Columbia Banking System, Inc. (the “Corporation,” “we,” “our,” “Columbia” or the “Company”) is the holding company for Columbia State Bank (“Columbia Bank” or the “Bank”) and Columbia Trust Company (“Columbia Trust”). The Bank provides a full range of financial services through 152 branch locations, including 67 in the State of Washington, 59 in Oregon, 15 in Idaho and 11 in California. Columbia Trust provides fiduciary, agency, trust and related services, and life insurance products. Because the Bank comprises substantially all of the business of the Corporation, references to the “Company” mean the Corporation, the Bank and Columbia Trust together. The Corporation is approved as a bank holding company pursuant to the Gramm-Leach-Bliley Act of 1999.

The Company’s accounting and reporting policies conform to GAAP and practices in the financial services industry. To prepare the financial statements in conformity with GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements, and income and expenses during the reporting period. Circumstances and events that differ significantly from those underlying our estimates and assumptions could cause actual financial results to differ from our estimates. The most significant estimates included in the financial statements relate to the ACL, business combinations and goodwill impairment.

Debt securities are classified based on management’s intention on the date of purchase. The Company has debt securities that are classified as AFS and are presented at fair value and debt securities classified as HTM that are presented at amortized cost. Realized gains or losses on sales of debt securities AFS, determined on the basis of the cost of specific securities sold, are included in earnings. Unrealized gains or losses on debt securities AFS are excluded from net income but are included in other comprehensive income as a separate component of shareholders' equity, net of tax. Purchase premiums or discounts on debt securities AFS are amortized or accreted into income using the interest method over the terms of the individual securities.

The Company performs a quarterly assessment to determine whether a decline in fair value below amortized cost exists. Amortized cost includes adjustments made to the cost of an investment for accretion, amortization, collection of cash and previous credit losses recognized in earnings.

When the fair value of an AFS debt security falls below the amortized cost basis, it is evaluated to determine if any of the decline in value is attributable to credit loss. Decreases in fair value attributable to credit loss would be recorded directly to earnings with a corresponding allowance for credit losses, limited by the amount that the fair value is less than the amortized cost basis. If the credit quality subsequently improves the allowance would be reversed up to a maximum of the previously recorded credit losses. If the Company intends to sell an impaired AFS debt security, or if it is more likely than not that the Company will be required to sell the security prior to recovering the amortized cost basis, the entire fair value adjustment would be immediately recognized in earnings with no corresponding allowance for credit losses.

Our equity securities currently consist of Visa Class B restricted stock which do not have readily determinable fair values. These securities are accounted for at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer. Any adjustments to the carrying value of these investments are recorded in Investment securities gains (losses), net in the Consolidated Statements of Income.

The Company holds shares of Class B stock issued by the FHLB, which has been designated as FHLB membership stock or FHLB activity based stock in accordance with the capital plan of the FHLB. Membership stock is stock we are required to purchase and hold as a condition of membership in the FHLB. The Company’s membership stock purchase requirement is measured as a percentage of our year end assets, subject to a $10 million cap. Class B stock may be redeemed, subject to certain limitations, on five years’ written notice to the FHLB. Activity based stock is stock we are required to purchase and hold in order to obtain an advance or participate in FHLB mortgage programs. The Company’s activity based stock purchase requirement is measured as a percentage of our advance proceeds. Our FHLB stock is carried at par value because the shares are issued, transferred, redeemed, and repurchased by the FHLB at a par value of $100. The FHLB stock is subject to recoverability testing per the Financial Services-Depository and Lending topic of the FASB ASC.

One-to-four family residential real estate loans originated with the intent to be sold in the secondary market are considered held for sale. One-to-four family residential real estate loans under best efforts delivery commitments are carried at the lower of amortized cost or fair value. There are no economic hedges on these loans. Due to the short period of time between the origination and sale of these loans, the carrying amount of these loans approximates fair value. For one-to-four family residential real estate loans under mandatory delivery commitments, the Company has elected to account for these loans at fair value. The use of the fair value option allows the change in the fair value of the loans to more effectively offset the change in the fair value of derivative instruments that are used as economic hedges for these loans held for sale. Loan origination fees and direct origination costs are recognized immediately in net income. Interest income on loans held for sale is included in interest income in the Consolidated Statements of Income and recognized when earned. Loans held for sale are placed on nonaccrual in a manner consistent with loans held for investment. The Company recognizes a gain or loss on the sale of loans when the sales criteria for derecognition are met. See Note 22. "Fair Value Accounting and Measurement” for additional information on loans held for sale.

