COLUMBIA BANKING SYSTEM, INC. REPORTS FIRST QUARTER 2025 RESULTS

, /PRNewswire/ -- $87 million $140 million $0.41 $0.67 Net income Operating net income 1 Earnings per diluted common share Operating earnings per diluted common share 1 CEO Commentary "Our consistent, repeatable performance in 2024 carried through to the first quarter of 2025," said Clint Stein, President and CEO. "Although the global environment is rife with uncertainty, our operations remain steadfast. Our consistent approach to banking is a key contributor to Columbia's success through business and credit cycles, and our teams' dedication to fostering strong customer relationships serves as the cornerstone of our ability to thrive during historically volatile periods. Customer deposits increased notably during the first quarter, despite anticipated seasonal balance declines, highlighting the success of small business campaigns and our bankers' ability to win new relationships as we deploy our Business Bank of Choice strategy through our eight-state western footprint. Our announced acquisition of Pacific Premier Bancorp accelerates our expansion in Southern California by approximately a decade, advancing our opportunities and enhancing long-term shareholder value." –Clint Stein, President and CEO of Columbia Banking System, Inc. 1Q25 HIGHLIGHTS (COMPARED TO 4Q24) Net Interest Income and NIM • Net interest income decreased by $12 million from the prior quarter, largely due to lower accretion income from the investment securities portfolio. • Net interest margin was 3.60%, down 4 basis points from the prior quarter, as lower earning asset yields were not fully offset by lower funding costs. Lower accretion income contributed to a decline in the yield on investment securities. Non-Interest Income and Expense • Non-interest income increased by $17 million due to the quarterly fluctuation in cumulative fair value accounting and hedges, which drove $15 million of the change. Income was also higher due to a loss on loan sales in the fourth quarter that did not repeat. • Non-interest expense increased by $74 million primarily due to a legal settlement and severance expense, as well as seasonally higher payroll taxes. Credit Quality • Net charge-offs were 0.32% of average loans and leases (annualized), compared to 0.27% in the prior quarter. The increase reflects the partial charge-off of a loan with a previously established reserve. • Provision expense of $27 million compares to $28 million in the prior quarter. • Non-performing assets to total assets was 0.35%, compared to 0.33% as of December 31, 2024. Capital • Estimated total risk-based capital ratio of 12.8% and estimated common equity tier 1 risk-based capital ratio of 10.6%. • Declared a quarterly cash dividend of $0.36 per common share on February 14, 2025, which was paid March 17, 2025. Notable Items • Executed a successful small business and retail campaign using bundled solutions for customers without promotional pricing. The first quarter's campaign brought $425 million in new deposits to the bank. • Opened our first branch location in Colorado, supporting our commercial, wealth, trust, retail business, and healthcare banking teams already serving customers in the market. • We will host a conference call on April 23, 2025 to discuss our financial results and announced acquisition of Pacific Premier Bancorp, replacing the call previously scheduled for April 24, 2025. 1Q25 KEY FINANCIAL DATA PERFORMANCE METRICS 1Q25 4Q24 1Q24 Return on average assets 0.68 % 1.10 % 0.96 % Return on average common equity 6.73 % 10.91 % 10.01 % Return on average tangible common equity 1 9.45 % 15.41 % 14.82 % Operating return on average assets 1 1.10 % 1.15 % 1.04 % Operating return on average common equity 1 10.87 % 11.40 % 10.89 % Operating return on average tangible common equity 1 15.26 % 16.11 % 16.12 % Net interest margin 3.60 % 3.64 % 3.52 % Efficiency ratio 69.06 % 54.61 % 60.57 % Operating efficiency ratio, as adjusted 1 55.11 % 52.51 % 56.97 % INCOME STATEMENT ($ in 000s, excl. per share data) 1Q25 4Q24 1Q24 Net interest income $424,995 $437,373 $423,362 Provision for credit losses $27,403 $28,199 $17,136 Non-interest income $66,377 $49,747 $50,357 Non-interest expense $340,122 $266,576 $287,516 Pre-provision net revenue 1 $151,250 $220,544 $186,203 Operating pre-provision net revenue 1 $211,833 $229,178 $200,683 Earnings per common share - diluted $0.41 $0.68 $0.59 Operating earnings per common share - diluted 1 $0.67 $0.71 $0.65 Dividends paid per share $0.36 $0.36 $0.36 BALANCE SHEET 1Q25 4Q24 1Q24 Total assets $51.5B $51.6B $52.2B Loans and leases $37.6B $37.7B $37.6B Deposits $42.2B $41.7B $41.7B Book value per common share $24.93 $24.43 $23.68 Tangible book value per share 1 $17.86 $17.20 $16.03 Organizational UpdateColumbia Banking System, Inc. ("Columbia," the "Company," "we," or "our"), the parent company of Umpqua Bank, and Pacific Premier Bancorp, Inc. ("Pacific Premier") (Nasdaq: PPBI), the parent company of Pacific Premier Bank, National Association, jointly announced in a separate press release on April 23, 2025 that they have entered into a definitive merger agreement, pursuant to which Columbia will acquire Pacific Premier in an all-stock transaction. The combined company will have approximately $70 billion in assets and will be a market leader in the largest banking markets within the Western U.S. The acquisition, which is anticipated to close in the second half of 2025, is projected to deliver mid-teens earnings-per-share accretion and enhance scale in key market areas, including Southern California. Columbia and Pacific Premier will hold a joint conference call to discuss this announcement, and details are available in the "Earnings Presentation and Conference Call" section of this press release. During the first quarter, Columbia opened a branch location in Denver, Colorado. Our first retail office in Colorado supports our commercial, wealth, trust, retail business, and healthcare banking teams already serving customers in the market. We continue to make progress on our plans to open additional branches in the coming months in support of our customers and bankers. Net Interest IncomeNet interest income was $425 million for the first quarter of 2025, down $12 million from the prior quarter. The decrease reflects lower interest income that was only partially offset by lower funding costs, due in part to the reductions in the federal funds rate that occurred in November and December. Lower accretion income, primarily related to investment securities income, accounted for the majority of the decline in net interest income. Columbia's net interest margin was 3.60% for the first quarter of 2025, down 4 basis points from the fourth quarter of 2024. Lower earning asset yields were only partially offset by lower funding costs. Lower accretion income contributed to a decline in the yield on investment securities. The cost of interest-bearing deposits decreased 14 basis points from the prior quarter to 2.52% for the first quarter of 2025, which compares to 2.51% for the month of March and 2.50% as of March 31, 2025. Columbia's cost of interest-bearing liabilities decreased 18 basis points from the prior quarter to 2.80% for the first quarter of 2025, which compares to 2.76% for the month of March and 2.74% as of March 31, 2025. Please refer to the Q1 2025 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 IncomeNon-interest income was $66 million for the first quarter of 2025, up $17 million from the prior quarter. The increase was driven by quarterly changes in fair value adjustments and mortgage servicing rights ("MSR") hedging activity, due to interest rate fluctuations during the quarter, collectively resulting in a net fair value gain of $9 million in the first quarter compared to a net fair value loss of $6 million in the fourth quarter, as detailed in our non-GAAP disclosures. Excluding these items, non-interest income was up $2 million2 between periods, due primarily to a $2 million loss on the sale of loans in the fourth quarter that did not repeat in the first quarter. Other changes include a slower level of customer activity that is typical for the first quarter. Non-interest Expense Non-interest expense was $340 million for the first quarter of 2025, up $74 million from the prior quarter. The quarter included a $55 million accrual related to a legal settlement, as previously disclosed, and $15 million in severance expense. Excluding the legal settlement, exit and disposal costs, and merger and restructuring expense, which includes the severance expense, non-interest expense was $270 million2, up $7 million from the prior quarter, due primarily to higher payroll taxes and elevated legal expense separate