Umpqua Holdings Corporation 4th Quarter 2021 Earnings Conference Call Presentation January 20, 2022

2 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 transaction, the plans, objectives, expectations and intentions of Umpqua Holdings Corporation (“Umpqua”) and Columbia Banking System, Inc. (“Columbia”), 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,” “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. While 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: changes in general economic, political, or industry conditions; the magnitude and duration of the COVID-19 pandemic and its impact on the global economy and financial market conditions and Umpqua’s and Columbia’s respective businesses, results of operations, and financial condition; uncertainty in U.S. fiscal and monetary 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, or any slowdown in economic growth particularly in the western United States; volatility and disruptions in global capital and credit markets; movements in interest rates; reform of LIBOR; competitive pressures, including on product pricing and services; success, impact, and timing of Umpqua’s and Columbia’s respective business strategies, including market acceptance of any new products or services and Umpqua and Columbia’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 Umpqua and Columbia are parties; the outcome of any legal proceedings that may be instituted against Umpqua or Columbia; 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 approvals or to satisfy any of the other conditions to the transaction on a timely basis or at all; changes in Umpqua’s or Columbia’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 Umpqua and Columbia 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 Umpqua and Columbia 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 Umpqua and Columbia. Additional factors that could cause results to differ materially from those described above can be found in Umpqua’s Annual Report on Form 10-K for the year ended December 31, 2020 and its Quarterly Reports on Form 10-Q for the three-month periods ended March 31, 2021, June 30, 2021, and September 30, 2021, which are on file with the Securities and Exchange Commission (the “SEC”) and available on Umpqua’s investor relations website, www.umpquabank.com, under the heading “Financials,” and in other documents Umpqua files with the SEC, and in Columbia’s Registration Statement on Form S-4, its Annual Report on Form 10-K for the year ended December 31, 2020, and its Quarterly Reports on Form 10-Q for the three-month periods ended March 31, 2021, June 30, 2021, and September 30, 2021, which are on file with the SEC and available on Columbia’s website, www.columbiabank.com, under the heading “Financial Information” and in other documents Columbia 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 Umpqua nor Columbia 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. Disclaimer

3 IMPORTANT ADDITIONAL INFORMATION AND WHERE TO FIND IT In connection with the proposed transaction (the “Transaction”), Columbia filed with the SEC a Registration Statement on Form S-4 that includes a joint proxy statement of Umpqua and Columbia and a prospectus of Columbia, which the SEC declared effective December 3, 2021. Umpqua and Columbia commenced mailing of the definitive joint proxy statement/prospectus to Umpqua’s and Columbia’s shareholders seeking certain approvals related to the Transaction on or about December 7, 2021. Umpqua and Columbia may also file other relevant documents concerning the Transaction with the SEC. 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 AND SHAREHOLDERS ARE URGED TO READ THE REGISTRATION STATEMENT AS WELL AS THE JOINT PROXY STATEMENT/PROSPECTUS REGARDING THE TRANSACTION 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 CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION. Shareholders can obtain a free copy of the definitive joint proxy statement/prospectus, as well as other filings containing information about Umpqua and Columbia, without charge, at the SEC’s website, www.sec.gov. Copies of these documents and the filings with the SEC incorporated by reference in these documents can also be obtained, without charge, by directing a request to Umpqua Holdings Corporation, Attention: Andrew Ognall, One SW Columbia Street, Suite 1200, Portland, OR 97204, 503-727-4100 or to Columbia Banking System, Inc., Attention: Investor Relations, P. O. Box 2156, MS 3100, Tacoma, WA 98401-2156, 253-471-4065. PARTICIPANTS IN THE SOLICITATION Umpqua, Columbia, and certain of their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from the shareholders of Umpqua and Columbia in connection with the Transaction under the rules of the SEC. Information regarding Umpqua’s directors and executive officers is available in Umpqua’s definitive proxy statement relating to its 2021 Annual Meeting of Shareholders, which was filed with the SEC on March 5, 2021, and other documents filed by Umpqua with the SEC. Information regarding Columbia’s directors and executive officers is available in Columbia’s definitive proxy statement relating to its 2021 Annual Meeting of Shareholders, which was filed with the SEC on April 12, 2021, and other documents filed by Columbia 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, is 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. NON-GAAP FINANCIAL MEASURES In addition to results in accordance with GAAP, this presentation contains certain non-GAAP financial measures. A reconciliation of core cash earnings per share, tangible book value, and other ratios, as adjusted, is included in the Appendix that begins on page 30. We believe that providing certain non-GAAP financial measures provides investors with information useful in understanding our financial performance, our performance trends and 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. Disclaimer (con’t)

Strategic Updates

5 Synergies anticipated to drive growth in loans, deposits, and fee-based products and services* 2596936-002 Creating a Leading West Coast Franchise Source: S&P Global Market Intelligence; FactSet; Company filings. *Revenue synergies are anticipated but not modeled in EPS accretion guidance. Note: Market data as of October 9, 2021; Financial data as of quarter ended June 30, 2021; Pro forma financial data shown for 2023 with fully phased-in cost savings for illustrative purposes; Pro forma for Columbia’s completed acquisition of Bank of Commerce. ¹ Core cash EPS excludes standalone intangible amortization, pro forma CDI amortization, amortization of non-PCD fair value mark and amortization of other fair value marks. ² EPS accretion does not assume pro forma excess capital is used for pro forma share repurchases. . . . creating a West Coast regional powerhouse Phoenix Salt Lake City 8 0 5 5 9 0 8 2 8 4 1 5 1 5 1 7 8 5 8 4 5 9 0 5 8 0 5 San Diego Long Beach Los Angeles Sacramento Carson City Boise Portland Tacoma Helena Seattle Tacoma Sacramento Spokane Kennewick Seattle Portland Salem Santa Rosa Redding San Francisco (217) (153) Combined company deepens its foothold in the Northwest and California . . . $50bn assets 15% 2023E ROATCE 44% non-interest bearing deposits 23% / 25% GAAP / core cash1 EPS accretion to Columbia2 80% Commercial loans 8% / 11% GAAP / core cash¹ EPS accretion to Umpqua² Dramatically increases delivery channel for small business lending as Umpqua locations bring upwards of 120 new communities within 19 new MSA’s to Columbia, where small business lending expertise is executed through its branch network The combination increases market density within thriving Idaho markets, moving the pro forma bank to the No. 10 deposit market share position in the state The natural compatibility between specific lending verticals, like leasing from Umpqua and healthcare from Columbia, is expected to provide enhanced opportunity for relationship development and growth Synergies in fee-generating businesses, like Wealth Management and Home Lending, are anticipated to provide additional avenues to grow revenue above expectations Scale and associated talent and technology synergies are expected to increase net-revenue generating opportunities including organic lending expansion into new western markets and deposit- gathering opportunities in existing markets, like southern California ü ü ü ü ü Washington Oregon California $15.3bn deposits $82K median household income ~7.8mm population $16.4bn deposits $70K median household income ~4.3mm population $9.5bn deposits $83K median household income ~39.7mm population

