EX-99.1 2 colb-20230930ex991earnings.htm PRESS RELEASE ANNOUNCING THIRD QUARTER 2023 FINANCIAL RESULTS
EXHIBIT 99.1

| Third Quarter 2023 Results •Net income of $136 million, or $0.65 per diluted common share •Operating net income of $164 million, or $0.79 per diluted common share 1 •Consolidated asset balances of $52 billion at quarter end •Loan balances of $37 billion and deposit balances of $42 billion at quarter end •Estimated CET1 and total capital ratios of 9.4% and 11.5% at quarter end

00

COLUMBIA BANKING SYSTEM, INC. REPORTS THIRD QUARTER 2023 RESULTS
$0.65 |  | $0.79 |  | $22.21 |  | $14.22
Earnings per diluted common share |  | Operating earnings per diluted common share 1 |  | Book value per common share |  | Tangible book value per common share 1

0

CEO Commentary
"Our teams remain focused on their customers and communities as we continue to drive balanced growth for the organization,” said Clint Stein, President and CEO. “We are back to business as usual, and our third quarter results highlight stabilizing customer deposit trends, relationship-driven growth in our loan portfolio and customer-based fee income, and a smaller impact from merger-related expense that affect our reported results. We achieved $140 million in annualized net merger-related cost savings through quarter end, surpassing our originally announced target of $135 million despite continued investment in our growing franchise, which includes the opening of our first branch in Utah during the third quarter. Our talented associates, expanding footprint, and customer-focused business model enable us to continue to win business and drive shareholder value.”
–Clint Stein, President and CEO of Columbia Banking System, Inc.

3Q23 HIGHLIGHTS (COMPARED TO 2Q23) |
Net Interest Income and NIM | •Net interest income decreased by $3 million or 1% on a linked-quarter basis as the increase in interest income due to higher yields was more than offset by higher funding costs. |
•Net interest margin was 3.91%, down 2 basis points from the prior quarter. The second full quarter as a combined organization, higher customer balances, and consistent purchase accounting trends contributed to net interest margin stabilization between quarters. |
Non-Interest Income and Expense | •Non-interest income increased by $4 million due primarily to higher customer-related fee income and loan gain-on-sale income as well as a lower loss due to cumulative non-merger fair value accounting and hedges. |
•Non-interest expense decreased by $24 million due to the realization of cost savings and lower merger-related expense. |
Credit Quality | •Net charge-offs were 0.25% of average loans and leases (annualized) compared to 0.30% in the prior quarter. Charge-off activity remains centered in the FinPac portfolio. |
•Provision expense of $37 million relates to portfolio mix changes and credit migration trends. |
•Non-performing assets to total assets was 0.20% compared to 0.15% at June 30, 2023. |
Capital | •Estimated total risk-based capital ratio of 11.5% and estimated common equity tier 1 risk-based capital ratio of 9.4%. |
•Declared a quarterly cash dividend of $0.36 per common share on August 14, 2023, which was paid September 11, 2023. |
Notable items | •Sold $159 million in non-relationship jumbo residential mortgage loans that were marked to fair value at merger close. |
•Completed the sale of approximately one-third of the MSR portfolio. |
•Incurred $19 million in merger-related expense. |

3Q23 KEY FINANCIAL DATA
PERFORMANCE METRICS | 3Q23 |  | 2Q23 |  | 3Q22
Return on average assets | 1.02% |  | 1.00% |  | 1.09%
Return on average common equity | 11.07% |  | 10.84% |  | 12.99%
Return on average tangible common equity 1 | 16.93% |  | 16.63% |  | 13.02%
Operating return on average assets 1 | 1.23% |  | 1.27% |  | 1.33%
Operating return on average common equity 1 | 13.40% |  | 13.77% |  | 15.86%
Operating return on average tangible common equity 1 | 20.48% |  | 21.13% |  | 15.90%
Net interest margin | 3.91% |  | 3.93% |  | 3.88%
Efficiency ratio | 57.82% |  | 62.60% |  | 56.07%
INCOME STATEMENT ($ in 000s, excl. per share data) | 3Q23 |  | 2Q23 |  | 3Q22
Net interest income | $480,875 |  | $483,975 |  | $287,604
Provision for credit losses | $36,737 |  | $16,014 |  | $27,572
Non-interest income | $43,981 |  | $39,678 |  | $29,445
Non-interest expense | $304,147 |  | $328,559 |  | $177,964
Pre-provision net revenue 1 | $220,709 |  | $195,094 |  | $139,085
Operating pre-provision net revenue 1 | $258,687 |  | $243,114 |  | $163,793
Earnings per common share - diluted 2 | $0.65 |  | $0.64 |  | $0.65
Operating earnings per common share - diluted 1,2 | $0.79 |  | $0.81 |  | $0.79
Dividends paid per share 2 | $0.36 |  | $0.36 |  | $0.35
BALANCE SHEET | 3Q23 |  | 2Q23 |  | 3Q22
Total assets | $52.0 | B |  | $53.6 | B |  | $31.5 | B
Loans and leases | $37.2 | B |  | $37.0 | B |  | $25.5 | B
Total deposits | $41.6 | B |  | $40.8 | B |  | $26.8 | B
Book value per common share 2 | $22.21 |  | $23.16 |  | $18.69
Tangible book value per share1,2 | $14.22 |  | $15.02 |  | $18.65

Investor Contact
Jacquelynne "Jacque" Bohlen, SVP/Investor Relations Director, 503-727-4117, jacquebohlen@umpquabank.com
1 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for the comparable GAAP measurement.
2 Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 2
Organizational Update
Columbia Banking System, Inc. ("Columbia", "we", or "our") has completed substantially all integration priorities, driving the realization of $140 million in annualized net merger-related cost-savings as of September 30, 2023, outpacing the $135 million target communicated when the combination was announced. Further, Umpqua Bank, the primary subsidiary of Columbia, continued to expand its presence in Utah with the opening of its first branch in the state during the third quarter.
On February 28, 2023, Columbia completed its merger with Umpqua Holdings Corporation ("UHC"), combining the two premier banks in the Northwest to create one of the largest banks headquartered in the West (the "merger"). Columbia's financial results for any periods ended prior to February 28, 2023 reflect UHC results only on a standalone basis. In addition, Columbia's reported financial results for the first quarter of 2023 reflect UHC financial results only until the closing of the merger after the close of business on February 28, 2023. As a result of these two factors, Columbia's financial results for the first, second, and third quarters of 2023 and the nine months ended September 30, 2023 may not be directly comparable to prior reported periods. The number of shares issued and outstanding, earnings per share, additional paid-in capital, and all references to share quantities or metrics of Columbia have been retrospectively restated to reflect the equivalent number of shares issued in the merger as the merger was treated as a reverse merger. Under the reverse acquisition method of accounting, the assets and liabilities of Columbia as of February 28, 2023 ("historical Columbia") were recorded at their respective fair values.
Net Interest Income
Net interest income was $481 million for the third quarter of 2023, down $3 million from the prior quarter. The slight decline reflects higher interest income given expanded earning asset yields that were more than offset by higher funding costs.
Columbia's net interest margin was 3.91% for the third quarter of 2023, down 2 basis points from 3.93% for the second quarter of 2023. The second full quarter as a combined organization, higher customer balances, and consistent purchase accounting trends contributed to net interest margin stabilization between quarters. The cost of interest-bearing deposits increased 37 basis points on a linked-quarter basis to 2.01% for the third quarter of 2023, which compares to 2.18% for the month of September and 2.27% at September 30, 2023. Deposit costs were impacted by the decision to replace a portion of maturing FHLB advances with brokered deposits during the third quarter, which increased our cost of deposits but was fairly neutral to our cost of interest-bearing liabilities. Columbia's cost of interest-bearing liabilities increased 27 basis points on a linked-quarter basis to 2.72% for the third quarter of 2023, which compares to 2.77% for the month of September and 2.78% at September 30, 2023. Please refer to the Q3 2023 Earnings Presentation for additional net interest margin change details and interest rate sensitivity information as well as to our non-GAAP disclosures in this press release for the impact of purchase accounting accretion and amortization on individual line items.
Non-interest Income
Non-interest income was $44 million for the third quarter of 2023, up $4 million from the prior quarter. Higher customer-related fee income, loan gain-on-sale income from select portfolio sales, and a smaller loss related to fair value adjustments and mortgage servicing rights ("MSR") hedging activity drove the increase. A net fair value loss of $15 million in the third quarter compares to a net fair value loss of $16 million in the second quarter, as detailed in our non-GAAP disclosures. As previously communicated, Columbia entered an agreement to sell approximately one-third of its MSR portfolio that relates to a non-relationship component of the serviced loan portfolio. The transaction closed in late September without any income statement impact.
Non-interest Expense
Non-interest expense was $304 million for the third quarter of 2023, down $24 million from the prior quarter level. The decrease reflects the realization of cost savings as well as an $11 million decline in merger-related expense, which were $19 million in the third quarter. Please refer to the Q3 2023 Earnings Presentation for additional expense details, including an update on realized merger-related cost-savings through September 30, 2023.
Balance Sheet
Total consolidated assets were $52.0 billion as of September 30, 2023, compared to $53.6 billion as of June 30, 2023. Cash and cash equivalents was $2.4 billion as of September 30, 2023, a decrease of $1.0 billion relative to June 30, 2023. We reduced our cash position during the third quarter given stabilizing industry trends and ample sources of available liquidity. Excess cash was used to pay off maturing FHLB advances, which declined to $4.0 billion as of September 30, 2023, compared to $6.3 billion as of June 30, 2023. Including secured off-balance sheet lines of credit, total available liquidity was $19.1 billion as of September 30, 2023, representing 37% of total assets, 46% of total deposits, and 142% of uninsured deposits. Please refer to the Q3 2023 Earnings Presentation for additional details related to our liquidity position.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 3
Available for sale securities, which are held on balance sheet at fair value, were $8.5 billion as of September 30, 2023, a decrease of $494 million relative to June 30, 2023, as paydowns and a decline in the fair value of the portfolio were only partially offset by accretion of the discount on historical Columbia securities. Please refer to the Q3 2023 Earnings Presentation for additional details related to our securities portfolio.
Gross loans and leases were $37.2 billion as of September 30, 2023, an increase of $121 million relative to June 30, 2023, as organic growth during the quarter more than offset the sale of $159 million in non-relationship jumbo residential mortgage loans that were marked to fair value at merger close. "We continued to selectively prune the portfolio during the third quarter, bringing the transfer and sale of loans that were transactional in nature to approximately $650 million over the past two quarters," commented Tory Nixon, President of Umpqua Bank. "Higher outstanding commercial line balances and other relationship-driven expansion contributed to 3% annualized loan growth in the third quarter when loan sales are excluded." Please refer to the Q3 2023 Earnings Presentation for additional details related to our loan portfolio, which include underwriting characteristics, the composition of our commercial portfolios, and disclosure related to our office portfolio.
Total deposits were $41.6 billion as of September 30, 2023, an increase of $789 million relative to June 30, 2023. "Customer deposit balances stabilized during the third quarter, increasing slightly between September and June," stated Mr. Nixon. "While market liquidity tightening, the impact of inflation on customer spending, and businesses' use of cash continue to impact our deposit flows, our teams' focus on balancing deposit generation alongside other growth resulted in net deposit increases throughout many business lines." Please refer to the Q3 2023 Earnings Presentation for additional details related to deposit characteristics and flows.
Credit Quality
The allowance for credit losses was $438 million, or 1.18% of loans and leases, as of September 30, 2023, compared to $424 million, or 1.15% of loans and leases, as of June 30, 2023. The provision for credit losses was $37 million for the third quarter of 2023 and reflects portfolio mix changes and credit migration trends. Please refer to the Q3 2023 Earnings Presentation for additional details related to the allowance for credit losses and other credit trends.
Net charge-offs were 0.25% of average loans and leases (annualized) for the third quarter of 2023, compared to 0.30% for the second quarter of 2023. Net charge-off activity continued to be centered in the FinPac portfolio, which experienced a decline in charge-offs. Bank charge-off activity remained low at 0.01% of average bank loans. As of September 30, 2023, non-performing assets were $106 million, or 0.20% of total assets, compared to $80 million, or 0.15% as of June 30, 2023.
Capital
As of September 30, 2023, Columbia's book value per common share decreased to $22.21, compared to $23.16 at June 30, 2023. The linked-quarter change in book value primarily reflects a change in accumulated other comprehensive (loss) income ("AOCI") to $(680) million at September 30, 2023, compared to $(419) million at the prior quarter-end. The change in AOCI is due primarily to an increase in the tax-effected net unrealized loss on available for sale securities to $650 million as of September 30, 2023, compared to $403 million as of June 30, 2023. Tangible book value per common share 3 decreased to $14.22, compared to $15.02 at June 30, 2023.
Columbia's estimated total risk-based capital ratio was 11.5% and its estimated common equity tier 1 risk-based capital ratio was 9.4% as of September 30, 2023, compared to 11.3% and 9.2%, respectively, at June 30, 2023. Columbia remains above current “well-capitalized” regulatory minimums. "We continued to build capital during the quarter through organic earnings generation and the realization of loan and investment securities discount accretion," stated Ron Farnsworth, Chief Financial Officer of Columbia. "We expect our capital position to continue to build over time, supporting our growing franchise and increasing flexibility for capital return." The regulatory capital ratios as of September 30, 2023 are estimates, pending completion and filing of Columbia's regulatory reports.
3 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for the comparable GAAP measurement.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 4
Earnings Presentation and Conference Call Information
Columbia's Q3 2023 Earnings Presentation provides additional disclosure. A copy will be available on our investor relations page: www.columbiabankingsystem.com.
Columbia will host its third quarter 2023 earnings conference call on October 18, 2023, 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 2023 financial results. Participants may register for the call using the below link to receive dial-in details and their own unique PINs or join the audiocast. It is recommended you join 10 minutes prior to the start time.
Register for the call: https://register.vevent.com/register/BIcd18f9ce2ec34fdf915aa619af3a3d01
Join the audiocast: https://edge.media-server.com/mmc/p/ih23hqkg/
Access the replay through Columbia's investor relations page: www.columbiabankingsystem.com
About Columbia Banking System, Inc.
Columbia (Nasdaq: COLB) is headquartered in Tacoma, Washington and is the parent company of Umpqua Bank, an award-winning western U.S. regional bank based in Lake Oswego, Oregon. In March of 2023, Columbia and Umpqua combined two of the Pacific Northwest's premier financial institutions under the Umpqua Bank brand to create one of the largest banks headquartered in the West and a top-30 U.S. bank. With over $50 billion of assets, Umpqua Bank combines the resources, sophistication and expertise of a national bank with a commitment to deliver personalized service at scale. The bank operates in Arizona, California, Colorado, Idaho, Nevada, Oregon, Utah, and Washington and supports consumers and businesses through a full suite of services, including retail and commercial banking; Small Business Administration lending; institutional and corporate banking; and equipment leasing. Umpqua Bank customers also have access to comprehensive investment and wealth management expertise as well as healthcare and private banking through Columbia Wealth Management and Columbia Trust Company, a subsidiary of Columbia. Learn more at www.columbiabankingsystem.com.
Forward-Looking Statements
This press release includes forward-looking statements within the meaning of the "Safe-Harbor" provisions of the Private Securities Litigation Reform Act of 1995, which management believes are a benefit to shareholders. These statements are necessarily subject to risk and uncertainty and actual results could differ materially due to various risk factors, including those set forth from time to time in our filings with the Securities and Exchange Commission (the "SEC"). 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 that could cause results to differ from forward-looking statements we make include, without limitation: current and future economic and market conditions, including the effects of declines in housing and commercial real estate prices, high unemployment rates, continued inflation and any recession or slowdown in economic growth particularly in the western United States; economic forecast variables that are either materially worse or better than end of quarter projections and deterioration in the economy that could result in increased loan and lease losses, especially those risks associated with concentrations in real estate related loans; our ability to effectively manage problem credits; the impact of bank failures or adverse developments at or news developments concerning other banks on general investor sentiment regarding the liquidity and stability of banks; changes in interest rates that could significantly reduce net interest income and negatively affect asset yields and valuations and funding sources; changes in the scope and cost of FDIC insurance and other coverage; our ability to successfully implement efficiency and operational excellence initiatives; our ability to successfully develop and market new products and technology; changes in laws or regulations; any failure to realize the anticipated benefits of the UHC merger when expected or at all; the possibility that the integration following the UHC merger may be more expensive than anticipated, including as a result of unexpected factors or events, diversion of management’s attention from ongoing business operations and opportunities; potential adverse reactions or changes to business or employee relationships, including those resulting from the completion of the UHC merger and integration of the companies; the effect of geopolitical instability, including wars, conflicts and terrorist attacks; and natural disasters and other similar unexpected events outside of our control. We also caution that the amount and timing of any future common stock dividends or repurchases will depend on the earnings, cash requirements and financial condition of Columbia, market conditions, capital requirements, applicable law and regulations (including federal securities laws and federal banking regulations), and other factors deemed relevant by Columbia's Board of Directors, and may be subject to regulatory approval or conditions.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 5

| TABLE INDEX
|  | Page
| Consolidated Statements of Operations | 6
| Consolidated Balance Sheets | 8
| Financial Highlights | 9
| Loan & Lease Portfolio Balances and Mix | 11
| Deposit Portfolio Balances and Mix | 12
| Credit Quality - Non-performing Assets | 13
| Credit Quality - Allowance for Credit Losses | 14
| Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates | 16
| Residential Mortgage Banking Activity | 18
| GAAP to Non-GAAP Reconciliation | 20

