.0% and 10.8%, respectively, as of June 30, 2025. Columbia remains above current “well-capitalized” regulatory minimums. The regulatory capital ratios as of September 30, 2025 are estimates, pending completion and filing of Columbia's regulatory reports.
Earnings Presentation and Conference Call Information
Columbia's Q3 2025 Earnings Presentation provides additional disclosure. A copy will be available on our investor relations page: www.columbiabankingsystem.com.
Columbia will host its third quarter 2025 earnings conference call on October 30, 2025 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 third quarter 2025 financial results. Participants may join the audiocast or register for the call using the link below to receive dial-in details and their own unique PINs. It is recommended you join 10 minutes prior to the start time.
Join the audiocast: https://edge.media-server.com/mmc/p/i6z93t5w/
Register for the call: https://register-conf.media-server.com/register/BIde1295f868b04a969240d44867cade1a
Access the replay through Columbia's investor relations page: https://www.columbiabankingsystem.com/news-market-data/event-calendar/default.aspx
About Columbia Banking System, Inc.
Columbia Banking System, Inc. (Nasdaq: COLB) is headquartered in Tacoma, Washington and is the parent company of Columbia Bank, an award-winning western U.S. regional bank. Columbia 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. Columbia 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. Columbia Bank customers also have access to comprehensive investment and wealth management expertise as well as healthcare and private banking through Columbia Wealth Management. Learn more at www.columbiabankingsystem.com.
3 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 5
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 or renewed 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; risks related to our acquisition of Pacific Premier (the "Transaction"), including, among others, (i) diversion of management’s attention from ongoing business operations and opportunities, (ii) cost savings and any revenue or expense synergies from the Transaction may not be fully realized or may take longer than anticipated to be realized, (iii) deposit attrition, customer or employee loss, and/or revenue loss as a result of the Transaction, and (iv) shareholder litigation that could negatively impact our business and operations; the impact of proposed or imposed tariffs by the U.S. government and retaliatory tariffs proposed or imposed by U.S. trading partners that could have an adverse impact on customers; 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; potential adverse reactions or changes to business or employee relationships; 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 Third Quarter 2025 Results
October 30, 2025
Page 6

| TABLE INDEX
|  | Page
| Consolidated Statements of Income | 7
| Consolidated Balance Sheets | 9
| Financial Highlights | 10
| Loan & Lease Portfolio Balances and Mix | 12
| Deposit Portfolio Balances and Mix | 13
| Credit Quality - Non-performing Assets | 14
| Credit Quality - Allowance for Credit Losses | 15
| Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates | 17
| Residential Mortgage Banking Activity | 19
| Purchase Price Allocation | 21
| GAAP to Non-GAAP Reconciliation | 22

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 7

Columbia Banking System, Inc.
Consolidated Statements of Income
(Unaudited)
| Quarter Ended |  | % Change
($ in millions, shares in thousands) | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Interest income: |  |  |  |  |  |  |  |  |  |  |  |  |
Loans and leases | $ | 619 |  |  | $ | 564 |  |  | $ | 553 |  |  | $ | 572 |  |  | $ | 589 |  |  | 10 | % |  | 5 | %
Interest and dividends on investments: |  |  |  |  |  |  |  |  |  |  |  |  |
Taxable | 89 |  |  | 80 |  |  | 69 |  |  | 75 |  |  | 76 |  |  | 11 | % |  | 17 | %
Exempt from federal income tax | 8 |  |  | 7 |  |  | 7 |  |  | 7 |  |  | 7 |  |  | 14 | % |  | 14 | %
Dividends | 4 |  |  | 3 |  |  | 3 |  |  | 3 |  |  | 2 |  |  | 33 | % |  | 100 | %
Temporary investments and interest bearing deposits | 20 |  |  | 16 |  |  | 16 |  |  | 19 |  |  | 25 |  |  | 25 | % |  | (20) | %
Total interest income | 740 |  |  | 670 |  |  | 648 |  |  | 676 |  |  | 699 |  |  | 10 | % |  | 6 | %
Interest expense: |  |  |  |  |  |  |  |  |  |  |  |  |
Deposits | 195 |  |  | 180 |  |  | 177 |  |  | 189 |  |  | 208 |  |  | 8 | % |  | (6) | %
Securities sold under agreement to repurchase and federal funds purchased | 1 |  |  | 1 |  |  | 1 |  |  | 1 |  |  | 1 |  |  | — | % |  | — | %
Borrowings | 30 |  |  | 35 |  |  | 36 |  |  | 40 |  |  | 50 |  |  | (14) | % |  | (40) | %
Junior and other subordinated debentures | 9 |  |  | 8 |  |  | 9 |  |  | 9 |  |  | 10 |  |  | 13 | % |  | (10) | %
Total interest expense | 235 |  |  | 224 |  |  | 223 |  |  | 239 |  |  | 269 |  |  | 5 | % |  | (13) | %
Net interest income | 505 |  |  | 446 |  |  | 425 |  |  | 437 |  |  | 430 |  |  | 13 | % |  | 17 | %
Provision for credit losses | 70 |  |  | 30 |  |  | 27 |  |  | 28 |  |  | 29 |  |  | 133 | % |  | 141 | %
Non-interest income: |  |  |  |  |  |  |  |  |  |  |  |  |
Service charges on deposits | 21 |  |  | 20 |  |  | 19 |  |  | 18 |  |  | 18 |  |  | 5 | % |  | 17 | %
Card-based fees | 15 |  |  | 14 |  |  | 13 |  |  | 15 |  |  | 15 |  |  | 7 | % |  | — | %
Financial services and trust revenue | 9 |  |  | 6 |  |  | 5 |  |  | 5 |  |  | 5 |  |  | 50 | % |  | 80 | %
Residential mortgage banking revenue, net | 7 |  |  | 8 |  |  | 9 |  |  | 7 |  |  | 7 |  |  | (13) | % |  | — | %
Gain (loss) on investment securities, net | 2 |  |  | — |  |  | 2 |  |  | (1) |  |  | 2 |  |  | nm |  | — | %
Loss on loan and lease sales, net | — |  |  | — |  |  | — |  |  | (2) |  |  | — |  |  | nm |  | nm
Gain (loss) on loans held for investment, at fair value | 4 |  |  | — |  |  | 7 |  |  | (7) |  |  | 9 |  |  | nm |  | (56) | %
BOLI income | 6 |  |  | 5 |  |  | 5 |  |  | 5 |  |  | 5 |  |  | 20 | % |  | 20 | %
Other income | 13 |  |  | 12 |  |  | 6 |  |  | 10 |  |  | 5 |  |  | 8 | % |  | 160 | %
Total non-interest income | 77 |  |  | 65 |  |  | 66 |  |  | 50 |  |  | 66 |  |  | 18 | % |  | 17 | %
Non-interest expense: |  |  |  |  |  |  |  |  |  |  |  |  |
Salaries and employee benefits | 171 |  |  | 155 |  |  | 145 |  |  | 142 |  |  | 147 |  |  | 10 | % |  | 16 | %
Occupancy and equipment, net | 54 |  |  | 47 |  |  | 48 |  |  | 47 |  |  | 45 |  |  | 15 | % |  | 20 | %
Intangible amortization | 31 |  |  | 26 |  |  | 28 |  |  | 29 |  |  | 29 |  |  | 19 | % |  | 7 | %
FDIC assessments | 8 |  |  | 8 |  |  | 8 |  |  | 8 |  |  | 9 |  |  | — | % |  | (11) | %
Merger and restructuring expense | 87 |  |  | 8 |  |  | 14 |  |  | 2 |  |  | 2 |  |  | nm |  | nm
Legal settlement | — |  |  | — |  |  | 55 |  |  | — |  |  | — |  |  | nm |  | nm
Other expenses | 42 |  |  | 34 |  |  | 42 |  |  | 39 |  |  | 39 |  |  | 24 | % |  | 8 | %
Total non-interest expense | 393 |  |  | 278 |  |  | 340 |  |  | 267 |  |  | 271 |  |  | 41 | % |  | 45 | %
Income before provision for income taxes | 119 |  |  | 203 |  |  | 124 |  |  | 192 |  |  | 196 |  |  | (41) | % |  | (39) | %
Provision for income taxes | 23 |  |  | 51 |  |  | 37 |  |  | 49 |  |  | 50 |  |  | (55) | % |  | (54) | %
Net income | $ | 96 |  |  | $ | 152 |  |  | $ | 87 |  |  | $ | 143 |  |  | $ | 146 |  |  | (37) | % |  | (34) | %
Weighted average basic shares outstanding (in thousands) | 237,838 |  |  | 209,125 |  |  | 208,800 |  |  | 208,548 |  |  | 208,545 |  |  | 14 | % |  | 14 | %
Weighted average diluted shares outstanding (in thousands) | 238,925 |  |  | 209,975 |  |  | 210,023 |  |  | 209,889 |  |  | 209,454 |  |  | 14 | % |  | 14 | %
Earnings per common share – basic | $ | 0.40 |  |  | $ | 0.73 |  |  | $ | 0.41 |  |  | $ | 0.69 |  |  | $ | 0.70 |  |  | (45) | % |  | (43) | %
Earnings per common share – diluted | $ | 0.40 |  |  | $ | 0.73 |  |  | $ | 0.41 |  |  | $ | 0.68 |  |  | $ | 0.70 |  |  | (45) | % |  | (43) | %
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 8

Columbia Banking System, Inc.
Consolidated Statements of Income
(Unaudited)
|  | Nine Months Ended |  | % Change
($ in millions, shares in thousands) |  | Sep 30, 2025 |  | Sep 30, 2024 |  | Year over Year
Interest income: |  |  |  |  |  |
Loans and leases |  | $ | 1,736 |  |  | $ | 1,748 |  |  | (1) | %
Interest and dividends on investments: |  |  |  |  |  |
Taxable |  | 238 |  |  | 230 |  |  | 3 | %
Exempt from federal income tax |  | 22 |  |  | 21 |  |  | 5 | %
Dividends |  | 10 |  |  | 9 |  |  | 11 | %
Temporary investments and interest bearing deposits |  | 52 |  |  | 71 |  |  | (27) | %
Total interest income |  | 2,058 |  |  | 2,079 |  |  | (1) | %
Interest expense: |  |  |  |  |  |
Deposits |  | 552 |  |  | 614 |  |  | (10) | %
Securities sold under agreement to repurchase and federal funds purchased |  | 3 |  |  | 4 |  |  | (25) | %
Borrowings |  | 101 |  |  | 150 |  |  | (33) | %
Junior and other subordinated debentures |  | 26 |  |  | 30 |  |  | (13) | %
Total interest expense |  | 682 |  |  | 798 |  |  | (15) | %
Net interest income |  | 1,376 |  |  | 1,281 |  |  | 7 | %
Provision for credit losses |  | 127 |  |  | 78 |  |  | 63 | %
Non-interest income: |  |  |  |  |  |
Service charges on deposits |  | 60 |  |  | 53 |  |  | 13 | %
Card-based fees |  | 42 |  |  | 42 |  |  | — | %
Financial services and trust revenue |  | 20 |  |  | 15 |  |  | 33 | %
Residential mortgage banking revenue, net |  | 24 |  |  | 17 |  |  | 41 | %
Gain on investment securities, net |  | 4 |  |  | 1 |  |  | 300 | %
Loss on loan and lease sales, net |  | — |  |  | (1) |  |  | nm
Gain (loss) on loans held for investment, at fair value |  | 11 |  |  | (3) |  |  | nm
BOLI income |  | 16 |  |  | 14 |  |  | 14 | %
Other income |  | 31 |  |  | 23 |  |  | 35 | %
Total non-interest income |  | 208 |  |  | 161 |  |  | 29 | %
Non-interest expense: |  |  |  |  |  |
Salaries and employee benefits |  | 471 |  |  | 447 |  |  | 5 | %
Occupancy and equipment, net |  | 149 |  |  | 135 |  |  | 10 | %
Intangible amortization |  | 85 |  |  | 90 |  |  | (6) | %
FDIC assessments |  | 24 |  |  | 33 |  |  | (27) | %
Merger and restructuring expense |  | 109 |  |  | 21 |  |  | 419 | %
Legal settlement |  | 55 |  |  | — |  |  | nm
Other expenses |  | 118 |  |  | 112 |  |  | 5 | %
Total non-interest expense |  | 1,011 |  |  | 838 |  |  | 21 | %
Income before provision for income taxes |  | 446 |  |  | 526 |  |  | (15) | %
Provision for income taxes |  | 111 |  |  | 136 |  |  | (18) | %
Net income |  | $ | 335 |  |  | $ | 390 |  |  | (14) | %
Weighted average basic shares outstanding (in thousands) |  | 218,694 |  |  | 208,435 |  |  | 5 | %
Weighted average diluted shares outstanding (in thousands) |  | 219,712 |  |  | 209,137 |  |  | 5 | %
Earnings per common share – basic |  | $ | 1.53 |  |  | $ | 1.87 |  |  | (18) | %
Earnings per common share – diluted |  | $ | 1.53 |  |  | $ | 1.87 |  |  | (18) | %
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 9