6 Current Priorities: Integration and Growth ◦ The top priorities at Columbia and Umpqua are to prepare for and execute the seamless integration of our two banks following the closing without disrupting the growth momentum that began in 2H 2020 and that we expect to continue into 2023. ◦ The establishment of the Integration Management Office (IMO) enables our respective front lines to remain focused on what they do best: generating balanced growth in loans, deposits, and fee-based products and services. ◦ We established the IMO to lead our integration, track against key milestones, and ultimately ensure a seamless experience for our teams and clients. • The IMO leadership team includes senior executive leadership from both banks representing operations, technology, finance, legal & regulatory, communications, and project management. • The separation of integration responsibilities from our growth initiatives is expected to enable Columbia’s and Umpqua’s bankers to continue to operate separately and seamlessly ahead of the transaction’s anticipated close. ◦ The organizational design for leaders that are expected to report directly to our post-closing executive team is complete, and it was jointly communicated to both organizations. We continue to make strides finalizing further layers of the post-closing organization’s design. ◦ Cost savings realization plans are progressing well, and we remain confident our $135 million original target will be achievable. ◦ Following the pandemic-driven slow-down in non-PPP loan generation, each of Columbia and Umpqua re-established growth momentum in 2H 2020. ◦ Non-PPP loan growth at each bank accelerated in 2021, and held strong through year end. Each of the banks’ pipelines and expectations for seasonal build support our favorable outlook through 2022 and into 2023 at each of our respective banks. ◦ We expect product synergies and our larger pro forma balance sheet, alongside the proven success of relationship-driven operation models at Columbia and Umpqua, to support a favorable growth profile at our combined organization following our anticipated mid-2022 deal close. ◦ See Appendix for a numerical example of the power we expect our larger pro forma balance sheet to support following closing. Integration Update Growth Update

7 Revenue: Scale Expected to Enhance Opportunities Lend with a bigger balance sheet Magnifies the opportunity to grow the loan book as it reduces the need to participate out larger deals, favorably impacting new business and enabling the expansion of existing client relationships. Increases customer retention as small business customers can travel with us from inception through their corporate lending needs, which limits the number of customers who grow out of the bank. Enhances loan portfolio granularity and diversification, which supports the pro forma bank’s risk profile and presents additional opportunities to expand existing verticals (e.g., healthcare and leasing). Invest in net-revenue generating business opportunities given expected enhanced profitability Increases ability to explore new risk-appropriate verticals that provide attractive returns and further balance sheet diversification (e.g., the addition of a new national vertical without shifting away from our local strategy). Opens opportunities to organically expand into other Western markets as the larger bank is expected to be attractive to sophisticated customers and the talent needed to serve them. Grow noninterest, non-mortgage fee income by expanding relationships with combined customer base Broadens overall Wealth Management reach by extending Columbia Trust and Columbia Bank Financial Services across the combined client base. Generates additional opportunities to deepen relationships as data science capabilities from Umpqua that provide customer behavior analysis are applied across a broader customer base. For example, analytics uncover a customer who makes routine, large deposits and does not use treasury management services: this provides a “Smart Lead” to a banker to improve customer satisfaction while generating additional income for the bank. ü Our combination would enable us to: ü ü + + + + + + +

Financial Highlights Q4 2021 & FY2021

9 Total gross loans and leases increased $583 million as balanced non-PPP loan growth of $930 million, or 4.4%, offset an expected decrease in PPP loan balances of $346 million due to processed forgiveness and payoffs. Remaining PPP balances were only 1.7% of the total loan portfolio at December 31, 2021. Q4 2021 Highlights (Compared to Q3 2021) Deposit balances decreased by $314 million, or 1.2%. This decrease was primarily attributable to anticipated outflows related to the April 2021 sale of Umpqua Investments, a continued decline in personal certificates of deposit balances, and normal seasonal trends related to customer tax and escrow payments. Net interest income decreased by $1.7 million on a quarter-to-quarter basis due to lower income related to PPP loans. Excluding this income, net interest income increased by $5.6 million on a quarter-to- quarter basis due to growth in average non-PPP loans and investment securities and a reduction in the cost of interest-bearing deposits. The recapture of provision for credit losses was $0.7 million for the quarter, compared to a recapture of $18.9 million for the third quarter of 2021. The current quarter’s recapture reflects improvement in economic forecasts used in credit models that was largely offset by allowance requirements for new loan generation. Net charge-offs increased by two basis points to 0.13% of average loans and leases (annualized), but remained low as net charge-off activity within the FinPac portfolio remained below its historical average for the second consecutive quarter. Non-interest income increased by $9.0 million, primarily due to higher net mortgage banking revenue of $9.0 million given a write-up of the MSR asset. Non-interest expense increased by $16.0 million, primarily due to increases of $15.2 million in merger-related expenses, $2.3 million in production incentive compensation related to portfolio loan growth, and $1.9 million in one-time write-offs. A $1.8 million decrease in home lending direct expense and a $2.9 million decrease in municipal taxes related to a reclassification from other expense to tax expense also impacted the quarter’s results compared to the third quarter of 2021. Non-performing assets to total assets was 0.17%, consistent with the prior period. Estimated total risk-based capital ratio of 14.3% and estimated Tier 1 capital to risk-weighted assets ratio of 11.6%. Paid a quarterly cash dividend of $0.21 per common share on November 30, 2021, to shareholders of record as of November 19, 2021.