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 6

Columbia Banking System, Inc.
Consolidated Statements of Operations
(Unaudited)
| Quarter Ended |  | % Change
($ in thousands, except per share data) | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Interest income: |  |  |  |  |  |  |  |  |  |  |  |  |
Loans and leases | $ | 569,670 |  |  | $ | 552,679 |  |  | $ | 413,525 |  |  | $ | 322,350 |  |  | $ | 278,830 |  |  | 3 | % |  | 104 | %
Interest and dividends on investments: |  |  |  |  |  |  |  |  |  |  |  |  |
Taxable | 80,066 |  |  | 79,036 |  |  | 39,729 |  |  | 18,108 |  |  | 18,175 |  |  | 1 | % |  | 341 | %
Exempt from federal income tax | 6,929 |  |  | 6,817 |  |  | 3,397 |  |  | 1,288 |  |  | 1,322 |  |  | 2 | % |  | 424 | %
Dividends | 4,941 |  |  | 2,581 |  |  | 719 |  |  | 182 |  |  | 86 |  |  | 91 | % |  | nm
Temporary investments and interest bearing deposits | 34,407 |  |  | 34,616 |  |  | 18,581 |  |  | 10,319 |  |  | 5,115 |  |  | (1) | % |  | nm
Total interest income | 696,013 |  |  | 675,729 |  |  | 475,951 |  |  | 352,247 |  |  | 303,528 |  |  | 3 | % |  | 129 | %
Interest expense: |  |  |  |  |  |  |  |  |  |  |  |  |
Deposits | 126,974 |  |  | 100,408 |  |  | 63,613 |  |  | 31,174 |  |  | 9,090 |  |  | 26 | % |  | nm
Securities sold under agreement to repurchase and federal funds purchased | 1,220 |  |  | 1,071 |  |  | 406 |  |  | 323 |  |  | 545 |  |  | 14 | % |  | 124 | %
Borrowings | 77,080 |  |  | 81,004 |  |  | 28,764 |  |  | 8,023 |  |  | 798 |  |  | (5) | % |  | nm
Junior and other subordinated debentures | 9,864 |  |  | 9,271 |  |  | 8,470 |  |  | 7,248 |  |  | 5,491 |  |  | 6 | % |  | 80 | %
Total interest expense | 215,138 |  |  | 191,754 |  |  | 101,253 |  |  | 46,768 |  |  | 15,924 |  |  | 12 | % |  | nm
Net interest income | 480,875 |  |  | 483,975 |  |  | 374,698 |  |  | 305,479 |  |  | 287,604 |  |  | (1) | % |  | 67 | %
Provision for credit losses | 36,737 |  |  | 16,014 |  |  | 105,539 |  |  | 32,948 |  |  | 27,572 |  |  | 129 | % |  | 33 | %
Non-interest income: |  |  |  |  |  |  |  |  |  |  |  |  |
Service charges on deposits | 17,410 |  |  | 16,454 |  |  | 14,312 |  |  | 12,139 |  |  | 12,632 |  |  | 6 | % |  | 38 | %
Card-based fees | 15,674 |  |  | 13,435 |  |  | 11,561 |  |  | 9,017 |  |  | 9,115 |  |  | 17 | % |  | 72 | %
Financial services and trust revenue | 4,651 |  |  | 4,512 |  |  | 1,297 |  |  | 25 |  |  | 27 |  |  | 3 | % |  | nm
Residential mortgage banking revenue (loss), net | 7,103 |  |  | (2,342) |  |  | 7,816 |  |  | (1,812) |  |  | 17,341 |  |  | nm |  | (59) | %
Gain on sale of debt securities, net | 4 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | nm |  | nm
(Loss) gain on equity securities, net | (2,055) |  |  | (697) |  |  | 2,416 |  |  | 284 |  |  | (2,647) |  |  | 195 | % |  | (22) | %
Gain on loan and lease sales, net | 1,871 |  |  | 442 |  |  | 940 |  |  | 1,531 |  |  | 1,525 |  |  | 323 | % |  | 23 | %
BOLI income | 4,440 |  |  | 4,063 |  |  | 2,790 |  |  | 2,033 |  |  | 2,023 |  |  | 9 | % |  | 119 | %
Other (loss) income | (5,117) |  |  | 3,811 |  |  | 13,603 |  |  | 11,662 |  |  | (10,571) |  |  | (234) | % |  | (52) | %
Total non-interest income | 43,981 |  |  | 39,678 |  |  | 54,735 |  |  | 34,879 |  |  | 29,445 |  |  | 11 | % |  | 49 | %
Non-interest expense: |  |  |  |  |  |  |  |  |  |  |  |  |
Salaries and employee benefits | 159,041 |  |  | 163,398 |  |  | 136,092 |  |  | 107,982 |  |  | 109,164 |  |  | (3) | % |  | 46 | %
Occupancy and equipment, net | 43,070 |  |  | 50,550 |  |  | 41,700 |  |  | 34,021 |  |  | 35,042 |  |  | (15) | % |  | 23 | %
Intangible amortization | 29,879 |  |  | 35,553 |  |  | 12,660 |  |  | 1,019 |  |  | 1,025 |  |  | (16) | % |  | nm
FDIC assessments | 11,200 |  |  | 11,579 |  |  | 6,113 |  |  | 3,487 |  |  | 3,007 |  |  | (3) | % |  | 272 | %
Merger related expense | 18,938 |  |  | 29,649 |  |  | 115,898 |  |  | 11,637 |  |  | 769 |  |  | (36) | % |  | nm
Other expenses | 42,019 |  |  | 37,830 |  |  | 30,355 |  |  | 36,836 |  |  | 28,957 |  |  | 11 | % |  | 45 | %
Total non-interest expense | 304,147 |  |  | 328,559 |  |  | 342,818 |  |  | 194,982 |  |  | 177,964 |  |  | (7) | % |  | 71 | %
Income (loss) before provision (benefit) for income taxes | 183,972 |  |  | 179,080 |  |  | (18,924) |  |  | 112,428 |  |  | 111,513 |  |  | 3 | % |  | 65 | %
Provision (benefit) for income taxes | 48,127 |  |  | 45,703 |  |  | (4,886) |  |  | 29,464 |  |  | 27,473 |  |  | 5 | % |  | 75 | %
Net income (loss) | $ | 135,845 |  |  | $ | 133,377 |  |  | $ | (14,038) |  |  | $ | 82,964 |  |  | $ | 84,040 |  |  | 2 | % |  | 62 | %
Weighted average basic shares outstanding (1) | 208,070 |  |  | 207,977 |  |  | 156,383 |  |  | 129,321 |  |  | 129,319 |  |  | 0 | % |  | 61 | %
Weighted average diluted shares outstanding (1) | 208,645 |  |  | 208,545 |  |  | 156,383 |  |  | 129,801 |  |  | 129,733 |  |  | 0 | % |  | 61 | %
Earnings (loss) per common share – basic (1) | $ | 0.65 |  |  | $ | 0.64 |  |  | $ | (0.09) |  |  | $ | 0.64 |  |  | $ | 0.65 |  |  | 2 | % |  | 0 | %
Earnings (loss) per common share – diluted (1) | $ | 0.65 |  |  | $ | 0.64 |  |  | $ | (0.09) |  |  | $ | 0.64 |  |  | $ | 0.65 |  |  | 2 | % |  | 0 | %
nm = not meaningful |  |  |  |  |  |  |  |  |  |  |  |  |

(1) Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 7

Columbia Banking System, Inc.
Consolidated Statements of Operations
(Unaudited)
|  | Nine Months Ended |  | % Change
($ in thousands, except per share data) |  | Sep 30, 2023 |  | Sep 30, 2022 |  | Year over Year
Interest income: |  |  |  |  |  |
Loans and leases |  | $ | 1,535,874 |  |  | $ | 727,908 |  |  | 111 | %
Interest and dividends on investments: |  |  |  |  |  |
Taxable |  | 198,831 |  |  | 54,156 |  |  | 267 | %
Exempt from federal income tax |  | 17,143 |  |  | 4,063 |  |  | 322 | %
Dividends |  | 8,241 |  |  | 256 |  |  | nm
Temporary investments and interest bearing deposits |  | 87,604 |  |  | 9,387 |  |  | nm
Total interest income |  | 1,847,693 |  |  | 795,770 |  |  | 132 | %
Interest expense: |  |  |  |  |  |
Deposits |  | 290,995 |  |  | 17,021 |  |  | nm
Securities sold under agreement to repurchase and federal funds purchased |  | 2,697 |  |  | 674 |  |  | 300 | %
Borrowings |  | 186,848 |  |  | 897 |  |  | nm
Junior and other subordinated debentures |  | 27,605 |  |  | 12,641 |  |  | 118 | %
Total interest expense |  | 508,145 |  |  | 31,233 |  |  | nm
Net interest income |  | 1,339,548 |  |  | 764,537 |  |  | 75 | %
Provision for credit losses |  | 158,290 |  |  | 51,068 |  |  | 210 | %
Non-interest income: |  |  |  |  |  |
Service charges on deposits |  | 48,176 |  |  | 36,226 |  |  | 33 | %
Card-based fees |  | 40,670 |  |  | 28,353 |  |  | 43 | %
Brokerage revenue |  | 10,460 |  |  | 65 |  |  | nm
Residential mortgage banking revenue, net |  | 12,577 |  |  | 108,671 |  |  | (88) | %
Gain on sale of debt securities, net |  | 4 |  |  | 2 |  |  | 100 | %
Loss on equity securities, net |  | (336) |  |  | (7,383) |  |  | (95) | %
Gain on loan and lease sales, net |  | 3,253 |  |  | 5,165 |  |  | (37) | %
BOLI income |  | 11,293 |  |  | 6,220 |  |  | 82 | %
Other income (loss) |  | 12,297 |  |  | (12,670) |  |  | nm
Total non-interest income |  | 138,394 |  |  | 164,649 |  |  | (16) | %
Non-interest expense: |  |  |  |  |  |
Salaries and employee benefits |  | 458,531 |  |  | 333,244 |  |  | 38 | %
Occupancy and equipment, net |  | 135,320 |  |  | 104,430 |  |  | 30 | %
Intangible amortization |  | 78,092 |  |  | 3,076 |  |  | nm
FDIC assessments |  | 28,892 |  |  | 10,477 |  |  | 176 | %
Merger related expense |  | 164,485 |  |  | 5,719 |  |  | nm
Other expenses |  | 110,204 |  |  | 83,022 |  |  | 33 | %
Total non-interest expense |  | 975,524 |  |  | 539,968 |  |  | 81 | %
Income before provision for income taxes |  | 344,128 |  |  | 338,150 |  |  | 2 | %
Provision for income taxes |  | 88,944 |  |  | 84,362 |  |  | 5 | %
Net income |  | $ | 255,184 |  |  | $ | 253,788 |  |  | 1 | %
Weighted average basic shares outstanding (1) |  | 190,997 |  |  | 129,262 |  |  | 48 | %
Weighted average diluted shares outstanding (1) |  | 191,546 |  |  | 129,702 |  |  | 48 | %
Earnings per common share – basic (1) |  | $ | 1.34 |  |  | $ | 1.96 |  |  | (32) | %
Earnings per common share – diluted (1) |  | $ | 1.33 |  |  | $ | 1.96 |  |  | (32) | %
nm = not meaningful |  |  |  |  |  |

