Exhibit 99.2

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

The following unaudited pro forma condensed combined financial information combines the historical consolidated financial position and results of operations of Columbia Banking System, Inc. (“Columbia”) and Umpqua Holdings Corporation (“Umpqua”) as a reverse acquisition of Columbia by Umpqua. The merger of Columbia and Umpqua (the “merger”) closed after close of business on February 28, 2023 and provided that each share of common stock of Umpqua issued and outstanding immediately prior to the effective time of the merger was automatically converted into the right to receive 0.5958 of a share (the “exchange ratio” and such shares, the “merger consideration”) of common stock of Columbia. The following unaudited pro forma condensed combined financial information and the accompanying notes (the “unaudited pro forma financial information”) are presented to illustrate the estimated effects of the following:

The accompanying unaudited pro forma condensed combined balance sheet as of December 31, 2022, combines the historical consolidated balance sheets of Columbia and Umpqua as of such date and includes adjustments that depict the accounting for the reverse acquisition, donation, and divestitures (as defined herein) as required by GAAP (“pro forma balance sheet transaction accounting adjustments”) as of February 28, 2023. Also, the unaudited pro forma condensed combined statements of income for the year ended December 31, 2022, combine the historical consolidated statements of income of Columbia and Umpqua for the same period and include adjustments that depict the effects of the pro forma balance sheet transaction accounting adjustments assuming those adjustments were made as of January 1, 2022 (“pro forma income statement transaction accounting adjustments”). We refer to pro forma balance sheet transaction accounting adjustments and pro forma income statement transaction accounting adjustments collectively as the “transaction accounting adjustments.”

The unaudited pro forma financial information is based on and should be read in conjunction with the separate historical financial statements and notes thereto in each of Columbia’s and Umpqua’s SEC filings including:

The unaudited pro forma financial information is provided for illustrative information purposes only. The unaudited pro forma financial information is not necessarily, and should not be assumed to be, an indication of the actual results that would have been achieved had the reverse acquisition, donations, and the divestitures been completed as of the dates indicated or that may be achieved in the future. The unaudited pro forma financial information has been prepared in accordance with Regulation S-X Article 11, Pro Forma Financial.

The unaudited pro forma financial information also does not consider any potential effects of changes in market conditions on revenues, expense efficiencies, asset dispositions (other than the divestitures), and share repurchases, among other factors. In addition, as explained in more detail in the accompanying notes, the preliminary allocation of the pro forma purchase price reflected in the unaudited pro forma financial information is subject to adjustment and may vary significantly from the final purchase price allocation.

The Company has not completed the valuation analysis and calculations in sufficient detail necessary to arrive at the required estimates of the fair market value of the Columbia assets to be acquired or liabilities to be assumed, other than a preliminary estimate for intangible assets and certain financial assets and financial liabilities. Accordingly, apart from the aforementioned estimates, certain Columbia assets and liabilities are presented at their respective carrying amounts and should be treated as preliminary values.

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A final determination of the fair value of Columbia’s assets and liabilities will be based on Columbia’s actual assets and liabilities as of February 28, 2023. Any changes in the fair values of the net assets or total purchase consideration as compared with the information shown in the unaudited pro forma financial information may change the amount of the total purchase consideration allocated to goodwill and other assets and liabilities and may impact the combined company’s statement of income. The final purchase consideration allocation may be materially different than the preliminary purchase consideration allocation presented in the unaudited pro forma financial information.

Certain reclassifications to conform historical financial statement presentations of Columbia to Umpqua have been made in the unaudited pro forma financial information. The transaction accounting adjustments have been made solely for the purpose of providing the unaudited pro forma financial information.

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UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

The unaudited pro forma condensed combined balance sheet as of December 31, 2022, is presented as if the reverse acquisition had occurred on December 31, 2022.

See accompanying notes to the unaudited pro forma condensed combined financial statements.

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UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF INCOME

The unaudited pro forma condensed combined income statements for the year ended December 31, 2022, are presented as if the reverse acquisition had occurred on January 1, 2022.

See accompanying notes to the unaudited pro forma condensed combined financial statements.

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NOTES TO THE UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

Note 1—Basis of Presentation

The accompanying unaudited pro forma financial information has been prepared in accordance with Article 11 of Regulation S-X to illustrate the effects of the reverse acquisition, the donations, and the divestitures. The unaudited pro forma condensed combined income statement for the year ended December 31, 2022 combine the historical consolidated income statement of Columbia and Umpqua, giving effect to the reverse acquisition as if it had been completed on January 1, 2022. The accompanying unaudited pro forma condensed combined balance sheet as of December 31, 2022 combines the historical consolidated balance sheets of Columbia and Umpqua, giving effect to the reverse acquisition as if it had been completed on December 31, 2022.

Columbia estimated common equity tier 1 capital ratio was 8.7% and the estimated total capital ratio was 10.9%, the estimated total capital ratio for Umpqua Bank was 10.3%, based on the pro forma financials as of December 31, 2022 (without giving effect to the divestitures). Please see “Unaudited Pro Forma Capital Ratios” of this Exhibit 99.2.

The reverse acquisition will be accounted for under the reverse acquisition method of accounting with Umpqua treated as the accounting acquirer. Under the reverse acquisition method of accounting, the assets and liabilities of Columbia, as of the closing date, will be recorded by Umpqua at their respective fair values and the excess of the merger consideration over the fair value of Columbia’s net assets will be recognized as goodwill.

The donations will be accounted for as an other expense immediately following close of the reverse acquisition.