10 Selected Ratios Footnotes: 1. Non-GAAP financial measure. A reconciliation to the comparable GAAP measurement is provided at the end of this slide presentation. 2. Capital ratio estimated for current quarter, pending completion and filing of regulatory reports. For the year ended For the quarter ended FY 2021 FY 2020 Q4 2021 Q3 2021 Q2 2021 Q1 2021 Q4 2020 Performance Return on average assets 1.39 % (5.22) % 1.13 % 1.40 % 1.54 % 1.49 % 2.04 % Return on average tangible assets 1.39 % (5.30) % 1.14 % 1.40 % 1.55 % 1.49 % 2.04 % Return on average common equity 15.56 % (51.08) % 12.90 % 15.82 % 17.25 % 16.33 % 22.92 % Return on average tangible common equity 15.63 % (60.34) % 12.94 % 15.88 % 17.33 % 16.43 % 23.07 % Efficiency ratio - consolidated 59.53 % 196.47 % 63.10 % 59.44 % 58.96 % 56.74 % 58.82 % Net interest margin - consolidated 3.18 % 3.23 % 3.15 % 3.21 % 3.20 % 3.18 % 3.35 % Credit Quality Non-performing loans and leases to loans and leases 0.23 % 0.31 % 0.23 % 0.24 % 0.22 % 0.25 % 0.31 % Non-performing assets to total assets 0.17 % 0.24 % 0.17 % 0.17 % 0.17 % 0.19 % 0.24 % Net charge-offs to average loans and leases (annualized) 0.20 % 0.32 % 0.13 % 0.11 % 0.25 % 0.33 % 0.35 % Capital Tangible common equity to tangible assets 1 8.9 % 9.2 % 8.9 % 8.8 % 9.1 % 8.9 % 9.2 % Tier 1 common to risk-weighted asset ratio 2 11.6 % 12.3 % 11.6 % 12.0 % 12.4 % 12.6 % 12.3 % Total risk-based capital ratio 2 14.3 % 15.6 % 14.3 % 14.9 % 15.4 % 15.8 % 15.6 %

Summary Financial Statements Q4 2021

12 Summary Income Statement Footnotes: Tables may not foot due to rounding. (in millions) For the year ended For the Quarter Ended FY 2021 FY 2020 Q4 2021 Q3 2021 Q2 2021 Q1 2021 Q4 2020 Net interest income before provision $919.6 $882.5 $233.4 $235.1 $229.8 $221.4 $234.9 (Recapture) provision for credit losses (42.7) 204.9 (0.7) (18.9) (23.0) — — Net interest income after provision 962.3 677.7 234.1 254.0 252.8 221.4 234.9 Non-interest income 356.3 412.0 82.7 73.7 91.1 108.8 124.0 Non-interest expense 760.5 2,546.1 199.7 183.8 189.4 187.6 211.3 Income (loss) before provision for income taxes 558.2 (1,456.4) 117.1 143.9 154.4 142.6 147.5 Provision (benefit) for income taxes 137.9 67.0 28.8 35.9 38.3 34.9 (3.2) Net income (loss) $420.3 ($1,523.4) $88.4 $108.1 $116.1 $107.7 $150.7 Earnings (loss) per share, diluted $1.91 ($6.92) $0.41 $0.49 $0.53 $0.49 $0.68

13 Selected Balance Sheet Footnotes: Tables may not foot due to rounding. 1. Non-GAAP financial measure. A reconciliation to the comparable GAAP measurement is provided in the appendix of this slide presentation. (in millions) Q4 2021 Q3 2021 Q2 2021 Q1 2021 Q4 2020 Total assets $30,640.9 $30,891.5 $30,285.0 $30,036.7 $29,235.2 Interest bearing cash and temporary investments 2,539.6 3,349.0 2,688.3 2,861.8 2,203.0 Investment securities available for sale, fair value 3,870.4 3,723.2 3,474.0 3,167.8 2,932.6 Loans and leases, gross 22,553.2 21,969.9 22,143.7 22,160.9 21,779.4 Allowance for credit losses on loans and leases (248.4) (257.6) (279.9) (311.3) (328.4) Goodwill and other intangibles, net 8.8 10.0 11.1 14.9 16.1 Deposits 26,594.7 26,908.4 26,153.6 25,886.8 24,622.2 Securities sold under agreements to repurchase 492.2 467.8 480.3 420.4 375.4 Borrowings 6.3 6.4 111.4 281.4 771.5 Total shareholders' equity 2,749.3 2,722.4 2,766.3 2,681.9 2,704.6 Ratios: Loan to deposit ratio 84.8% 81.6% 84.7% 85.6% 88.5% Book value per common share $12.69 $12.57 $12.54 $12.16 $12.28 Tangible book value per common share¹ $12.65 $12.52 $12.49 $12.10 $12.21 Tangible common equity to tangible assets¹ 8.9% 8.8% 9.1% 8.9% 9.2%

Income Statement Highlights & Segment Financials Q4 2021

15 Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 Reported Net Interest Income $234.9 $221.4 $229.8 $235.1 $233.4 Accretion Related to Acquired Loans (2.8) (2.2) (2.3) (2.0) (1.6) PPP Accrued Interest (5.0) (4.6) (4.6) (2.7) (1.4) PPP Processing Fees (24.2) (14.9) (15.8) (15.6) (9.6) Adjusted Net Interest Income excluding acquired loan accretion and PPP $202.9 $199.7 $207.1 $214.8 $220.8 Net Interest Income Reported Net Interest Income $234.9 $221.4 $229.8 $235.1 $233.4 Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 $150.0 $160.0 $170.0 $180.0 $190.0 $200.0 $210.0 $220.0 $230.0 $240.0 Adjusted Net Interest Income excluding acquired loan accretion and PPP $202.9 $199.7 $207.1 $214.8 $220.8 Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 $150.0 $160.0 $170.0 $180.0 $190.0 $200.0 $210.0 $220.0 $230.0 $240.0 (in m ill io ns ) (in m ill io ns )