(1) Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 8

Columbia Banking System, Inc. Consolidated Balance Sheets
(Unaudited)
|  |  |  |  |  |  |  |  |  |  | % Change
($ in thousands, except per share data) | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Assets: |  |  |  |  |  |  |  |  |  |  |  |  |
Cash and due from banks | $ | 492,474 |  |  | $ | 538,653 |  |  | $ | 555,919 |  |  | $ | 327,313 |  |  | $ | 321,447 |  |  | (9) | % |  | 53 | %
Interest bearing cash and temporary investments | 1,911,221 |  |  | 2,868,563 |  |  | 3,079,266 |  |  | 967,330 |  |  | 1,232,412 |  |  | (33) | % |  | 55 | %
Investment securities: |  |  |  |  |  |  |  |  |  |  |  |  |
Equity and other, at fair value | 73,638 |  |  | 76,361 |  |  | 76,532 |  |  | 72,959 |  |  | 72,277 |  |  | (4) | % |  | 2 | %
Available for sale, at fair value | 8,503,986 |  |  | 8,998,428 |  |  | 9,249,600 |  |  | 3,196,166 |  |  | 3,136,391 |  |  | (5) | % |  | 171 | %
Held to maturity, at amortized cost | 2,344 |  |  | 2,388 |  |  | 2,432 |  |  | 2,476 |  |  | 2,547 |  |  | (2) | % |  | (8) | %
Loans held for sale | 60,313 |  |  | 183,633 |  |  | 49,338 |  |  | 71,647 |  |  | 148,275 |  |  | (67) | % |  | (59) | %
Loans and leases | 37,170,598 |  |  | 37,049,299 |  |  | 37,091,280 |  |  | 26,155,981 |  |  | 25,507,951 |  |  | 0 | % |  | 46 | %
Allowance for credit losses on loans and leases | (416,560) |  |  | (404,603) |  |  | (417,464) |  |  | (301,135) |  |  | (283,065) |  |  | 3 | % |  | 47 | %
Net loans and leases | 36,754,038 |  |  | 36,644,696 |  |  | 36,673,816 |  |  | 25,854,846 |  |  | 25,224,886 |  |  | 0 | % |  | 46 | %
Restricted equity securities | 168,524 |  |  | 258,524 |  |  | 246,525 |  |  | 47,144 |  |  | 40,993 |  |  | (35) | % |  | 311 | %
Premises and equipment, net | 337,855 |  |  | 368,698 |  |  | 375,190 |  |  | 176,016 |  |  | 165,305 |  |  | (8) | % |  | 104 | %
Operating lease right-of-use assets | 114,220 |  |  | 119,255 |  |  | 127,296 |  |  | 78,598 |  |  | 81,729 |  |  | (4) | % |  | 40 | %
Goodwill | 1,029,234 |  |  | 1,029,234 |  |  | 1,030,142 |  |  | — |  |  | — |  |  | 0 | % |  | nm
Other intangible assets, net | 636,883 |  |  | 666,762 |  |  | 702,315 |  |  | 4,745 |  |  | 5,764 |  |  | (4) | % |  | nm
Residential mortgage servicing rights, at fair value | 117,640 |  |  | 172,929 |  |  | 178,800 |  |  | 185,017 |  |  | 196,177 |  |  | (32) | % |  | (40) | %
Bank owned life insurance | 648,232 |  |  | 643,727 |  |  | 641,922 |  |  | 331,759 |  |  | 329,699 |  |  | 1 | % |  | 97 | %
Deferred tax asset, net | 469,841 |  |  | 362,880 |  |  | 351,229 |  |  | 132,823 |  |  | 128,120 |  |  | 29 | % |  | 267 | %
Other assets | 669,150 |  |  | 657,365 |  |  | 653,904 |  |  | 399,800 |  |  | 385,938 |  |  | 2 | % |  | 73 | %
Total assets | $ | 51,989,593 |  |  | $ | 53,592,096 |  |  | $ | 53,994,226 |  |  | $ | 31,848,639 |  |  | $ | 31,471,960 |  |  | (3) | % |  | 65 | %
Liabilities: |  |  |  |  |  |  |  |  |  |  |  |  |
Deposits |  |  |  |  |  |  |  |  |  |  |  |  |
Non-interest bearing | $ | 15,532,948 |  |  | $ | 16,019,408 |  |  | $ | 17,215,781 |  |  | $ | 10,288,849 |  |  | $ | 11,246,358 |  |  | (3) | % |  | 38 | %
Interest bearing | 26,091,420 |  |  | 24,815,509 |  |  | 24,370,566 |  |  | 16,776,763 |  |  | 15,570,749 |  |  | 5 | % |  | 68 | %
Total deposits | 41,624,368 |  |  | 40,834,917 |  |  | 41,586,347 |  |  | 27,065,612 |  |  | 26,817,107 |  |  | 2 | % |  | 55 | %
Securities sold under agreements to repurchase | 258,383 |  |  | 294,914 |  |  | 271,047 |  |  | 308,769 |  |  | 383,569 |  |  | (12) | % |  | (33) | %
Borrowings | 3,985,000 |  |  | 6,250,000 |  |  | 5,950,000 |  |  | 906,175 |  |  | 756,214 |  |  | (36) | % |  | 427 | %
Junior subordinated debentures, at fair value | 331,545 |  |  | 312,872 |  |  | 297,721 |  |  | 323,639 |  |  | 325,744 |  |  | 6 | % |  | 2 | %
Junior and other subordinated debentures, at amortized cost | 107,952 |  |  | 108,009 |  |  | 108,066 |  |  | 87,813 |  |  | 87,870 |  |  | 0 | % |  | 23 | %
Operating lease liabilities | 129,845 |  |  | 132,099 |  |  | 140,648 |  |  | 91,694 |  |  | 95,512 |  |  | (2) | % |  | 36 | %
Other liabilities | 920,338 |  |  | 831,097 |  |  | 755,674 |  |  | 585,111 |  |  | 588,430 |  |  | 11 | % |  | 56 | %
Total liabilities | 47,357,431 |  |  | 48,763,908 |  |  | 49,109,503 |  |  | 29,368,813 |  |  | 29,054,446 |  |  | (3) | % |  | 63 | %
Shareholders' equity: |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock | 5,798,167 |  |  | 5,792,792 |  |  | 5,788,553 |  |  | 3,450,493 |  |  | 3,448,007 |  |  | 0 | % |  | 68 | %
Accumulated deficit | (485,576) |  |  | (545,842) |  |  | (603,696) |  |  | (543,803) |  |  | (580,933) |  |  | (11) | % |  | (16) | %
Accumulated other comprehensive loss | (680,429) |  |  | (418,762) |  |  | (300,134) |  |  | (426,864) |  |  | (449,560) |  |  | 62 | % |  | 51 | %
Total shareholders' equity | 4,632,162 |  |  | 4,828,188 |  |  | 4,884,723 |  |  | 2,479,826 |  |  | 2,417,514 |  |  | (4) | % |  | 92 | %
Total liabilities and shareholders' equity | $ | 51,989,593 |  |  | $ | 53,592,096 |  |  | $ | 53,994,226 |  |  | $ | 31,848,639 |  |  | $ | 31,471,960 |  |  | (3) | % |  | 65 | %
Common shares outstanding at period end (1) | 208,575 |  |  | 208,514 |  |  | 208,429 |  |  | 129,321 |  |  | 129,320 |  |  | 0 | % |  | 61 | %
nm = not meaningful |  |  |  |  |  |  |  |  |  |  |  |  |

(1) Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 9

Columbia Banking System, Inc.
Financial Highlights
(Unaudited)
|  | Quarter Ended |  | % Change
|  | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Per Common Share Data: (5) |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends (5) |  | $ | 0.36 |  |  | $ | 0.36 |  |  | $ | 0.35 |  |  | $ | 0.35 |  |  | $ | 0.35 |  |  | 0 | % |  | 3 | %
Book value (5) |  | $ | 22.21 |  |  | $ | 23.16 |  |  | $ | 23.44 |  |  | $ | 19.18 |  |  | $ | 18.69 |  |  | (4) | % |  | 19 | %
Tangible book value (1),(5) |  | $ | 14.22 |  |  | $ | 15.02 |  |  | $ | 15.12 |  |  | $ | 19.14 |  |  | $ | 18.65 |  |  | (5) | % |  | (24) | %
Performance Ratios: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Efficiency ratio (2) |  | 57.82 | % |  | 62.60 | % |  | 79.71 | % |  | 57.24 | % |  | 56.07 | % |  | (4.78) |  |  | 1.75 |
Return on average assets ("ROAA") |  | 1.02 | % |  | 1.00 | % |  | (0.14) | % |  | 1.04 | % |  | 1.09 | % |  | 0.02 |  |  | (0.07) |
Pre-provision net revenue ("PPNR") ROAA (1) |  | 1.65 | % |  | 1.46 | % |  | 0.89 | % |  | 1.82 | % |  | 1.80 | % |  | 0.19 |  |  | (0.15) |
Return on average common equity |  | 11.07 | % |  | 10.84 | % |  | (1.70) | % |  | 13.50 | % |  | 12.99 | % |  | 0.23 |  |  | (1.92) |
Return on average tangible common equity (1) |  | 16.93 | % |  | 16.63 | % |  | (2.09) | % |  | 13.53 | % |  | 13.02 | % |  | 0.30 |  |  | 3.91 |
Performance Ratios - Operating: (1) |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating efficiency ratio (1), (2) |  | 51.97 | % |  | 54.85 | % |  | 53.46 | % |  | 52.01 | % |  | 51.72 | % |  | (2.88) |  |  | 0.25 |
Operating return on average assets (1) |  | 1.23 | % |  | 1.27 | % |  | 0.74 | % |  | 1.24 | % |  | 1.33 | % |  | (0.04) |  |  | (0.10) |
Operating PPNR return on average assets (1) |  | 1.94 | % |  | 1.82 | % |  | 2.01 | % |  | 2.10 | % |  | 2.12 | % |  | 0.12 |  |  | (0.18) |
Operating return on average common equity (1) |  | 13.40 | % |  | 13.77 | % |  | 8.66 | % |  | 16.14 | % |  | 15.86 | % |  | (0.37) |  |  | (2.46) |
Operating return on average tangible common equity (1) |  | 20.48 | % |  | 21.13 | % |  | 10.64 | % |  | 16.18 | % |  | 15.90 | % |  | (0.65) |  |  | 4.58 |
Average Balance Sheet Yields, Rates, & Ratios: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Yield on loans and leases |  | 6.08 | % |  | 5.95 | % |  | 5.55 | % |  | 4.92 | % |  | 4.41 | % |  | 0.13 |  |  | 1.67 |
Yield on earning assets (2) |  | 5.65 | % |  | 5.48 | % |  | 5.19 | % |  | 4.62 | % |  | 4.10 | % |  | 0.17 |  |  | 1.55 |
Cost of interest bearing deposits |  | 2.01 | % |  | 1.64 | % |  | 1.32 | % |  | 0.77 | % |  | 0.23 | % |  | 0.37 |  |  | 1.78 |
Cost of interest bearing liabilities |  | 2.72 | % |  | 2.45 | % |  | 1.82 | % |  | 1.05 | % |  | 0.39 | % |  | 0.27 |  |  | 2.33 |
Cost of total deposits |  | 1.23 | % |  | 0.99 | % |  | 0.80 | % |  | 0.46 | % |  | 0.14 | % |  | 0.24 |  |  | 1.09 |
Cost of total funding (3) |  | 1.81 | % |  | 1.61 | % |  | 1.16 | % |  | 0.65 | % |  | 0.23 | % |  | 0.20 |  |  | 1.58 |
Net interest margin (2) |  | 3.91 | % |  | 3.93 | % |  | 4.08 | % |  | 4.01 | % |  | 3.88 | % |  | (0.02) |  |  | 0.03 |
Average interest bearing cash / Average interest earning assets |  | 5.17 | % |  | 5.47 | % |  | 4.33 | % |  | 3.62 | % |  | 3.04 | % |  | (0.30) |  |  | 2.13 |
Average loans and leases / Average interest earning assets |  | 75.64 | % |  | 75.18 | % |  | 80.96 | % |  | 85.32 | % |  | 84.54 | % |  | 0.46 |  |  | (8.90) |
Average loans and leases / Average total deposits |  | 90.63 | % |  | 90.98 | % |  | 93.01 | % |  | 95.85 | % |  | 93.55 | % |  | (0.35) |  |  | (2.92) |
Average non-interest bearing deposits / Average total deposits |  | 38.55 | % |  | 40.05 | % |  | 39.55 | % |  | 40.30 | % |  | 42.29 | % |  | (1.50) |  |  | (3.74) |
Average total deposits / Average total funding (3) |  | 86.66 | % |  | 85.59 | % |  | 91.36 | % |  | 94.52 | % |  | 96.34 | % |  | 1.07 |  |  | (9.68) |
Select Credit & Capital Ratios: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-performing loans and leases to total loans and leases |  | 0.28 | % |  | 0.22 | % |  | 0.20 | % |  | 0.22 | % |  | 0.20 | % |  | 0.06 |  |  | 0.08 |
Non-performing assets to total assets |  | 0.20 | % |  | 0.15 | % |  | 0.14 | % |  | 0.18 | % |  | 0.16 | % |  | 0.05 |  |  | 0.04 |
Allowance for credit losses to loans and leases |  | 1.18 | % |  | 1.15 | % |  | 1.18 | % |  | 1.21 | % |  | 1.16 | % |  | 0.03 |  |  | 0.02 |
Total risk-based capital ratio (4) |  | 11.5 | % |  | 11.3 | % |  | 10.9 | % |  | 13.7 | % |  | 13.2 | % |  | 0.20 |  |  | (1.70) |
Common equity tier 1 risk-based capital ratio (4) |  | 9.4 | % |  | 9.2 | % |  | 8.9 | % |  | 11.0 | % |  | 10.7 | % |  | 0.20 |  |  | (1.30) |

(1) See GAAP to Non-GAAP Reconciliation.
(2) Tax exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.
(3) Total funding = Total deposits + Total borrowings.
(4) Estimated holding company ratios.
(5) Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 10

Columbia Banking System, Inc.
Financial Highlights
(Unaudited)
|  | Nine Months Ended |  | % Change
|  | Sep 30, 2023 |  | Sep 30, 2022 |  | Year over Year
Per Common Share Data: (4) |  |  |  |  |  |
Dividends (4) |  | $ | 1.07 |  |  | $ | 1.05 |  |  | 1.90 | %
Performance Ratios: |  |  |  |  |  |
Efficiency ratio (2) |  | 65.87 | % |  | 58.05 | % |  | 7.82 |
Return on average assets |  | 0.70 | % |  | 1.11 | % |  | (0.41) |
PPNR return on average assets (1) |  | 1.38 | % |  | 1.70 | % |  | (0.32) |
Return on average common equity |  | 7.77 | % |  | 12.94 | % |  | (5.17) |
Return on average tangible common equity (1) |  | 11.21 | % |  | 12.98 | % |  | (1.77) |
Performance Ratios - Operating: (1) |  |  |  |  |  |
Operating efficiency ratio (1), (2) |  | 53.43 | % |  | 57.03 | % |  | (3.60) |
Operating return on average assets (1) |  | 1.11 | % |  | 1.14 | % |  | (0.03) |
Operating PPNR return on average assets (1) |  | 1.91 | % |  | 1.74 | % |  | 0.17 |
Operating return on average common equity (1) |  | 12.34 | % |  | 13.28 | % |  | (0.94) |
Operating return on average tangible common equity (1) |  | 17.80 | % |  | 13.32 | % |  | 4.48 |
Average Balance Sheet Yields, Rates, & Ratios: |  |  |  |  |  |
Yield on loans and leases |  | 5.88 | % |  | 4.06 | % |  | 1.82 |
Yield on earning assets (2) |  | 5.46 | % |  | 3.62 | % |  | 1.84 |
Cost of interest bearing deposits |  | 1.68 | % |  | 0.15 | % |  | 1.53 |
Cost of interest bearing liabilities |  | 2.38 | % |  | 0.26 | % |  | 2.12 |
Cost of total deposits |  | 1.02 | % |  | 0.09 | % |  | 0.93 |
Cost of total funding (3) |  | 1.56 | % |  | 0.15 | % |  | 1.41 |
Net interest margin (2) |  | 3.96 | % |  | 3.48 | % |  | 0.48 |
Average interest bearing cash / Average interest earning assets |  | 5.05 | % |  | 5.87 | % |  | (0.82) |
Average loans and leases / Average interest earning assets |  | 76.91 | % |  | 80.80 | % |  | (3.89) |
Average loans and leases / Average total deposits |  | 91.42 | % |  | 89.21 | % |  | 2.21 |
Average non-interest bearing deposits / Average total deposits |  | 39.28 | % |  | 41.89 | % |  | (2.61) |
Average total deposits / Average total funding (3) |  | 87.53 | % |  | 96.61 | % |  | (9.08) |

(1) See GAAP to Non-GAAP Reconciliation.
(2) Tax exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.
(3) Total funding = Total deposits + Total borrowings.
(4) Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 11