Columbia Banking System, Inc.
Consolidated Balance Sheets
(Unaudited)
|  |  |  |  |  |  |  |  |  |  | % Change
($ in millions, shares in thousands) | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Assets: |  |  |  |  |  |  |  |  |  |  |  |  |
Cash and due from banks | $ | 535 |  |  | $ | 608 |  |  | $ | 591 |  |  | $ | 497 |  |  | $ | 591 |  |  | (12) | % |  | (9) | %
Interest-bearing cash and temporary investments | 1,808 |  |  | 1,334 |  |  | 1,481 |  |  | 1,382 |  |  | 1,520 |  |  | 36 | % |  | 19 | %
Investment securities: |  |  |  |  |  |  |  |  |  |  |  |  |
Equity and other, at fair value | 112 |  |  | 93 |  |  | 92 |  |  | 78 |  |  | 80 |  |  | 20 | % |  | 40 | %
Available for sale, at fair value | 11,013 |  |  | 8,653 |  |  | 8,229 |  |  | 8,275 |  |  | 8,677 |  |  | 27 | % |  | 27 | %
Held to maturity, at amortized cost | 18 |  |  | 2 |  |  | 2 |  |  | 2 |  |  | 2 |  |  | nm |  | nm
Loans held for sale | 340 |  |  | 66 |  |  | 65 |  |  | 72 |  |  | 67 |  |  | 415 | % |  | 407 | %
Loans and leases | 48,462 |  |  | 37,637 |  |  | 37,616 |  |  | 37,681 |  |  | 37,503 |  |  | 29 | % |  | 29 | %
Allowance for credit losses on loans and leases | (473) |  |  | (421) |  |  | (421) |  |  | (425) |  |  | (420) |  |  | 12 | % |  | 13 | %
Net loans and leases | 47,989 |  |  | 37,216 |  |  | 37,195 |  |  | 37,256 |  |  | 37,083 |  |  | 29 | % |  | 29 | %
Restricted equity securities | 119 |  |  | 161 |  |  | 125 |  |  | 150 |  |  | 116 |  |  | (26) | % |  | 3 | %
Premises and equipment, net | 416 |  |  | 357 |  |  | 345 |  |  | 349 |  |  | 338 |  |  | 17 | % |  | 23 | %
Operating lease right-of-use assets | 156 |  |  | 110 |  |  | 107 |  |  | 111 |  |  | 106 |  |  | 42 | % |  | 47 | %
Goodwill | 1,481 |  |  | 1,029 |  |  | 1,029 |  |  | 1,029 |  |  | 1,029 |  |  | 44 | % |  | 44 | %
Other intangible assets, net | 754 |  |  | 430 |  |  | 456 |  |  | 484 |  |  | 513 |  |  | 75 | % |  | 47 | %
Residential mortgage servicing rights, at fair value | 101 |  |  | 103 |  |  | 106 |  |  | 108 |  |  | 102 |  |  | (2) | % |  | (1) | %
Bank-owned life insurance | 1,199 |  |  | 705 |  |  | 701 |  |  | 694 |  |  | 691 |  |  | 70 | % |  | 74 | %
Deferred tax asset, net | 392 |  |  | 299 |  |  | 311 |  |  | 359 |  |  | 286 |  |  | 31 | % |  | 37 | %
Other assets | 1,063 |  |  | 735 |  |  | 684 |  |  | 730 |  |  | 708 |  |  | 45 | % |  | 50 | %
Total assets | $ | 67,496 |  |  | $ | 51,901 |  |  | $ | 51,519 |  |  | $ | 51,576 |  |  | $ | 51,909 |  |  | 30 | % |  | 30 | %
Liabilities: |  |  |  |  |  |  |  |  |  |  |  |  |
Deposits |  |  |  |  |  |  |  |  |  |  |  |  |
Non-interest-bearing | $ | 17,810 |  |  | $ | 13,220 |  |  | $ | 13,414 |  |  | $ | 13,308 |  |  | $ | 13,534 |  |  | 35 | % |  | 32 | %
Interest-bearing | 37,961 |  |  | 28,523 |  |  | 28,804 |  |  | 28,413 |  |  | 27,981 |  |  | 33 | % |  | 36 | %
Total deposits | 55,771 |  |  | 41,743 |  |  | 42,218 |  |  | 41,721 |  |  | 41,515 |  |  | 34 | % |  | 34 | %
Securities sold under agreements to repurchase | 167 |  |  | 191 |  |  | 192 |  |  | 237 |  |  | 184 |  |  | (13) | % |  | (9) | %
Borrowings | 2,300 |  |  | 3,350 |  |  | 2,550 |  |  | 3,100 |  |  | 3,650 |  |  | (31) | % |  | (37) | %
Junior subordinated debentures, at fair value | 331 |  |  | 323 |  |  | 321 |  |  | 331 |  |  | 312 |  |  | 2 | % |  | 6 | %
Junior and other subordinated debentures, at amortized cost | 107 |  |  | 108 |  |  | 108 |  |  | 108 |  |  | 108 |  |  | (1) | % |  | (1) | %
Operating lease liabilities | 168 |  |  | 125 |  |  | 121 |  |  | 126 |  |  | 121 |  |  | 34 | % |  | 39 | %
Other liabilities | 862 |  |  | 719 |  |  | 771 |  |  | 835 |  |  | 745 |  |  | 20 | % |  | 16 | %
Total liabilities | 59,706 |  |  | 46,559 |  |  | 46,281 |  |  | 46,458 |  |  | 46,635 |  |  | 28 | % |  | 28 | %
Shareholders' equity: |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock | 8,189 |  |  | 5,826 |  |  | 5,823 |  |  | 5,817 |  |  | 5,812 |  |  | 41 | % |  | 41 | %
Accumulated deficit | (131) |  |  | (151) |  |  | (227) |  |  | (237) |  |  | (304) |  |  | (13) | % |  | (57) | %
Accumulated other comprehensive loss | (268) |  |  | (333) |  |  | (358) |  |  | (462) |  |  | (234) |  |  | (20) | % |  | 15 | %
Total shareholders' equity | 7,790 |  |  | 5,342 |  |  | 5,238 |  |  | 5,118 |  |  | 5,274 |  |  | 46 | % |  | 48 | %
Total liabilities and shareholders' equity | $ | 67,496 |  |  | $ | 51,901 |  |  | $ | 51,519 |  |  | $ | 51,576 |  |  | $ | 51,909 |  |  | 30 | % |  | 30 | %
Common shares outstanding at period end (in thousands) | 299,147 |  |  | 210,213 |  |  | 210,112 |  |  | 209,536 |  |  | 209,532 |  |  | 42 | % |  | 43 | %
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 10