from the legal settlement. Please refer to the Q1 2025 Earnings Presentation for additional expense details. Balance SheetTotal consolidated assets were $51.5 billion as of March 31, 2025, down slightly from $51.6 billion as of December 31, 2024. Cash and cash equivalents were $2.1 billion as of March 31, 2025, up from $1.9 billion as of December 31, 2024. Including secured off-balance sheet lines of credit, total available liquidity was $19.0 billion as of March 31, 2025, representing 37% of total assets, 45% of total deposits, and 131% of uninsured deposits. Available-for-sale securities, which are held on balance sheet at fair value, were $8.2 billion as of March 31, 2025, a decrease of $46 million relative to December 31, 2024, as paydowns slightly offset an increase in the fair value of the portfolio. Please refer to the Q1 2025 Earnings Presentation for additional details related to our securities portfolio and liquidity position. Gross loans and leases were $37.6 billion as of March 31, 2025, a decrease of $65 million relative to December 31, 2024. "Loan payoffs and a slower pace of origination volume contributed to a slight portfolio contraction in the quarter," commented Tory Nixon, President of Umpqua Bank. "Our teams remain focused on relationship-driven loan volume, which expands our deposit and core fee income generation opportunities as we deliver needs-based solutions to our customers and prospects." Please refer to the Q1 2025 Earnings Presentation for additional details related to our loan portfolio, which include underwriting characteristics, the composition of our commercial portfolios, and disclosure related to our office portfolio. Total deposits were $42.2 billion as of March 31, 2025, an increase of $497 million relative to December 31, 2024, as customer deposits increased $440 million during the quarter. "We experienced strong customer deposit growth in March, following anticipated seasonal balance declines earlier in the quarter," stated Mr. Nixon. "Our small business campaigns continue to bring new business to the bank, complementing our success with middle-market and corporate customers." Customer deposit growth was used to help pay down $550 million in FHLB Advances during the first quarter. Please refer to the Q1 2025 Earnings Presentation for additional details related to deposit characteristics and flows. Credit QualityThe allowance for credit losses was $439 million, or 1.17% of loans and leases, as of March 31, 2025, compared to $441 million, or 1.17% of loans and leases, as of December 31, 2024. The provision for credit losses was $27 million for the first quarter of 2025, and reflects credit migration trends, charge-off activity, and changes in the economic forecasts used in credit models. Net charge-offs were 0.32% of average loans and leases (annualized) for the first quarter of 2025, compared to 0.27% for the fourth quarter of 2025. Net charge-offs in the FinPac portfolio were $17 million in the first quarter, down from $19 million in the fourth quarter as improvement continues within the transportation sector of the portfolio. Net charge-offs excluding the FinPac portfolio were $13 million in the first quarter, compared to $6 million in the fourth quarter. The increase reflects the partial charge-off of a loan with a previously established reserve. Non-performing assets were $178 million, or 0.35% of total assets, as of March 31, 2025, compared to $170 million, or 0.33% of total assets, as of December 31, 2024. Please refer to the Q1 2025 Earnings Presentation for additional details related to the allowance for credit losses and other credit trends. CapitalColumbia's book value per common share was $24.93 as of March 31, 2025, compared to $24.43 as of December 31, 2024. The increase primarily reflects a change in accumulated other comprehensive (loss) income ("AOCI") to $(358) million at March 31, 2025, compared to $(462) million at the prior quarter-end. The change in AOCI is due primarily to a decrease in the tax-effected net unrealized loss on available-for-sale securities to $337 million as of March 31, 2025, compared to $434 million as of December 31, 2024. Tangible book value per common share3 was $17.86 as of March 31, 2025, compared to $17.20 as of December 31, 2024. Columbia's estimated total risk-based capital ratio was 12.8%, and its estimated common equity tier 1 risk-based capital ratio was 10.6% as of March 31, 2025, compared to 12.8% and 10.5%, respectively, as of December 31, 2024. Columbia remains above current "well-capitalized" regulatory minimums. The regulatory capital ratios as of March 31, 2025 are estimates, pending completion and filing of Columbia's regulatory reports. Earnings Presentation and Conference Call InformationColumbia's Q1 2025 Earnings Presentation provides additional disclosure. A copy will be available on our investor relations page: www.columbiabankingsystem.com. Columbia and Pacific Premier will hold a joint conference call to discuss the definitive merger agreement on April 23, 2025 at 3:00 p.m. PT (6:00 p.m. ET). During the call, Columbia's management team will also discuss its first quarter 2025 financial results, replacing the call previously scheduled for April 24, 2025. Participants may join the audiocast or register for the call using the link below to receive dial-in details and their own unique PINs. It is recommended you join 10 minutes prior to the start time. Join the audiocast: https://edge.media-server.com/mmc/p/ruitqcd6/Register for the call: https://register-conf.media-server.com/register/BIf5345fce534d4cddaaa08c0ab8dc548bAccess the replay through Columbia's investor relations page: https://www.columbiabankingsystem.com/news-market-data/event-calendar/default.aspx About Columbia Banking System, Inc.Columbia (Nasdaq: COLB) is headquartered in Tacoma, Washington and is the parent company of Umpqua Bank, an award-winning western U.S. regional bank based in Lake Oswego, Oregon. Umpqua Bank is the largest bank headquartered in the Northwest and one of the largest banks headquartered in the West with locations in Arizona, California, Colorado, Idaho, Nevada, Oregon, Utah, and Washington. With over $50 billion of assets, Umpqua Bank combines the resources, sophistication, and expertise of a national bank with a commitment to deliver superior, personalized service. The bank supports consumers and businesses through a full suite of services, including retail and commercial banking; Small Business Administration lending; institutional and corporate banking; and equipment leasing. Umpqua Bank customers also have access to comprehensive investment and wealth management expertise as well as healthcare and private banking through Columbia Wealth Advisors and Columbia Trust Company, a division of Umpqua Bank. Learn more at www.columbiabankingsystem.com. 1 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information. 2 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information. 3 "Non-GAAP" financial measure. See GAAP to Non-GAAP Reconciliation for additional information. Forward-Looking StatementsThis press release includes forward-looking statements within the meaning of the "Safe-Harbor" provisions of the Private Securities Litigation Reform Act of 1995, which management believes are a benefit to shareholders. These statements are necessarily subject to risk and uncertainty and actual results could differ materially due to various risk factors, including those set forth from time to time in our filings with the Securities and Exchange Commission. You should not place undue reliance on forward-looking statements and we undertake no obligation to update any such statements. Forward-looking statements can be identified by words such as "anticipates," "intends," "plans," "seeks," "believes," "estimates," "expects," "target," "projects," "outlook," "forecast," "will," "may," "could," "should," "can" and similar references to future periods. In this press release we make forward-looking statements about strategic and growth initiatives and the result of such activity. Risks and uncertainties that could cause results to differ from forward-looking statements we make include, without limitation: current and future economic and market conditions, including the effects of declines in housing and commercial real estate prices, high unemployment rates, continued or renewed inflation and any recession or slowdown in economic growth particularly in the western United States; economic forecast variables that are either materially worse or better than end of quarter projections and deterioration in the economy that could result in increased loan and lease losses, especially those risks associated with concentrations in real estate related loans; the