Columbia Banking System, Inc.
Loan & Lease Portfolio Balances and Mix
(Unaudited)
| Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | % Change
($ in thousands) | Amount |  | Amount |  | Amount |  | Amount |  | Amount |  | Seq. Quarter |  | Year over Year
Loans and leases: |  |  |  |  |  |  |  |  |  |  |  |  |
Commercial real estate: |  |  |  |  |  |  |  |  |  |  |  |  |
Non-owner occupied term, net | $ | 6,490,638 |  |  | $ | 6,434,673 |  |  | $ | 6,353,550 |  |  | $ | 3,894,840 |  |  | $ | 3,846,426 |  |  | 1 | % |  | 69 | %
Owner occupied term, net | 5,235,227 |  |  | 5,254,401 |  |  | 5,156,848 |  |  | 2,567,761 |  |  | 2,549,761 |  |  | 0 | % |  | 105 | %
Multifamily, net | 5,684,495 |  |  | 5,622,875 |  |  | 5,590,587 |  |  | 5,285,791 |  |  | 5,090,661 |  |  | 1 | % |  | 12 | %
Construction & development, net | 1,669,918 |  |  | 1,528,924 |  |  | 1,467,561 |  |  | 1,077,346 |  |  | 1,036,931 |  |  | 9 | % |  | 61 | %
Residential development, net | 354,922 |  |  | 388,641 |  |  | 440,667 |  |  | 200,838 |  |  | 205,935 |  |  | (9) | % |  | 72 | %
Commercial: |  |  |  |  |  |  |  |  |  |  |  |  |
Term, net | 5,437,915 |  |  | 5,449,787 |  |  | 5,906,774 |  |  | 3,029,547 |  |  | 3,003,424 |  |  | 0 | % |  | 81 | %
Lines of credit & other, net | 2,353,548 |  |  | 2,268,790 |  |  | 2,184,762 |  |  | 960,054 |  |  | 914,507 |  |  | 4 | % |  | 157 | %
Leases & equipment finance, net | 1,728,991 |  |  | 1,740,037 |  |  | 1,746,267 |  |  | 1,706,172 |  |  | 1,669,817 |  |  | (1) | % |  | 4 | %
Residential: |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage, net | 6,121,838 |  |  | 6,272,898 |  |  | 6,187,964 |  |  | 5,647,035 |  |  | 5,470,624 |  |  | (2) | % |  | 12 | %
Home equity loans & lines, net | 1,899,948 |  |  | 1,898,958 |  |  | 1,870,002 |  |  | 1,631,965 |  |  | 1,565,094 |  |  | 0 | % |  | 21 | %
Consumer & other, net | 193,158 |  |  | 189,315 |  |  | 186,298 |  |  | 154,632 |  |  | 154,771 |  |  | 2 | % |  | 25 | %
Total loans and leases, net of deferred fees and costs | $ | 37,170,598 |  |  | $ | 37,049,299 |  |  | $ | 37,091,280 |  |  | $ | 26,155,981 |  |  | $ | 25,507,951 |  |  | 0 | % |  | 46 | %
Loans and leases mix: |  |  |  |  |  |  |  |  |  |  |  |  |
Commercial real estate: |  |  |  |  |  |  |  |  |  |  |  |  |
Non-owner occupied term, net | 17 | % |  | 17 | % |  | 16 | % |  | 15 | % |  | 15 | % |  |  |  |
Owner occupied term, net | 14 | % |  | 14 | % |  | 14 | % |  | 10 | % |  | 10 | % |  |  |  |
Multifamily, net | 15 | % |  | 15 | % |  | 15 | % |  | 20 | % |  | 20 | % |  |  |  |
Construction & development, net | 4 | % |  | 4 | % |  | 4 | % |  | 4 | % |  | 4 | % |  |  |  |
Residential development, net | 1 | % |  | 1 | % |  | 1 | % |  | 1 | % |  | 1 | % |  |  |  |
Commercial: |  |  |  |  |  |  |  |  |  |  |  |  |
Term, net | 15 | % |  | 15 | % |  | 16 | % |  | 12 | % |  | 12 | % |  |  |  |
Lines of credit & other, net | 6 | % |  | 6 | % |  | 6 | % |  | 4 | % |  | 4 | % |  |  |  |
Leases & equipment finance, net | 5 | % |  | 5 | % |  | 5 | % |  | 6 | % |  | 6 | % |  |  |  |
Residential: |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage, net | 17 | % |  | 17 | % |  | 17 | % |  | 21 | % |  | 21 | % |  |  |  |
Home equity loans & lines, net | 5 | % |  | 5 | % |  | 5 | % |  | 6 | % |  | 6 | % |  |  |  |
Consumer & other, net | 1 | % |  | 1 | % |  | 1 | % |  | 1 | % |  | 1 | % |  |  |  |
Total | 100 | % |  | 100 | % |  | 100 | % |  | 100 | % |  | 100 | % |  |  |  |

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 12

Columbia Banking System, Inc.
Deposit Portfolio Balances and Mix
(Unaudited)
| Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | % Change
($ in thousands) | Amount |  | Amount |  | Amount |  | Amount |  | Amount |  | Seq. Quarter |  | Year over Year
Deposits: |  |  |  |  |  |  |  |  |  |  |  |  |
Demand, non-interest bearing | $ | 15,532,948 |  |  | $ | 16,019,408 |  |  | $ | 17,215,781 |  |  | $ | 10,288,849 |  |  | $ | 11,246,358 |  |  | (3) | % |  | 38 | %
Demand, interest bearing | 6,898,831 |  |  | 6,300,082 |  |  | 5,900,462 |  |  | 4,080,469 |  |  | 3,903,746 |  |  | 10 | % |  | 77 | %
Money market | 10,349,217 |  |  | 10,115,908 |  |  | 10,681,422 |  |  | 7,721,011 |  |  | 7,601,506 |  |  | 2 | % |  | 36 | %
Savings | 3,018,706 |  |  | 3,171,714 |  |  | 3,469,112 |  |  | 2,265,052 |  |  | 2,455,917 |  |  | (5) | % |  | 23 | %
Time | 5,824,666 |  |  | 5,227,805 |  |  | 4,319,570 |  |  | 2,710,231 |  |  | 1,609,580 |  |  | 11 | % |  | 262 | %
Total | $ | 41,624,368 |  |  | $ | 40,834,917 |  |  | $ | 41,586,347 |  |  | $ | 27,065,612 |  |  | $ | 26,817,107 |  |  | 2 | % |  | 55 | %
Total core deposits (1) | $ | 37,597,830 |  |  | $ | 37,639,368 |  |  | $ | 39,155,298 |  |  | $ | 25,616,010 |  |  | $ | 26,292,548 |  |  | 0 | % |  | 43 | %
Deposit mix: |  |  |  |  |  |  |  |  |  |  |  |  |
Demand, non-interest bearing | 37 | % |  | 39 | % |  | 41 | % |  | 38 | % |  | 42 | % |  |  |  |
Demand, interest bearing | 17 | % |  | 15 | % |  | 14 | % |  | 15 | % |  | 15 | % |  |  |  |
Money market | 25 | % |  | 25 | % |  | 26 | % |  | 29 | % |  | 28 | % |  |  |  |
Savings | 7 | % |  | 8 | % |  | 9 | % |  | 8 | % |  | 9 | % |  |  |  |
Time | 14 | % |  | 13 | % |  | 10 | % |  | 10 | % |  | 6 | % |  |  |  |
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 2023 Results
October 18, 2023
Page 13

| Columbia Banking System, Inc.
| Credit Quality – Non-performing Assets
| (Unaudited)
|  | Quarter Ended |  | % Change
($ in thousands) | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Non-performing assets: |  |  |  |  |  |  |  |  |  |  |  |  |
Loans and leases on non-accrual status: |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial real estate, net | $ | 26,053 |  |  | $ | 10,994 |  |  | $ | 15,612 |  |  | $ | 5,011 |  |  | $ | 5,403 |  |  | 137 | % |  | 382 | %
| Commercial, net | 44,341 |  |  | 39,316 |  |  | 42,301 |  |  | 25,691 |  |  | 18,652 |  |  | 13 | % |  | 138 | %
| Residential, net | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | nm |  | nm
| Consumer & other, net | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | nm |  | nm
| Total loans and leases on non-accrual status | 70,394 |  |  | 50,310 |  |  | 57,913 |  |  | 30,702 |  |  | 24,055 |  |  | 40 | % |  | 193 | %
Loans and leases past due 90+ days and accruing (1): |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial real estate, net | 71 |  |  | 184 |  |  | 1 |  |  | 1 |  |  | 1 |  |  | (61) | % |  | nm
| Commercial, net | 8,606 |  |  | 7,720 |  |  | 151 |  |  | 7,909 |  |  | 5,143 |  |  | 11 | % |  | 67 | %
| Residential, net (1) | 25,180 |  |  | 21,370 |  |  | 17,423 |  |  | 19,894 |  |  | 21,411 |  |  | 18 | % |  | 18 | %
| Consumer & other, net | 240 |  |  | 399 |  |  | 140 |  |  | 134 |  |  | 152 |  |  | (40) | % |  | 58 | %
| Total loans and leases past due 90+ days and accruing (1) | 34,097 |  |  | 29,673 |  |  | 17,715 |  |  | 27,938 |  |  | 26,707 |  |  | 15 | % |  | 28 | %
Total non-performing loans and leases | 104,491 |  |  | 79,983 |  |  | 75,628 |  |  | 58,640 |  |  | 50,762 |  |  | 31 | % |  | 106 | %
Other real estate owned | 1,170 |  |  | 278 |  |  | 409 |  |  | 203 |  |  | — |  |  | 321 | % |  | nm
Total non-performing assets | $ | 105,661 |  |  | $ | 80,261 |  |  | $ | 76,037 |  |  | $ | 58,843 |  |  | $ | 50,762 |  |  | 32 | % |  | 108 | %
Loans and leases past due 31-89 days | $ | 82,918 |  |  | $ | 73,376 |  |  | $ | 78,641 |  |  | $ | 64,893 |  |  | $ | 53,538 |  |  | 13 | % |  | 55 | %
Loans and leases past due 31-89 days to total loans and leases | 0.22 | % |  | 0.20 | % |  | 0.21 | % |  | 0.25 | % |  | 0.21 | % |  | 0.02 |  |  | 0.01 |
Non-performing loans and leases to total loans and leases (1) | 0.28 | % |  | 0.22 | % |  | 0.20 | % |  | 0.22 | % |  | 0.20 | % |  | 0.06 |  |  | 0.08 |
Non-performing assets to total assets (1) | 0.20 | % |  | 0.15 | % |  | 0.14 | % |  | 0.18 | % |  | 0.16 | % |  | 0.05 |  |  | 0.04 |
nm = not meaningful |  |  |  |  |  |  |  |  |  |  |  |  |

(1) Excludes certain mortgage loans guaranteed by Ginnie Mae, which Columbia has the unilateral right to repurchase but has not done so, totaling $700,000, $1.6 million, $5.4 million, $6.6 million and $1.0 million at September 30, 2023, June 30, 2023, March 31, 2023, December 31, 2022 and September 30, 2022, respectively.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 14

| Columbia Banking System, Inc.
| Credit Quality – Allowance for Credit Losses
| (Unaudited)
|  | Quarter Ended |  | % Change
($ in thousands) | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Allowance for credit losses on loans and leases (ACLLL) |  |  |  |  |  |  |  |  |  |  |  |  |
Balance, beginning of period | $ | 404,603 |  |  | $ | 417,464 |  |  | $ | 301,135 |  |  | $ | 283,065 |  |  | $ | 261,111 |  |  | (3) | % |  | 55 | %
Initial ACL recorded for PCD loans acquired during the period | — |  |  | — |  |  | 26,492 |  |  | — |  |  | — |  |  | nm |  | nm
Provision for credit losses on loans and leases (1) | 35,082 |  |  | 15,216 |  |  | 106,498 |  |  | 30,580 |  |  | 28,542 |  |  | 131 | % |  | 23 | %
Charge-offs |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial real estate, net | — |  |  | (174) |  |  | — |  |  | (128) |  |  | — |  |  | nm |  | nm
| Commercial, net | (26,629) |  |  | (32,036) |  |  | (19,248) |  |  | (14,721) |  |  | (9,459) |  |  | (17) | % |  | 182 | %
| Residential, net | (206) |  |  | (4) |  |  | (248) |  |  | (53) |  |  | (4) |  |  | nm |  | nm
| Consumer & other, net | (1,884) |  |  | (1,264) |  |  | (773) |  |  | (906) |  |  | (929) |  |  | 49 | % |  | 103 | %
| Total charge-offs | (28,719) |  |  | (33,478) |  |  | (20,269) |  |  | (15,808) |  |  | (10,392) |  |  | (14) | % |  | 176 | %
Recoveries |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial real estate, net | 31 |  |  | 209 |  |  | 58 |  |  | 163 |  |  | 123 |  |  | (85) | % |  | (75) | %
| Commercial, net | 4,901 |  |  | 4,511 |  |  | 3,058 |  |  | 2,708 |  |  | 2,842 |  |  | 9 | % |  | 72 | %
| Residential, net | 156 |  |  | 63 |  |  | 123 |  |  | 24 |  |  | 249 |  |  | 148 | % |  | (37) | %
| Consumer & other, net | 506 |  |  | 618 |  |  | 369 |  |  | 403 |  |  | 590 |  |  | (18) | % |  | (14) | %
| Total recoveries | 5,594 |  |  | 5,401 |  |  | 3,608 |  |  | 3,298 |  |  | 3,804 |  |  | 4 | % |  | 47 | %
Net (charge-offs) recoveries |  |  |  |  |  |  |  |  |  |  |  |  |
| Commercial real estate, net | 31 |  |  | 35 |  |  | 58 |  |  | 35 |  |  | 123 |  |  | (11) | % |  | (75) | %
| Commercial, net | (21,728) |  |  | (27,525) |  |  | (16,190) |  |  | (12,013) |  |  | (6,617) |  |  | (21) | % |  | 228 | %
| Residential, net | (50) |  |  | 59 |  |  | (125) |  |  | (29) |  |  | 245 |  |  | (185) | % |  | (120) | %
| Consumer & other, net | (1,378) |  |  | (646) |  |  | (404) |  |  | (503) |  |  | (339) |  |  | 113 | % |  | 306 | %
| Total net charge-offs | (23,125) |  |  | (28,077) |  |  | (16,661) |  |  | (12,510) |  |  | (6,588) |  |  | (18) | % |  | 251 | %
Balance, end of period | $ | 416,560 |  |  | $ | 404,603 |  |  | $ | 417,464 |  |  | $ | 301,135 |  |  | $ | 283,065 |  |  | 3 | % |  | 47 | %
Reserve for unfunded commitments |  |  |  |  |  |  |  |  |  |  |  |  |
Balance, beginning of period | $ | 19,827 |  |  | $ | 19,029 |  |  | $ | 14,221 |  |  | $ | 11,853 |  |  | $ | 12,823 |  |  | 4 | % |  | 55 | %
Initial ACL recorded for unfunded commitments acquired during the period | — |  |  | — |  |  | 5,767 |  |  | — |  |  | — |  |  | nm |  | nm
Provision (recapture) for credit losses on unfunded commitments | 1,655 |  |  | 798 |  |  | (959) |  |  | 2,368 |  |  | (970) |  |  | 107 | % |  | nm
Balance, end of period | 21,482 |  |  | 19,827 |  |  | 19,029 |  |  | 14,221 |  |  | 11,853 |  |  | 8 | % |  | 81 | %
Total Allowance for credit losses (ACL) | $ | 438,042 |  |  | $ | 424,430 |  |  | $ | 436,493 |  |  | $ | 315,356 |  |  | $ | 294,918 |  |  | 3 | % |  | 49 | %
Net charge-offs to average loans and leases (annualized) | 0.25 | % |  | 0.30 | % |  | 0.23 | % |  | 0.19 | % |  | 0.11 | % |  | (0.05) |  |  | 0.14 |
Recoveries to gross charge-offs | 19.48 | % |  | 16.13 | % |  | 17.80 | % |  | 20.86 | % |  | 36.61 | % |  | 3.35 |  |  | (17.13) |
ACLLL to loans and leases | 1.12 | % |  | 1.09 | % |  | 1.13 | % |  | 1.15 | % |  | 1.11 | % |  | 0.03 |  |  | 0.01 |
ACL to loans and leases | 1.18 | % |  | 1.15 | % |  | 1.18 | % |  | 1.21 | % |  | 1.16 | % |  | 0.03 |  |  | 0.02 |
nm = not meaningful |  |  |  |  |  |  |  |  |  |  |  |  |