Columbia Banking System, Inc.
Financial Highlights
(Unaudited)
|  | Quarter Ended |  | % Change
|  | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Per Common Share Data: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends |  | $ | 0.36 |  |  | $ | 0.36 |  |  | $ | 0.36 |  |  | $ | 0.36 |  |  | $ | 0.36 |  |  | — | % |  | — | %
Book value |  | $ | 26.04 |  |  | $ | 25.41 |  |  | $ | 24.93 |  |  | $ | 24.43 |  |  | $ | 25.17 |  |  | 2 | % |  | 3 | %
Tangible book value (1) |  | $ | 18.57 |  |  | $ | 18.47 |  |  | $ | 17.86 |  |  | $ | 17.20 |  |  | $ | 17.81 |  |  | 1 | % |  | 4 | %
Performance Ratios: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Efficiency ratio (2) |  | 67.29 | % |  | 54.29 | % |  | 69.06 | % |  | 54.61 | % |  | 54.56 | % |  | 13.00 |  |  | 12.73 |
Non-interest expense to average assets (1) |  | 2.74 | % |  | 2.16 | % |  | 2.68 | % |  | 2.06 | % |  | 2.08 | % |  | 0.58 |  |  | 0.66 |
Return on average assets ("ROAA") |  | 0.67 | % |  | 1.19 | % |  | 0.68 | % |  | 1.10 | % |  | 1.12 | % |  | (0.52) |  |  | (0.45) |
Pre-provision net revenue ("PPNR") ROAA (1) |  | 1.32 | % |  | 1.81 | % |  | 1.19 | % |  | 1.70 | % |  | 1.72 | % |  | (0.49) |  |  | (0.40) |
Return on average common equity |  | 6.19 | % |  | 11.56 | % |  | 6.73 | % |  | 10.91 | % |  | 11.36 | % |  | (5.37) |  |  | (5.17) |
Return on average tangible common equity (1) |  | 8.58 | % |  | 16.03 | % |  | 9.45 | % |  | 15.41 | % |  | 16.34 | % |  | (7.45) |  |  | (7.76) |
Performance Ratios - Operating: (1) |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating efficiency ratio, as adjusted (1), (2) |  | 52.32 | % |  | 51.79 | % |  | 55.11 | % |  | 52.51 | % |  | 53.89 | % |  | 0.53 |  |  | (1.57) |
Operating non-interest expense to average assets (1) |  | 2.14 | % |  | 2.10 | % |  | 2.13 | % |  | 2.03 | % |  | 2.05 | % |  | 0.04 |  |  | 0.09 |
Operating ROAA (1) |  | 1.42 | % |  | 1.25 | % |  | 1.10 | % |  | 1.15 | % |  | 1.10 | % |  | 0.17 |  |  | 0.32 |
Operating PPNR ROAA (1) |  | 1.89 | % |  | 1.88 | % |  | 1.67 | % |  | 1.77 | % |  | 1.69 | % |  | 0.01 |  |  | 0.20 |
Operating return on average common equity (1) |  | 13.15 | % |  | 12.16 | % |  | 10.87 | % |  | 11.40 | % |  | 11.15 | % |  | 0.99 |  |  | 2.00 |
Operating return on average tangible common equity (1) |  | 18.24 | % |  | 16.85 | % |  | 15.26 | % |  | 16.11 | % |  | 16.04 | % |  | 1.39 |  |  | 2.20 |
Average Balance Sheet Yields, Rates, & Ratios: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Yield on loans and leases |  | 5.96 | % |  | 6.00 | % |  | 5.92 | % |  | 6.05 | % |  | 6.22 | % |  | (0.04) |  |  | (0.26) |
Yield on earning assets (2) |  | 5.62 | % |  | 5.62 | % |  | 5.49 | % |  | 5.63 | % |  | 5.78 | % |  | — |  |  | (0.16) |
Cost of interest bearing deposits |  | 2.43 | % |  | 2.52 | % |  | 2.52 | % |  | 2.66 | % |  | 2.95 | % |  | (0.09) |  |  | (0.52) |
Cost of interest bearing liabilities |  | 2.65 | % |  | 2.78 | % |  | 2.80 | % |  | 2.98 | % |  | 3.29 | % |  | (0.13) |  |  | (0.64) |
Cost of total deposits |  | 1.66 | % |  | 1.73 | % |  | 1.72 | % |  | 1.80 | % |  | 1.99 | % |  | (0.07) |  |  | (0.33) |
Cost of total funding (3) |  | 1.87 | % |  | 1.98 | % |  | 1.99 | % |  | 2.09 | % |  | 2.32 | % |  | (0.11) |  |  | (0.45) |
Net interest margin (2) |  | 3.84 | % |  | 3.75 | % |  | 3.60 | % |  | 3.64 | % |  | 3.56 | % |  | 0.09 |  |  | 0.28 |
Average interest bearing cash / Average interest earning assets |  | 3.41 | % |  | 2.97 | % |  | 3.13 | % |  | 3.29 | % |  | 3.74 | % |  | 0.44 |  |  | (0.33) |
Average loans and leases / Average interest earning assets |  | 78.39 | % |  | 78.64 | % |  | 78.93 | % |  | 78.42 | % |  | 77.91 | % |  | (0.25) |  |  | 0.48 |
Average loans and leases / Average total deposits |  | 88.39 | % |  | 90.07 | % |  | 90.36 | % |  | 89.77 | % |  | 90.42 | % |  | (1.68) |  |  | (2.03) |
Average non-interest bearing deposits / Average total deposits |  | 31.41 | % |  | 31.39 | % |  | 31.75 | % |  | 32.45 | % |  | 32.52 | % |  | 0.02 |  |  | (1.11) |
Average total deposits / Average total funding (3) |  | 93.47 | % |  | 91.92 | % |  | 91.86 | % |  | 91.88 | % |  | 90.25 | % |  | 1.55 |  |  | 3.22 |
Select Credit & Capital Ratios: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-performing loans and leases to total loans and leases |  | 0.40 | % |  | 0.47 | % |  | 0.47 | % |  | 0.44 | % |  | 0.44 | % |  | (0.07) |  |  | (0.04) |
Non-performing assets to total assets |  | 0.29 | % |  | 0.35 | % |  | 0.35 | % |  | 0.33 | % |  | 0.32 | % |  | (0.06) |  |  | (0.03) |
Allowance for credit losses to loans and leases |  | 1.01 | % |  | 1.17 | % |  | 1.17 | % |  | 1.17 | % |  | 1.17 | % |  | (0.16) |  |  | (0.16) |
Total risk-based capital ratio (4) |  | 13.4 | % |  | 13.0 | % |  | 12.9 | % |  | 12.8 | % |  | 12.5 | % |  | 0.40 |  |  | 0.90 |
Common equity tier 1 risk-based capital ratio (4) |  | 11.6 | % |  | 10.8 | % |  | 10.6 | % |  | 10.5 | % |  | 10.3 | % |  | 0.80 |  |  | 1.30 |

(1) See GAAP to Non-GAAP Reconciliation.
(2) Tax-exempt interest was adjusted to a taxable equivalent basis using a 21% tax rate.
(3) Total funding = total deposits + total borrowings.
(4) Estimated holding company ratios.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 11

Columbia Banking System, Inc.
Financial Highlights
(Unaudited)
|  | Nine Months Ended |  | % Change
|  | Sep 30, 2025 |  | Sep 30, 2024 |  | Year over Year
Per Common Share Data: |  |  |  |  |  |
Dividends |  | $ | 1.08 |  |  | $ | 1.08 |  |  | — | %
Performance Ratios: |  |  |  |  |  |
Efficiency ratio (2) |  | 63.66 | % |  | 57.99 | % |  | 5.67 |
Non-interest expense to average assets (1) |  | 2.54 | % |  | 2.15 | % |  | 0.39 |
Return on average assets |  | 0.84 | % |  | 1.00 | % |  | (0.16) |
PPNR ROAA (1) |  | 1.44 | % |  | 1.55 | % |  | (0.11) |
Return on average common equity |  | 8.06 | % |  | 10.42 | % |  | (2.36) |
Return on average tangible common equity (1) |  | 11.22 | % |  | 15.27 | % |  | (4.05) |
Performance Ratios - Operating: (1) |  |  |  |  |  |
Operating efficiency ratio, as adjusted (1), (2) |  | 53.07 | % |  | 54.80 | % |  | (1.73) |
Operating non-interest expense to average assets (1) |  | 2.12 | % |  | 2.07 | % |  | 0.05 |
Operating ROAA (1) |  | 1.26 | % |  | 1.07 | % |  | 0.19 |
Operating PPNR ROAA (1) |  | 1.81 | % |  | 1.65 | % |  | 0.16 |
Operating return on average common equity (1) |  | 12.10 | % |  | 11.17 | % |  | 0.93 |
Operating return on average tangible common equity (1) |  | 16.85 | % |  | 16.36 | % |  | 0.49 |
Average Balance Sheet Yields, Rates, & Ratios: |  |  |  |  |  |
Yield on loans and leases |  | 5.96 | % |  | 6.18 | % |  | (0.22) |
Yield on earning assets (2) |  | 5.58 | % |  | 5.76 | % |  | (0.18) |
Cost of interest bearing deposits |  | 2.49 | % |  | 2.93 | % |  | (0.44) |
Cost of interest bearing liabilities |  | 2.74 | % |  | 3.28 | % |  | (0.54) |
Cost of total deposits |  | 1.70 | % |  | 1.97 | % |  | (0.27) |
Cost of total funding (3) |  | 1.94 | % |  | 2.31 | % |  | (0.37) |
Net interest margin (2) |  | 3.73 | % |  | 3.55 | % |  | 0.18 |
Average interest bearing cash / Average interest earning assets |  | 3.18 | % |  | 3.61 | % |  | (0.43) |
Average loans and leases / Average interest earning assets |  | 78.64 | % |  | 78.02 | % |  | 0.62 |
Average loans and leases / Average total deposits |  | 89.55 | % |  | 90.48 | % |  | (0.93) |
Average non-interest bearing deposits / Average total deposits |  | 31.51 | % |  | 32.78 | % |  | (1.27) |
Average total deposits / Average total funding (3) |  | 92.46 | % |  | 90.16 | % |  | 2.30 |

(1) See GAAP to Non-GAAP Reconciliation.
(2) Tax-exempt interest was adjusted to a taxable equivalent basis using a 21% tax rate.
(3) Total funding = Total deposits + Total borrowings.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 12

Columbia Banking System, Inc.
Loan & Lease Portfolio Balances and Mix
(Unaudited)
| Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | % Change
($ in millions) | Amount |  | Amount |  | Amount |  | Amount |  | Amount |  | Seq. Quarter |  | Year over Year
Loans and leases: |  |  |  |  |  |  |  |  |  |  |  |  |
Commercial real estate: |  |  |  |  |  |  |  |  |  |  |  |  |
Non-owner occupied term | $ | 8,444 |  |  | $ | 6,190 |  |  | $ | 6,179 |  |  | $ | 6,278 |  |  | $ | 6,392 |  |  | 36 | % |  | 32 | %
Owner occupied term | 7,361 |  |  | 5,320 |  |  | 5,303 |  |  | 5,270 |  |  | 5,210 |  |  | 38 | % |  | 41 | %
Multifamily | 10,377 |  |  | 5,735 |  |  | 5,831 |  |  | 5,804 |  |  | 5,780 |  |  | 81 | % |  | 80 | %
Construction & development | 2,071 |  |  | 2,070 |  |  | 2,071 |  |  | 1,983 |  |  | 1,989 |  |  | — | % |  | 4 | %
Residential development | 367 |  |  | 286 |  |  | 252 |  |  | 232 |  |  | 245 |  |  | 28 | % |  | 50 | %
Commercial: |  |  |  |  |  |  |  |  |  |  |  |  |
Term | 6,590 |  |  | 5,353 |  |  | 5,490 |  |  | 5,538 |  |  | 5,429 |  |  | 23 | % |  | 21 | %
Lines of credit & other | 3,582 |  |  | 2,951 |  |  | 2,754 |  |  | 2,770 |  |  | 2,641 |  |  | 21 | % |  | 36 | %
Leases & equipment finance | 1,614 |  |  | 1,641 |  |  | 1,644 |  |  | 1,661 |  |  | 1,670 |  |  | (2) | % |  | (3) | %
Residential: |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage | 5,722 |  |  | 5,830 |  |  | 5,878 |  |  | 5,933 |  |  | 5,945 |  |  | (2) | % |  | (4) | %
Home equity loans & lines | 2,153 |  |  | 2,083 |  |  | 2,039 |  |  | 2,032 |  |  | 2,017 |  |  | 3 | % |  | 7 | %
Consumer & other | 181 |  |  | 178 |  |  | 175 |  |  | 180 |  |  | 185 |  |  | 2 | % |  | (2) | %
Total loans and leases, net of deferred fees and costs | $ | 48,462 |  |  | $ | 37,637 |  |  | $ | 37,616 |  |  | $ | 37,681 |  |  | $ | 37,503 |  |  | 29 | % |  | 29 | %
Loans and leases mix: |  |  |  |  |  |  |  |  |  |  |  |  |
Commercial real estate: |  |  |  |  |  |  |  |  |  |  |  |  |
Non-owner occupied term | 18 | % |  | 16 | % |  | 16 | % |  | 17 | % |  | 17 | % |  |  |  |
Owner occupied term | 15 | % |  | 14 | % |  | 14 | % |  | 14 | % |  | 14 | % |  |  |  |
Multifamily | 21 | % |  | 15 | % |  | 15 | % |  | 15 | % |  | 15 | % |  |  |  |
Construction & development | 4 | % |  | 6 | % |  | 6 | % |  | 5 | % |  | 5 | % |  |  |  |
Residential development | 1 | % |  | 1 | % |  | 1 | % |  | 1 | % |  | 1 | % |  |  |  |
Commercial: |  |  |  |  |  |  |  |  |  |  |  |  |
Term | 14 | % |  | 14 | % |  | 15 | % |  | 15 | % |  | 15 | % |  |  |  |
Lines of credit & other | 7 | % |  | 8 | % |  | 7 | % |  | 7 | % |  | 7 | % |  |  |  |
Leases & equipment finance | 3 | % |  | 4 | % |  | 4 | % |  | 4 | % |  | 4 | % |  |  |  |
Residential: |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage | 12 | % |  | 15 | % |  | 16 | % |  | 16 | % |  | 16 | % |  |  |  |
Home equity loans & lines | 4 | % |  | 6 | % |  | 5 | % |  | 5 | % |  | 5 | % |  |  |  |
Consumer & other | 1 | % |  | 1 | % |  | 1 | % |  | 1 | % |  | 1 | % |  |  |  |
Total | 100 | % |  | 100 | % |  | 100 | % |  | 100 | % |  | 100 | % |  |  |  |