impact of proposed or imposed tariffs by the U.S. government and retaliatory tariffs proposed or imposed by U.S. trading partners that could have an adverse impact on customers; our ability to effectively manage problem credits; the impact of bank failures or adverse developments at other banks on general investor sentiment regarding the liquidity and stability of banks; changes in interest rates that could significantly reduce net interest income and negatively affect asset yields and valuations and funding sources; changes in the scope and cost of FDIC insurance and other coverage; our ability to successfully implement efficiency and operational excellence initiatives; our ability to successfully develop and market new products and technology; changes in laws or regulations; potential adverse reactions or changes to business or employee relationships; the effect of geopolitical instability, including wars, conflicts and terrorist attacks; and natural disasters and other similar unexpected events outside of our control. We also caution that the amount and timing of any future common stock dividends or repurchases will depend on the earnings, cash requirements and financial condition of Columbia, market conditions, capital requirements, applicable law and regulations (including federal securities laws and federal banking regulations), and other factors deemed relevant by Columbia's Board of Directors, and may be subject to regulatory approval or conditions. TABLE INDEX Page Consolidated Statements of Income 7 Consolidated Balance Sheets 7 Financial Highlights 9 Loan & Lease Portfolio Balances and Mix 9 Deposit Portfolio Balances and Mix 11 Credit Quality - Non-performing Assets 12 Credit Quality - Allowance for Credit Losses 13 Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates 14 Residential Mortgage Banking Activity 15 GAAP to Non-GAAP Reconciliation 16 Columbia Banking System, Inc. Consolidated Statements of Income (Unaudited) Quarter Ended % Change ($ in thousands, except per share data) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Interest income: Loans and leases $ 552,562 $ 572,843 $ 588,603 $ 583,874 $ 575,044 (4) % (4) % Interest and dividends on investments: Taxable 68,688 75,254 76,074 78,828 75,017 (9) % (8) % Exempt from federal income tax 6,807 6,852 6,855 6,904 6,904 (1) % (1) % Dividends 2,792 2,678 2,681 2,895 3,707 4 % (25) % Temporary investments and interest bearing deposits 16,394 18,956 24,683 23,035 23,553 (14) % (30) % Total interest income 647,243 676,583 698,896 695,536 684,225 (4) % (5) % Interest expense: Deposits 176,634 189,037 208,027 207,307 198,435 (7) % (11) % Securities sold under agreement to repurchase and federal funds purchased 974 971 1,121 1,515 1,266 — % (23) % Borrowings 36,074 39,912 49,636 49,418 51,275 (10) % (30) % Junior and other subordinated debentures 8,566 9,290 9,894 9,847 9,887 (8) % (13) % Total interest expense 222,248 239,210 268,678 268,087 260,863 (7) % (15) % Net interest income 424,995 437,373 430,218 427,449 423,362 (3) % — % Provision for credit losses 27,403 28,199 28,769 31,820 17,136 (3) % 60 % Non-interest income: Service charges on deposits 19,301 18,401 18,549 18,503 16,064 5 % 20 % Card-based fees 12,571 14,634 14,591 14,681 13,183 (14) % (5) % Financial services and trust revenue 5,187 5,265 5,083 5,396 4,464 (1) % 16 % Residential mortgage banking revenue, net 9,334 6,958 6,668 5,848 4,634 34 % 101 % Gain (loss) on sale of debt securities, net 4 10 3 (1) 12 (60) % (67) % Gain (loss) on equity securities, net 1,702 (1,424) 2,272 325 (1,565) nm nm Gain (loss) on loan and lease sales, net 97 (1,719) 161 (1,516) 221 nm (56) % BOLI income 4,883 4,742 4,674 4,705 4,639 3 % 5 % Other income (loss) 13,298 2,880 14,158 (3,238) 8,705 362 % 53 % Total non-interest income 66,377 49,747 66,159 44,703 50,357 33 % 32 % Non-interest expense: Salaries and employee benefits 145,239 141,958 147,268 145,066 154,538 2 % (6) % Occupancy and equipment, net 48,170 46,878 45,056 45,147 45,291 3 % 6 % Intangible amortization 27,979 29,055 29,055 29,230 32,091 (4) % (13) % FDIC assessments 8,022 8,121 9,332 9,664 14,460 (1) % (45) % Merger and restructuring expense 14,379 2,230 2,364 14,641 4,478 nm 221 % Other expenses 96,333 38,334 38,283 35,496 36,658 151 % 163 % Total non-interest expense 340,122 266,576 271,358 279,244 287,516 28 % 18 % Income before provision for income taxes 123,847 192,345 196,250 161,088 169,067 (36) % (27) % Provision for income taxes 37,238 49,076 50,068 40,944 44,987 (24) % (17) % Net income $ 86,609 $ 143,269 $ 146,182 $ 120,144 $ 124,080 (40) % (30) % Weighted average basic shares outstanding 208,800 208,548 208,545 208,498 208,260 — % — % Weighted average diluted shares outstanding 210,023 209,889 209,454 209,011 208,956 — % 1 % Earnings per common share – basic $ 0.41 $ 0.69 $ 0.70 $ 0.58 $ 0.60 (41) % (32) % Earnings per common share – diluted $ 0.41 $ 0.68 $ 0.70 $ 0.57 $ 0.59 (40) % (31) % nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm." Columbia Banking System, Inc. Consolidated Balance Sheets (Unaudited) % Change ($ in thousands, except per share data) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Assets: Cash and due from banks $ 591,265 $ 496,666 $ 591,364 $ 515,263 $ 440,215 19 % 34 % Interest-bearing cash and temporary investments 1,481,441 1,381,589 1,519,658 1,553,568 1,760,902 7 % (16) % Investment securities: Equity and other, at fair value 91,580 78,133 79,996 77,221 77,203 17 % 19 % Available for sale, at fair value 8,228,805 8,274,615 8,676,807 8,503,000 8,616,545 (1) % (4) % Held to maturity, at amortized cost 2,057 2,101 2,159 2,203 2,247 (2) % (8) % Loans held for sale 64,747 71,535 66,639 56,310 47,201 (9) % 37 % Loans and leases 37,616,101 37,680,901 37,503,002 37,709,987 37,642,413 — % — % Allowance for credit losses on loans and leases (421,495) (424,629) (420,054) (418,671) (414,344) (1) % 2 % Net loans and leases 37,194,606 37,256,272 37,082,948 37,291,316 37,228,069 — % — % Restricted equity securities 125,300 150,024 116,274 116,274 116,274 (16) % 8 % Premises and equipment, net 344,926 348,670 338,107 337,842 336,869 (1) % 2 % Operating lease right-of-use assets 106,696 111,227 106,224 108,278 113,833 (4) % (6) % Goodwill 1,029,234 1,029,234 1,029,234 1,029,234 1,029,234 — % — % Other intangible assets, net 456,269 484,248 513,303 542,358 571,588 (6) % (20) % Residential mortgage servicing rights, at fair value 105,663 108,358 101,919 110,039 110,444 (2) % (4) % Bank-owned life insurance 700,768 693,839 691,160 686,485 682,293 1 % 3 % Deferred tax asset, net 311,192 359,425 286,432 361,773 356,031 (13) % (13) % Other assets 684,717 730,461 706,375 756,319 735,058 (6) % (7) % Total assets $ 51,519,266 $ 51,576,397 $ 51,908,599 $ 52,047,483 $ 52,224,006 — % (1) % Liabilities: Deposits Non-interest-bearing $ 13,413,927 $ 13,307,905 $ 13,534,065 $ 13,481,616 $ 13,808,554 1 % (3) % Interest-bearing 28,803,767 28,412,827 27,980,623 28,041,656 27,897,606 1 % 3 % Total deposits 42,217,694 41,720,732 41,514,688 41,523,272 41,706,160 1 % 1 % Securities sold under agreements to repurchase 192,386 236,627 183,833 197,860 213,573 (19) % (10) % Borrowings 2,550,000 3,100,000 3,650,000 3,900,000 3,900,000 (18) % (35) % Junior subordinated debentures, at fair value 320,774 330,895 311,896 310,187 309,544 (3) % 4 % Junior and other subordinated debentures, at amortized cost 107,611 107,668 107,725 107,781 107,838 — % — % Operating lease liabilities 121,282 125,710 121,298 123,082 129,240 (4) % (6) % Other liabilities 771,710 836,541 745,331 908,629 900,406 (8) % (14) % Total liabilities 46,281,457 46,458,173 46,634,771 47,070,811 47,266,761 — % (2) % Shareholders' equity: Common stock 5,823,287 5,817,458 5,812,237 5,807,041 5,802,322 — % — % Accumulated deficit (227,006) (237,254) (304,525) (374,687) (418,946) (4) % (46) % Accumulated other comprehensive loss (358,472) (461,980) (233,884) (455,682) (426,131) (22) % (16) % Total shareholders' equity 5,237,809 5,118,224 5,273,828 4,976,672 4,957,245 2 % 6 % Total liabilities and shareholders' equity $ 51,519,266 $ 51,576,397 $ 51,908,599 $ 52,047,483 $ 52,224,006 — % (1) % Common shares outstanding at period end 210,112 209,536 209,532 209,459 209,370 — % — % Columbia Banking System, Inc. Financial Highlights (Unaudited) Quarter Ended % Change Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Per Common Share Data: Dividends $ 0.36 $ 0.36 $ 0.36 $ 0.36 $ 0.36 — % — % Book value $ 24.93 $ 24.43 $ 25.17 $ 23.76 $ 23.68 2 % 5 % Tangible book value (1) $ 17.86 $ 17.20 $ 17.81 $ 16.26 $ 16.03 4 % 11 % Performance Ratios: Efficiency ratio (2) 69.06 % 54.61 % 54.56 % 59.02 % 60.57 % 14.45 8.49 Non-interest expense to average assets (1) 2.68 % 2.06 % 2.08 % 2.16 % 2.22 % 0.62 