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

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 15

Columbia Banking System, Inc.
Credit Quality – Allowance for Credit Losses
(Unaudited)
|  | Nine Months Ended |  | % Change
($ in thousands) |  | Sep 30, 2023 |  | Sep 30, 2022 |  | Year over Year
Allowance for credit losses on loans and leases (ACLLL) |  |  |  |  |  |
Balance, beginning of period |  | $ | 301,135 |  |  | $ | 248,412 |  |  | 21 | %
Initial ACL recorded for PCD loans acquired during the period |  | 26,492 |  |  | — |  |  | nm
Provision for credit losses on loans and leases (1) |  | 156,796 |  |  | 53,025 |  |  | 196 | %
Charge-offs |  |  |  |  |  |
| Commercial real estate, net |  | (174) |  |  | (8) |  |  | nm
| Commercial, net |  | (77,913) |  |  | (26,352) |  |  | 196 | %
| Residential, net |  | (458) |  |  | (171) |  |  | 168 | %
| Consumer & other, net |  | (3,921) |  |  | (2,650) |  |  | 48 | %
| Total charge-offs |  | (82,466) |  |  | (29,181) |  |  | 183 | %
Recoveries |  |  |  |  |  |
| Commercial real estate, net |  | 298 |  |  | 221 |  |  | 35 | %
| Commercial, net |  | 12,470 |  |  | 8,321 |  |  | 50 | %
| Residential, net |  | 342 |  |  | 638 |  |  | (46) | %
| Consumer & other, net |  | 1,493 |  |  | 1,629 |  |  | (8) | %
| Total recoveries |  | 14,603 |  |  | 10,809 |  |  | 35 | %
Net (charge-offs) recoveries |  |  |  |  |  |
| Commercial real estate, net |  | 124 |  |  | 213 |  |  | (42) | %
| Commercial, net |  | (65,443) |  |  | (18,031) |  |  | 263 | %
| Residential, net |  | (116) |  |  | 467 |  |  | (125) | %
| Consumer & other, net |  | (2,428) |  |  | (1,021) |  |  | 138 | %
| Total net charge-offs |  | (67,863) |  |  | (18,372) |  |  | 269 | %
Balance, end of period |  | $ | 416,560 |  |  | $ | 283,065 |  |  | 47 | %
Reserve for unfunded commitments |  |  |  |  |  |
Balance, beginning of period |  | $ | 14,221 |  |  | $ | 12,767 |  |  | 11 | %
Initial ACL recorded for unfunded commitments acquired during the period |  | 5,767 |  |  | — |  |  | nm
Provision (recapture) for credit losses on unfunded commitments |  | 1,494 |  |  | (914) |  |  | nm
Balance, end of period |  | 21,482 |  |  | 11,853 |  |  | 81 | %
Total Allowance for credit losses (ACL) |  | $ | 438,042 |  |  | $ | 294,918 |  |  | 49 | %
Net charge-offs to average loans and leases (annualized) |  | 0.26 | % |  | 0.10 | % |  | 0.16 |
Recoveries to gross charge-offs |  | 17.71 | % |  | 37.04 | % |  | (19.33) |
nm = not meaningful |  |  |  |  |  |

(1) For the nine months ended September 30, 2023, the provision for credit losses on loans and leases includes $88.4 million initial provision related to non-PCD loans acquired during the period.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 16

Columbia Banking System, Inc.
Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates
(Unaudited)
| Quarter Ended
| September 30, 2023 |  | June 30, 2023 |  | September 30, 2022
($ in thousands) | Average Balance |  | Interest Income or Expense |  | Average Yields or Rates |  | Average Balance |  | Interest Income or Expense |  | Average Yields or Rates |  | Average Balance |  | Interest Income or Expense |  | Average Yields or Rates
INTEREST-EARNING ASSETS: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans held for sale | $ | 199,855 |  |  | $ | 1,741 |  |  | 3.49 | % |  | $ | 46,794 |  |  | $ | 682 |  |  | 5.83 | % |  | $ | 173,397 |  |  | $ | 2,205 |  |  | 5.09 | %
Loans and leases (1) | 37,050,518 |  |  | 567,929 |  |  | 6.08 | % |  | 37,169,315 |  |  | 551,997 |  |  | 5.95 | % |  | 24,886,203 |  |  | 276,625 |  |  | 4.41 | %
Taxable securities | 8,356,165 |  |  | 85,007 |  |  | 4.07 | % |  | 8,656,147 |  |  | 81,617 |  |  | 3.77 | % |  | 3,271,185 |  |  | 18,261 |  |  | 2.23 | %
Non-taxable securities (2) | 844,417 |  |  | 8,085 |  |  | 3.83 | % |  | 865,278 |  |  | 8,010 |  |  | 3.70 | % |  | 212,847 |  |  | 1,651 |  |  | 3.10 | %
Temporary investments and interest-bearing cash | 2,530,150 |  |  | 34,407 |  |  | 5.40 | % |  | 2,704,984 |  |  | 34,616 |  |  | 5.13 | % |  | 893,471 |  |  | 5,115 |  |  | 2.27 | %
Total interest-earning assets | 48,981,105 |  |  | $ | 697,169 |  |  | 5.65 | % |  | 49,442,518 |  |  | $ | 676,922 |  |  | 5.48 | % |  | 29,437,103 |  |  | $ | 303,857 |  |  | 4.10 | %
Goodwill and other intangible assets | 1,684,093 |  |  |  |  |  |  | 1,718,705 |  |  |  |  |  |  | 6,343 |  |  |  |  |
Other assets | 2,346,163 |  |  |  |  |  |  | 2,379,351 |  |  |  |  |  |  | 1,224,731 |  |  |  |  |
Total assets | $ | 53,011,361 |  |  |  |  |  |  | $ | 53,540,574 |  |  |  |  |  |  | $ | 30,668,177 |  |  |  |  |
INTEREST-BEARING LIABILITIES: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest-bearing demand deposits | $ | 6,578,849 |  |  | $ | 25,209 |  |  | 1.52 | % |  | $ | 6,131,117 |  |  | $ | 17,277 |  |  | 1.15 | % |  | $ | 3,829,688 |  |  | $ | 1,705 |  |  | 0.18 | %
Money market deposits | 10,249,028 |  |  | 50,039 |  |  | 1.94 | % |  | 10,362,495 |  |  | 41,703 |  |  | 1.60 | % |  | 7,550,791 |  |  | 5,817 |  |  | 0.31 | %
Savings deposits | 3,109,779 |  |  | 1,253 |  |  | 0.16 | % |  | 3,297,138 |  |  | 877 |  |  | 0.11 | % |  | 2,468,187 |  |  | 250 |  |  | 0.04 | %
Time deposits | 5,184,089 |  |  | 50,473 |  |  | 3.86 | % |  | 4,703,967 |  |  | 40,551 |  |  | 3.46 | % |  | 1,501,724 |  |  | 1,318 |  |  | 0.35 | %
Total interest-bearing deposits | 25,121,745 |  |  | 126,974 |  |  | 2.01 | % |  | 24,494,717 |  |  | 100,408 |  |  | 1.64 | % |  | 15,350,390 |  |  | 9,090 |  |  | 0.23 | %
Repurchase agreements and federal funds purchased | 268,444 |  |  | 1,220 |  |  | 1.80 | % |  | 284,347 |  |  | 1,071 |  |  | 1.51 | % |  | 509,559 |  |  | 545 |  |  | 0.42 | %
Borrowings | 5,603,207 |  |  | 77,080 |  |  | 5.46 | % |  | 6,187,363 |  |  | 81,004 |  |  | 5.25 | % |  | 90,475 |  |  | 798 |  |  | 3.50 | %
Junior and other subordinated debentures | 420,582 |  |  | 9,864 |  |  | 9.30 | % |  | 405,989 |  |  | 9,271 |  |  | 9.16 | % |  | 409,151 |  |  | 5,491 |  |  | 5.33 | %
Total interest-bearing liabilities | 31,413,978 |  |  | $ | 215,138 |  |  | 2.72 | % |  | 31,372,416 |  |  | $ | 191,754 |  |  | 2.45 | % |  | 16,359,575 |  |  | $ | 15,924 |  |  | 0.39 | %
Non-interest-bearing deposits | 15,759,720 |  |  |  |  |  |  | 16,361,541 |  |  |  |  |  |  | 11,250,764 |  |  |  |  |
Other liabilities | 970,688 |  |  |  |  |  |  | 871,378 |  |  |  |  |  |  | 490,572 |  |  |  |  |
Total liabilities | 48,144,386 |  |  |  |  |  |  | 48,605,335 |  |  |  |  |  |  | 28,100,911 |  |  |  |  |
Common equity | 4,866,975 |  |  |  |  |  |  | 4,935,239 |  |  |  |  |  |  | 2,567,266 |  |  |  |  |
Total liabilities and shareholders' equity | $ | 53,011,361 |  |  |  |  |  |  | $ | 53,540,574 |  |  |  |  |  |  | $ | 30,668,177 |  |  |  |  |
NET INTEREST INCOME (2) |  |  | $ | 482,031 |  |  |  |  |  |  | $ | 485,168 |  |  |  |  |  |  | $ | 287,933 |  |  |
NET INTEREST SPREAD |  |  |  |  | 2.93 | % |  |  |  |  |  | 3.03 | % |  |  |  |  |  | 3.71 | %
NET INTEREST INCOME TO EARNING ASSETS OR NET INTEREST MARGIN (1), (2) |  |  |  |  | 3.91 | % |  |  |  |  |  | 3.93 | % |  |  |  |  |  | 3.88 | %

(1)Non-accrual loans and leases are included in the average balance.
(2)Tax-exempt income has been adjusted to a tax equivalent basis at a 21% tax rate. The amount of such adjustment was an addition to recorded income of approximately $1.2 million for the three months ended September 30, 2023, as compared to $1.2 million for the three months ended June 30, 2023 and $329,000 for the three months ended September 30, 2022.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 17

Columbia Banking System, Inc.
Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates
(Unaudited)
| Nine Months Ended
| September 30, 2023 |  | September 30, 2022
($ in thousands) | 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 | $ | 100,753 |  |  | $ | 3,222 |  |  | 4.26 | % |  | $ | 240,928 |  |  | $ | 7,209 |  |  | 3.99 | %
Loans and leases (1) | 34,765,319 |  |  | 1,532,652 |  |  | 5.88 | % |  | 23,676,201 |  |  | 720,699 |  |  | 4.06 | %
Taxable securities | 7,336,862 |  |  | 207,072 |  |  | 3.76 | % |  | 3,445,386 |  |  | 54,412 |  |  | 2.11 | %
Non-taxable securities (2) | 717,064 |  |  | 20,163 |  |  | 3.75 | % |  | 222,375 |  |  | 5,098 |  |  | 3.06 | %
Temporary investments and interest-bearing cash | 2,283,461 |  |  | 87,604 |  |  | 5.13 | % |  | 1,718,832 |  |  | 9,387 |  |  | 0.73 | %
Total interest-earning assets | 45,203,459 |  |  | $ | 1,850,713 |  |  | 5.46 | % |  | 29,303,722 |  |  | $ | 796,805 |  |  | 3.62 | %
Goodwill and other intangible assets | 1,345,833 |  |  |  |  |  |  | 7,369 |  |  |  |  |
Other assets | 2,159,775 |  |  |  |  |  |  | 1,229,936 |  |  |  |  |
Total assets | $ | 48,709,067 |  |  |  |  |  |  | $ | 30,541,027 |  |  |  |  |
INTEREST-BEARING LIABILITIES: |  |  |  |  |  |  |  |  |  |  |
Interest-bearing demand deposits | $ | 5,829,737 |  |  | $ | 52,301 |  |  | 1.20 | % |  | $ | 3,846,202 |  |  | $ | 2,813 |  |  | 0.10 | %
Money market deposits | 9,857,001 |  |  | 123,980 |  |  | 1.68 | % |  | 7,519,200 |  |  | 8,942 |  |  | 0.16 | %
Savings deposits | 3,032,653 |  |  | 2,686 |  |  | 0.12 | % |  | 2,433,651 |  |  | 654 |  |  | 0.04 | %
Time deposits | 4,371,643 |  |  | 112,028 |  |  | 3.43 | % |  | 1,623,742 |  |  | 4,612 |  |  | 0.38 | %
Total interest-bearing deposits | 23,091,034 |  |  | 290,995 |  |  | 1.68 | % |  | 15,422,795 |  |  | 17,021 |  |  | 0.15 | %
Repurchase agreements and federal funds purchased | 277,896 |  |  | 2,697 |  |  | 1.30 | % |  | 502,998 |  |  | 674 |  |  | 0.18 | %
Borrowings | 4,726,335 |  |  | 186,848 |  |  | 5.29 | % |  | 34,662 |  |  | 897 |  |  | 3.46 | %
Junior and other subordinated debentures | 414,855 |  |  | 27,605 |  |  | 8.90 | % |  | 394,803 |  |  | 12,641 |  |  | 4.28 | %
Total interest-bearing liabilities | 28,510,120 |  |  | $ | 508,145 |  |  | 2.38 | % |  | 16,355,258 |  |  | $ | 31,233 |  |  | 0.26 | %
Non-interest-bearing deposits | 14,937,028 |  |  |  |  |  |  | 11,115,618 |  |  |  |  |
Other liabilities | 872,370 |  |  |  |  |  |  | 448,426 |  |  |  |  |
Total liabilities | 44,319,518 |  |  |  |  |  |  | 27,919,302 |  |  |  |  |
Common equity | 4,389,549 |  |  |  |  |  |  | 2,621,725 |  |  |  |  |
Total liabilities and shareholders' equity | $ | 48,709,067 |  |  |  |  |  |  | $ | 30,541,027 |  |  |  |  |
NET INTEREST INCOME (2) |  |  | $ | 1,342,568 |  |  |  |  |  |  | $ | 765,572 |  |  |
NET INTEREST SPREAD |  |  |  |  | 3.08 | % |  |  |  |  |  | 3.36 | %
NET INTEREST INCOME TO EARNING ASSETS OR NET INTEREST MARGIN (1), (2) |  |  |  |  | 3.96 | % |  |  |  |  |  | 3.48 | %

(1)Non-accrual loans and leases are included in the average balance.
(2)Tax-exempt income has been adjusted to a tax equivalent basis at a 21% tax rate. The amount of such adjustment was an addition to recorded income of approximately $3.0 million for the nine months ended September 30, 2023, as compared to $1.0 million for the same period in 2022.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 18

Columbia Banking System, Inc.
Residential Mortgage Banking Activity
(Unaudited)
| Quarter Ended |  | % Change
($ in thousands) | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Residential mortgage banking revenue: |  |  |  |  |  |  |  |  |  |  |  |  |
Origination and sale | $ | 2,442 |  |  | $ | 3,166 |  |  | $ | 3,587 |  |  | $ | 4,252 |  |  | $ | 10,515 |  |  | (23) | % |  | (77) | %
Servicing | 8,887 |  |  | 9,167 |  |  | 9,397 |  |  | 9,184 |  |  | 9,529 |  |  | (3) | % |  | (7) | %
Change in fair value of MSR asset: |  |  |  |  |  |  |  |  |  |  |  |  |
Changes due to collection/realization of expected cash flows over time | (4,801) |  |  | (4,797) |  |  | (4,881) |  |  | (4,986) |  |  | (4,978) |  |  | 0 | % |  | (4) | %
Changes due to valuation inputs or assumptions | 5,308 |  |  | (2,242) |  |  | (2,937) |  |  | (9,914) |  |  | 16,403 |  |  | nm |  | (68) | %
MSR hedge (loss) gain | (4,733) |  |  | (7,636) |  |  | 2,650 |  |  | (348) |  |  | (14,128) |  |  | (38) | % |  | (66) | %
Total | $ | 7,103 |  |  | $ | (2,342) |  |  | $ | 7,816 |  |  | $ | (1,812) |  |  | $ | 17,341 |  |  | nm |  | (59) | %
Closed loan volume for-sale | $ | 103,333 |  |  | $ | 119,476 |  |  | $ | 131,726 |  |  | $ | 216,833 |  |  | $ | 396,979 |  |  | (14) | % |  | (74) | %
Gain on sale margin | 2.36 | % |  | 2.65 | % |  | 2.72 | % |  | 1.96 | % |  | 2.65 | % |  | (0.29) |  |  | (0.29) |
Residential mortgage servicing rights: |  |  |  |  |  |  |  |  |  |  |  |  |
Balance, beginning of period | $ | 172,929 |  |  | $ | 178,800 |  |  | $ | 185,017 |  |  | $ | 196,177 |  |  | $ | 179,558 |  |  | (3) | % |  | (4) | %
Additions for new MSR capitalized | 1,658 |  |  | 1,168 |  |  | 1,601 |  |  | 3,740 |  |  | 5,194 |  |  | 42 | % |  | (68) | %
Sale of MSR assets | (57,454) |  |  | — |  |  | — |  |  | — |  |  | — |  |  | nm |  | nm
Change in fair value of MSR asset: |  |  |  |  |  |  |  |  |  |  |  |  |
Changes due to collection/realization of expected cash flows over time | (4,801) |  |  | (4,797) |  |  | (4,881) |  |  | (4,986) |  |  | (4,978) |  |  | 0 | % |  | (4) | %
Changes due to valuation inputs or assumptions | 5,308 |  |  | (2,242) |  |  | (2,937) |  |  | (9,914) |  |  | 16,403 |  |  | nm |  | (68) | %
Balance, end of period | $ | 117,640 |  |  | $ | 172,929 |  |  | $ | 178,800 |  |  | $ | 185,017 |  |  | $ | 196,177 |  |  | (32) | % |  | (40) | %
Residential mortgage loans serviced for others | $ | 8,240,950 |  |  | $ | 12,726,615 |  |  | $ | 12,914,046 |  |  | $ | 13,020,189 |  |  | $ | 12,997,911 |  |  | (35) | % |  | (37) | %
MSR as % of serviced portfolio | 1.43 | % |  | 1.36 | % |  | 1.38 | % |  | 1.42 | % |  | 1.51 | % |  | 0.07 |  |  | (0.08) |
nm = not meaningful |  |  |  |  |  |  |  |  |  |  |  |  |