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 13

Columbia Banking System, Inc.
Deposit Portfolio Balances and Mix
(Unaudited)
| Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | % Change
($ in millions) | Amount |  | Amount |  | Amount |  | Amount |  | Amount |  | Seq. Quarter |  | Year over Year
Deposits: |  |  |  |  |  |  |  |  |  |  |  |  |
Demand, non-interest bearing | $ | 17,810 |  |  | $ | 13,220 |  |  | $ | 13,414 |  |  | $ | 13,308 |  |  | $ | 13,534 |  |  | 35 | % |  | 32 | %
Demand, interest bearing | 11,675 |  |  | 8,335 |  |  | 8,494 |  |  | 8,476 |  |  | 8,445 |  |  | 40 | % |  | 38 | %
Money market | 16,816 |  |  | 11,694 |  |  | 11,971 |  |  | 11,475 |  |  | 11,351 |  |  | 44 | % |  | 48 | %
Savings | 2,504 |  |  | 2,276 |  |  | 2,337 |  |  | 2,360 |  |  | 2,451 |  |  | 10 | % |  | 2 | %
Time | 6,966 |  |  | 6,218 |  |  | 6,002 |  |  | 6,102 |  |  | 5,734 |  |  | 12 | % |  | 21 | %
Total | $ | 55,771 |  |  | $ | 41,743 |  |  | $ | 42,218 |  |  | $ | 41,721 |  |  | $ | 41,515 |  |  | 34 | % |  | 34 | %
Total core deposits (1) | $ | 51,535 |  |  | $ | 37,294 |  |  | $ | 38,079 |  |  | $ | 37,488 |  |  | $ | 37,775 |  |  | 38 | % |  | 36 | %
Deposit mix: |  |  |  |  |  |  |  |  |  |  |  |  |
Demand, non-interest bearing | 32 | % |  | 32 | % |  | 32 | % |  | 32 | % |  | 33 | % |  |  |  |
Demand, interest bearing | 21 | % |  | 20 | % |  | 20 | % |  | 20 | % |  | 20 | % |  |  |  |
Money market | 30 | % |  | 28 | % |  | 28 | % |  | 27 | % |  | 27 | % |  |  |  |
Savings | 5 | % |  | 5 | % |  | 6 | % |  | 6 | % |  | 6 | % |  |  |  |
Time | 12 | % |  | 15 | % |  | 14 | % |  | 15 | % |  | 14 | % |  |  |  |
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 Third Quarter 2025 Results
October 30, 2025
Page 14

Columbia Banking System, Inc.
Credit Quality – Non-performing Assets
(Unaudited)
| Quarter Ended |  | % Change
($ in millions) | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Non-performing assets: (1) |  |  |  |  |  |  |  |  |  |  |  |  |
Loans and leases on non-accrual status: |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial real estate | $ | 53 |  |  | $ | 31 |  |  | $ | 42 |  |  | $ | 39 |  |  | $ | 37 |  |  | 71 | % |  | 43 | %
| Commercial | 67 |  |  | 67 |  |  | 80 |  |  | 57 |  |  | 62 |  |  | 0 | % |  | 8 | %
| Total loans and leases on non-accrual status | 120 |  |  | 98 |  |  | 122 |  |  | 96 |  |  | 99 |  |  | 22 | % |  | 21 | %
Loans and leases past due 90+ days and accruing: (2) |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial | 5 |  |  | 5 |  |  | — |  |  | 5 |  |  | 6 |  |  | 0 | % |  | (17) | %
| Residential (2) | 71 |  |  | 74 |  |  | 53 |  |  | 66 |  |  | 61 |  |  | (4) | % |  | 16 | %
| Total loans and leases past due 90+ days and accruing (2) | 76 |  |  | 79 |  |  | 53 |  |  | 71 |  |  | 67 |  |  | (4) | % |  | 13 | %
Total non-performing loans and leases (1), (2) | 196 |  |  | 177 |  |  | 175 |  |  | 167 |  |  | 166 |  |  | 11 | % |  | 18 | %
Other real estate owned | 3 |  |  | 3 |  |  | 3 |  |  | 3 |  |  | 2 |  |  | 0 | % |  | 50 | %
Total non-performing assets (1), (2) | $ | 199 |  |  | $ | 180 |  |  | $ | 178 |  |  | $ | 170 |  |  | $ | 168 |  |  | 11 | % |  | 18 | %
Loans and leases past due 31-89 days | $ | 85 |  |  | $ | 142 |  |  | $ | 158 |  |  | $ | 105 |  |  | $ | 67 |  |  | (40) | % |  | 27 | %
Loans and leases past due 31-89 days to total loans and leases | 0.18 | % |  | 0.38 | % |  | 0.42 | % |  | 0.28 | % |  | 0.18 | % |  | (0.20) |  |  | — |
Non-performing loans and leases to total loans and leases (1), (2) | 0.40 | % |  | 0.47 | % |  | 0.47 | % |  | 0.44 | % |  | 0.44 | % |  | (0.07) |  |  | (0.04) |
Non-performing assets to total assets (1), (2) | 0.29 | % |  | 0.35 | % |  | 0.35 | % |  | 0.33 | % |  | 0.32 | % |  | (0.06) |  |  | (0.03) |
Non-accrual loans and leases to total loan and leases (2) | 0.25 | % |  | 0.26 | % |  | 0.33 | % |  | 0.26 | % |  | 0.26 | % |  | (0.01) |  |  | (0.01) |

(1) Non-accrual and 90+ days past due loans include government guarantees of $70 million, $68 million, $67 million, $74 million, and $66 million at September 30, 2025, June 30, 2025, March 31, 2025, December 31, 2024, and September 30, 2024, respectively.
(2) Excludes certain mortgage loans guaranteed by GNMA, which Columbia has the unilateral right to repurchase but has not done so, totaling $2 million, $2 million, $3 million, $2 million, and $4 million at September 30, 2025, June 30, 2025, March 31, 2025, December 31, 2024, and September 30, 2024, respectively.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 15

Columbia Banking System, Inc.
Credit Quality – Allowance for Credit Losses
(Unaudited)
|  | Quarter Ended |  | % Change
($ in millions) | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Allowance for credit losses on loans and leases (ACLLL) |  |  |  |  |  |  |  |  |  |  |  |  |
Balance, beginning of period | $ | 421 |  |  | $ | 421 |  |  | $ | 425 |  |  | $ | 420 |  |  | $ | 419 |  |  | 0 | % |  | 0 | %
Initial ACL recorded for PCD loans acquired during the period | 5 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | nm |  | nm
Provision for credit losses on loans and leases | 69 |  |  | 29 |  |  | 26 |  |  | 30 |  |  | 31 |  |  | 138 | % |  | 123 | %
Charge-offs |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial real estate | (3) |  |  | — |  |  | — |  |  | (3) |  |  | — |  |  | nm |  | nm
| Commercial | (22) |  |  | (33) |  |  | (33) |  |  | (26) |  |  | (33) |  |  | (33) | % |  | (33) | %
| Residential | — |  |  | — |  |  | (1) |  |  | — |  |  | (1) |  |  | nm |  | nm
| Consumer & other | (2) |  |  | (1) |  |  | (1) |  |  | (1) |  |  | (1) |  |  | 100 | % |  | 100 | %
| Total charge-offs | (27) |  |  | (34) |  |  | (35) |  |  | (30) |  |  | (35) |  |  | (21) | % |  | (23) | %
Recoveries |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial | 4 |  |  | 5 |  |  | 4 |  |  | 4 |  |  | 5 |  |  | (20) | % |  | (20) | %
| Consumer & other | 1 |  |  | — |  |  | 1 |  |  | 1 |  |  | — |  |  | nm |  | nm
| Total recoveries | 5 |  |  | 5 |  |  | 5 |  |  | 5 |  |  | 5 |  |  | 0 | % |  | 0 | %
Net (charge-offs) recoveries |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial real estate | (3) |  |  | — |  |  | — |  |  | (3) |  |  | — |  |  | nm |  | nm
| Commercial | (18) |  |  | (28) |  |  | (29) |  |  | (22) |  |  | (28) |  |  | (36) | % |  | (36) | %
| Residential | — |  |  | — |  |  | (1) |  |  | — |  |  | (1) |  |  | nm |  | nm
| Consumer & other | (1) |  |  | (1) |  |  | — |  |  | — |  |  | (1) |  |  | 0 | % |  | 0 | %
| Total net charge-offs | (22) |  |  | (29) |  |  | (30) |  |  | (25) |  |  | (30) |  |  | (24) | % |  | (27) | %
Balance, end of period | $ | 473 |  |  | $ | 421 |  |  | $ | 421 |  |  | $ | 425 |  |  | $ | 420 |  |  | 12 | % |  | 13 | %
Reserve for unfunded commitments |  |  |  |  |  |  |  |  |  |  |  |  |
Balance, beginning of period | $ | 18 |  |  | $ | 17 |  |  | $ | 16 |  |  | $ | 18 |  |  | $ | 20 |  |  | 6 | % |  | (10) | %
Provision (recapture) for credit losses on unfunded commitments | 1 |  |  | 1 |  |  | 1 |  |  | (2) |  |  | (2) |  |  | 0 | % |  | nm
Balance, end of period | 19 |  |  | 18 |  |  | 17 |  |  | 16 |  |  | 18 |  |  | 6 | % |  | 6 | %
Total Allowance for credit losses (ACL) | $ | 492 |  |  | $ | 439 |  |  | $ | 438 |  |  | $ | 441 |  |  | $ | 438 |  |  | 12 | % |  | 12 | %
Net charge-offs to average loans and leases (annualized) | 0.22 | % |  | 0.31 | % |  | 0.32 | % |  | 0.27 | % |  | 0.31 | % |  | (0.09) |  |  | (0.09) |
Recoveries to gross charge-offs | 18.52 | % |  | 15.19 | % |  | 14.05 | % |  | 15.23 | % |  | 16.76 | % |  | 3.33 |  |  | 1.76 |
ACLLL to loans and leases | 0.98 | % |  | 1.12 | % |  | 1.12 | % |  | 1.13 | % |  | 1.12 | % |  | (0.14) |  |  | (0.14) |
ACL to loans and leases | 1.01 | % |  | 1.17 | % |  | 1.17 | % |  | 1.17 | % |  | 1.17 | % |  | (0.16) |  |  | (0.16) |
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm." |