0.46 Return on average assets ("ROAA") 0.68 % 1.10 % 1.12 % 0.93 % 0.96 % (0.42) (0.28) Pre-provision net revenue ("PPNR") ROAA (1) 1.19 % 1.70 % 1.72 % 1.49 % 1.44 % (0.51) (0.25) Return on average common equity 6.73 % 10.91 % 11.36 % 9.85 % 10.01 % (4.18) (3.28) Return on average tangible common equity (1) 9.45 % 15.41 % 16.34 % 14.55 % 14.82 % (5.96) (5.37) Performance Ratios - Operating: (1) Operating efficiency ratio, as adjusted (1), (2) 55.11 % 52.51 % 53.89 % 53.56 % 56.97 % 2.60 (1.86) Operating non-interest expense to average assets (1) 2.13 % 2.03 % 2.05 % 2.03 % 2.14 % 0.10 (0.01) Operating ROAA (1) 1.10 % 1.15 % 1.10 % 1.08 % 1.04 % (0.05) 0.06 Operating PPNR ROAA (1) 1.67 % 1.77 % 1.69 % 1.70 % 1.55 % (0.10) 0.12 Operating return on average common equity (1) 10.87 % 11.40 % 11.15 % 11.47 % 10.89 % (0.53) (0.02) Operating return on average tangible common equity (1) 15.26 % 16.11 % 16.04 % 16.96 % 16.12 % (0.85) (0.86) Average Balance Sheet Yields, Rates, & Ratios: Yield on loans and leases 5.92 % 6.05 % 6.22 % 6.20 % 6.13 % (0.13) (0.21) Yield on earning assets (2) 5.49 % 5.63 % 5.78 % 5.80 % 5.69 % (0.14) (0.20) Cost of interest bearing deposits 2.52 % 2.66 % 2.95 % 2.97 % 2.88 % (0.14) (0.36) Cost of interest bearing liabilities 2.80 % 2.98 % 3.29 % 3.31 % 3.25 % (0.18) (0.45) Cost of total deposits 1.72 % 1.80 % 1.99 % 2.01 % 1.92 % (0.08) (0.20) Cost of total funding (3) 1.99 % 2.09 % 2.32 % 2.34 % 2.27 % (0.10) (0.28) Net interest margin (2) 3.60 % 3.64 % 3.56 % 3.56 % 3.52 % (0.04) 0.08 Average interest bearing cash / Average interest earning assets 3.13 % 3.29 % 3.74 % 3.51 % 3.56 % (0.16) (0.43) Average loans and leases / Average interest earning assets 78.93 % 78.42 % 77.91 % 78.27 % 77.87 % 0.51 1.06 Average loans and leases / Average total deposits 90.36 % 89.77 % 90.42 % 90.61 % 90.41 % 0.59 (0.05) Average non-interest bearing deposits / Average total deposits 31.75 % 32.45 % 32.52 % 32.54 % 33.29 % (0.70) (1.54) Average total deposits / Average total funding (3) 91.86 % 91.88 % 90.25 % 90.15 % 90.09 % (0.02) 1.77 Select Credit & Capital Ratios: Non-performing loans and leases to total loans and leases 0.47 % 0.44 % 0.44 % 0.41 % 0.38 % 0.03 0.09 Non-performing assets to total assets 0.35 % 0.33 % 0.32 % 0.30 % 0.28 % 0.02 0.07 Allowance for credit losses to loans and leases 1.17 % 1.17 % 1.17 % 1.16 % 1.16 % — 0.01 Total risk-based capital ratio (4) 12.8 % 12.8 % 12.5 % 12.2 % 12.0 % — 0.80 Common equity tier 1 risk-based capital ratio (4) 10.6 % 10.5 % 10.3 % 10.0 % 9.8 % 0.10 0.80 (1) See GAAP to Non-GAAP Reconciliation. (2) Tax-exempt interest was adjusted to a taxable equivalent basis using a 21% tax rate. (3) Total funding = total deposits + total borrowings. (4) Estimated holding company ratios. Columbia Banking System, Inc. Loan & Lease Portfolio Balances and Mix (Unaudited) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 % Change ($ in thousands) Amount Amount Amount Amount Amount Seq. Quarter Year over Year Loans and leases: Commercial real estate: Non-owner occupied term, net $ 6,179,261 $ 6,278,154 $ 6,391,806 $ 6,407,351 $ 6,557,768 (2) % (6) % Owner occupied term, net 5,303,424 5,270,294 5,210,485 5,230,511 5,231,676 1 % 1 % Multifamily, net 5,831,266 5,804,364 5,779,737 5,868,848 5,828,960 — % — % Construction & development, net 2,070,732 1,983,213 1,988,923 1,946,693 1,728,652 4 % 20 % Residential development, net 252,349 231,647 244,579 269,106 284,117 9 % (11) % Commercial: Term, net 5,490,189 5,537,618 5,429,209 5,559,548 5,544,450 (1) % (1) % Lines of credit & other, net 2,753,613 2,769,643 2,640,669 2,558,633 2,491,557 (1) % 11 % Leases & equipment finance, net 1,644,052 1,660,835 1,670,427 1,701,943 1,706,759 (1) % (4) % Residential: Mortgage, net 5,878,427 5,933,352 5,944,734 5,992,163 6,128,884 (1) % (4) % Home equity loans & lines, net 2,039,061 2,031,653 2,017,336 1,982,786 1,950,421 — % 5 % Consumer & other, net 173,727 180,128 185,097 192,405 189,169 (4) % (8) % Total loans and leases, net of deferred fees and costs $ 37,616,101 $ 37,680,901 $ 37,503,002 $ 37,709,987 $ 37,642,413 — % — % Loans and leases mix: Commercial real estate: Non-owner occupied term, net 16 % 17 % 17 % 17 % 17 % Owner occupied term, net 14 % 14 % 14 % 14 % 14 % Multifamily, net 15 % 15 % 15 % 15 % 15 % Construction & development, net 6 % 5 % 5 % 5 % 5 % Residential development, net 1 % 1 % 1 % 1 % 1 % Commercial: Term, net 15 % 15 % 15 % 15 % 15 % Lines of credit & other, net 7 % 7 % 7 % 6 % 6 % Leases & equipment finance, net 4 % 4 % 4 % 5 % 5 % Residential: Mortgage, net 16 % 16 % 16 % 16 % 16 % Home equity loans & lines, net 5 % 5 % 5 % 5 % 5 % Consumer & other, net 1 % 1 % 1 % 1 % 1 % Total 100 % 100 % 100 % 100 % 100 % Columbia Banking System, Inc. Deposit Portfolio Balances and Mix (Unaudited) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 % Change ($ in thousands) Amount Amount Amount Amount Amount Seq. Quarter Year over Year Deposits: Demand, non-interest bearing $ 13,413,927 $ 13,307,905 $ 13,534,065 $ 13,481,616 $ 13,808,554 1 % (3) % Demand, interest bearing 8,494,493 8,475,693 8,444,424 8,195,284 8,095,211 0 % 5 % Money market 11,970,785 11,475,055 11,351,066 10,927,813 10,822,498 4 % 11 % Savings 2,336,727 2,360,040 2,450,924 2,508,598 2,640,060 (1) % (11) % Time 6,001,762 6,102,039 5,734,209 6,409,961 6,339,837 (2) % (5) % Total $ 42,217,694 $ 41,720,732 $ 41,514,688 $ 41,523,272 $ 41,706,160 1 % 1 % Total core deposits (1) $ 38,079,274 $ 37,487,909 $ 37,774,870 $ 37,159,069 $ 37,436,569 2 % 2 % Deposit mix: Demand, non-interest bearing 32 % 32 % 33 % 33 % 34 % Demand, interest bearing 20 % 20 % 20 % 20 % 19 % Money market 28 % 27 % 27 % 26 % 26 % Savings 6 % 6 % 6 % 6 % 6 % Time 14 % 15 % 14 % 15 % 15 % Total 100 % 100 % 100 % 100 % 100 % (1) Core deposits are defined as total deposits less time deposits greater than $250,000 and all brokered deposits. Columbia Banking System, Inc. Credit Quality – Non-performing Assets (Unaudited) Quarter Ended % Change ($ in thousands) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Non-performing assets: (1) Loans and leases on non-accrual status: Commercial real estate, net $ 41,910 $ 39,332 $ 37,332 $ 37,584 $ 39,736 7 % 5 % Commercial, net 80,492 57,146 61,464 54,986 58,960 41 % 37 % Total loans and leases on non-accrual status 122,402 96,478 98,796 92,570 98,696 27 % 24 % Loans and leases past due 90+ days and accruing: (2) Commercial real estate, net — — 136 — 253 nm (100) % Commercial, net 75 4,684 6,012 5,778 10,733 (98) % (99) % Residential, net (2) 52,392 65,552 59,961 54,525 31,916 (20) % 64 % Consumer & other, net 278 179 317 220 437 55 % (36) % Total loans and leases past due 90+ days and accruing (2) 52,745 70,415 66,426 60,523 43,339 (25) % 22 % Total non-performing loans and leases (1), (2) 175,147 166,893 165,222 153,093 142,035 5 % 23 % Other real estate owned 2,849 2,666 2,395 2,839 1,762 7 % 62 % Total non-performing assets (1), (2) $ 177,996 $ 169,559 $ 167,617 $ 155,932 $ 143,797 5 % 24 % Loans and leases past due 31-89 days $ 158,026 $ 105,199 $ 67,310 $ 85,998 $ 109,673 50 % 44 % Loans and leases past due 31-89 days to total loans and leases 0.42 % 0.28 % 0.18 % 0.23 % 0.29 % 0.14 0.13 Non-performing loans and leases to total loans andleases (1), (2) 0.47 % 0.44 % 0.44 % 0.41 % 0.38 % 0.03 0.09 Non-performing assets to total assets (1), (2) 0.35 % 0.33 % 0.32 % 0.30 % 0.28 % 0.02 0.07 Non-accrual loans and leases to total loan and leases (2) 0.33 % 0.26 % 0.26 % 0.25 % 0.26 % 0.07 0.07 nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm." (1) Non-accrual and 90+ days past due loans include government guarantees of $66.5 million, $73.6 million, $65.8 million, $64.6 million, and $43.0 million at March 31, 2025, December 31, 2024, September 30, 2024, June 30, 2024, and March 31, 2024, respectively. (2) Excludes certain mortgage loans guaranteed by GNMA, which Columbia has the unilateral right to repurchase but has not done so, totaling $2.6 million, $2.4 million, $3.7 million, $1.0 million, and $1.6 million at March 31, 2025, December 31, 2024, September 30, 2024, June 30, 2024, and March 31, 2024, respectively. Columbia Banking System, Inc. Credit Quality – Allowance for Credit Losses (Unaudited) Quarter Ended % Change ($ in thousands) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Allowance for credit losses on loans and leases (ACLLL) Balance, beginning of period $ 424,629 $ 420,054 $ 418,671 $ 414,344 $ 440,871 1 % (4) % Provision for credit losses on loans and leases 26,187 30,230 30,498 34,760 17,476 (13) % 50 % Charge-offs Commercial real estate, net (119) (2,935) — (585) (161) (96) % (26) % Commercial, net (32,611) (25,780) (32,645) (33,561) (47,232) 26 % (31) % Residential, net (303) (26) (936) (504) (490) nm (38) % Consumer & other, net (1,080) (1,523) (1,395) (1,551) (1,870) (29) % (42) % Total charge-offs (34,113) (30,264) (34,976) (36,201) (49,753) 13 % (31) % Recoveries Commercial real estate, net 19 3 44 551 358 nm (95) % Commercial, net 4,336 4,104 5,258 4,198 4,732 6 % (8) % Residential, net 98 163 143 411 170 (40) % (42) % Consumer & other, net 339 339 416 608 490 0 % (31) % Total recoveries 4,792 4,609 5,861 5,768 5,750 4 % (17) % Net (charge-offs) recoveries Commercial real estate, net (100) (2,932) 44 (34) 197 (97) % (151) % Commercial, net (28,275) (21,676) (27,387) (29,363) (42,500) 30 % (33) % Residential, net (205) 137 (793) (93) (320) (250) % (36) % Consumer & other, net (741) (1,184) (979) (943) (1,380) (37) % (46) % Total net charge-offs (29,321) (25,655) (29,115) (30,433) (44,003) 14 % (33) % Balance, end of period $ 421,495 $ 424,629 $ 420,054 $ 418,671 $ 414,344 (1) % 2 % Reserve for unfunded commitments Balance, beginning of period $ 16,168 $ 18,199 $ 19,928 $ 22,868 $ 23,208 (11) % (30) % Provision (recapture) for credit losses on unfunded commitments 1,216 (2,031) (1,729) (2,940) (340) nm nm Balance, end of period 17,384 16,168 18,199 19,928 22,868 8 % (24) % Total Allowance for credit losses (ACL) $ 438,879 $ 440,797 $ 438,253 $ 438,599 $ 437,212 0 % — % Net charge-offs to average loans and leases (annualized) 0.32 % 0.27 % 0.31 % 0.32 % 0.47 % 0.05 (0.15) Recoveries to gross charge-offs 14.05 % 15.23 % 16.76 % 15.93 % 11.56 % (1.18) 2.49 ACLLL to loans and leases 1.12 % 1.13 % 1.12 % 1.11 % 1.10 % (0.01) 0.02 ACL to loans and leases 1.17 % 1.17 % 1.17 % 1.16 % 1.16 % — 0.01 nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm." Columbia Banking System, Inc. Consolidated Average Balance Sheets, Net Interest Income, and Yields/Rates (Unaudited) Quarter Ended March 31, 2025 December 31, 2024 March 31, 2024 ($ 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 orRates INTEREST-EARNING ASSETS: Loans held for sale $ 59,223 $ 935 6.32 % $ 77,492 $ 1,230 6.35 % $ 30,550 $ 525 6.88 % Loans and leases (1) 37,678,820 551,627 5.92 % 37,538,617 571,613 6.05 % 37,597,101 574,519 6.13 % Taxable securities 7,690,610 71,480 3.72 % 7,850,888 77,932 3.97 % 8,081,003 78,724 3.90 % Non-taxable securities (2) 817,392 7,910 3.87 % 831,021 7,903 3.80 % 851,342 7,886 3.71 % Temporary investments and interest-bearing cash 1,493,815 16,394 4.45 % 1,572,680 18,956 4.80 % 1,720,791 23,553 5.51 % Total interest-earning assets (1), (2) 47,739,860 $ 648,346 5.49 % 47,870,698 $ 677,634 5.63 % 48,280,787 $ 685,207 5.69 % Goodwill and other intangible assets 1,501,590 1,528,431 1,619,134 Other assets 2,211,158 2,189,102 2,184,052 Total assets $ 51,452,608 $ 51,588,231 $ 52,083,973 INTEREST-BEARING LIABILITIES: Interest-bearing demand deposits $ 8,370,584 $ 46,632 2.26 % $ 8,562,817 $ 52,364 2.43 % $ 8,035,339 $ 51,378 2.57 % Money market deposits 11,603,140 68,719 2.40 % 11,441,154 72,830 2.53 % 10,612,073 72,497 2.75 % Savings deposits 2,350,459 574 0.10 % 2,393,348 680 0.11 % 2,688,360 715 0.11 % Time deposits 6,136,389 60,709 4.01 % 5,848,516 63,163 4.30 % 6,406,807 73,845 4.64 % Total interest-bearing deposits 28,460,572 176,634 2.52 % 28,245,835 189,037 2.66 % 27,742,579 198,435 2.88 % Repurchase agreements and federal funds purchased 215,962 974 1.83 % 197,843 971 1.95 % 231,667 1,266 2.20 % Borrowings 3,039,227 36,074 4.82 % 3,076,087 39,912 5.16 % 3,920,879 51,275 5.26 % Junior and other subordinated debentures 437,729 8,566 7.94 % 419,607 9,290 8.81 % 423,528 9,887 9.39 % Total interest-bearing liabilities 32,153,490 $ 222,248 2.80 % 31,939,372 $ 239,210 2.98 % 32,318,653 $ 260,863 3.25 % Non-interest-bearing deposits 13,238,678 13,569,118 13,841,582 Other liabilities 843,885 853,451 937,863 Total liabilities 46,236,053 46,361,941 47,098,098 Common equity 5,216,555 5,226,290 4,985,875 Total liabilities and shareholders' equity $ 51,452,608 $ 51,588,231 $ 52,083,973 NET INTEREST INCOME (2) $ 426,098 $ 438,424 $ 424,344 NET INTEREST SPREAD (2) 2.69 % 2.65 % 2.44 % NET INTEREST INCOME TO EARNING ASSETS OR NET INTEREST MARGIN (1), (2) 3.60 % 3.64 % 3.52 % (1) Non-accrual loans and leases are included in the average balance. (2) Tax-exempt income was adjusted to a tax equivalent basis at a 21% tax rate. The amount of such adjustment was an addition to recorded income of approximately $1.1 million for the three months ended March 31, 2025, as compared to $1.1 million for the three months ended December 31, 2024 and $982,000 for the three months ended March 31, 2024. Columbia Banking System, Inc. Residential Mortgage Banking Activity (Unaudited) Quarter Ended % Change ($ in thousands) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Residential mortgage banking revenue: Origination and sale $ 4,391 $ 4,519 $ 5,225 $ 3,452 $ 2,920 (3) % 50 % Servicing 5,855 5,947 6,012 5,952 6,021 (2) % (3) % Change in fair value of MSR asset: Changes due to collection/realization of expected cash flows over time (3,141) (3,103) (3,127) (3,183) (3,153) 1 % — % Changes due to valuation inputs or assumptions (983) 7,414 (6,540) 1,238 3,117 (113) % (132) % MSR hedge gain (loss) 3,212 (7,819) 5,098 (1,611) (4,271) nm nm Total $ 9,334 $ 6,958 $ 6,668 $ 5,848 $ 4,634 34 % 101 % Closed loan volume for-sale $ 136,084 $ 175,046 $ 161,094 $ 140,875 $ 86,903 (22) % 57 % Gain on sale margin 3.23 % 2.58 % 3.24 % 2.45 % 3.36 % 0.65 -0.13 Residential mortgage servicing rights: Balance, beginning of period $ 108,358 $ 101,919 $ 110,039 $ 110,444 $ 109,243 6 % (1) % Additions for new MSR capitalized 1,429 2,128 1,547 1,540 1,237 (33) % 16 % Change in fair value of MSR asset: Changes due to collection/realization of expected cash flows over time (3,141) (3,103) (3,127) (3,183) (3,153) 1 % — % Changes due to valuation inputs or assumptions (983) 7,414 (6,540) 1,238 3,117 (113) % (132) % Balance, end of period $ 105,663 $ 108,358 $ 101,919 $ 110,039 $ 110,444 (2) % (4) % Residential mortgage loans serviced for others $ 7,888,235 $ 7,939,445 $ 7,965,538 $ 8,120,046 $ 8,081,039 (1) % (2) % MSR as % of serviced portfolio 1.34 % 1.36 % 1.28 % 1.36 % 1.37 % (0.02) (0.03) nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm." Non-GAAP Financial MeasuresIn addition to results presented in accordance with generally accepted accounting principles in the United States of America ("GAAP"), this press release contains certain non-GAAP financial measures. The Company believes presenting certain non-GAAP financial measures provides investors with information useful in understanding our financial performance, our performance trends, and our financial position. We utilize these measures for internal planning and forecasting purposes, and operating pre-provision net revenue and operating return on tangible common equity are also used as part of our incentive compensation program for our executive officers. We, as well as securities analysts, investors, and other interested parties, also use these measures to compare peer company operating performance. We believe that our presentation and discussion, together with the accompanying reconciliations, provides a complete understanding of factors and trends affecting our business and allows investors to view performance in a manner similar to management. These non-GAAP measures should not be considered a substitution for GAAP basis measures and results, and we strongly encourage investors to review our consolidated financial statements in their entirety and not to rely on any single financial measure. Because non-GAAP financial measures are not standardized, it may not be possible to compare these financial measures with other companies' non-GAAP financial measures having the same or similar names. Columbia Banking System, Inc. GAAP to Non-GAAP Reconciliation (Unaudited) Quarter Ended % Change ($ in thousands, except per share data) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Total shareholders' equity a $ 5,237,809 $ 5,118,224 $ 5,273,828 $ 4,976,672 $ 4,957,245 2 % 6 % Less: Goodwill 1,029,234 1,029,234 1,029,234 1,029,234 1,029,234 — % — % Less: Other intangible assets, net 456,269 484,248 513,303 542,358 571,588 (6) % (20) % Tangible common shareholders' equity b $ 3,752,306 $ 3,604,742 $ 3,731,291 $ 3,405,080 $ 3,356,423 4 % 12 % Total assets c $ 51,519,266 $ 51,576,397 $ 51,908,599 $ 52,047,483 $ 52,224,006 — % (1) % Less: Goodwill 1,029,234 1,029,234 1,029,234 1,029,234 1,029,234 — % — % Less: Other intangible assets, net 456,269 484,248 513,303 542,358 571,588 (6) % (20) % Tangible assets d $ 50,033,763 $ 50,062,915 $ 50,366,062 $ 50,475,891 $ 50,623,184 — % (1) % Common shares outstanding at period end e 210,112 209,536 209,532 209,459 209,370 — % — % Total shareholders' equity to total assets ratio a / c 10.17 % 