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 19

Columbia Banking System, Inc.
Residential Mortgage Banking Activity
(Unaudited)
| Nine Months Ended |  | % Change
($ in thousands) | Sep 30, 2023 |  | Sep 30, 2022 |  | Year over Year
Residential mortgage banking revenue: |  |  |  |  |
Origination and sale | $ | 9,195 |  |  | $ | 42,460 |  |  | (78) | %
Servicing | 27,451 |  |  | 28,174 |  |  | (3) | %
Change in fair value of MSR asset: |  |  |  |  |
Changes due to collection/realization of expected cash flows over time | (14,479) |  |  | (15,286) |  |  | (5) | %
Changes due to valuation inputs or assumptions | 129 |  |  | 67,451 |  |  | (100) | %
MSR hedge loss | (9,719) |  |  | (14,128) |  |  | (31) | %
Total | $ | 12,577 |  |  | $ | 108,671 |  |  | (88) | %
Closed loan volume for-sale | $ | 354,535 |  |  | $ | 1,622,633 |  |  | (78) | %
Gain on sale margin | 2.59 | % |  | 2.62 | % |  | (0.03) |
Residential mortgage servicing rights: |  |  |  |  |
Balance, beginning of period | $ | 185,017 |  |  | $ | 123,615 |  |  | 50 | %
Additions for new MSR capitalized | 4,427 |  |  | 20,397 |  |  | (78) | %
Sale of MSR assets | (57,454) |  |  | — |  |  | nm
Change in fair value of MSR asset: |  |  |  |  |
Changes due to collection/realization of expected cash flows over time | (14,479) |  |  | (15,286) |  |  | (5) | %
Changes due to valuation inputs or assumptions | 129 |  |  | 67,451 |  |  | (100) | %
Balance, end of period | $ | 117,640 |  |  | $ | 196,177 |  |  | (40) | %
nm = not meaningful |  |  |  |  |

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 20
Non-GAAP Financial Measures
In addition to results presented in accordance with generally accepted accounting principles in the United States of America ("GAAP"), this press release contains certain non-GAAP financial measures. The company believes presenting certain non-GAAP financial measures provides investors with information useful in understanding our financial performance, our performance trends, and our financial position. We utilize these measures for internal planning and forecasting purposes. We, as well as securities analysts, investors, and other interested parties, also use these measures to compare peer company operating performance. We believe that our presentation and discussion, together with the accompanying reconciliations, provides a complete understanding of factors and trends affecting our business and allows investors to view performance in a manner similar to management. These non-GAAP measures should not be considered a substitution for GAAP basis measures and results, and we strongly encourage investors to review our consolidated financial statements in their entirety and not to rely on any single financial measure. Because non-GAAP financial measures are not standardized, it may not be possible to compare these financial measures with other companies’ non-GAAP financial measures having the same or similar names.

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in thousands, except per share data) |  |  | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Total shareholders' equity | a |  | $ | 4,632,162 |  |  | $ | 4,828,188 |  |  | $ | 4,884,723 |  |  | $ | 2,479,826 |  |  | $ | 2,417,514 |  |  | (4) | % |  | 92 | %
Less: Goodwill |  |  | 1,029,234 |  |  | 1,029,234 |  |  | 1,030,142 |  |  | — |  |  | — |  |  | — | % |  | nm
Less: Other intangible assets, net |  |  | 636,883 |  |  | 666,762 |  |  | 702,315 |  |  | 4,745 |  |  | 5,764 |  |  | (4) | % |  | nm
Tangible common shareholders' equity | b |  | $ | 2,966,045 |  |  | $ | 3,132,192 |  |  | $ | 3,152,266 |  |  | $ | 2,475,081 |  |  | $ | 2,411,750 |  |  | (5) | % |  | 23 | %
Total assets | c |  | $ | 51,989,593 |  |  | $ | 53,592,096 |  |  | $ | 53,994,226 |  |  | $ | 31,848,639 |  |  | $ | 31,471,960 |  |  | (3) | % |  | 65 | %
Less: Goodwill |  |  | 1,029,234 |  |  | 1,029,234 |  |  | 1,030,142 |  |  | — |  |  | — |  |  | 0 | % |  | nm
Less: Other intangible assets, net |  |  | 636,883 |  |  | 666,762 |  |  | 702,315 |  |  | 4,745 |  |  | 5,764 |  |  | (4) | % |  | nm
Tangible assets | d |  | $ | 50,323,476 |  |  | $ | 51,896,100 |  |  | $ | 52,261,769 |  |  | $ | 31,843,894 |  |  | $ | 31,466,196 |  |  | (3) | % |  | 60 | %
Common shares outstanding at period end (1) | e |  | 208,575 |  |  | 208,514 |  |  | 208,429 |  |  | 129,321 |  |  | 129,320 |  |  | 0 | % |  | 61 | %
Total shareholders' equity to total assets ratio | a / c |  | 8.91 | % |  | 9.01 | % |  | 9.05 | % |  | 7.79 | % |  | 7.68 | % |  | (0.10) |  |  | 1.23 |
Tangible common equity ratio | b / d |  | 5.89 | % |  | 6.04 | % |  | 6.03 | % |  | 7.77 | % |  | 7.66 | % |  | (0.15) |  |  | (1.77) |
Book value per common share (1) | a / e |  | $ | 22.21 |  |  | $ | 23.16 |  |  | $ | 23.44 |  |  | $ | 19.18 |  |  | $ | 18.69 |  |  | (4) | % |  | 19 | %
Tangible book value per common share (1) | b / e |  | $ | 14.22 |  |  | $ | 15.02 |  |  | $ | 15.12 |  |  | $ | 19.14 |  |  | $ | 18.65 |  |  | (5) | % |  | (24) | %
nm = not meaningful |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

(1) Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 21

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in thousands) |  |  | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Non-Interest Income Adjustments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gain on sale of debt securities, net |  |  | $ | 4 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | nm |  | nm
(Loss) gain on equity securities, net |  |  | (2,055) |  |  | (697) |  |  | 2,416 |  |  | 284 |  |  | (2,647) |  |  | 195 | % |  | (22) | %
Gain (loss) on swap derivatives |  |  | 5,700 |  |  | 1,288 |  |  | (3,543) |  |  | (2,329) |  |  | 4,194 |  |  | 343 | % |  | 36 | %
Change in fair value of certain loans held for investment |  |  | (19,247) |  |  | (6,965) |  |  | 9,488 |  |  | 4,192 |  |  | (26,397) |  |  | 176 | % |  | (27) | %
Change in fair value of MSR due to valuation inputs or assumptions |  |  | 5,308 |  |  | (2,242) |  |  | (2,937) |  |  | (9,914) |  |  | 16,403 |  |  | nm |  | (68) | %
MSR hedge (loss) gain |  |  | (4,733) |  |  | (7,636) |  |  | 2,650 |  |  | (348) |  |  | (14,128) |  |  | (38) | % |  | (66) | %
Total non-interest income adjustments | a |  | $ | (15,023) |  |  | $ | (16,252) |  |  | $ | 8,074 |  |  | $ | (8,115) |  |  | $ | (22,575) |  |  | (8) | % |  | (33) | %
Non-Interest Expense Adjustments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Merger related expense |  |  | $ | 18,938 |  |  | $ | 29,649 |  |  | $ | 115,898 |  |  | $ | 11,637 |  |  | $ | 769 |  |  | (36) | % |  | nm
Exit and disposal costs |  |  | 4,017 |  |  | 2,119 |  |  | 1,291 |  |  | 1,966 |  |  | 1,364 |  |  | 90 | % |  | 195 | %
Total non-interest expense adjustments | b |  | $ | 22,955 |  |  | $ | 31,768 |  |  | $ | 117,189 |  |  | $ | 13,603 |  |  | $ | 2,133 |  |  | (28) | % |  | nm
Net interest income | c |  | $ | 480,875 |  |  | $ | 483,975 |  |  | $ | 374,698 |  |  | $ | 305,479 |  |  | $ | 287,604 |  |  | (1) | % |  | 67 | %
Non-interest income (GAAP) | d |  | $ | 43,981 |  |  | $ | 39,678 |  |  | $ | 54,735 |  |  | $ | 34,879 |  |  | $ | 29,445 |  |  | 11 | % |  | 49 | %
Less: Non-interest income adjustments | a |  | 15,023 |  |  | 16,252 |  |  | (8,074) |  |  | 8,115 |  |  | 22,575 |  |  | (8) | % |  | (33) | %
Operating non-interest income (non-GAAP) | e |  | $ | 59,004 |  |  | $ | 55,930 |  |  | $ | 46,661 |  |  | $ | 42,994 |  |  | $ | 52,020 |  |  | 5 | % |  | 13 | %
Revenue (GAAP) | f=c+d |  | $ | 524,856 |  |  | $ | 523,653 |  |  | $ | 429,433 |  |  | $ | 340,358 |  |  | $ | 317,049 |  |  | — | % |  | 66 | %
Operating revenue (non-GAAP) | g=c+e |  | $ | 539,879 |  |  | $ | 539,905 |  |  | $ | 421,359 |  |  | $ | 348,473 |  |  | $ | 339,624 |  |  | — | % |  | 59 | %
Non-interest expense (GAAP) | h |  | $ | 304,147 |  |  | $ | 328,559 |  |  | $ | 342,818 |  |  | $ | 194,982 |  |  | $ | 177,964 |  |  | (7) | % |  | 71 | %
Less: Non-interest expense adjustments | b |  | (22,955) |  |  | (31,768) |  |  | (117,189) |  |  | (13,603) |  |  | (2,133) |  |  | (28) | % |  | nm
Operating non-interest expense (non-GAAP) | i |  | $ | 281,192 |  |  | $ | 296,791 |  |  | $ | 225,629 |  |  | $ | 181,379 |  |  | $ | 175,831 |  |  | (5) | % |  | 60 | %
Net income (loss) (GAAP) | j |  | $ | 135,845 |  |  | $ | 133,377 |  |  | $ | (14,038) |  |  | $ | 82,964 |  |  | $ | 84,040 |  |  | 2 | % |  | 62 | %
Provision (benefit) for income taxes |  |  | 48,127 |  |  | 45,703 |  |  | (4,886) |  |  | 29,464 |  |  | 27,473 |  |  | 5 | % |  | 75 | %
Income (loss) before provision for income taxes |  |  | 183,972 |  |  | 179,080 |  |  | (18,924) |  |  | 112,428 |  |  | 111,513 |  |  | 3 | % |  | 65 | %
Provision for credit losses |  |  | 36,737 |  |  | 16,014 |  |  | 105,539 |  |  | 32,948 |  |  | 27,572 |  |  | 129 | % |  | 33 | %
Pre-provision net revenue (PPNR) (non-GAAP) | k |  | 220,709 |  |  | 195,094 |  |  | 86,615 |  |  | 145,376 |  |  | 139,085 |  |  | 13 | % |  | 59 | %
Less: Non-interest income adjustments | a |  | 15,023 |  |  | 16,252 |  |  | (8,074) |  |  | 8,115 |  |  | 22,575 |  |  | (8) | % |  | (33) | %
Add: Non-interest expense adjustments | b |  | 22,955 |  |  | 31,768 |  |  | 117,189 |  |  | 13,603 |  |  | 2,133 |  |  | (28) | % |  | nm
Operating PPNR (non-GAAP) | l |  | $ | 258,687 |  |  | $ | 243,114 |  |  | $ | 195,730 |  |  | $ | 167,094 |  |  | $ | 163,793 |  |  | 6 | % |  | 58 | %
Net income (loss) (GAAP) | j |  | $ | 135,845 |  |  | $ | 133,377 |  |  | $ | (14,038) |  |  | $ | 82,964 |  |  | $ | 84,040 |  |  | 2 | % |  | 62 | %
Less: Non-interest income adjustments | a |  | 15,023 |  |  | 16,252 |  |  | (8,074) |  |  | 8,115 |  |  | 22,575 |  |  | (8) | % |  | (33) | %
Add: Non-interest expense adjustments | b |  | 22,955 |  |  | 31,768 |  |  | 117,189 |  |  | 13,603 |  |  | 2,133 |  |  | (28) | % |  | nm
Tax effect of adjustments |  |  | (9,482) |  |  | (11,981) |  |  | (23,565) |  |  | (5,459) |  |  | (6,116) |  |  | (21) | % |  | 55 | %
Operating net income (non-GAAP) | m |  | $ | 164,341 |  |  | $ | 169,416 |  |  | $ | 71,512 |  |  | $ | 99,223 |  |  | $ | 102,632 |  |  | (3) | % |  | 60 | %
nm = not meaningful |  |  |  |  |  |  |  |  |  |  |  |  |  |