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 16

Columbia Banking System, Inc.
Credit Quality – Allowance for Credit Losses
(Unaudited)
|  | Nine Months Ended |  | % Change
($ in millions) |  | Sep 30, 2025 |  | Sep 30, 2024 |  | Year over Year
Allowance for credit losses on loans and leases (ACLLL) |  |  |  |  |  |
Balance, beginning of period |  | $ | 425 |  |  | $ | 441 |  |  | (4) | %
Initial ACL recorded for PCD loans acquired during the period | 5 |  |  | — |  |  | nm
Provision for credit losses on loans and leases |  | 124 |  |  | 83 |  |  | 49 | %
Charge-offs |  |  |  |  |  |
| Commercial real estate |  | (3) |  |  | (1) |  |  | 200 | %
| Commercial |  | (88) |  |  | (113) |  |  | (22) | %
| Residential |  | (1) |  |  | (2) |  |  | (50) | %
| Consumer & other |  | (4) |  |  | (5) |  |  | (20) | %
| Total charge-offs |  | (96) |  |  | (121) |  |  | (21) | %
Recoveries |  |  |  |  |  |
| Commercial real estate |  | — |  |  | 1 |  |  | (100) | %
| Commercial |  | 13 |  |  | 14 |  |  | (7) | %
| Residential |  | — |  |  | 1 |  |  | (100) | %
| Consumer & other |  | 2 |  |  | 1 |  |  | 100 | %
| Total recoveries |  | 15 |  |  | 17 |  |  | (12) | %
Net (charge-offs) recoveries |  |  |  |  |  |
| Commercial real estate |  | (3) |  |  | — |  |  | nm
| Commercial |  | (75) |  |  | (99) |  |  | (24) | %
| Residential |  | (1) |  |  | (1) |  |  | 0 | %
| Consumer & other |  | (2) |  |  | (4) |  |  | (50) | %
| Total net charge-offs |  | (81) |  |  | (104) |  |  | (22) | %
Balance, end of period |  | $ | 473 |  |  | $ | 420 |  |  | 13 | %
Reserve for unfunded commitments |  |  |  |  |  |
Balance, beginning of period |  | $ | 16 |  |  | $ | 23 |  |  | (30) | %
Provision (recapture) for credit losses on unfunded commitments |  | 3 |  |  | (5) |  |  | nm
Balance, end of period |  | 19 |  |  | 18 |  |  | 6 | %
Total Allowance for credit losses (ACL) |  | $ | 492 |  |  | $ | 438 |  |  | 12 | %
Net charge-offs to average loans and leases (annualized) |  | 0.28 | % |  | 0.37 | % |  | (0.09) |
Recoveries to gross charge-offs |  | 15.63 | % |  | 14.37 | % |  | 1.26 |
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 17

Columbia Banking System, Inc.
Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates
(Unaudited)
| Quarter Ended
| September 30, 2025 |  | June 30, 2025 |  | September 30, 2024
($ in millions) | 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 | $ | 80 |  |  | $ | 1 |  |  | 7.14 | % |  | $ | 67 |  |  | $ | 1 |  |  | 6.66 | % |  | $ | 68 |  |  | $ | 1 |  |  | 6.62 | %
Loans and leases (1) | 41,164 |  |  | 618 |  |  | 5.96 | % |  | 37,648 |  |  | 563 |  |  | 6.00 | % |  | 37,544 |  |  | 588 |  |  | 6.22 | %
Taxable securities | 8,523 |  |  | 93 |  |  | 4.35 | % |  | 7,937 |  |  | 83 |  |  | 4.22 | % |  | 7,943 |  |  | 78 |  |  | 3.97 | %
Non-taxable securities (2) | 950 |  |  | 10 |  |  | 4.26 | % |  | 798 |  |  | 8 |  |  | 3.95 | % |  | 828 |  |  | 8 |  |  | 3.78 | %
Temporary investments and interest-bearing cash | 1,793 |  |  | 20 |  |  | 4.40 | % |  | 1,421 |  |  | 16 |  |  | 4.46 | % |  | 1,802 |  |  | 25 |  |  | 5.45 | %
Total interest-earning assets (1), (2) | 52,510 |  |  | $ | 742 |  |  | 5.62 | % |  | 47,871 |  |  | $ | 671 |  |  | 5.62 | % |  | 48,185 |  |  | $ | 700 |  |  | 5.78 | %
Goodwill and other intangible assets | 1,719 |  |  |  |  |  |  | 1,472 |  |  |  |  |  |  | 1,560 |  |  |  |  |
Other assets | 2,594 |  |  |  |  |  |  | 2,209 |  |  |  |  |  |  | 2,264 |  |  |  |  |
Total assets | $ | 56,823 |  |  |  |  |  |  | $ | 51,552 |  |  |  |  |  |  | $ | 52,009 |  |  |  |  |
INTEREST-BEARING LIABILITIES: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest-bearing demand deposits | $ | 9,630 |  |  | $ | 53 |  |  | 2.17 | % |  | $ | 8,480 |  |  | $ | 48 |  |  | 2.28 | % |  | $ | 8,313 |  |  | $ | 57 |  |  | 2.74 | %
Money market deposits | 13,476 |  |  | 83 |  |  | 2.46 | % |  | 11,783 |  |  | 72 |  |  | 2.46 | % |  | 11,085 |  |  | 78 |  |  | 2.80 | %
Savings deposits | 2,358 |  |  | 1 |  |  | 0.16 | % |  | 2,287 |  |  | 1 |  |  | 0.13 | % |  | 2,480 |  |  | 1 |  |  | 0.17 | %
Time deposits | 6,481 |  |  | 58 |  |  | 3.57 | % |  | 6,126 |  |  | 59 |  |  | 3.85 | % |  | 6,141 |  |  | 72 |  |  | 4.65 | %
Total interest-bearing deposits | 31,945 |  |  | 195 |  |  | 2.43 | % |  | 28,676 |  |  | 180 |  |  | 2.52 | % |  | 28,019 |  |  | 208 |  |  | 2.95 | %
Repurchase agreements and federal funds purchased | 176 |  |  | 1 |  |  | 2.15 | % |  | 186 |  |  | 1 |  |  | 2.06 | % |  | 195 |  |  | 1 |  |  | 2.29 | %
Borrowings | 2,648 |  |  | 30 |  |  | 4.54 | % |  | 3,058 |  |  | 35 |  |  | 4.53 | % |  | 3,874 |  |  | 50 |  |  | 5.10 | %
Junior and other subordinated debentures | 430 |  |  | 9 |  |  | 7.99 | % |  | 428 |  |  | 8 |  |  | 8.05 | % |  | 417 |  |  | 10 |  |  | 9.43 | %
Total interest-bearing liabilities | 35,199 |  |  | $ | 235 |  |  | 2.65 | % |  | 32,348 |  |  | $ | 224 |  |  | 2.78 | % |  | 32,505 |  |  | $ | 269 |  |  | 3.29 | %
Non-interest-bearing deposits | 14,627 |  |  |  |  |  |  | 13,123 |  |  |  |  |  |  | 13,500 |  |  |  |  |
Other liabilities | 840 |  |  |  |  |  |  | 794 |  |  |  |  |  |  | 885 |  |  |  |  |
Total liabilities | 50,666 |  |  |  |  |  |  | 46,265 |  |  |  |  |  |  | 46,890 |  |  |  |  |
Common equity | 6,157 |  |  |  |  |  |  | 5,287 |  |  |  |  |  |  | 5,119 |  |  |  |  |
Total liabilities and shareholders' equity | $ | 56,823 |  |  |  |  |  |  | $ | 51,552 |  |  |  |  |  |  | $ | 52,009 |  |  |  |  |
NET INTEREST INCOME (2) |  |  | $ | 507 |  |  |  |  |  |  | $ | 447 |  |  |  |  |  |  | $ | 431 |  |  |
NET INTEREST SPREAD (2) |  |  |  |  | 2.97 | % |  |  |  |  |  | 2.84 | % |  |  |  |  |  | 2.49 | %
NET INTEREST INCOME TO EARNING ASSETS OR NET INTEREST MARGIN (1), (2) |  |  |  |  | 3.84 | % |  |  |  |  |  | 3.75 | % |  |  |  |  |  | 3.56 | %

(1)Non-accrual loans and leases are included in the average balance.
(2)Tax-exempt income was adjusted to a tax equivalent basis at a 21% tax rate. The amount of such adjustment was an addition to recorded income of approximately $2 million for the three months ended September 30, 2025, as compared to $1 million for the three months ended June 30, 2025 and $1 million for the three months ended September 30, 2024.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 18

Columbia Banking System, Inc.
Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates
(Unaudited)
| Nine Months Ended
| September 30, 2025 |  | September 30, 2024
($ in millions) | 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 | $ | 69 |  |  | $ | 3 |  |  | 6.74 | % |  | $ | 67 |  |  | $ | 3 |  |  | 6.56 | %
Loans and leases (1) | 38,843 |  |  | 1,733 |  |  | 5.96 | % |  | 37,601 |  |  | 1,745 |  |  | 6.18 | %
Taxable securities | 8,053 |  |  | 248 |  |  | 4.11 | % |  | 7,954 |  |  | 239 |  |  | 4.01 | %
Non-taxable securities (2) | 856 |  |  | 26 |  |  | 4.04 | % |  | 835 |  |  | 24 |  |  | 3.77 | %
Temporary investments and interest-bearing cash | 1,570 |  |  | 52 |  |  | 4.44 | % |  | 1,738 |  |  | 71 |  |  | 5.48 | %
Total interest-earning assets (1), (2) | 49,391 |  |  | $ | 2,062 |  |  | 5.58 | % |  | 48,195 |  |  | $ | 2,082 |  |  | 5.76 | %
Goodwill and other intangible assets | 1,565 |  |  |  |  |  |  | 1,589 |  |  |  |  |
Other assets | 2,340 |  |  |  |  |  |  | 2,241 |  |  |  |  |
Total assets | $ | 53,296 |  |  |  |  |  |  | $ | 52,025 |  |  |  |  |
INTEREST-BEARING LIABILITIES: |  |  |  |  |  |  |  |  |  |  |
Interest-bearing demand deposits | $ | 8,832 |  |  | $ | 147 |  |  | 2.23 | % |  | $ | 8,166 |  |  | $ | 162 |  |  | 2.66 | %
Money market deposits | 12,295 |  |  | 225 |  |  | 2.44 | % |  | 10,850 |  |  | 227 |  |  | 2.79 | %
Savings deposits | 2,332 |  |  | 2 |  |  | 0.13 | % |  | 2,574 |  |  | 3 |  |  | 0.14 | %
Time deposits | 6,249 |  |  | 178 |  |  | 3.81 | % |  | 6,345 |  |  | 222 |  |  | 4.67 | %
Total interest-bearing deposits | 29,708 |  |  | 552 |  |  | 2.49 | % |  | 27,935 |  |  | 614 |  |  | 2.93 | %
Repurchase agreements and federal funds purchased | 192 |  |  | 3 |  |  | 2.09 | % |  | 217 |  |  | 4 |  |  | 2.40 | %
Borrowings | 2,913 |  |  | 101 |  |  | 4.63 | % |  | 3,898 |  |  | 150 |  |  | 5.15 | %
Junior and other subordinated debentures | 432 |  |  | 26 |  |  | 7.99 | % |  | 419 |  |  | 30 |  |  | 9.44 | %
Total interest-bearing liabilities | 33,245 |  |  | $ | 682 |  |  | 2.74 | % |  | 32,469 |  |  | $ | 798 |  |  | 3.28 | %
Non-interest-bearing deposits | 13,668 |  |  |  |  |  |  | 13,622 |  |  |  |  |
Other liabilities | 826 |  |  |  |  |  |  | 929 |  |  |  |  |
Total liabilities | 47,739 |  |  |  |  |  |  | 47,020 |  |  |  |  |
Common equity | 5,557 |  |  |  |  |  |  | 5,005 |  |  |  |  |
Total liabilities and shareholders' equity | $ | 53,296 |  |  |  |  |  |  | $ | 52,025 |  |  |  |  |
NET INTEREST INCOME (2) |  |  | $ | 1,380 |  |  |  |  |  |  | $ | 1,284 |  |  |
NET INTEREST SPREAD (2) |  |  |  |  | 2.84 | % |  |  |  |  |  | 2.48 | %
NET INTEREST INCOME TO EARNING ASSETS OR NET INTEREST MARGIN (1), (2) |  |  |  |  | 3.73 | % |  |  |  |  |  | 3.55 | %