16 NIM – MBS & CMO Premium Amortization & Recapture Details Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 MBS & CMO Premium in $ millions (Amortization)/Recapture $(5.4)mm $(3.3)mm $(2.6)mm $(1.6)mm $(2.3)mm Net NIM Impact in basis points Accretive/(Dilutive) (0.08) % (0.05) % (0.04) % (0.02) % (0.03) % Net Interest Margin Footnotes: 1. PPP net impact includes both accrued interest on PPP loans and PPP processing fees. 2. Chart Abbreviations: LHFI = loans held for investment; PPP = Paycheck Protection Program; PAA = purchase accounting adjustments. Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 Reported Net Interest Margin 3.35 % 3.18 % 3.20 % 3.21 % 3.15 % (Accretion) Related to Acquired Loans (0.04) % (0.03) % (0.03) % (0.03) % (0.02) % (Accretion)/Dilution Related to Net PPP Impact¹ (0.20) % (0.08) % (0.09) % (0.14) % (0.09) % Adjusted Net Interest Margin excluding acquired loan accretion and PPP 3.11 % 3.07 % 3.08 % 3.04 % 3.04 % Net Interest Margin Reported vs Adjusted 3.35% 3.18% 3.20% 3.21% 3.15%3.11% 3.07% 3.08% 3.04% 3.04% Reported Net Interest Margin Adjusted Net Interest Margin excluding acquired loan accretion and PPP Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 —% 1.00% 2.00% 3.00% 4.00% Net Interest Margin Q3 2021 vs Q4 2021 3.21% (0.01)% (0.04)% (0.01)% (0.02)% 0.01% 3.15% Q3 2021 Reported LHFI - Not PPP/PAA² LHFI - PPP² LHFI - PAA² Investment Portfolio Deposits Q4 2021 Reported

17 Loan Repricing Detail1,2 (in millions) Q3 2021 Q4 2021 Q3 2021 Q4 2021 Fixed $ 7,034 $ 7,459 32 % 33 % PPP 748 392 3 % 2 % Prime 1,783 1,747 8 % 8 % 1 Month 4,867 5,358 22 % 24 % Floating 6,650 7,105 30 % 32 % Prime 309 300 1 % 1 % 6 month 3,496 3,798 16 % 17 % 1 Year 1,482 1,264 7 % 5 % 3 Year 210 224 1 % 1 % 5 Year 1,472 1,399 7 % 6 % 10 Year 524 564 3 % 3 % Adjustable 7,493 7,549 35 % 33 % Total $ 21,925 $ 22,505 100 % 100 % Loan Maturities at December 31, 2021 <=6 7 to 12 13 to 24 25 to 36 37 to 59 60+ (in millions) Mos Mos Mos Mos Mos Mos Total Fixed $ 1,243 $ 152 $ 333 $ 496 $ 1,409 $ 4,218 $ 7,851 Floating 646 491 672 488 897 3,911 7,105 Adjustable 33 77 97 116 536 6,690 7,549 Total $ 1,922 $ 720 $ 1,102 $ 1,100 $ 2,842 $ 14,819 $ 22,505 Upward Rate Change to Move from Floor at December 31, 2021 Loans at Floor <25 26-50 51-75 76-100 101-125 126-150 >150 Balance (in millions) bps bps bps bps bps bps bps Total Floating $ 459 $ 856 $ 179 $ 180 $ 82 $ 22 $ 66 $ 1,844 Adjustable 246 275 734 776 591 532 672 3,826 Total $ 705 $ 1,131 $ 913 $ 956 $ 673 $ 554 $ 738 $ 5,670 Weighted Average Rate Change to Move Above Floor Floating 0.07 % 0.45 % 0.65 % 0.91 % 1.17 % 1.44 % 2.10 % 0.52 % Adjustable 0.09 % 0.40 % 0.63 % 0.88 % 1.13 % 1.37 % 1.91 % 1.03 % Floors: Floating and Adjustable Rate Loans at December 31, 20213 (in millions) No Floor At Floor Above Floor Total Floating $4,588 $1,844 $673 $7,105 Adjustable 1,270 3,826 2,453 7,549 Total $5,858 $5,670 $3,126 $14,654 % of Total 40% 39% 21% 100% Interest Rate Sensitivity: Loans Footnotes: 1. Index rates with relatively immaterial balances are mapped to the closest material index. For example, $49 million in loans repricing on a 3-month index are included in the 6-month category and represent only 1% of 6-month loans at December 31, 2021. 2. Deferred fees and costs drive variances between loan totals on this slide and loan totals in the earnings press release. 3. Loans were grouped into three buckets: (1) No Floor: no contractual floor on the loan; (2) At Floor: current rate = floor; (3) Above Floor: current rate exceeds floor. The amount above the floor was based on the current margin plus the current index assuming the loan repriced on December 31, 2021. The adjustable loans may not reprice until well into the future, depending on the timing and size of interest rate changes.