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 22

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in thousands, except per share data) |  |  | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Average assets | n |  | $ | 53,011,361 |  |  | $ | 53,540,574 |  |  | $ | 39,425,975 |  |  | $ | 31,637,490 |  |  | $ | 30,668,177 |  |  | (1) | % |  | 73 | %
Less: Average goodwill and other intangible assets, net |  |  | 1,684,093 |  |  | 1,718,705 |  |  | 623,042 |  |  | 5,298 |  |  | 6,343 |  |  | (2) | % |  | nm
Average tangible assets | o |  | $ | 51,327,268 |  |  | $ | 51,821,869 |  |  | $ | 38,802,933 |  |  | $ | 31,632,192 |  |  | $ | 30,661,834 |  |  | (1) | % |  | 67 | %
Average common shareholders' equity | p |  | $ | 4,866,975 |  |  | $ | 4,935,239 |  |  | $ | 3,349,761 |  |  | $ | 2,438,639 |  |  | $ | 2,567,266 |  |  | (1) | % |  | 90 | %
Less: Average goodwill and other intangible assets, net |  |  | 1,684,093 |  |  | 1,718,705 |  |  | 623,042 |  |  | 5,298 |  |  | 6,343 |  |  | (2) | % |  | nm
Average tangible common equity | q |  | $ | 3,182,882 |  |  | $ | 3,216,534 |  |  | $ | 2,726,719 |  |  | $ | 2,433,341 |  |  | $ | 2,560,923 |  |  | (1) | % |  | 24 | %
Weighted average basic shares outstanding (1) | r |  | 208,070 |  |  | 207,977 |  |  | 156,383 |  |  | 129,321 |  |  | 129,319 |  |  | 0 | % |  | 61 | %
Weighted average diluted shares outstanding (1) | s |  | 208,645 |  |  | 208,545 |  |  | 156,383 |  |  | 129,801 |  |  | 129,733 |  |  | 0 | % |  | 61 | %
Select Per-Share & Performance Metrics |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Earnings-per-share - basic (1) | j / r |  | $ | 0.65 |  |  | $ | 0.64 |  |  | $ | (0.09) |  |  | $ | 0.64 |  |  | $ | 0.65 |  |  | 2 | % |  | — | %
Earnings-per-share - diluted (1) | j / s |  | $ | 0.65 |  |  | $ | 0.64 |  |  | $ | (0.09) |  |  | $ | 0.64 |  |  | $ | 0.65 |  |  | 2 | % |  | — | %
Efficiency ratio (2) | h / f |  | 57.82 | % |  | 62.60 | % |  | 79.71 | % |  | 57.24 | % |  | 56.07 | % |  | (4.78) |  |  | 1.75 |
Return on average assets | j / n |  | 1.02 | % |  | 1.00 | % |  | (0.14) | % |  | 1.04 | % |  | 1.09 | % |  | 0.02 |  |  | (0.07) |
Return on average tangible assets | j / o |  | 1.05 | % |  | 1.03 | % |  | (0.15) | % |  | 1.04 | % |  | 1.09 | % |  | 0.02 |  |  | (0.04) |
PPNR return on average assets | k / n |  | 1.65 | % |  | 1.46 | % |  | 0.89 | % |  | 1.82 | % |  | 1.80 | % |  | 0.19 |  |  | (0.15) |
Return on average common equity | j / p |  | 11.07 | % |  | 10.84 | % |  | (1.70) | % |  | 13.50 | % |  | 12.99 | % |  | 0.23 |  |  | (1.92) |
Return on average tangible common equity | j / q |  | 16.93 | % |  | 16.63 | % |  | (2.09) | % |  | 13.53 | % |  | 13.02 | % |  | 0.30 |  |  | 3.91 |
Operating Per-Share & Performance Metrics |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating earnings-per-share - basic (1) | m / r |  | $ | 0.79 |  |  | $ | 0.81 |  |  | $ | 0.46 |  |  | $ | 0.77 |  |  | $ | 0.79 |  |  | (2) | % |  | — | %
Operating earnings-per-share - diluted (1) | m / s |  | $ | 0.79 |  |  | $ | 0.81 |  |  | $ | 0.46 |  |  | $ | 0.76 |  |  | $ | 0.79 |  |  | (2) | % |  | — | %
Operating efficiency ratio (2) | i / g |  | 51.97 | % |  | 54.85 | % |  | 53.46 | % |  | 52.01 | % |  | 51.72 | % |  | (2.88) |  |  | 0.25 |
Operating return on average assets | m / n |  | 1.23 | % |  | 1.27 | % |  | 0.74 | % |  | 1.24 | % |  | 1.33 | % |  | (0.04) |  |  | (0.10) |
Operating return on average tangible assets | m / o |  | 1.27 | % |  | 1.31 | % |  | 0.75 | % |  | 1.24 | % |  | 1.33 | % |  | (0.04) |  |  | (0.06) |
Operating PPNR return on average assets | l / n |  | 1.94 | % |  | 1.82 | % |  | 2.01 | % |  | 2.10 | % |  | 2.12 | % |  | 0.12 |  |  | (0.18) |
Operating return on average common equity | m / p |  | 13.40 | % |  | 13.77 | % |  | 8.66 | % |  | 16.14 | % |  | 15.86 | % |  | (0.37) |  |  | (2.46) |
Operating return on average tangible common equity | m / q |  | 20.48 | % |  | 21.13 | % |  | 10.64 | % |  | 16.18 | % |  | 15.90 | % |  | (0.65) |  |  | 4.58 |

(1) Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.
(2) Tax exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate and added to stated revenue for this calculation.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 23

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
|  |  | Nine Months Ended |  | % Change
($ in thousands) |  |  | Sep 30, 2023 |  | Sep 30, 2022 |  | Year over Year
Non-Interest Income Adjustments |  |  |  |  |  |  |
Gain on sale of debt securities, net |  |  | $ | 4 |  |  | $ | 2 |  |  | 100 | %
Loss on equity securities, net |  |  | (336) |  |  | (7,383) |  |  | (95) | %
Gain on swap derivatives |  |  | 3,445 |  |  | 18,578 |  |  | (81) | %
Change in fair value of certain loans held for investment |  |  | (16,724) |  |  | (62,656) |  |  | (73) | %
Change in fair value of MSR due to valuation inputs or assumptions |  |  | 129 |  |  | 67,451 |  |  | (100) | %
MSR hedge loss |  |  | (9,719) |  |  | (14,128) |  |  | (31) | %
Total non-interest income adjustments | a |  | $ | (23,201) |  |  | $ | 1,864 |  |  | nm
Non-Interest Expense Adjustments |  |  |  |  |  |  |
Merger related expense |  |  | $ | 164,485 |  |  | $ | 5,719 |  |  | nm
Exit and disposal costs |  |  | 7,427 |  |  | 4,839 |  |  | 53 | %
Total non-interest expense adjustments | b |  | $ | 171,912 |  |  | $ | 10,558 |  |  | nm
Net interest income | c |  | $ | 1,339,548 |  |  | $ | 764,537 |  |  | 75 | %
Non-interest income (GAAP) | d |  | $ | 138,394 |  |  | $ | 164,649 |  |  | (16) | %
Less: Non-interest income adjustments | a |  | 23,201 |  |  | (1,864) |  |  | nm
Operating non-interest income (non-GAAP) | e |  | $ | 161,595 |  |  | $ | 162,785 |  |  | (1) | %
Revenue (GAAP) | f=c+d |  | $ | 1,477,942 |  |  | $ | 929,186 |  |  | 59 | %
Operating revenue (non-GAAP) | g=c+e |  | $ | 1,501,143 |  |  | $ | 927,322 |  |  | 62 | %
Non-interest expense (GAAP) | h |  | $ | 975,524 |  |  | $ | 539,968 |  |  | 81 | %
Less: Non-interest expense adjustments | b |  | (171,912) |  |  | (10,558) |  |  | nm
Operating non-interest expense (non-GAAP) | i |  | $ | 803,612 |  |  | $ | 529,410 |  |  | 52 | %
Net income (GAAP) | j |  | $ | 255,184 |  |  | $ | 253,788 |  |  | 1 | %
Provision for income taxes |  |  | 88,944 |  |  | 84,362 |  |  | 5 | %
Income before provision for income taxes |  |  | 344,128 |  |  | 338,150 |  |  | 2 | %
Provision for credit losses |  |  | 158,290 |  |  | 51,068 |  |  | 210 | %
Pre-provision net revenue (PPNR) (non-GAAP) | k |  | 502,418 |  |  | 389,218 |  |  | 29 | %
Less: Non-interest income adjustments | a |  | 23,201 |  |  | (1,864) |  |  | nm
Add: Non-interest expense adjustments | b |  | 171,912 |  |  | 10,558 |  |  | nm
Operating PPNR (non-GAAP) | l |  | $ | 697,531 |  |  | $ | 397,912 |  |  | 75 | %
Net income (GAAP) | j |  | $ | 255,184 |  |  | $ | 253,788 |  |  | 1 | %
Less: Non-interest income adjustments | a |  | 23,201 |  |  | (1,864) |  |  | nm
Add: Non-interest expense adjustments | b |  | 171,912 |  |  | 10,558 |  |  | nm
Tax effect of adjustments |  |  | (45,028) |  |  | (2,020) |  |  | nm
Operating net income (non-GAAP) | m |  | $ | 405,269 |  |  | $ | 260,462 |  |  | 56 | %
nm = not meaningful |  |  |  |  |  |

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 24

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
|  |  | Nine Months Ended |  | % Change
($ in thousands) |  |  | Sep 30, 2023 |  | Sep 30, 2022 |  | Year over Year
Average assets | n |  | $ | 48,709,067 |  |  | $ | 30,541,027 |  |  | 59 | %
Less: Average goodwill and other intangible assets, net |  |  | 1,345,833 |  |  | 7,369 |  |  | nm
Average tangible assets | o |  | $ | 47,363,234 |  |  | $ | 30,533,658 |  |  | 55 | %
Average common shareholders' equity | p |  | $ | 4,389,549 |  |  | $ | 2,621,725 |  |  | 67 | %
Less: Average goodwill and other intangible assets, net |  |  | 1,345,833 |  |  | 7,369 |  |  | nm
Average tangible common equity | q |  | $ | 3,043,716 |  |  | $ | 2,614,356 |  |  | 16 | %
Weighted average basic shares outstanding (1) | r |  | 190,997 |  |  | 129,262 |  |  | 48 | %
Weighted average diluted shares outstanding (1) | s |  | 191,546 |  |  | 129,702 |  |  | 48 | %
Select Per-Share & Performance Metrics |  |  |  |  |  |  |
Earnings-per-share - basic (1) | j / r |  | $ | 1.34 |  |  | $ | 1.96 |  |  | (32) | %
Earnings-per-share - diluted (1) | j / s |  | $ | 1.33 |  |  | $ | 1.96 |  |  | (32) | %
Efficiency ratio (2) | h / f |  | 65.87 | % |  | 58.05 | % |  | 7.82 |
Return on average assets | j / n |  | 0.70 | % |  | 1.11 | % |  | (0.41) |
Return on average tangible assets | j / o |  | 0.72 | % |  | 1.11 | % |  | (0.39) |
PPNR return on average assets | k/n |  | 1.38 | % |  | 1.70 | % |  | (0.32) |
Return on average common equity | j / p |  | 7.77 | % |  | 12.94 | % |  | (5.17) |
Return on average tangible common equity | j / q |  | 11.21 | % |  | 12.98 | % |  | (1.77) |
Operating Per-Share & Performance Metrics |  |  |  |  |  |  |
Operating earnings-per-share - basic (1) | m / r |  | $ | 2.12 |  |  | $ | 2.01 |  |  | 5 | %
Operating earnings-per-share - diluted (1) | m / s |  | $ | 2.12 |  |  | $ | 2.01 |  |  | 5 | %
Operating efficiency ratio (2) | i / g |  | 53.43 | % |  | 57.03 | % |  | (3.60) |
Operating return on average assets | m / n |  | 1.11 | % |  | 1.14 | % |  | (0.03) |
Operating return on average tangible assets | m / o |  | 1.14 | % |  | 1.14 | % |  | — |
Operating PPNR return on average assets | l / n |  | 1.91 | % |  | 1.74 | % |  | 0.17 |
Operating return on average common equity | m / p |  | 12.34 | % |  | 13.28 | % |  | (0.94) |
Operating return on average tangible common equity | m / q |  | 17.80 | % |  | 13.32 | % |  | 4.48 |

(1) Periods prior to February 28, 2023, have been restated as a result of the adjustment to common shares outstanding based on the exchange ratio from the UHC merger of 0.5958.
(2) Tax exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate and added to stated revenue for this calculation.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 25

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in thousands) |  |  | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Loans and leases interest income | a |  | $ | 567,929 |  |  | $ | 551,997 |  |  | $ | 412,726 |  |  | $ | 320,747 |  |  | $ | 276,625 |  |  | 3 | % |  | 105 | %
Less: Acquired loan accretion - rate related (2), (3) | b |  | 28,963 |  |  | 30,548 |  |  | 11,832 |  |  | 387 |  |  | 789 |  |  | (5) | % |  | nm
Less: Acquired loan accretion - credit related (3) | c |  | 6,370 |  |  | 7,100 |  |  | 3,806 |  |  | — |  |  | — |  |  | (10) | % |  | nm
Adjusted loans and leases interest income | d=a-b-c |  | $ | 532,596 |  |  | $ | 514,349 |  |  | $ | 397,088 |  |  | $ | 320,360 |  |  | $ | 275,836 |  |  | 4 | % |  | 93 | %
Taxable securities interest income | e |  | $ | 85,007 |  |  | $ | 81,617 |  |  | $ | 40,448 |  |  | $ | 18,290 |  |  | $ | 18,261 |  |  | 4 | % |  | 366 | %
Less: Acquired taxable securities accretion - rate related | f |  | 39,219 |  |  | 34,801 |  |  | 15,356 |  |  | — |  |  | — |  |  | 13 | % |  | nm
Adjusted Taxable securities interest income | g=e-f |  | $ | 45,788 |  |  | $ | 46,816 |  |  | $ | 25,092 |  |  | $ | 18,290 |  |  | $ | 18,261 |  |  | (2) | % |  | 151 | %
Non-taxable securities interest income (1) | h |  | $ | 8,085 |  |  | $ | 8,010 |  |  | $ | 4,068 |  |  | $ | 1,571 |  |  | $ | 1,651 |  |  | 1 | % |  | 390 | %
Less: Acquired non-taxable securities accretion - rate related | i |  | 2,288 |  |  | 2,274 |  |  | 901 |  |  | — |  |  | — |  |  | 1 | % |  | nm
Adjusted Taxable securities interest income (1) | j=h-i |  | $ | 5,797 |  |  | $ | 5,736 |  |  | $ | 3,167 |  |  | $ | 1,571 |  |  | $ | 1,651 |  |  | 1 | % |  | 251 | %
Interest income (1) | k |  | $ | 697,169 |  |  | $ | 676,922 |  |  | $ | 476,622 |  |  | $ | 352,530 |  |  | $ | 303,857 |  |  | 3 | % |  | 129 | %
Less: Acquired loan and securities accretion - rate related | l=b+f+i |  | 70,470 |  |  | 67,623 |  |  | 28,089 |  |  | 387 |  |  | 789 |  |  | 4 | % |  | nm
Less: Acquired loan accretion - credit related | c |  | 6,370 |  |  | 7,100 |  |  | 3,806 |  |  | — |  |  | — |  |  | (10) | % |  | nm
Adjusted interest income (1) | m=k-l-c |  | $ | 620,329 |  |  | $ | 602,199 |  |  | $ | 444,727 |  |  | $ | 352,143 |  |  | $ | 303,068 |  |  | 3 | % |  | 105 | %
Interest-bearing deposits interest expense | n |  | $ | 126,974 |  |  | $ | 100,408 |  |  | $ | 63,613 |  |  | $ | 31,174 |  |  | $ | 9,090 |  |  | 26 | % |  | nm
Less: Acquired deposit accretion | o |  | (373) |  |  | (280) |  |  | (93) |  |  | — |  |  | — |  |  | 33 | % |  | nm
Adjusted interest-bearing deposits interest expense | p=n-o |  | $ | 127,347 |  |  | $ | 100,688 |  |  | $ | 63,706 |  |  | $ | 31,174 |  |  | $ | 9,090 |  |  | 26 | % |  | nm
Interest expense | q |  | $ | 215,138 |  |  | $ | 191,754 |  |  | $ | 101,253 |  |  | $ | 46,768 |  |  | $ | 15,924 |  |  | 12 | % |  | nm
Less: Acquired interest-bearing liabilities accretion (2) | r |  | (430) |  |  | (337) |  |  | (150) |  |  | (57) |  |  | (57) |  |  | 28 | % |  | nm
Adjusted interest expense | s=q-r |  | $ | 215,568 |  |  | $ | 192,091 |  |  | $ | 101,403 |  |  | $ | 46,825 |  |  | $ | 15,981 |  |  | 12 | % |  | nm
Net Interest Income (1) | t |  | $ | 482,031 |  |  | $ | 485,168 |  |  | $ | 375,369 |  |  | $ | 305,762 |  |  | $ | 287,933 |  |  | (1) | % |  | 67 | %
Less: Acquired loan, securities, and interest-bearing liabilities accretion - rate related (3) | u=l-r |  | 70,900 |  |  | 67,960 |  |  | 28,239 |  |  | 444 |  |  | 846 |  |  | 4 | % |  | nm
Less: Acquired loan accretion - credit related (3) | c |  | 6,370 |  |  | 7,100 |  |  | 3,806 |  |  | — |  |  | — |  |  | (10) | % |  | nm
Adjusted net interest income (1) | v=t-u-c |  | $ | 404,761 |  |  | $ | 410,108 |  |  | $ | 343,324 |  |  | $ | 305,318 |  |  | $ | 287,087 |  |  | (1) | % |  | 41 | %
Average loans and leases | aa |  | 37,050,518 |  |  | 37,169,315 |  |  | 29,998,630 |  |  | 25,855,556 |  |  | 24,886,203 |  |  | 0 | % |  | 49 | %
Average taxable securities | ab |  | 8,356,165 |  |  | 8,656,147 |  |  | 4,960,966 |  |  | 3,042,044 |  |  | 3,271,185 |  |  | (3) | % |  | 155 | %
Average non-taxable securities | ac |  | 844,417 |  |  | 865,278 |  |  | 437,020 |  |  | 200,825 |  |  | 212,847 |  |  | (2) | % |  | 297 | %
Average interest-earning assets | ad |  | 48,981,105 |  |  | 49,442,518 |  |  | 37,055,705 |  |  | 30,305,129 |  |  | 29,437,103 |  |  | (1) | % |  | 66 | %
Average interest-bearing deposits | ae |  | 25,121,745 |  |  | 24,494,717 |  |  | 19,496,551 |  |  | 16,103,984 |  |  | 15,350,390 |  |  | 3 | % |  | 64 | %
Average interest-bearing liabilities | af |  | 31,413,978 |  |  | 31,372,416 |  |  | 22,548,264 |  |  | 17,668,730 |  |  | 16,359,575 |  |  | 0 | % |  | 92 | %