9.92 % 10.16 % 9.56 % 9.49 % 0.25 0.68 Tangible common equity to tangible assets ratio b / d 7.50 % 7.20 % 7.41 % 6.75 % 6.63 % 0.30 0.87 Book value per common share a / e $ 24.93 $ 24.43 $ 25.17 $ 23.76 $ 23.68 2 % 5 % Tangible book value per common share b / e $ 17.86 $ 17.20 $ 17.81 $ 16.26 $ 16.03 4 % 11 % Columbia Banking System, Inc. GAAP to Non-GAAP Reconciliation - Continued (Unaudited) Quarter Ended % Change ($ in thousands) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Non-Interest Income Adjustments Gain (loss) on sale of debt securities, net $ 4 $ 10 $ 3 $ (1) $ 12 (60) % (67) % Gain (loss) on equity securities, net 1,702 (1,424) 2,272 325 (1,565) nm nm (Loss) gain on swap derivatives (1,494) 3,642 (3,596) 424 1,197 (141) % (225) % Change in fair value of certain loans held for investment 7,016 (7,355) 9,365 (10,114) (2,372) nm nm Change in fair value of MSR due to valuation inputs or assumptions (983) 7,414 (6,540) 1,238 3,117 (113) % (132) % MSR hedge gain (loss) 3,212 (7,819) 5,098 (1,611) (4,271) nm nm Total non-interest income adjustments a $ 9,457 $ (5,532) $ 6,602 $ (9,739) $ (3,882) nm nm Non-Interest Expense Adjustments Merger and restructuring expense $ 14,379 $ 2,230 $ 2,364 $ 14,641 $ 4,478 nm 221 % Exit and disposal costs 661 872 631 1,218 1,272 (24) % (48) % FDIC special assessment — — — 884 4,848 nm (100) % Legal settlement 55,000 — — — — nm nm Total non-interest expense adjustments b $ 70,040 $ 3,102 $ 2,995 $ 16,743 $ 10,598 nm nm Net interest income c $ 424,995 $ 437,373 $ 430,218 $ 427,449 $ 423,362 (3) % — % Non-interest income (GAAP) d $ 66,377 $ 49,747 $ 66,159 $ 44,703 $ 50,357 33 % 32 % Less: Non-interest income adjustments a (9,457) 5,532 (6,602) 9,739 3,882 (271) % (344) % Operating non-interest income (non-GAAP) e $ 56,920 $ 55,279 $ 59,557 $ 54,442 $ 54,239 3 % 5 % Revenue (GAAP) f=c+d $ 491,372 $ 487,120 $ 496,377 $ 472,152 $ 473,719 1 % 4 % Operating revenue (non-GAAP) g=c+e $ 481,915 $ 492,652 $ 489,775 $ 481,891 $ 477,601 (2) % 1 % Non-interest expense (GAAP) h $ 340,122 $ 266,576 $ 271,358 $ 279,244 $ 287,516 28 % 18 % Less: Non-interest expense adjustments b (70,040) (3,102) (2,995) (16,743) (10,598) nm nm Operating non-interest expense (non-GAAP) i $ 270,082 $ 263,474 $ 268,363 $ 262,501 $ 276,918 3 % (2) % Net income (GAAP) j $ 86,609 $ 143,269 $ 146,182 $ 120,144 $ 124,080 (40) % (30) % Provision for income taxes 37,238 49,076 50,068 40,944 44,987 (24) % (17) % Income before provision for income taxes 123,847 192,345 196,250 161,088 169,067 (36) % (27) % Provision for credit losses 27,403 28,199 28,769 31,820 17,136 (3) % 60 % Pre-provision net revenue (PPNR) (non-GAAP) k 151,250 220,544 225,019 192,908 186,203 (31) % (19) % Less: Non-interest income adjustments a (9,457) 5,532 (6,602) 9,739 3,882 (271) % (344) % Add: Non-interest expense adjustments b 70,040 3,102 2,995 16,743 10,598 nm nm Operating PPNR (non-GAAP) l $ 211,833 $ 229,178 $ 221,412 $ 219,390 $ 200,683 (8) % 6 % Net income (GAAP) j $ 86,609 $ 143,269 $ 146,182 $ 120,144 $ 124,080 (40) % (30) % Less: Non-interest income adjustments a (9,457) 5,532 (6,602) 9,739 3,882 (271) % (344) % Add: Non-interest expense adjustments b 70,040 3,102 2,995 16,743 10,598 nm nm Tax effect of adjustments (7,419) (2,158) 902 (6,621) (3,620) 244 % 105 % Operating net income (non-GAAP) m $ 139,773 $ 149,745 $ 143,477 $ 140,005 $ 134,940 (7) % 4 % nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm." Columbia Banking System, Inc. GAAP to Non-GAAP Reconciliation - Continued (Unaudited) Quarter Ended % Change ($ in thousands, except per share data) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Average assets n $ 51,452,608 $ 51,588,231 $ 52,009,017 $ 51,981,555 $ 52,083,973 — % (1) % Less: Average goodwill and other intangible assets, net 1,501,590 1,528,431 1,559,696 1,588,239 1,619,134 (2) % (7) % Average tangible assets o $ 49,951,018 $ 50,059,800 $ 50,449,321 $ 50,393,316 $ 50,464,839 — % (1) % Average common shareholders' equity p $ 5,216,555 $ 5,226,290 $ 5,118,592 $ 4,908,239 $ 4,985,875 0 % 5 % Less: Average goodwill and other intangible assets, net 1,501,590 1,528,431 1,559,696 1,588,239 1,619,134 (2) % (7) % Average tangible common equity q $ 3,714,965 $ 3,697,859 $ 3,558,896 $ 3,320,000 $ 3,366,741 0 % 10 % Weighted average basic shares outstanding r 208,800 208,548 208,545 208,498 208,260 — % — % Weighted average diluted shares outstanding s 210,023 209,889 209,454 209,011 208,956 — % 1 % Select Per-Share & Performance Metrics Earnings-per-share - basic j / r $ 0.41 $ 0.69 $ 0.70 $ 0.58 $ 0.60 (41) % (32) % Earnings-per-share - diluted j / s $ 0.41 $ 0.68 $ 0.70 $ 0.57 $ 0.59 (40) % (31) % Efficiency ratio (1) h / f 69.06 % 54.61 % 54.56 % 59.02 % 60.57 % 14.45 8.49 Non-interest expense to average assets h / n 2.68 % 2.06 % 2.08 % 2.16 % 2.22 % 0.62 0.46 Return on average assets j / n 0.68 % 1.10 % 1.12 % 0.93 % 0.96 % (0.42) (0.28) Return on average tangible assets j / o 0.70 % 1.14 % 1.15 % 0.96 % 0.99 % (0.44) (0.29) PPNR return on average assets k / n 1.19 % 1.70 % 1.72 % 1.49 % 1.44 % (0.51) (0.25) Return on average common equity j / p 6.73 % 10.91 % 11.36 % 9.85 % 10.01 % (4.18) (3.28) Return on average tangible common equity j / q 9.45 % 15.41 % 16.34 % 14.55 % 14.82 % (5.96) (5.37) Operating Per-Share & Performance Metrics Operating earnings-per-share - basic m / r $ 0.67 $ 0.72 $ 0.69 $ 0.67 $ 0.65 (7) % 3 % Operating earnings-per-share - diluted m / s $ 0.67 $ 0.71 $ 0.69 $ 0.67 $ 0.65 (6) % 3 % Operating efficiency ratio, as adjusted (1) u / y 55.11 % 52.51 % 53.89 % 53.56 % 56.97 % 2.60 (1.86) Operating non-interest expense to average assets i / n 2.13 % 2.03 % 2.05 % 2.03 % 2.14 % 0.10 (0.01) Operating return on average assets m / n 1.10 % 1.15 % 1.10 % 1.08 % 1.04 % (0.05) 0.06 Operating return on average tangible assets m / o 1.13 % 1.19 % 1.13 % 1.12 % 1.08 % (0.06) 0.05 Operating PPNR return on average assets l / n 1.67 % 1.77 % 1.69 % 1.70 % 1.55 % (0.10) 0.12 Operating return on average common equity m / p 10.87 % 11.40 % 11.15 % 11.47 % 10.89 % (0.53) (0.02) Operating return on average tangible common equity m / q 15.26 % 16.11 % 16.04 % 16.96 % 16.12 % (0.85) (0.86) (1) Tax-exempt interest was adjusted to a taxable equivalent basis using a 21% tax rate and added to stated revenue for this calculation. Columbia Banking System, Inc. GAAP to Non-GAAP Reconciliation - Continued Operating Efficiency Ratio, as adjusted (Unaudited) Quarter Ended % Change ($ in thousands) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Non-interest expense (GAAP) h $ 340,122 $ 266,576 $ 271,358 $ 279,244 $ 287,516 28 % 18 % Less: Non-interest expense adjustments b (70,040) (3,102) (2,995) (16,743) (10,598) nm nm Operating non-interest expense (non-GAAP) i 270,082 263,474 268,363 262,501 276,918 3 % (2) % Less: B&O taxes t (3,150) (3,495) (3,248) (3,183) (3,223) (10) % (2) % Operating non-interest expense, excluding B&O taxes (non-GAAP) u $ 266,932 $ 259,979 $ 265,115 $ 259,318 $ 273,695 3 % (2) % Net interest income (tax equivalent) (1) v $ 426,098 $ 438,424 $ 431,184 $ 428,434 $ 424,344 (3) % — % Non-interest income (GAAP) d 66,377 49,747 66,159 44,703 50,357 33 % 32 % Add: BOLI tax equivalent adjustment (1) w 1,362 1,390 1,248 1,291 1,809 (2) % (25) % Total Revenue, excluding BOLI tax equivalent adjustments (tax equivalent) x 493,837 489,561 498,591 474,428 476,510 1 % 4 % Less: Non-interest income adjustments a (9,457) 5,532 (6,602) 9,739 3,882 (271) % (344) % Total Adjusted Operating Revenue, excluding BOLI tax equivalent adjustments (tax equivalent) (non-GAAP) y $ 484,380 $ 495,093 $ 491,989 $ 484,167 $ 480,392 (2) % 1 % Efficiency ratio (1) h / f 69.06 % 54.61 % 54.56 % 59.02 % 60.57 % 14.45 8.49 Operating efficiency ratio, as adjusted (non-GAAP) (1) u / y 55.11 % 52.51 % 53.89 % 53.56 % 56.97 % 2.60 (1.86) nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm." (1) Tax-exempt income was adjusted to a taxable equivalent basis using a 21% tax rate and added to stated revenue for this calculation. Columbia Banking System, Inc. GAAP to Non-GAAP Reconciliation - Continued (Unaudited) Quarter Ended % Change ($ in thousands) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Loans and leases interest income a $ 551,627 $ 571,613 $ 587,481 $ 582,246 $ 574,519 (3) % (4) % Less: Acquired loan accretion - rate related (2), (3) b 21,371 22,188 21,963 24,942 23,482 (4) % (9) % Less: Acquired loan accretion - credit related (3) c 3,561 4,313 4,127 4,835 5,119 (17) % (30) % Adjusted loans and leases interest income d=a-b-c $ 526,695 $ 545,112 $ 561,391 $ 552,469 $ 545,918 (3) % (4) % Taxable securities interest income e $ 71,480 $ 77,932 $ 78,755 $ 81,723 $ 78,724 (8) % (9) % Less: Acquired taxable securities accretion - rate