18 Interest Rate Sensitivity: Balance Sheet Is Asset Sensitive Interest Rate Simulation Impact on Net Interest Income1 Year 1 Year 2 Year 1 Year 2 Ramp Shock Up 400 basis points 13.0% 28.0% 24.0% 33.7% Up 300 basis points 9.7% 21.2% 18.0% 25.6% Up 200 basis points 6.3% 14.2% 11.9% 17.3% Up 100 basis points 3.0% 7.0% 5.7% 8.7% Down 100 basis points (1.2)% (4.3)% (2.8)% (6.0)% Footnotes: 1. For the scenarios shown, the interest rate simulations assume a parallel and sustained shift in market interest rates ratably over a twelve-month period (ramp) or immediately (shock). There is no change in the composition of the size of the balance sheet in either scenario. Interest rate sensitivity in the first year of the net interest income simulation for increasing interest rate ramp scenarios is negatively impacted by the cost of non-maturity deposits repricing immediately while interest earning assets reprice at a slower rate. 2. Deposit repricing betas are calculated between Q3 2015 and Q3 2019. We use Q3 2019 as our end point despite a 50-basis point reduction in the fed funds target rate during the quarter as it represents our peak deposit costs during the last rising rate cycle and it captures the repricing lag effect. Interest-Bearing Deposit Repricing Beta During the Last Rising-Rate Cycle Cost of Umpqua Deposits Non-Interest Bearing Deposits as % of Total Fed Funds Target Rate Interest- Bearing Total Q4 2021 0.25% 0.11% 0.06% 41.5% Q3 2019 2.00% 1.19% 0.82% 31.8% Q2 2019 2.50% 1.16% 0.81% 31.0% Q3 2015 0.25% 0.24% 0.17% 29.8% Variance: Peak (Peak Value less Q3 2015) +2.25% +0.95% +0.65% Umpqua Beta (based on peak Umpqua deposit rate)2 42% 29% • The simulation repricing betas applied to interest-bearing deposits in the rising rate shock scenarios range from 43% to 45%, generally consistent with the actual betas observed in the last rising rate cycle. • Every 10% change to the beta in the +100 basis points shock simulation results in an approximate 1.3% change to the net interest income results. For example: ◦ A 10% decrease to a 45% beta in the +100 basis points shock simulation results in a repricing beta of 40.5% applied to interest-bearing deposits and an approximate 1.3% increase to net interest income. ◦ A 10% increase to a 45% beta in the +100 basis points shock simulation results in a repricing beta of 49.5% applied to interest-bearing deposits and an approximate 1.3% decrease to net interest income.

19 Non-Interest Income Footnotes: Tables may not foot due to rounding. 1. Commercial product revenue includes Swaps, M&A Advisory, Syndication, and International Banking revenue. (in millions) For the year ended For the quarter ended FY 2021 FY 2020 Q4 2021 Q3 2021 Q2 2021 Q1 2021 Q4 2020 Service charges on deposits $42.1 $40.8 $11.2 $10.9 $10.3 $9.6 $10.2 Card-based fees 36.1 28.2 9.4 9.1 10.3 7.4 7.8 Brokerage revenue 5.1 15.6 — — 1.1 3.9 4.1 Residential mortgage banking revenue, net 186.8 270.8 43.2 34.2 44.4 65.0 79.0 Gain on sale of debt securities, net — 0.2 — — — — — (Loss) gain on equity securities, net (1.5) 0.8 (0.5) (0.3) — (0.7) (0.2) Gain on loan and lease sales, net 15.7 6.7 4.8 4.2 5.3 1.4 3.4 BOLI income 8.3 8.4 2.1 2.0 2.1 2.1 2.1 Other Income Commercial product revenue¹ $23.6 $17.1 $9.0 $3.8 $8.1 $2.8 $3.3 Commercial servicing revenue 2.9 2.6 0.7 0.8 0.7 0.7 0.6 Loan-related fees 11.7 11.6 3.1 3.0 3.0 2.6 2.8 Change in fair value of certain loans held for investment 3.0 — (2.7) 3.4 2.8 (0.5) — Misc. Income 14.1 18.6 2.7 1.2 7.4 2.7 6.9 Swap derivative gain/(loss) 8.4 (9.4) (0.3) 1.4 (4.5) 11.8 4.0

20 $211.3 $187.6 $189.4 $183.8 $199.7 58.8% 56.7% 59.0% 59.4% 63.1% Non-interest expense Efficiency ratio Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 $155.0 $160.0 $165.0 $170.0 $175.0 $180.0 $185.0 $190.0 $195.0 $200.0 $205.0 $210.0 $215.0 40.0% 50.0% 60.0% 70.0% 80.0% 90.0% 100.0% 110.0% Non-Interest Expense Non-Interest Expense and Efficiency Ratio (in millions) Non-Interest Expense Bridge (in millions) $183.8 $15.2 $0.8 $0.7 $2.3 $1.9 $(2.9) $(1.8) $(0.3) $199.7 Q 3 N on -In te re st E xp en se M er ge r E xp en se s FD IC A ss es sm en ts M ar ke tin g H FI P ro du ct io n In ce nt iv e C om p O ne -T im e W rit e- O ffs M un ic ip al T ax es * H om e Le nd in g D ire ct E xp O th er Q 4 N on -In te re st E xp en se Footnotes: * Driven by a reclassification from other expense to income tax that resulted in a credit during the quarter. HFI = held for investment

21 Segments - Core Banking Footnotes: 1. Represents the internal charge of centrally provided support services and other corporate overhead to the mortgage banking segment. (In thousands) For the Quarter Ended Q4 2021 Q3 2021 Q2 2021 Q1 2021 Q4 2020 Net interest income $ 231,250 $ 232,348 $ 226,915 $ 217,574 $ 230,430 (Recapture) provision for credit losses (736) (18,919) (22,996) — 29 Non-interest income Gain on sale of debt securities, net 4 — — 4 — (Loss) gain on equity securities, net (466) (343) 4 (706) (173) (Loss) gain on swap derivatives, net (303) 1,429 (4,481) 11,750 3,955 Change in fair value of certain loans held for investment (2,672) 3,432 2,782 (510) — Non-interest income (excluding above items) 42,812 34,849 48,151 32,913 40,921 Total non-interest income 39,375 39,367 46,456 43,451 44,703 Non-interest expense Merger related expenses 15,183 — — — — Exit and disposal costs 3,022 3,813 4,728 1,200 725 Non-interest expense (excluding above items) 150,587 146,931 146,877 145,161 171,634 Allocated expenses, net1 4,314 3,680 970 (790) (3,565) Total non-interest expense 173,106 154,424 152,575 145,571 168,794 Income before income taxes 98,255 136,210 143,792 115,454 106,310 Provision (benefit) for income taxes 24,067 33,945 35,630 28,106 (13,508) Net income $ 74,188 $ 102,265 $ 108,162 $ 87,348 $ 119,818 Effective Tax Rate 24 % 25 % 25 % 24 % (13) % Efficiency Ratio 64 % 57 % 56 % 56 % 61 % Total assets $ 30,155,058 $ 30,419,108 $ 29,720,182 $ 29,529,769 $ 28,438,813 Loans held for sale $ — $ — $ — $ — $ 78,146 Total loans and leases $ 22,553,180 $ 21,969,940 $ 22,143,739 $ 22,160,860 $ 21,779,367 Total deposits $ 26,370,568 $ 26,510,938 $ 25,820,776 $ 25,425,339 $ 24,200,012 Key Rates, end of period: 10 year CMT 1.52 % 1.52 % 1.45 % 1.74 % 0.93 % FHLMC 30 year fixed 3.11 % 3.01 % 2.98 % 3.18 % 2.67 %