(1)Non-accrual loans and leases are included in the average balance.
(2)Tax-exempt income was adjusted to a tax equivalent basis at a 21% tax rate. The amount of such adjustment was an addition to recorded income of approximately $4 million for the nine months ended September 30, 2025, as compared to $3 million for the same period in 2024.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 19

Columbia Banking System, Inc.
Residential Mortgage Banking Activity
(Unaudited)
| Quarter Ended |  | %
($ in millions) | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Residential mortgage banking revenue: |  |  |  |  |  |  |  |  |  |  |  |  |
Origination and sale | $ | 5 |  |  | $ | 5 |  |  | $ | 4 |  |  | $ | 5 |  |  | $ | 5 |  |  | — | % |  | — | %
Servicing | 5 |  |  | 6 |  |  | 6 |  |  | 6 |  |  | 6 |  |  | (17) | % |  | (17) | %
Change in fair value of MSR asset: |  |  |  |  |  |  |  |  |  |  |  |  |
Changes due to collection/realization of expected cash flows over time | (3) |  |  | (3) |  |  | (3) |  |  | (3) |  |  | (3) |  |  | — | % |  | — | %
Changes due to valuation inputs or assumptions | — |  |  | (2) |  |  | (1) |  |  | 7 |  |  | (6) |  |  | nm |  | nm
MSR hedge gain (loss) | — |  |  | 2 |  |  | 3 |  |  | (8) |  |  | 5 |  |  | (100) | % |  | (100) | %
Total | $ | 7 |  |  | $ | 8 |  |  | $ | 9 |  |  | $ | 7 |  |  | $ | 7 |  |  | (13) | % |  | — | %
Closed loan volume for sale | $ | 166 |  |  | $ | 164 |  |  | $ | 136 |  |  | $ | 175 |  |  | $ | 161 |  |  | 1 | % |  | 3 | %
Gain on sale margin | 3.01 | % |  | 2.77 | % |  | 3.23 | % |  | 2.58 | % |  | 3.24 | % |  | 0.24 |  | -0.23
Residential mortgage servicing rights: |  |  |  |  |  |  |  |  |  |  |  |  |
Balance, beginning of period | $ | 103 |  |  | $ | 106 |  |  | $ | 108 |  |  | $ | 102 |  |  | $ | 110 |  |  | (3) | % |  | (6) | %
Additions for new MSR capitalized | 1 |  |  | 2 |  |  | 2 |  |  | 2 |  |  | 1 |  |  | (50) | % |  | — | %
Change in fair value of MSR asset: |  |  |  |  |  |  |  |  |  |  |  |  |
Changes due to collection/realization of expected cash flows over time | (3) |  |  | (3) |  |  | (3) |  |  | (3) |  |  | (3) |  |  | — | % |  | — | %
Changes due to valuation inputs or assumptions | — |  |  | (2) |  |  | (1) |  |  | 7 |  |  | (6) |  |  | nm |  | nm
Balance, end of period | $ | 101 |  |  | $ | 103 |  |  | $ | 106 |  |  | $ | 108 |  |  | $ | 102 |  |  | (2) | % |  | (1) | %
Residential mortgage loans serviced for others | $ | 7,797 |  |  | $ | 7,852 |  |  | $ | 7,888 |  |  | $ | 7,939 |  |  | $ | 7,966 |  |  | (1) | % |  | (2) | %
MSR as % of serviced portfolio | 1.30 | % |  | 1.31 | % |  | 1.34 | % |  | 1.36 | % |  | 1.28 | % |  | (0.01) |  |  | 0.02 |
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 20

Columbia Banking System, Inc.
Residential Mortgage Banking Activity
(Unaudited)
| Nine Months Ended |  | % Change
($ in millions) | Sep 30, 2025 |  | Sep 30, 2024 |  | Year over Year
Residential mortgage banking revenue: |  |  |  |  |
Origination and sale | $ | 14 |  |  | $ | 11 |  |  | 27 | %
Servicing | 17 |  |  | 18 |  |  | (6) | %
Change in fair value of MSR asset: |  |  |  |  |
Changes due to collection/realization of expected cash flows over time | (9) |  |  | (9) |  |  | 0 | %
Changes due to valuation inputs or assumptions | (3) |  |  | (2) |  |  | 50 | %
MSR hedge gain (loss) | 5 |  |  | (1) |  |  | nm
Total | $ | 24 |  |  | $ | 17 |  |  | 41 | %
Closed loan volume for sale | $ | 466 |  |  | $ | 389 |  |  | 20 | %
Gain on sale margin | 3.00 | % |  | 2.98 | % |  | 0.02 |
Residential mortgage servicing rights: |  |  |  |  |
Balance, beginning of period | $ | 108 |  |  | $ | 109 |  |  | (1) | %
Additions for new MSR capitalized | 5 |  |  | 4 |  |  | 25 | %
Change in fair value of MSR asset: |  |  |  |  |
Changes due to collection/realization of expected cash flows over time | (9) |  |  | (9) |  |  | 0 | %
Changes due to valuation inputs or assumptions | (3) |  |  | (2) |  |  | 50 | %
Balance, end of period | $ | 101 |  |  | $ | 102 |  |  | (1) | %
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 21

Columbia Banking System, Inc. Purchase Price Allocation (1)
(Unaudited)
($ in millions) | August 31, 2025
Purchase price consideration |  |  |
| Fair value of common shares issued and exchanged |  |  | $ | 2,355 |
| Total consideration |  |  | $ | 2,355 |
Fair value of assets acquired: |  |  |
| Cash and due from banks | $ | 874 |  |  |
| Investment securities | 2,828 |  |  |
| Loans held for sale | 1 |  |  |
| Loans and leases | 11,382 |  |  |
| Restricted equity securities | 98 |  |  |
| Premises and equipment | 53 |  |  |
| Other intangible assets | 355 |  |  |
| Deferred tax assets | 132 |  |  |
| Other assets | 889 |  |  |
| Total assets acquired | $ | 16,612 |  |  |
Fair value of liabilities assumed: |  |  |
| Deposits | $ | 14,542 |  |  |
| Other liabilities | 167 |  |  |
| Total liabilities assumed | $ | 14,709 |  |  |
Net assets acquired |  |  | $ | 1,903 |
Goodwill |  |  | $ | 452 |

(1) The estimates of fair value were recorded based on initial valuations available at August 31, 2025 and these estimates, including initial accounting for deferred taxes, were considered preliminary as of September 30, 2025 and subject to adjustment for up to one year after the acquisition date.

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 22
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, and operating pre-provision net revenue and operating return on tangible common equity are also used as part of our incentive compensation program for our executive officers. 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
Tangible Capital, as adjusted
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in millions, shares in thousands) |  |  | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Total shareholders' equity | a |  | $ | 7,790 |  |  | $ | 5,342 |  |  | $ | 5,238 |  |  | $ | 5,118 |  |  | $ | 5,274 |  |  | 46 | % |  | 48 | %
Less: Goodwill |  |  | 1,481 |  |  | 1,029 |  |  | 1,029 |  |  | 1,029 |  |  | 1,029 |  |  | 44 | % |  | 44 | %
Less: Other intangible assets, net |  |  | 754 |  |  | 430 |  |  | 456 |  |  | 484 |  |  | 513 |  |  | 75 | % |  | 47 | %
Tangible common shareholders' equity | b |  | $ | 5,555 |  |  | $ | 3,883 |  |  | $ | 3,753 |  |  | $ | 3,605 |  |  | $ | 3,732 |  |  | 43 | % |  | 49 | %
Total assets | c |  | $ | 67,496 |  |  | $ | 51,901 |  |  | $ | 51,519 |  |  | $ | 51,576 |  |  | $ | 51,909 |  |  | 30 | % |  | 30 | %
Less: Goodwill |  |  | 1,481 |  |  | 1,029 |  |  | 1,029 |  |  | 1,029 |  |  | 1,029 |  |  | 44 | % |  | 44 | %
Less: Other intangible assets, net |  |  | 754 |  |  | 430 |  |  | 456 |  |  | 484 |  |  | 513 |  |  | 75 | % |  | 47 | %
Tangible assets | d |  | $ | 65,261 |  |  | $ | 50,442 |  |  | $ | 50,034 |  |  | $ | 50,063 |  |  | $ | 50,367 |  |  | 29 | % |  | 30 | %
Common shares outstanding at period end (in thousands) | e |  | 299,147 |  |  | 210,213 |  |  | 210,112 |  |  | 209,536 |  |  | 209,532 |  |  | 42 | % |  | 43 | %
Total shareholders' equity to total assets ratio | a / c |  | 11.54 | % |  | 10.29 | % |  | 10.17 | % |  | 9.92 | % |  | 10.16 | % |  | 1.25 |  |  | 1.38 |
Tangible common equity to tangible assets ratio | b / d |  | 8.51 | % |  | 7.70 | % |  | 7.50 | % |  | 7.20 | % |  | 7.41 | % |  | 0.81 |  |  | 1.10 |
Book value per common share | a / e |  | $ | 26.04 |  |  | $ | 25.41 |  |  | $ | 24.93 |  |  | $ | 24.43 |  |  | $ | 25.17 |  |  | 2 | % |  | 3 | %
Tangible book value per common share | b / e |  | $ | 18.57 |  |  | $ | 18.47 |  |  | $ | 17.86 |  |  | $ | 17.20 |  |  | $ | 17.81 |  |  | 1 | % |  | 4 | %