related f 25,729 36,980 35,359 40,120 31,527 (30) % (18) % Adjusted Taxable securities interest income g=e-f $ 45,751 $ 40,952 $ 43,396 $ 41,603 $ 47,197 12 % (3) % Non-taxable securities interest income (1) h $ 7,910 $ 7,903 $ 7,821 $ 7,889 $ 7,886 — % — % Less: Acquired non-taxable securities accretion - rate related i 2,233 2,274 2,241 2,256 2,270 (2) % (2) % Adjusted Taxable securities interest income (1) j=h-i $ 5,677 $ 5,629 $ 5,580 $ 5,633 $ 5,616 1 % 1 % Interest income (1) k $ 648,346 $ 677,634 $ 699,862 $ 696,521 $ 685,207 (4) % (5) % Less: Acquired loan and securities accretion - rate related (3) l=b+f+i 49,333 61,442 59,563 67,318 57,279 (20) % (14) % Less: Acquired loan accretion - credit related (3) c 3,561 4,313 4,127 4,835 5,119 (17) % (30) % Adjusted interest income (1) m=k-l-c $ 595,452 $ 611,879 $ 636,172 $ 624,368 $ 622,809 (3) % (4) % Interest-bearing deposits interest expense n $ 176,634 $ 189,037 $ 208,027 $ 207,307 $ 198,435 (7) % (11) % Less: Acquired deposit accretion o — — — — — nm nm Adjusted interest-bearing deposits interest expense p=n-o $ 176,634 $ 189,037 $ 208,027 $ 207,307 $ 198,435 (7) % (11) % Interest expense q $ 222,248 $ 239,210 $ 268,678 $ 268,087 $ 260,863 (7) % (15) % Less: Acquired interest-bearing liabilities accretion (2) r (57) (57) (57) (57) (57) — % — % Adjusted interest expense s=q-r $ 222,305 $ 239,267 $ 268,735 $ 268,144 $ 260,920 (7) % (15) % Net Interest Income (1) t $ 426,098 $ 438,424 $ 431,184 $ 428,434 $ 424,344 (3) % — % Less: Acquired loan, securities, and interest-bearing liabilities accretion - rate related (3) u=l-r 49,390 61,499 59,620 67,375 57,336 (20) % (14) % Less: Acquired loan accretion - credit related (3) c 3,561 4,313 4,127 4,835 5,119 (17) % (30) % Adjusted net interest income (1) v=t-u-c $ 373,147 $ 372,612 $ 367,437 $ 356,224 $ 361,889 — % 3 % Average loans and leases aa 37,678,820 37,538,617 37,543,561 37,663,396 37,597,101 — % — % Average taxable securities ab 7,690,610 7,850,888 7,943,391 7,839,202 8,081,003 (2) % (5) % Average non-taxable securities ac 817,392 831,021 828,362 825,030 851,342 (2) % (4) % Average interest-earning assets ad 47,739,860 47,870,698 48,185,474 48,117,746 48,280,787 — % (1) % Average interest-bearing deposits ae 28,460,572 28,245,835 28,019,046 28,041,156 27,742,579 1 % 3 % Average interest-bearing liabilities af 32,153,490 31,939,372 32,505,157 32,583,458 32,318,653 1 % (1) % nm = Percentage changes greater than +/-500% are considered not meaningful and are presented as "nm." (1) Tax-exempt interest was adjusted to a taxable equivalent basis using a 21% tax rate. (2) Includes discount accretion related to the 2014 acquisition of Sterling Financial Corporation. (3) The cumulative fair value discount on historical Columbia loans was established as of February 28, 2023, and the allocation between the credit-related discount and the rate-related discount was established at that time. Our disclosure of credit-related and rate-related discount accretion is an estimate based on the relative allocation of these two items to the discount at the closing of the merger. Columbia Banking System, Inc. GAAP to Non-GAAP Reconciliation - Continued (Unaudited) Quarter Ended % Change ($ in thousands) Mar 31, 2025 Dec 31, 2024 Sep 30, 2024 Jun 30, 2024 Mar 31, 2024 Seq. Quarter Year over Year Average yield on loans and leases a / aa 5.92 % 6.05 % 6.22 % 6.20 % 6.13 % (0.13) (0.21) Less: Acquired loan accretion - rate related (2),(3) b / aa 0.23 % 0.24 % 0.23 % 0.27 % 0.25 % (0.01) (0.02) Less: Acquired loan accretion - credit related (3) c / aa 0.04 % 0.05 % 0.04 % 0.05 % 0.05 % (0.01) (0.01) Adjusted average yield on loans and leases d / aa 5.65 % 5.76 % 5.95 % 5.88 % 5.83 % (0.11) (0.18) Average yield on taxable securities e / ab 3.72 % 3.97 % 3.97 % 4.17 % 3.90 % (0.25) (0.18) Less: Acquired taxable securities accretion - rate related f / ab 1.36 % 1.87 % 1.77 % 2.06 % 1.57 % (0.51) (0.21) Adjusted average yield on taxable securities g / ab 2.36 % 2.10 % 2.20 % 2.11 % 2.33 % 0.26 0.03 Average yield on non-taxable securities (1) h / ac 3.87 % 3.80 % 3.78 % 3.82 % 3.71 % 0.07 0.16 Less: Acquired non-taxable securities accretion - rate related i / ac 1.11 % 1.09 % 1.08 % 1.10 % 1.07 % 0.02 0.04 Adjusted yield on non-taxable securities (1) j / ac 2.76 % 2.71 % 2.70 % 2.72 % 2.64 % 0.05 0.12 Average yield on interest-earning assets (1) k / ad 5.49 % 5.63 % 5.78 % 5.80 % 5.69 % (0.14) (0.20) Less: Acquired loan and securities accretion - rate related (3) l / ad 0.42 % 0.51 % 0.49 % 0.56 % 0.48 % (0.09) (0.06) Less: Acquired loan accretion - credit related (3) c / ad 0.03 % 0.03 % 0.04 % 0.04 % 0.04 % — (0.01) Adjusted average yield on interest-earning assets (1) m / ad 5.04 % 5.09 % 5.25 % 5.20 % 5.17 % (0.05) (0.13) Average rate on interest-bearing deposits n / ae 2.52 % 2.66 % 2.95 % 2.97 % 2.88 % (0.14) (0.36) Less: Acquired deposit accretion o / ae — % — % — % — % — % — — Adjusted average rate on interest-bearing deposits p / ae 2.52 % 2.66 % 2.95 % 2.97 % 2.88 % (0.14) (0.36) Average rate on interest-bearing liabilities q / af 2.80 % 2.98 % 3.29 % 3.31 % 3.25 % (0.18) (0.45) Less: Acquired interest-bearing liabilities accretion (2) r / af — % — % — % — % — % — — Adjusted average rate on interest-bearing liabilities s / af 2.80 % 2.98 % 3.29 % 3.31 % 3.25 % (0.18) (0.45) Net interest margin (1) t / ad 3.60 % 3.64 % 3.56 % 3.56 % 3.52 % (0.04) 0.08 Less: Acquired loan, securities, and interest-bearing liabilities accretion - rate related (3) u / ad 0.42 % 0.51 % 0.49 % 0.56 % 0.48 % (0.09) (0.06) Less: Acquired loan accretion - credit related (3) c / ad 0.03 % 0.03 % 0.04 % 0.04 % 0.04 % — (0.01) Adjusted net interest margin (1) v / ad 3.15 % 3.10 % 3.03 % 2.96 % 3.00 % 0.05 0.15 (1) Tax-exempt interest was adjusted to a taxable equivalent basis using a 21% tax rate. (2) Includes discount accretion related to the 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. FORWARD-LOOKING STATEMENTS This communication may contain certain forward-looking statements, including, but not limited to, certain plans, expectations, goals, projections, and statements about the benefits of the proposed business combination transaction between Columbia Banking System, Inc. ("Columbia") and Pacific Premier Bancorp, Inc. ("Pacific Premier") (the "Transaction"), the plans, objectives, expectations and intentions of Columbia and Pacific Premier, the expected timing of completion of the Transaction, and other statements that are not historical facts. Such statements are subject to numerous assumptions, risks, and uncertainties. All statements other than statements of historical fact, including statements about beliefs and expectations, are forward-looking statements. Forward-looking statements may be identified by words such as "expect," "anticipate," "believe," "intend," "estimate," "plan," "believe," "target," "goal," or similar expressions, or future or conditional verbs such as "will," "may," "might," "should," "would," "could," or similar variations. The forward-looking statements are intended to be subject to the safe harbor provided by Section 27A of the Securities Act of 1933, Section 21E of the Securities Exchange Act of 1934, and the Private Securities Litigation Reform Act of 1995. Although there is no assurance that any list of risks and uncertainties or risk factors is complete, below are certain factors which could cause actual results to differ materially from those contained or implied in the forward-looking statements or historical performance: changes in general economic, political, or industry conditions, and in conditions impacting the banking industry specifically; uncertainty in U.S. fiscal, monetary and trade policy, including the interest rate policies of the Federal Reserve Board or the effects of any declines in housing and commercial real estate prices, high or increasing unemployment rates, continued or renewed inflation, the impact of proposed or imposed tariffs by the U.S. government or retaliatory tariffs proposed or imposed by U.S. trading partners that could have an adverse impact on customers or any recession or slowdown in economic growth particularly in the western United States; volatility and disruptions in global capital and credit markets; the impact of bank failures or adverse developments at other banks on general investor sentiment regarding the stability and liquidity of banks; changes in interest rates that could significantly reduce net interest income and negatively affect asset yields and valuations and funding sources, including impacts on prepayment speeds; competitive pressures among financial institutions and nontraditional providers of financial services, including on product pricing and services; concentrations