22 Segments - Mortgage Banking Footnotes: 1. Represents the internal charge of centrally provided support services and other corporate overhead to the Mortgage Banking segment, partially offset by allocations from the Mortgage Banking segment to Core Banking for new portfolio loan originations and portfolio servicing costs. (In thousands) For the Quarter Ended Q4 2021 Q3 2021 Q2 2021 Q1 2021 Q4 2020 Net interest income $ 2,129 $ 2,726 $ 2,848 $ 3,857 $ 4,477 Provision for credit losses — — — — — Non-interest income Residential mortgage banking revenue: Origination and sale 23,624 30,293 41,367 62,505 83,388 Servicing 9,457 9,172 9,120 9,087 9,497 Change in fair value of MSR asset: Changes due to collection/realization of expected cash flows over time (5,311) (4,681) (4,366) (4,545) (4,431) Changes due to valuation inputs or assumptions 15,415 (634) (1,678) (2,014) (9,426) Non-interest income (excluding above items) 178 188 176 316 229 Total non-interest income 43,363 34,338 44,619 65,349 79,257 Non-interest expense Non-interest expense 30,919 33,009 37,795 41,231 38,953 Allocated expenses, net1 (4,314) (3,680) (970) 790 3,565 Total non-interest expense 26,605 29,329 36,825 42,021 42,518 Income before income taxes 18,887 7,735 10,642 27,185 41,216 Provision for income taxes 4,721 1,934 2,661 6,796 10,304 Net income $ 14,166 $ 5,801 $ 7,981 $ 20,389 $ 30,912 Effective Tax Rate 25 % 25 % 25 % 25 % 25 % Efficiency Ratio 58 % 79 % 78 % 61 % 51 % Total assets $ 485,878 $ 472,371 $ 564,783 $ 506,911 $ 796,362 Loans held for sale $ 353,105 $ 352,466 $ 429,052 $ 376,481 $ 688,079 Total deposits $ 224,117 $ 397,459 $ 332,777 $ 461,494 $ 422,189 Key Rates, end of period: 10 year CMT 1.52 % 1.52 % 1.45 % 1.74 % 0.93 % FHLMC 30 year fixed 3.11 % 3.01 % 2.98 % 3.18 % 2.67 % For the Quarter Ended Q4 2021 Q3 2021 Q2 2021 Q1 2021 Q4 2020 LHFS Production Statistics: Closed loan volume for-sale 871,268 987,281 1,253,023 1,635,532 1,769,432 Gain on sale margin 2.71% 3.07% 3.30% 3.82% 4.71% Direct LHFS expense $ 18,150 $ 19,958 $ 25,459 $ 31,151 $ 33,210 Direct LHFS expenses as % of volume 2.08 % 2.02 % 2.03 % 1.90 % 1.88 % MSR Statistics: Residential mortgage loans serviced for others 12,755,671 12,853,291 12,897,032 13,030,467 13,026,720 MSR, net $ 123,615 $ 105,834 $ 102,699 $ 100,413 $ 92,907 MSR as % of serviced portfolio 0.97% 0.82% 0.80% 0.77% 0.71%

Balance Sheet Highlights Q4 2021

24 Loan and Deposit Growth Loans and Leases (Gross) ($ in billions) Total Deposits ($ in billions) As of December 31, 2021 As of December 31, 2021 $6.5 $7.2 $7.7 $15.3 $16.8 $17.4 $19.0 $20.4 $21.2 $21.8 $22.6 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 $— $5.0 $10.0 $15.0 $20.0 $25.0 $9.2 $9.4 $9.1 $16.9 $17.7 $19.0 $19.9 $21.1 $22.5 $24.6 $26.6 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 $— $5.0 $10.0 $15.0 $20.0 $25.0 50% 24% 25% 1% Commercial Real Estate Commercial Residential Consumer & Other —% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 41% 14% 29% 9% 7% Demand, non-interest bearing Demand, interest bearing Money market Savings Time —% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

25 Q4 2021 Loan Roll Forward $21,970 $2,321 ($83) ($1,157) ($145) ($346) ($7) $22,553 Beginning Balance (9/30/2021) New Originations Net Advances/ Payments Payoffs Maturities PPP Other Ending Balance (12/31/2021) $10,000 $12,500 $15,000 $17,500 $20,000 $22,500 $25,000 $ in millions

26 Loan and Lease Portfolio Characteristics Footnotes: Balances and delinquencies as of December 31, 2021. Annualized net charge-off rate for Q4 2021. LTV, FICO and Debt Service Coverage (DSC) are based on weighted average for portfolio. LTV for the Mortgage portfolio represents average LTV based on most recent appraisal against updated loan balance. Totals may not foot due to rounding. Mortgage • Represents 20% of overall portfolio • Total delinquencies of 0.70% • Annualized net charge-off rate of (0.01%) • Average loan size of $416,000 • Average FICO of 758 and LTV of 63% Non-owner Occupied CRE • Represents 17% of overall portfolio • Total delinquencies of 0.13% • Annualized net charge-off rate of 0.01% • Average loan size of $1.9 million • Average LTV of 54% and DSC of 1.7 Commercial & Industrial • Represents 17% of overall portfolio • Total delinquencies of 0.30% • Annualized net charge-off rate of 0.09% • Average loan size of $503,000 Multifamily • Represents 18% of overall portfolio • Total delinquencies of 0.00% • Annualized net charge-off rate of 0.00% • Average loan size of $2.1 million • Average LTV of 56% and DSC of 1.50 Owner Occupied CRE • Represents 10% of overall portfolio • Total delinquencies of 0.11% • Annualized net charge-off rate of 0.00% • Average loan size of $978,000 • Average LTV of 56% and DSC of 1.8 Lease & Equipment Finance (FinPac) • Represents 7% of overall portfolio • Total delinquencies of 1.94% • Annualized net charge-off rate of 1.75% • ~10% average yield • Average loan & lease size of $36,000 Geographic Diversification Puget Sound 16% OR Other 11% Northern CA 11% Southern CA 20% Portland/Vanc 14% Bay Area 10% WA Other 6% Other 12%