The divestiture of certain Columbia branches, including loans, premises and equipment, and deposits (the “divestitures”), in satisfaction of commitments to the Antitrust Division of the Department of Justice (the “DOJ”) and the Board of Governors of the Federal Reserve System (the “Federal Reserve”), are also reflected in the unaudited pro forma financial information.

Columbia has not identified all adjustments necessary to conform Columbia’s accounting policies to Umpqua’s accounting policies. Although the merger has closed, Columbia is in the process of performing a more detailed review. As a result of that review, differences could be identified between the accounting policies of the two companies that, when conformed, could have a material impact on the combined company’s financial information.

Note 2—Preliminary Purchase Accounting Allocation

The transaction accounting adjustments depict the completion of the merger, including the allocation of the preliminary purchase price. The impact of equity awards on the purchase price is immaterial and has been excluded in the unaudited pro forma financial information. The excess of the purchase price over the fair value of net assets acquired is recorded as goodwill. The transaction accounting adjustments included in the pro forma financial statements are based upon available information and certain assumptions considered reasonable, and may be revised as additional information becomes available.

The unaudited pro forma condensed combined balance sheet has been adjusted to reflect the preliminary calculation of the estimated purchase price to identifiable net assets acquired. Since the acquisition will be accounted for as a reverse acquisition, the estimated purchase price was determined in accordance with FASB ASC 805-40-30-2, which explains that the purchase price in a reverse acquisition is determined based on “the number of equity interests the legal acquiree would have had to issue to give the owners of the legal acquirer the same percentage equity interest in the combined entity that results from the reverse acquisition.”

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The first step in estimating the purchase price in the merger is to determine the pro forma ownership of the combined company following the merger. The table below summarizes, for each current shareholder group, the pro forma ownership of Columbia common stock following the merger as well as the pro forma market capitalization of the combined company using shares of Columbia common stock and Umpqua common stock outstanding at December 31, 2022 and the closing price of Columbia common stock on February 28, 2023.

Next, the hypothetical number of shares of Umpqua common stock that would have to be issued to give Columbia shareholders the same percentage ownership in the combined company is calculated in the table below (based on shares of Umpqua common stock outstanding at December 31, 2022):

Finally, the purchase price for purposes of the transaction accounting adjustments is calculated based on the number of hypothetical shares of Umpqua common stock to be issued to Columbia shareholders, multiplied by the share price as demonstrated in the table below (amounts in thousands except per share data):

The final purchase price paid by Columbia in shares of Columbia common stock upon the completion of the reverse acquisition were determined based on the closing price of Columbia common stock on the closing date and the number of issued and outstanding shares of Umpqua common stock immediately prior to the effective time. Actual adjustments may differ from the amounts reflected in the unaudited pro forma financial information, and the differences may be material.

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The following table shows the allocation of the preliminary purchase price:

Columbia estimated the fair value of certain Columbia assets and liabilities based on a preliminary valuation analysis, due diligence information, information presented in Columbia’s SEC filings and other publicly available information. As of the date of this Current Report on Form 8-K, Columbia has not completed the valuation analysis and calculations in sufficient detail necessary to arrive at the required estimates of the fair value of Columbia’s assets acquired or liabilities assumed for reverse acquisition accounting purposes, other than a preliminary estimate for intangible assets and certain financial assets and financial liabilities. Accordingly, apart from the aforementioned, certain Columbia assets and liabilities are presented at their respective carrying amounts and should be treated as preliminary fair values. A final determination of the fair value of Columbia’s assets and liabilities will be based on Columbia’s actual assets and liabilities as of the effective time. Actual adjustments may differ from the amounts reflected in the unaudited pro forma financial information, and the differences may be material.

A final determination of the fair value of Columbia’s assets acquired and liabilities assumed will be performed. Any changes in the fair values of the net assets or total purchase price as compared with the information shown in the unaudited pro forma financial information may change the amount of the total purchase price allocated to goodwill and other assets and liabilities and may impact the combined company’s statement of income. The final purchase price allocation may be materially different than the preliminary purchase price allocation presented in the unaudited pro forma financial information.

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Note 3—Transaction Accounting Adjustments

The following transaction accounting adjustments have been reflected in the unaudited pro forma financial information. All adjustments are based on current assumptions and valuations, which are subject to change.

Balance Sheet

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Balance Sheet

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Balance Sheet

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Income Statement

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Income Statement

Note 4—Divestitures in Connection with the Reverse Acquisition

In connection with the merger, Columbia sold seven branches in Washington and Oregon to 1st Security Bank of Washington, the wholly-owned subsidiary of FS Bancorp, Inc., and three branches in Northern California to First Northern Bank of Dixon, the wholly-owned subsidiary of First Northern Community Bancorp. The branches, with approximately $542 million in total deposits and $70 million in total loans, were divested in satisfaction of commitments to the Antitrust Division of the DOJ and the Federal Reserve in connection with the reverse acquisition. The divestitures occurred in the first quarter of 2023. As such, these divestitures are included in the unaudited pro forma financial information.

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UNAUDITED PRO FORMA CAPITAL RATIOS

The following presents the regulatory capital ratios of each of Columbia Banking System, Inc. (“Columbia”) and Umpqua Bank giving effect to the merger of Columbia and Umpqua Holdings Corporation (“Umpqua”) as a reverse acquisition of Columbia by Umpqua. The following unaudited pro forma capital ratios do not give effect to the divestiture of certain Columbia branches, including loans, premises, equipment and deposits prior to the closing of the reverse acquisition.

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