within Columbia's or Pacific Premier's loan portfolio (including commercial real estate loans), large loans to certain borrowers, and large deposits from certain clients; the success, impact, and timing of Columbia's and Pacific Premier's respective business strategies, including market acceptance of any new products or services and Columbia's and Pacific Premier's ability to successfully implement efficiency and operational excellence initiatives; the nature, extent, timing, and results of governmental actions, examinations, reviews, reforms, regulations, and interpretations; changes in laws or regulations; the occurrence of any event, change or other circumstances that could give rise to the right of one or both of the parties to terminate the merger agreement to which Columbia and Pacific Premier are parties; the outcome of any legal proceedings that may be instituted against Columbia or Pacific Premier; delays in completing the Transaction; the failure to obtain necessary regulatory approvals (and the risk that such approvals may result in the imposition of conditions that could adversely affect the combined company or the expected benefits of the Transaction); the failure to obtain shareholder or stockholder approvals, as applicable, or to satisfy any of the other conditions to the closing of the Transaction on a timely basis or at all; changes in Columbia's or Pacific Premier's share price before closing, including as a result of the financial performance of the other party prior to closing, or more generally due to broader stock market movements, and the performance of financial companies and peer group companies; the possibility that the anticipated benefits of the Transaction are not realized when expected or at all, including as a result of the impact of, or problems arising from, the integration of the two companies or as a result of the strength of the economy and competitive factors in the areas where Columbia and Pacific Premier do business; certain restrictions during the pendency of the proposed Transaction that may impact the parties' ability to pursue certain business opportunities or strategic Transactions; the possibility that the Transaction may be more expensive to complete 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 announcement or completion of the Transaction; the ability to complete the Transaction and integration of Columbia and Pacific Premier promptly and successfully; the dilution caused by Columbia's issuance of additional shares of its capital stock in connection with the Transaction; and other factors that may affect the future results of Columbia and Pacific Premier. Additional factors that could cause results to differ materially from those described above can be found in Columbia's Annual Report on Form 10-K for the year ended December 31, 2024, which is on file with the Securities and Exchange Commission (the "SEC") (available here) and available on Columbia's investor relations website, www.columbiabankingsystem.com, under the heading "SEC Filings," and in other documents Columbia files with the SEC, and in Pacific Premier's Annual Report on Form 10-K for the year ended December 31, 2024, which is on file with the SEC (available here) and available on Pacific Premier's website, www.investors.ppbi.com, under the heading "SEC Filings" and in other documents Pacific Premier files with the SEC. All forward-looking statements speak only as of the date they are made and are based on information available at that time. Neither Columbia nor Pacific Premier assumes any obligation to update forward-looking statements to reflect circumstances or events that occur after the date the forward-looking statements were made or to reflect the occurrence of unanticipated events except as required by federal securities laws. As forward-looking statements involve significant risks and uncertainties, caution should be exercised against placing undue reliance on such statements. IMPORTANT ADDITIONAL INFORMATION AND WHERE TO FIND IT In connection with the proposed Transaction, Columbia will file with the SEC a Registration Statement on Form S-4 that will include a Joint Proxy Statement of Columbia and Pacific Premier and a Prospectus of Columbia, as well as other relevant documents concerning the Transaction. Certain matters in respect of the Transaction involving Columbia and Pacific Premier will be submitted to Columbia's and Pacific Premier's shareholders or stockholders, as applicable, for their consideration. This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval, nor shall there be any sale of securities, in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. INVESTORS, COLUMBIA SHAREHOLDERS AND PACIFIC PREMIER STOCKHOLDERS ARE URGED TO READ THE REGISTRATION STATEMENT AND THE JOINT PROXY STATEMENT/PROSPECTUS REGARDING THE TRANSACTION WHEN THEY BECOME AVAILABLE AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC IN CONNECTION WITH THE TRANSACTION, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. Shareholders or stockholders, as applicable, will be able to obtain a free copy of the definitive joint proxy statement/prospectus, as well as other filings containing information about the Transaction, Columbia and Pacific Premier, without charge, at the SEC's website, www.sec.gov. Copies of the joint proxy statement/prospectus and the filings with the SEC that will be incorporated by reference in the joint proxy statement/prospectus can also be obtained, without charge, by directing a request to Columbia Banking System, Inc., Attention: Investor Relations, 1301 A Street, Tacoma, WA 98402-4200, (503) 727-4100 or to Pacific Premier Bancorp, Inc., Attention: Corporate Secretary, 17901 Von Karman Avenue, Suite 1200, Irvine, CA 92614, (949) 864-8000. PARTICIPANTS IN THE SOLICITATION Columbia, Pacific Premier, and certain of their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from Columbia shareholders or Pacific Premier stockholders in connection with the Transaction under the rules of the SEC. Information regarding Columbia's directors and executive officers is available in the sections entitled "Directors, Executive Officers and Corporate Governance" and "Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters" in Columbia's Annual Report on Form 10-K for the fiscal year ended December 31, 2024, which was filed with the SEC on February 25, 2025 (available here); in the sections entitled "Board Structure and Compensation," "Compensation Discussion and Analysis," "Compensation Tables," "Information about Executive Officers," "Beneficial Ownership of Directors and Executive Officers" and "Certain Relationships and Related Transactions" in Columbia's definitive proxy statement relating to its 2025 Annual Meeting of Shareholders, which was filed with the SEC on April 3, 2025 (available here); and other documents filed by Columbia with the SEC. Information regarding Pacific Premier's directors and executive officers is available in the sections entitled "Directors, Executive Officers and Corporate Governance" and "Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters" in Pacific Premier's Annual Report on Form 10-K for the fiscal year ended December 31, 2024, which was filed with the SEC on February 28, 2025 (available here); in the sections entitled "Compensation of Non-Employee Directors," "Security Ownership of Directors and Executive Officers," "Certain Relationships and Related Transactions," "Summary Compensation Table," "Employment Agreements, Salary Continuation Plans, Severance, and Change-in-Control Payments," and "Summary of Potential Termination Payments" in Pacific Premier's definitive proxy statement relating to its 2025 Annual Meeting of Stockholders, which was filed with the SEC on April 7, 2025 (available here); and other documents filed by Pacific Premier with the SEC. To the extent holdings of Columbia common stock by the directors and executive officers of Columbia or holdings of Pacific Premier common stock by directors and executive officers of Pacific Premier have changed from the amounts held by such persons as reflected in the documents described above, such changes have been or will be reflected on Statements of Change in Ownership on Form 4 filed with the SEC. Other information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the joint proxy statement/prospectus relating to the Transaction. Free copies of this document may be obtained as described in the preceding paragraph. SOURCE Columbia Banking System, Inc. WANT YOUR COMPANY'S NEWS FEATURED ON PRNEWSWIRE.COM? 440k+ Newsrooms & Influencers 9k+ Digital Media Outlets 270k+ Journalists Opted In

COLUMBIA BANKING SYSTEM, INC. REPORTS FIRST QUARTER 2025 RESULTS

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