27 Current Expected Credit Loss (“CECL”) Footnotes: 1. Total includes $11.8 mm for Reserve for Unfunded Commitments 2. Total includes $12.8 mm for Reserve for Unfunded Commitments Loan Segment 9/30/2021 Q4 2021 Net Charge-offs Reserve build 12/31/2021 % of loans and leases outstanding Commercial $45,526 ($1,259) ($3,329) $40,938 1.04 % Lease & Equipment Finance $75,993 ($6,353) $9,023 $78,663 5.36 % CRE $114,835 ($2) ($7,297) $107,536 0.95 % Residential/Home Equity $29,237 $326 $1,462 $31,025 0.54 % Consumer $3,721 ($109) ($595) $3,017 1.64 % Total $269,312 ¹ ($7,397) ($736) $261,179 ² 1.16 % % of loans and leases outstanding 1.23 % 1.16 % % of loans and leases outstanding – ex PPP loans 1.27 % 1.18 % Allowance For Credit Losses ($ in 000’s) CECL Notes Used Moody’s November consensus economic forecast Key Components of the Moody’s economic forecast include: • GDP average annualized growth of 3.9% through 2022 • Average annualized unemployment rate of 4.1% in 2022 dropping to 4.0% in 2023 • COVID infections abate in December 2021 • The Federal Reserve keeps the target range for the fed funds rate at 0% to 0.25% until Q4 2022

28 Credit Quality (R ec ap tu re ) o r Pr ov is io n Ex pe ns e ($ in m ill io ns ) N on Perform ing A ssets to Total A ssets (Recapture) or Provision Expense & Non-Performing Assets to Total Assets $— $— $(23.0) $(18.9) $(0.7) 0.24% 0.19% 0.17% 0.17% 0.17% (Recapture) or Provision expense Non Performing Assets To Total Assets Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 $(40.0) $(20.0) $— $20.0 $40.0 $60.0 $80.0 $100.0 $120.0 $140.0 —% 0.05% 0.10% 0.15% 0.20% 0.25% 0.30% 0.35% C la ss ifi ed L oa ns / To ta l L oa ns C lassified A ssets / R B C Classified Assets 0.92% 0.74% 0.74% 0.81% 0.71% 8.6% 7.0% 7.0% 7.7% 7.0% Classified Loans to Total Loans Classified Assets to Risk-Based Capital Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 —% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 6.0% 7.0% 8.0% 9.0% 10.0% 11.0% 12.0% 13.0% 14.0% 15.0% A C L ($ in m ill io ns ) A llow ance / Total Loans and Leases Allowance for Credit Losses $348.7 $331.0 $294.4 $269.3 $261.2 1.60% 1.49% 1.33% 1.23% 1.16% Allowance for Credit Losses Allowance for Credit Losses to Total Loans and Leases Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 $— $40.0 $80.0 $120.0 $160.0 $200.0 $240.0 $280.0 $320.0 $360.0 $400.0 $440.0 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Net Charge-offs to Average Loans and Leases (annualized) 4.87% 4.66% 3.80% 1.21% 1.75% 0.35% 0.33% 0.25% 0.11% 0.13% Umpqua Bank (ex FinPac) Fin Pac Umpqua Holding Consolidated Q4 2020 Q1 2021 Q2 2021 Q3 2021 Q4 2021 (0.50)% —% 0.50% 1.00% 1.50% 2.00% 2.50% 3.00% 3.50% 4.00% 4.50% 5.00% 0.04% 0.03% 0.01% 0.04% 0.02%

29 Capital Management Footnotes: 1. Regulatory capital ratios are estimates pending completion and filing of the Company’s regulatory reports. 2. Greater of Regulatory Well Capitalized Threshold or Capital Adequacy Threshold + Capital Conservation Buffer (2.5%). 3.“Excess” Capital defined as capital above thresholds above internal policy limits. All regulatory capital ratios¹ remained in excess of well-capitalized and internal policy limits. Focused on providing long-term value for our shareholders Paid a quarterly cash dividend of $0.21 per common share on November 30, 2021 to shareholders of record as of November 19, 2021. 8.9% 9.0% 11.6% 11.6% 14.3% 5.0% 7.0% 8.5% 10.5% 6.0% 1.5% 2.0% 0.5% 1.5% 2.9% 2.5% 2.6% 2.6% 2.3% Capital Threshold² In-House Policy Floor "Excess" Capital³ Tangible Common Equity/Tangible Assets Tier 1 Leverage Tier 1 Common Risk Based Tier 1 Risk Based Total Risk Based —% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% 16.0% Excess capital at the bank level is approximately $207mm. Holding company ratios are shown to the right.

Appendix

31 Non-GAAP Reconciliation Tangible Book Value: Umpqua (In thousands, except per share data) Dec 31, 2021 Sep 30, 2021 Jun 30, 2021 Mar 31, 2021 Dec 31, 2020 Total shareholders' equity $2,749,270 $2,722,379 $2,766,316 $2,681,869 $2,704,577 Subtract: Goodwill — — — 2,715 2,715 Other intangible assets, net 8,840 9,970 11,100 12,230 13,360 Tangible equity - common 2,740,430 2,712,409 2,755,216 2,666,924 2,688,502 Total assets $30,640,936 $30,891,479 $30,284,965 $30,036,680 $29,235,175 Subtract: Goodwill — — — 2,715 2,715 Other intangible assets, net 8,840 9,970 11,100 12,230 13,360 Tangible assets 30,632,096 30,881,509 30,273,865 30,021,735 29,219,100 Common shares outstanding at period end 216,626 216,622 220,626 220,491 220,226 Total shareholders' equity to total assets ratio 8.97 % 8.81 % 9.13 % 8.93 % 9.25 % Tangible common equity ratio 8.95 % 8.78 % 9.10 % 8.88 % 9.20 % Book value per common share $12.69 $12.57 $12.54 $12.16 $12.28 Tangible book value per common share $12.65 $12.52 $12.49 $12.10 $12.21