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 23

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
Income Statements, as adjusted
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in millions) |  |  | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Non-Interest Income Adjustments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on investment securities, net |  |  | $ | 2 |  |  | $ | — |  |  | $ | 2 |  |  | $ | (1) |  |  | $ | 2 |  |  | nm |  | — | %
(Loss) gain on swap derivatives |  |  | (1) |  |  | (1) |  |  | (1) |  |  | 3 |  |  | (3) |  |  | — | % |  | (67) | %
Gain (loss) on loans held for investment, at fair value |  |  | 4 |  |  | — |  |  | 7 |  |  | (7) |  |  | 9 |  |  | nm |  | (56) | %
Change in fair value of MSR due to valuation inputs or assumptions |  |  | — |  |  | (2) |  |  | (1) |  |  | 7 |  |  | (6) |  |  | nm |  | nm
MSR hedge gain (loss) |  |  | — |  |  | 2 |  |  | 3 |  |  | (8) |  |  | 5 |  |  | (100) | % |  | (100) | %
Total non-interest income adjustments | a |  | $ | 5 |  |  | $ | (1) |  |  | $ | 10 |  |  | $ | (6) |  |  | $ | 7 |  |  | nm |  | (29) | %
Non-Interest Expense Adjustments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Merger and restructuring expense |  |  | $ | 87 |  |  | $ | 8 |  |  | $ | 14 |  |  | $ | 2 |  |  | $ | 2 |  |  | nm |  | nm
Exit and disposal costs |  |  | — |  |  | — |  |  | 1 |  |  | 1 |  |  | 1 |  |  | nm |  | (100) | %
FDIC special assessment |  |  | (1) |  |  | — |  |  | — |  |  | — |  |  | — |  |  | nm |  | nm
Legal settlement |  |  | — |  |  | — |  |  | 55 |  |  | — |  |  | — |  |  | nm |  | nm
Total non-interest expense adjustments | b |  | $ | 86 |  |  | $ | 8 |  |  | $ | 70 |  |  | $ | 3 |  |  | $ | 3 |  |  | nm |  | nm
Net interest income | c |  | $ | 505 |  |  | $ | 446 |  |  | $ | 425 |  |  | $ | 437 |  |  | $ | 430 |  |  | 13 | % |  | 17 | %
Non-interest income (GAAP) | d |  | $ | 77 |  |  | $ | 65 |  |  | $ | 66 |  |  | $ | 50 |  |  | $ | 66 |  |  | 18 | % |  | 17 | %
Less: Non-interest income adjustments | a |  | (5) |  |  | 1 |  |  | (10) |  |  | 6 |  |  | (7) |  |  | nm |  | (29) | %
Operating non-interest income (non-GAAP) | e |  | $ | 72 |  |  | $ | 66 |  |  | $ | 56 |  |  | $ | 56 |  |  | $ | 59 |  |  | 9 | % |  | 22 | %
Revenue (GAAP) | f=c+d |  | $ | 582 |  |  | $ | 511 |  |  | $ | 491 |  |  | $ | 487 |  |  | $ | 496 |  |  | 14 | % |  | 17 | %
Operating revenue (non-GAAP) | g=c+e |  | $ | 577 |  |  | $ | 512 |  |  | $ | 481 |  |  | $ | 493 |  |  | $ | 489 |  |  | 13 | % |  | 18 | %
Non-interest expense (GAAP) | h |  | $ | 393 |  |  | $ | 278 |  |  | $ | 340 |  |  | $ | 267 |  |  | $ | 271 |  |  | 41 | % |  | 45 | %
Less: Non-interest expense adjustments | b |  | (86) |  |  | (8) |  |  | (70) |  |  | (3) |  |  | (3) |  |  | nm |  | nm
Operating non-interest expense (non-GAAP) | i |  | $ | 307 |  |  | $ | 270 |  |  | $ | 270 |  |  | $ | 264 |  |  | $ | 268 |  |  | 14 | % |  | 15 | %
Net income (GAAP) | j |  | $ | 96 |  |  | $ | 152 |  |  | $ | 87 |  |  | $ | 143 |  |  | $ | 146 |  |  | (37) | % |  | (34) | %
Provision for income taxes |  |  | 23 |  |  | 51 |  |  | 37 |  |  | 49 |  |  | 50 |  |  | (55) | % |  | (54) | %
Income before provision for income taxes |  |  | 119 |  |  | 203 |  |  | 124 |  |  | 192 |  |  | 196 |  |  | (41) | % |  | (39) | %
Provision for credit losses |  |  | 70 |  |  | 30 |  |  | 27 |  |  | 28 |  |  | 29 |  |  | 133 | % |  | 141 | %
Pre-provision net revenue (PPNR) (non-GAAP) | k |  | 189 |  |  | 233 |  |  | 151 |  |  | 220 |  |  | 225 |  |  | (19) | % |  | (16) | %
Less: Non-interest income adjustments | a |  | (5) |  |  | 1 |  |  | (10) |  |  | 6 |  |  | (7) |  |  | nm |  | (29) | %
Add: Non-interest expense adjustments | b |  | 86 |  |  | 8 |  |  | 70 |  |  | 3 |  |  | 3 |  |  | nm |  | nm
Operating PPNR (non-GAAP) | l |  | $ | 270 |  |  | $ | 242 |  |  | $ | 211 |  |  | $ | 229 |  |  | $ | 221 |  |  | 12 | % |  | 22 | %
Net income (GAAP) | j |  | $ | 96 |  |  | $ | 152 |  |  | $ | 87 |  |  | $ | 143 |  |  | $ | 146 |  |  | (37) | % |  | (34) | %
Day 1 acquisition provision expense |  |  | 70 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | nm |  | nm
Less: Non-interest income adjustments | a |  | (5) |  |  | 1 |  |  | (10) |  |  | 6 |  |  | (7) |  |  | nm |  | (29) | %
Add: Non-interest expense adjustments | b |  | 86 |  |  | 8 |  |  | 70 |  |  | 3 |  |  | 3 |  |  | nm |  | nm
Tax effect of adjustments |  |  | (43) |  |  | (1) |  |  | (8) |  |  | (2) |  |  | 1 |  |  | nm |  | nm
Operating net income (non-GAAP) | m |  | $ | 204 |  |  | $ | 160 |  |  | $ | 139 |  |  | $ | 150 |  |  | $ | 143 |  |  | 28 | % |  | 43 | %
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 24

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
Average Balances, Earnings Per Share, and Performance Metrics, as adjusted
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in millions, shares in thousands) |  |  | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Average assets | n |  | $ | 56,823 |  |  | $ | 51,552 |  |  | $ | 51,453 |  |  | $ | 51,588 |  |  | $ | 52,009 |  |  | 10 | % |  | 9 | %
Less: Average goodwill and other intangible assets, net |  |  | 1,719 |  |  | 1,472 |  |  | 1,502 |  |  | 1,528 |  |  | 1,560 |  |  | 17 | % |  | 10 | %
Average tangible assets | o |  | $ | 55,104 |  |  | $ | 50,080 |  |  | $ | 49,951 |  |  | $ | 50,060 |  |  | $ | 50,449 |  |  | 10 | % |  | 9 | %
Average common shareholders' equity | p |  | $ | 6,157 |  |  | $ | 5,287 |  |  | $ | 5,217 |  |  | $ | 5,226 |  |  | $ | 5,119 |  |  | 16 | % |  | 20 | %
Less: Average goodwill and other intangible assets, net |  |  | 1,719 |  |  | 1,472 |  |  | 1,502 |  |  | 1,528 |  |  | 1,560 |  |  | 17 | % |  | 10 | %
Average tangible common equity | q |  | $ | 4,438 |  |  | $ | 3,815 |  |  | $ | 3,715 |  |  | $ | 3,698 |  |  | $ | 3,559 |  |  | 16 | % |  | 25 | %
Weighted average basic shares outstanding (in thousands) | r |  | 237,838 |  |  | 209,125 |  |  | 208,800 |  |  | 208,548 |  |  | 208,545 |  |  | 14 | % |  | 14 | %
Weighted average diluted shares outstanding (in thousands) | s |  | 238,925 |  |  | 209,975 |  |  | 210,023 |  |  | 209,889 |  |  | 209,454 |  |  | 14 | % |  | 14 | %
Select Per-Share & Performance Metrics |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Earnings per share - basic | j / r |  | $ | 0.40 |  |  | $ | 0.73 |  |  | $ | 0.41 |  |  | $ | 0.69 |  |  | $ | 0.70 |  |  | (45) | % |  | (43) | %
Earnings per share - diluted | j / s |  | $ | 0.40 |  |  | $ | 0.73 |  |  | $ | 0.41 |  |  | $ | 0.68 |  |  | $ | 0.70 |  |  | (45) | % |  | (43) | %
Efficiency ratio (1) | h / f |  | 67.29 | % |  | 54.29 | % |  | 69.06 | % |  | 54.61 | % |  | 54.56 | % |  | 13.00 |  |  | 12.73 |
Non-interest expense to average assets | h / n |  | 2.74 | % |  | 2.16 | % |  | 2.68 | % |  | 2.06 | % |  | 2.08 | % |  | 0.58 |  |  | 0.66 |
Return on average assets | j / n |  | 0.67 | % |  | 1.19 | % |  | 0.68 | % |  | 1.10 | % |  | 1.12 | % |  | (0.52) |  |  | (0.45) |
Return on average tangible assets | j / o |  | 0.69 | % |  | 1.22 | % |  | 0.70 | % |  | 1.14 | % |  | 1.15 | % |  | (0.53) |  |  | (0.46) |
PPNR return on average assets | k / n |  | 1.32 | % |  | 1.81 | % |  | 1.19 | % |  | 1.70 | % |  | 1.72 | % |  | (0.49) |  |  | (0.40) |
Return on average common equity | j / p |  | 6.19 | % |  | 11.56 | % |  | 6.73 | % |  | 10.91 | % |  | 11.36 | % |  | (5.37) |  |  | (5.17) |
Return on average tangible common equity | j / q |  | 8.58 | % |  | 16.03 | % |  | 9.45 | % |  | 15.41 | % |  | 16.34 | % |  | (7.45) |  |  | (7.76) |
Operating Per-Share & Performance Metrics |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating earnings per share - basic | m / r |  | $ | 0.86 |  |  | $ | 0.77 |  |  | $ | 0.67 |  |  | $ | 0.72 |  |  | $ | 0.69 |  |  | 12 | % |  | 25 | %
Operating earnings per share - diluted | m / s |  | $ | 0.85 |  |  | $ | 0.76 |  |  | $ | 0.67 |  |  | $ | 0.71 |  |  | $ | 0.69 |  |  | 12 | % |  | 23 | %
Operating efficiency ratio, as adjusted (1) | u / y |  | 52.32 | % |  | 51.79 | % |  | 55.11 | % |  | 52.51 | % |  | 53.89 | % |  | 0.53 |  |  | (1.57) |
Operating non-interest expense to average assets | i / n |  | 2.14 | % |  | 2.10 | % |  | 2.13 | % |  | 2.03 | % |  | 2.05 | % |  | 0.04 |  |  | 0.09 |
Operating return on average assets | m / n |  | 1.42 | % |  | 1.25 | % |  | 1.10 | % |  | 1.15 | % |  | 1.10 | % |  | 0.17 |  |  | 0.32 |
Operating return on average tangible assets | m / o |  | 1.47 | % |  | 1.28 | % |  | 1.13 | % |  | 1.19 | % |  | 1.13 | % |  | 0.19 |  |  | 0.34 |
Operating PPNR return on average assets | l / n |  | 1.89 | % |  | 1.88 | % |  | 1.67 | % |  | 1.77 | % |  | 1.69 | % |  | 0.01 |  |  | 0.20 |
Operating return on average common equity | m / p |  | 13.15 | % |  | 12.16 | % |  | 10.87 | % |  | 11.40 | % |  | 11.15 | % |  | 0.99 |  |  | 2.00 |
Operating return on average tangible common equity | m / q |  | 18.24 | % |  | 16.85 | % |  | 15.26 | % |  | 16.11 | % |  | 16.04 | % |  | 1.39 |  |  | 2.20 |