(1)Tax exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.
(2)Includes discount accretion related to UHC's 2014 acquisition of Sterling Financial Corporation.
(3)The cumulative fair value discount on historical Columbia loans was established as of February 28, 2023, and the allocation between the credit-related discount and the rate-related discount was established at that time. Our disclosure of credit-related and rate-related discount accretion is an estimate based on the relative allocation of these two items to the discount at closing.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 26

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
|  |  | Quarter Ended |  | % Change
($ in thousands) |  |  | Sep 30, 2023 |  | Jun 30, 2023 |  | Mar 31, 2023 |  | Dec 31, 2022 |  | Sep 30, 2022 |  | Seq. Quarter |  | Year over Year
Average yield on loans and leases | a / aa |  | 6.08 | % |  | 5.95 | % |  | 5.55 | % |  | 4.92 | % |  | 4.41 | % |  | 0.13 |  |  | 1.67 |
Less: Acquired loan accretion - rate related (2),(3) | b / aa |  | 0.31 | % |  | 0.33 | % |  | 0.16 | % |  | 0.01 | % |  | 0.01 | % |  | (0.02) |  |  | 0.30 |
Less: Acquired loan accretion - credit related (3) | c / aa |  | 0.07 | % |  | 0.08 | % |  | 0.05 | % |  | — | % |  | — | % |  | (0.01) |  |  | 0.07 |
Adjusted average yield on loans and leases | d / aa |  | 5.70 | % |  | 5.54 | % |  | 5.34 | % |  | 4.91 | % |  | 4.40 | % |  | 0.16 |  |  | 1.30 |
Average yield on taxable securities | e / ab |  | 4.07 | % |  | 3.77 | % |  | 3.26 | % |  | 2.40 | % |  | 2.23 | % |  | 0.30 |  |  | 1.84 |
Less: Acquired taxable securities accretion - rate related | f / ab |  | 1.86 | % |  | 1.61 | % |  | 1.26 | % |  | — | % |  | — | % |  | 0.25 |  |  | 1.86 |
Adjusted average yield on taxable securities | g / ab |  | 2.21 | % |  | 2.16 | % |  | 2.00 | % |  | 2.40 | % |  | 2.23 | % |  | 0.05 |  |  | (0.02) |
Average yield on non-taxable securities (1) | h / ac |  | 3.83 | % |  | 3.70 | % |  | 3.72 | % |  | 3.13 | % |  | 3.10 | % |  | 0.13 |  |  | 0.73 |
Less: Acquired non-taxable securities accretion - rate related | i / ac |  | 1.07 | % |  | 1.05 | % |  | 0.84 | % |  | — | % |  | — | % |  | 0.02 |  |  | 1.07 |
Adjusted yield on non-taxable securities (1) | j / ac |  | 2.76 | % |  | 2.65 | % |  | 2.88 | % |  | 3.13 | % |  | 3.10 | % |  | 0.11 |  |  | (0.34) |
Average yield on interest-earning assets (1) | k / ad |  | 5.65 | % |  | 5.48 | % |  | 5.19 | % |  | 4.62 | % |  | 4.10 | % |  | 0.17 |  |  | 1.55 |
Less: Acquired loan and securities accretion - rate related | l / ad |  | 0.57 | % |  | 0.55 | % |  | 0.31 | % |  | 0.01 | % |  | 0.01 | % |  | 0.02 |  |  | 0.56 |
Less: Acquired loan accretion - credit related | c / ad |  | 0.05 | % |  | 0.06 | % |  | 0.04 | % |  | — | % |  | — | % |  | (0.01) |  |  | 0.05 |
Adjusted average yield on interest-earning assets (1) | m / ad |  | 5.03 | % |  | 4.87 | % |  | 4.84 | % |  | 4.61 | % |  | 4.09 | % |  | 0.16 |  |  | 0.94 |
Average rate on interest-bearing deposits | n / ae |  | 2.01 | % |  | 1.64 | % |  | 1.32 | % |  | 0.77 | % |  | 0.23 | % |  | 0.37 |  |  | 1.78 |
Less: Acquired deposit accretion | o / ae |  | (0.01) | % |  | — | % |  | — | % |  | — | % |  | — | % |  | (0.01) |  |  | (0.01) |
Adjusted average rate on interest-bearing deposits | p / ae |  | 2.02 | % |  | 1.64 | % |  | 1.32 | % |  | 0.77 | % |  | 0.23 | % |  | 0.38 |  |  | 1.79 |
Average rate on interest-bearing liabilities | q / af |  | 2.72 | % |  | 2.45 | % |  | 1.82 | % |  | 1.05 | % |  | 0.39 | % |  | 0.27 |  |  | 2.33 |
Less: Acquired interest-bearing liabilities accretion (2) | r / af |  | (0.01) | % |  | — | % |  | — | % |  | — | % |  | — | % |  | (0.01) |  |  | (0.01) |
Adjusted average rate on interest-bearing liabilities | s / af |  | 2.73 | % |  | 2.45 | % |  | 1.82 | % |  | 1.05 | % |  | 0.39 | % |  | 0.28 |  |  | 2.34 |
Net interest margin (1) | t / ad |  | 3.91 | % |  | 3.93 | % |  | 4.08 | % |  | 4.01 | % |  | 3.88 | % |  | (0.02) |  |  | 0.03 |
Less: Acquired loan, securities, and interest-bearing liabilities accretion - rate related (3) | u / ad |  | 0.58 | % |  | 0.55 | % |  | 0.31 | % |  | — | % |  | 0.01 | % |  | 0.03 |  |  | 0.57 |
Less: Acquired loan accretion - credit related (3) | c / ad |  | 0.05 | % |  | 0.06 | % |  | 0.04 | % |  | — | % |  | — | % |  | (0.01) |  |  | 0.05 |
Adjusted net interest margin (1) | v / ad |  | 3.28 | % |  | 3.32 | % |  | 3.73 | % |  | 4.01 | % |  | 3.87 | % |  | (0.04) |  |  | (0.59) |

(1)Tax exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.
(2) Includes discount accretion related to UHC's 2014 acquisition of Sterling Financial Corporation.
(3)The cumulative fair value discount on historical Columbia loans was established as of February 28, 2023, and the allocation between the credit-related discount and the rate-related discount was established at that time. Our disclosure of credit-related and rate-related discount accretion is an estimate based on the relative allocation of these two items to the discount at closing.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 27

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
|  |  | Nine Months Ended |  |
($ in thousands) |  |  | Sep 30, 2023 |  | Sep 30, 2022 |  | Year over Year
Loans and leases interest income | a |  | $ | 1,532,652 |  |  | $ | 720,699 |  |  | 113 | %
Less: Acquired loan accretion - rate related (2), (3) | b |  | 71,343 |  |  | 3,290 |  |  | nm
Less: Acquired loan accretion - credit related (3) | c |  | 17,276 |  |  | — |  |  | nm
Adjusted loans and leases interest income | d=a-b-c |  | $ | 1,444,033 |  |  | $ | 717,409 |  |  | 101 | %
Taxable securities interest income | e |  | $ | 207,072 |  |  | $ | 54,412 |  |  | 281 | %
Less: Acquired taxable securities accretion - rate related | f |  | 89,376 |  |  | — |  |  | nm
Adjusted Taxable securities interest income | g=e-f |  | $ | 117,696 |  |  | $ | 54,412 |  |  | 116 | %
Non-taxable securities interest income (1) | h |  | $ | 20,163 |  |  | $ | 5,098 |  |  | 296 | %
Less: Acquired non-taxable securities accretion - rate related | i |  | 5,463 |  |  | — |  |  | nm
Adjusted Taxable securities interest income (1) | j=h-i |  | $ | 14,700 |  |  | $ | 5,098 |  |  | 188 | %
Interest income (1) | k |  | $ | 1,850,713 |  |  | $ | 796,805 |  |  | 132 | %
Less: Acquired loan and securities accretion - rate related | l=b+f+i |  | 166,182 |  |  | 3,290 |  |  | nm
Less: Acquired loan accretion - credit related | c |  | 17,276 |  |  | — |  |  | nm
Adjusted interest income (1) | m=k-l-c |  | $ | 1,667,255 |  |  | $ | 793,515 |  |  | 110 | %
Interest-bearing deposits interest expense | n |  | $ | 290,995 |  |  | $ | 17,021 |  |  | nm
Less: Acquired deposit accretion | o |  | (746) |  |  | — |  |  | nm
Adjusted interest-bearing deposits interest expense | p=n-o |  | $ | 291,741 |  |  | $ | 17,021 |  |  | nm
Interest expense | q |  | $ | 508,145 |  |  | $ | 31,233 |  |  | nm
Less: Acquired interest-bearing liabilities accretion (2) | r |  | (917) |  |  | (171) |  |  | 436 | %
Adjusted interest expense | s=q-r |  | $ | 509,062 |  |  | $ | 31,404 |  |  | nm
Net Interest Income (1) | t |  | $ | 1,342,568 |  |  | $ | 765,572 |  |  | 75 | %
Less: Acquired loan, securities, and interest-bearing liabilities accretion - rate related (3) | u=l-r |  | 167,099 |  |  | 3,461 |  |  | nm
Less: Acquired loan accretion - credit related (3) | c |  | 17,276 |  |  | — |  |  | nm
Adjusted net interest income (1) | v=t-u-c |  | $ | 1,158,193 |  |  | $ | 762,111 |  |  | 52 | %
Average loans and leases | aa |  | 34,765,319 |  |  | 23,676,201 |  |  | 47 | %
Average taxable securities | ab |  | 7,336,862 |  |  | 3,445,386 |  |  | 113 | %
Average non-taxable securities | ac |  | 717,064 |  |  | 222,375 |  |  | 222 | %
Average interest-earning assets | ad |  | 45,203,459 |  |  | 29,303,722 |  |  | 54 | %
Average interest-bearing deposits | ae |  | 23,091,034 |  |  | 15,422,795 |  |  | 50 | %
Average interest-bearing liabilities | af |  | 28,510,120 |  |  | 16,355,258 |  |  | 74 | %

(1)Tax exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.
(2)Includes discount accretion related to UHC's 2014 acquisition of Sterling Financial Corporation.
(3)The cumulative fair value discount on historical Columbia loans was established as of February 28, 2023, and the allocation between the credit-related discount and the rate-related discount was established at that time. Our disclosure of credit-related and rate-related discount accretion is an estimate based on the relative allocation of these two items to the discount at closing.

Columbia Banking System, Inc. Reports Third Quarter 2023 Results
October 18, 2023
Page 28

Columbia Banking System, Inc.
GAAP to Non-GAAP Reconciliation - Continued
(Unaudited)
($ in thousands) |  |  | Sep 30, 2023 |  | Sep 30, 2022 |  | Year over Year
Average yield on loans and leases | a / aa |  | 5.88 | % |  | 4.06 | % |  | 1.82 |
Less: Acquired loan accretion - rate related (2),(3) | b / aa |  | 0.27 | % |  | 0.02 | % |  | 0.25 |
Less: Acquired loan accretion - credit related (3) | c / aa |  | 0.07 | % |  | — | % |  | 0.07 |
Adjusted average yield on loans and leases | d / aa |  | 5.54 | % |  | 4.04 | % |  | 1.50 |
Average yield on taxable securities | e / ab |  | 3.76 | % |  | 2.11 | % |  | 1.65 |
Less: Acquired taxable securities accretion - rate related | f / ab |  | 1.63 | % |  | — | % |  | 1.63 |
Adjusted average yield on taxable securities | g / ab |  | 2.13 | % |  | 2.11 | % |  | 0.02 |
Average yield on non-taxable securities (1) | h / ac |  | 3.75 | % |  | 3.06 | % |  | 0.69 |
Less: Acquired non-taxable securities accretion - rate related | i / ac |  | 1.02 | % |  | — | % |  | 1.02 |
Adjusted yield on non-taxable securities (1) | j / ac |  | 2.73 | % |  | 3.06 | % |  | (0.33) |
Average yield on interest-earning assets (1) | k / ad |  | 5.46 | % |  | 3.62 | % |  | 1.84 |
Less: Acquired loan and securities accretion - rate related | l / ad |  | 0.49 | % |  | 0.02 | % |  | 0.47 |
Less: Acquired loan accretion - credit related | c / ad |  | 0.05 | % |  | — | % |  | 0.05 |
Adjusted average yield on interest-earning assets (1) | m / ad |  | 4.92 | % |  | 3.60 | % |  | 1.32 |
Average rate on interest-bearing deposits | n / ae |  | 1.68 | % |  | 0.15 | % |  | 1.53 |
Less: Acquired deposit accretion | o / ae |  | — | % |  | — | % |  | — |
Adjusted average rate on interest-bearing deposits | p / ae |  | 1.68 | % |  | 0.15 | % |  | 1.53 |
Average rate on interest-bearing liabilities | q / af |  | 2.38 | % |  | 0.26 | % |  | 2.12 |
Less: Acquired interest-bearing liabilities accretion (2) | r / af |  | — | % |  | — | % |  | — |
Adjusted average rate on interest-bearing liabilities | s / af |  | 2.38 | % |  | 0.26 | % |  | 2.12 |
Net interest margin (1) | t / ad |  | 3.96 | % |  | 3.48 | % |  | 0.48 |
Less: Acquired loan, securities, and interest-bearing liabilities accretion - rate related (3) | u / ad |  | 0.49 | % |  | 0.02 | % |  | 0.47 |
Less: Acquired loan accretion - credit related (3) | c / ad |  | 0.05 | % |  | — | % |  | 0.05 |
Adjusted net interest margin (1) | v / ad |  | 3.42 | % |  | 3.46 | % |  | (0.04) |

(1)Tax exempt interest has been adjusted to a taxable equivalent basis using a 21% tax rate.
(2) Includes discount accretion related to UHC's 2014 acquisition of Sterling Financial Corporation.
(3)The cumulative fair value discount on historical Columbia loans was established as of February 28, 2023, and the allocation between the credit-related discount and the rate-related discount was established at that time. Our disclosure of credit-related and rate-related discount accretion is an estimate based on the relative allocation of these two items to the discount at closing.