32 • The opportunities to grow the loan book by expanding business with our existing customer base are dramatic, and they are potentially multiplicative as we continue to win business in our markets. Note: $ in millions. LQA = linked-quarter annualized. * TCE used (instead of risk-based capital) given prior disclosure for pro forma TCE. See slide 34 for the calculation of pro forma TCE, which is based on financial data for the quarter ended June 30, 2021, and market data as of October 11, 2021. ** The loan amounts and opportunities displayed on this slide are hypothetical and should only be viewed as illustrative examples. The internal hold limit of the pro forma company following closing is expected to be determined by the pro forma company's board. ^ Amount of loan application above hypothetical loan amount presented in the left-side table. For example, based on the hypothetical loan amounts in the left-most column in the right table, a loan application at Columbia for $50 million would result in a $20 million loan for Columbia's balance sheet and the participation out of $30 million, and a loan application at Umpqua for $50 million would result in a $35 million loan for Umpqua's balance sheet and the participation out of $15 million. The pro forma company's larger balance sheet (and correspondingly larger capital position) would enable the pro forma company to hold the entire $50 million loan while maintaining the same (or better) level of diversity and granularity. (a) Columbia 9/30/21 Tangible Common Equity* $1,536 (b) Umpqua 9/30/21 Tangible Common Equity* $2,712 (c) Pro Forma Company Tangible Common Equity* $4,412 Opportunities Many Some A Few Columbia Perspective (d) Loan Amount: Hypothetical** $20 $35 $60 (e) = (d) ÷ (a) % of Columbia 9/30/21 TCE 1.30% 2.28% 3.91% Umpqua Perspective (f) Loan Amount: Hypothetical** $35 $60 $100 (g) = (f) ÷ (b) % of Umpqua 9/30/21 TCE 1.29% 2.21% 3.69% Pro Forma Company (h) = avg of (e) & Average of Columbia & Umpqua 9/30/21 TCE 1.30% 2.25% 3.80% (i) = (c) x (h) Pro Forma Loan Amount** $57 $99 $167 A High-Quality Prospect… Adds to Loan Growth Lost Opportunity Net Benefit to the Pro Forma Bank Columbia Perspective Umpqua Perspective …applies for a $50 million loan Columbia Perspective: Today $20 $30 Umpqua Perspective: Today $35 $15 Pro Forma $50 $0 $30 $15 …applies for a $75 million loan Columbia Perspective: Today $35 $40 Umpqua Perspective: Today $60 $15 Pro Forma $75 $0 $40 $15 …applies for a $150 million loan Columbia Perspective: Today $60 $90 Umpqua Perspective: Today $100 $50 Pro Forma $150 $0 $90 $50 The Power of a Larger Balance Sheet: A Hypothetical Example 9/30/2021 Tangible Common Equity Columbia Umpqua Total Shareholders’ Equity $2,323 $2,722 -Preferred Equity $0 $0 -Goodwill -$766 $0 -Other Intangible Asset, net -$21 -$10 Tangible Common Equity $1,536 $2,712

33 Non-GAAP Reconciliation: GAAP and Core Cash Earnings per Share Accretion Source: S&P Global Market Intelligence, FactSet, Company filings; Note: Financial data as of quarter ended June 30, 2021; Market data as of October 11, 2021; Pro forma adjustments assume 26% marginal tax rate; Assumes fully phased-in cost savings for illustrative purposes ¹ $135mm fully phased-in reduction in combined company’s total noninterest expense base for illustrative purposes, quarterly synergies grown at 3.0% on an annual basis starting in 2023; Anticipated 66% phase-in during 2023 results in 17.5% GAAP and 19.2% cash EPS accretion for Columbia, and 2.6% GAAP and 6.2% cash EPS accretion for Umpqua ² Core deposit intangible estimate of 65bps ($108mm pre-tax) on non-time deposits, amortized through earnings over 10 years (sum-of-the-years-digits) ³ Loan rate mark of $76mm (pre-tax), amortized through earnings over 6 years (sum-of-the-years-digits) 4 HTM security rate mark of -$4mm (pre-tax), accreted through earnings over 6 years (sum-of-the-years-digits) 5 AOCI mark of $54mm (after-tax), amortized through earnings over 6 years (sum-of-the-years-digits) 6 Assumes ~$2mm (after-tax) per quarter run-down of rate collar accretion 7 Real estate mark of $20mm (pre-tax), amortized through earnings over 20 years (straight line) 8 Based on $104mm pre-tax reserve allocated to non-PCD loans (65%), accreted through earnings over 4 years (sum-of-the-years-digits) 9 Pro forma diluted shares outstanding include Columbia shares and shares issued to Umpqua based on 0.5958x exchange ratio 10 Assumes no standalone and pro forma repurchases

34 Non-GAAP Reconciliation: Purchase Accounting Summary Source: S&P Global Market Intelligence, FactSet, Company filings; See slide 14 in the deal-related slide deck published October 12, 2021, for “Key financial assumptions” for 2023 underlying forecasts Note: Financial data as of quarter ended June 30, 2021; Market data as of October 11, 2021; Pro forma adjustments assume 26% marginal tax rate; Pro forma for Columbia’s completed acquisition of Bank of Commerce Holdings; Assumes neither company repurchases shares between deal announcement and deal close ¹ Estimated Umpqua tangible common equity at close based on Q3 2021 – Q2 2022 consensus earnings and dividend estimates, and $78mm share repurchases completed in Q3 2021 (4mm shares). Communicated Umpqua NextGen cost savings targets are separate from deal- related cost savings as they are expected to be largely realized ahead of the transaction’s anticipated close ² Based on 0.5958 shares of Columbia stock for each Umpqua common share outstanding ³ Based on expectations and assumptions as of announcement date; subject to change at transaction closing (estimated at June 30, 2022 for illustrative purposes) 4 Based on $104mm pre-tax reserve allocated to non-PCD loans (65%) 5 Based on when pro forma tangible book value per share crosses over and begins to exceed projected standalone Columbia tangible book value per share Tangible Book Value per Share Dilution Calculation of Intangibles Created