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

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 25

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
Operating Efficiency Ratio, as adjusted
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in millions) |  |  | Sep 30, 2025 |  | Jun 30, 2025 |  | Mar 31, 2025 |  | Dec 31, 2024 |  | Sep 30, 2024 |  | Seq. Quarter |  | Year over Year
Non-interest expense (GAAP) | h |  | $ | 393 |  |  | $ | 278 |  |  | $ | 340 |  |  | $ | 267 |  |  | $ | 271 |  |  | 41 | % |  | 45 | %
Less: Non-interest expense adjustments | b |  | (86) |  |  | (8) |  |  | (70) |  |  | (3) |  |  | (3) |  |  | nm |  | nm
Operating non-interest expense (non-GAAP) | i |  | 307 |  |  | 270 |  |  | 270 |  |  | 264 |  |  | 268 |  |  | 14 | % |  | 15 | %
Less: B&O taxes | t |  | (3) |  |  | (3) |  |  | (3) |  |  | (4) |  |  | (3) |  |  | — | % |  | — | %
Operating non-interest expense, excluding B&O taxes (non-GAAP) | u |  | $ | 304 |  |  | $ | 267 |  |  | $ | 267 |  |  | $ | 260 |  |  | $ | 265 |  |  | 14 | % |  | 15 | %
Net interest income (tax equivalent) (1) | v |  | $ | 507 |  |  | $ | 447 |  |  | $ | 426 |  |  | $ | 438 |  |  | $ | 431 |  |  | 13 | % |  | 18 | %
Non-interest income (GAAP) | d |  | 77 |  |  | 65 |  |  | 66 |  |  | 50 |  |  | 66 |  |  | 18 | % |  | 17 | %
Add: BOLI tax equivalent adjustment (1) | w |  | 2 |  |  | 2 |  |  | 1 |  |  | 1 |  |  | 1 |  |  | — | % |  | 100 | %
Total Revenue, excluding BOLI tax equivalent adjustments (tax equivalent) | x |  | 586 |  |  | 514 |  |  | 493 |  |  | 489 |  |  | 498 |  |  | 14 | % |  | 18 | %
Less: Non-interest income adjustments | a |  | (5) |  |  | 1 |  |  | (10) |  |  | 6 |  |  | (7) |  |  | nm |  | (29) | %
Total Adjusted Operating Revenue, excluding BOLI tax equivalent adjustments (tax equivalent) (non-GAAP) | y |  | $ | 581 |  |  | $ | 515 |  |  | $ | 483 |  |  | $ | 495 |  |  | $ | 491 |  |  | 13 | % |  | 18 | %
Efficiency ratio (1) | h / f |  | 67.29 | % |  | 54.29 | % |  | 69.06 | % |  | 54.61 | % |  | 54.56 | % |  | 13.00 |  |  | 12.73 |
Operating efficiency ratio, as adjusted (non-GAAP) (1) | u / y |  | 52.32 | % |  | 51.79 | % |  | 55.11 | % |  | 52.51 | % |  | 53.89 | % |  | 0.53 |  |  | (1.57) |
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

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

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 26

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
Income Statements, as adjusted
(Unaudited)
|  |  | Nine Months Ended |  | % Change
($ in millions) |  |  | Sep 30, 2025 |  | Sep 30, 2024 |  | Year over Year
Non-Interest Income Adjustments |  |  |  |  |  |  |
Gain on investment securities, net |  |  | $ | 4 |  |  | $ | 1 |  |  | 300 | %
(Loss) gain on swap derivatives |  |  | (3) |  |  | (2) |  |  | 50 | %
Gain (loss) on loans held for investment, at fair value |  |  | 11 |  |  | (3) |  |  | nm
Change in fair value of MSR due to valuation inputs or assumptions |  |  | (3) |  |  | (2) |  |  | 50 | %
MSR hedge loss |  |  | 5 |  |  | (1) |  |  | nm
Total non-interest income adjustments | a |  | $ | 14 |  |  | $ | (7) |  |  | nm
Non-Interest Expense Adjustments |  |  |  |  |  |  |
Merger and restructuring expense |  |  | $ | 109 |  |  | $ | 21 |  |  | 419 | %
Exit and disposal costs |  |  | 1 |  |  | 3 |  |  | (67) | %
FDIC special assessment |  |  | (1) |  |  | 6 |  |  | (117) | %
Legal settlement |  |  | 55 |  |  | — |  |  | nm
Total non-interest expense adjustments | b |  | $ | 164 |  |  | $ | 30 |  |  | 447 | %
Net interest income | c |  | $ | 1,376 |  |  | $ | 1,281 |  |  | 7 | %
Non-interest income (GAAP) | d |  | $ | 208 |  |  | $ | 161 |  |  | 29 | %
Less: Non-interest income adjustments | a |  | (14) |  |  | 7 |  |  | (300) | %
Operating non-interest income (non-GAAP) | e |  | $ | 194 |  |  | $ | 168 |  |  | 15 | %
Revenue (GAAP) | f=c+d |  | $ | 1,584 |  |  | $ | 1,442 |  |  | 10 | %
Operating revenue (non-GAAP) | g=c+e |  | $ | 1,570 |  |  | $ | 1,449 |  |  | 8 | %
Non-interest expense (GAAP) | h |  | $ | 1,011 |  |  | $ | 838 |  |  | 21 | %
Less: Non-interest expense adjustments | b |  | (164) |  |  | (30) |  |  | 447 | %
Operating non-interest expense (non-GAAP) | i |  | $ | 847 |  |  | $ | 808 |  |  | 5 | %
Net income (GAAP) | j |  | $ | 335 |  |  | $ | 390 |  |  | (14) | %
Provision for income taxes |  |  | 111 |  |  | 136 |  |  | (18) | %
Income before provision for income taxes |  |  | 446 |  |  | 526 |  |  | (15) | %
Provision for credit losses |  |  | 127 |  |  | 78 |  |  | 63 | %
Pre-provision net revenue (PPNR) (non-GAAP) | k |  | 573 |  |  | 604 |  |  | (5) | %
Less: Non-interest income adjustments | a |  | (14) |  |  | 7 |  |  | (300) | %
Add: Non-interest expense adjustments | b |  | 164 |  |  | 30 |  |  | 447 | %
Operating PPNR (non-GAAP) | l |  | $ | 723 |  |  | $ | 641 |  |  | 13 | %
Net income (GAAP) | j |  | $ | 335 |  |  | $ | 390 |  |  | (14) | %
Day 1 acquisition provision expense |  |  | 70 |  |  | — |  |  | nm
Less: Non-interest income adjustments | a |  | (14) |  |  | 7 |  |  | (300) | %
Add: Non-interest expense adjustments | b |  | 164 |  |  | 30 |  |  | 447 | %
Tax effect of adjustments |  |  | (52) |  |  | (9) |  |  | 478 | %
Operating net income (non-GAAP) | m |  | $ | 503 |  |  | $ | 418 |  |  | 20 | %
nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm."

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 27

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
Average Balances, Earnings Per Share, and Performance Metrics, as adjusted
(Unaudited)
|  |  | Nine Months Ended |  | % Change
($ in millions, shares in thousands) |  |  | Sep 30, 2025 |  | Sep 30, 2024 |  | Year over Year
Average assets | n |  | $ | 53,296 |  |  | $ | 52,025 |  |  | 2 | %
Less: Average goodwill and other intangible assets, net |  |  | 1,565 |  |  | 1,589 |  |  | (2) | %
Average tangible assets | o |  | $ | 51,731 |  |  | $ | 50,436 |  |  | 3 | %
Average common shareholders' equity | p |  | $ | 5,557 |  |  | $ | 5,005 |  |  | 11 | %
Less: Average goodwill and other intangible assets, net |  |  | 1,565 |  |  | 1,589 |  |  | (2) | %
Average tangible common equity | q |  | $ | 3,992 |  |  | $ | 3,416 |  |  | 17 | %
Weighted average basic shares outstanding | r |  | 218,694 |  |  | 208,435 |  |  | 5 | %
Weighted average diluted shares outstanding | s |  | 219,712 |  |  | 209,137 |  |  | 5 | %
Select Per-Share & Performance Metrics |  |  |  |  |  |  |
Earnings per share - basic | j / r |  | $ | 1.53 |  |  | $ | 1.87 |  |  | (18) | %
Earnings per share - diluted | j / s |  | $ | 1.53 |  |  | $ | 1.87 |  |  | (18) | %
Efficiency ratio (1) | h / f |  | 63.66 | % |  | 57.99 | % |  | 5.67 |
Non-interest expense to average assets | h/n |  | 2.54 | % |  | 2.15 | % |  | 0.39 |
Return on average assets | j / n |  | 0.84 | % |  | 1.00 | % |  | (0.16) |
Return on average tangible assets | j / o |  | 0.87 | % |  | 1.03 | % |  | (0.16) |
PPNR return on average assets | k/n |  | 1.44 | % |  | 1.55 | % |  | (0.11) |
Return on average common equity | j / p |  | 8.06 | % |  | 10.42 | % |  | (2.36) |
Return on average tangible common equity | j / q |  | 11.22 | % |  | 15.27 | % |  | (4.05) |
Operating Per-Share & Performance Metrics |  |  |  |  |  |  |
Operating earnings per share - basic | m / r |  | $ | 2.30 |  |  | $ | 2.01 |  |  | 14 | %
Operating earnings per share - diluted | m / s |  | $ | 2.29 |  |  | $ | 2.00 |  |  | 15 | %
Operating efficiency ratio, as adjusted (1) | u / y |  | 53.07 | % |  | 54.80 | % |  | (1.73) |
Operating non-interest expense to average assets | i/n |  | 2.12 | % |  | 2.07 | % |  | 0.05 |
Operating return on average assets | m / n |  | 1.26 | % |  | 1.07 | % |  | 0.19 |
Operating return on average tangible assets | m / o |  | 1.30 | % |  | 1.11 | % |  | 0.19 |
Operating PPNR return on average assets | l / n |  | 1.81 | % |  | 1.65 | % |  | 0.16 |
Operating return on average common equity | m / p |  | 12.10 | % |  | 11.17 | % |  | 0.93 |
Operating return on average tangible common equity | m / q |  | 16.85 | % |  | 16.36 | % |  | 0.49 |

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

Columbia Banking System, Inc. Reports Third Quarter 2025 Results
October 30, 2025
Page 28

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
Operating Efficiency Ratio, as adjusted
(Unaudited)
|  |  | Nine Months Ended |  | % change
($ in millions) |  |  | Sep 30, 2025 |  | Sep 30, 2024 |  | Year over Year
Non-interest expense (GAAP) | h |  | $ | 1,011 |  |  | $ | 838 |  |  | 21 | %
Less: Non-interest expense adjustments | b |  | (164) |  |  | (30) |  |  | 447 | %
Operating non-interest expense (non-GAAP) | i |  | 847 |  |  | 808 |  |  | 5 | %
Less: B&O taxes | t |  | (9) |  |  | (10) |  |  | (10) | %
Operating non-interest expense, excluding B&O taxes (non-GAAP) | u |  | $ | 838 |  |  | $ | 798 |  |  | 5 | %
Net interest income (tax equivalent) (1) | v |  | $ | 1,380 |  |  | $ | 1,284 |  |  | 7 | %
Non-interest income (GAAP) | d |  | 208 |  |  | 161 |  |  | 29 | %
Add: BOLI tax equivalent adjustment (1) | w |  | 5 |  |  | 4 |  |  | 25 | %
Total Revenue, excluding BOLI tax equivalent adjustments (tax equivalent) | x |  | 1,593 |  |  | 1,449 |  |  | 10 | %
Less: Non-interest income adjustments | a |  | (14) |  |  | 7 |  |  | (300) | %
Total Adjusted Operating Revenue, excluding BOLI tax equivalent adjustments (tax equivalent) (non-GAAP) | y |  | $ | 1,579 |  |  | $ | 1,456 |  |  | 8 | %
Efficiency ratio (1) | h /f |  | 63.66 | % |  | 57.99 | % |  | 5.67 |
Operating efficiency ratio, as adjusted (non-GAAP) (1) | u / y |  | 53.07 | % |  | 54.80 | % |  | (1.73) |

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