Loans are generally carried at the unpaid principal balance, net of purchase premiums, purchase discounts and net deferred loan fees. Net deferred loan fees include nonrefundable loan origination fees less direct loan origination costs. Net deferred loan fees, purchase premiums and purchase discounts are amortized into interest income using either the interest method or straight-line method over the terms of the loans, adjusted for actual prepayments. The interest method is used for all loans except revolving loans, for which the straight-line method is used. Interest income is accrued as earned. Fees related to lending activities, other than the origination or purchase of loans, are recognized as noninterest income during the period the related services are performed.

Nonaccrual loans—Loans are placed on nonaccrual status when a loan becomes contractually past due 90 days with respect to interest or principal unless the loan is both well secured and in the process of collection, or if full collection of interest or principal becomes uncertain. When a loan is placed on nonaccrual status, any accrued and unpaid interest receivable is reversed and the amortization of net deferred loan fees, premiums and discounts ceases. The interest payments received on nonaccrual loans are generally accounted for on the cost-recovery method whereby the interest payment is applied to the principal balances. Loans may be returned to accrual status when improvements in credit quality eliminate the doubt as to the full collectability of both interest and principal and a period of sustained performance has occurred.

Restructured loans—A loan is classified as a TDR when a borrower is experiencing financial difficulties that lead to a restructuring of the loan, and the Company grants concessions to the borrower in the restructuring that it would not otherwise consider. These concessions may include interest rate reductions, principal forgiveness, extension of maturity date and other actions intended to minimize potential losses. Generally, a nonaccrual loan that is restructured remains on nonaccrual status for a period of six months to demonstrate that the borrower can meet the restructured terms. If the borrower’s performance under the new terms is not reasonably assured, the loan remains classified as a nonaccrual loan.

Unfunded loan commitments—Unfunded commitments are generally related to providing credit facilities to clients of the Bank and are not actively traded financial instruments. These unfunded commitments are disclosed as financial instruments with off-balance sheet risk in Note 19, “Commitments and Contingent Liabilities.”

The allowance for credit losses under ASC 326 is an accounting estimate of expected losses over the contractual life of assets carried at amortized cost within the Company’s loan portfolio at the balance sheet date. Financial assets (or group of financial assets) measured at amortized cost must be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset to present the net carrying value at the amount expected to be collected on the financial asset.

The quantitative allowance is calculated using a DCF approach with a probability of default methodology. The probability of default is an assumption derived from regression models which determines the relationship between historical defaults and certain economic variables. The Company determines a reasonable and supportable forecast and applies that forecast to the regression model to determine defaults over the forecast period. The Company leverages economic projections from an independent third-party provider on a quarterly basis that are vetted by the Company through quantifiable analysis and comparisons are evaluated by a committee before a final scenario is determined for the 18 month reasonable and supportable forecast period used by the Company. Following the forecast period, the economic variables used to calculate the probability of default reverts to its historical mean using a straight-line basis constructed on each macroeconomic factor’s absolute historical quarterly change at a constant rate. Other assumptions relevant to the discounted cash flow model to derive the quantitative allowance include the loss given default, which is the estimate of loss for a defaulted loan, and the discount rate applied to future cash flows. The DCF model calculates the net present value of each loan using both the contractual and expected cash flows, respectively.

Loans for which repayment is expected to be provided substantially through the operation or sale of collateral are considered collateral-dependent. The allowance for credit losses for collateral-dependent loans is measured on the basis of the fair value of the collateral when foreclosure is probable.

Unfunded Commitments and Letters of Credit—The estimate of expected credit losses under the CECL methodology is based on relevant information about past events, current conditions and reasonable and supportable forecasts that affect the collectability of the reported amounts. Expected credit losses are calculated based on the likelihood that funding will occur and an estimate of the amount that will be funded using recent utilization rates, current utilization and the Company’s quantitative ACL rate. The allowance for unfunded commitments is included in “Other liabilities” on the Consolidated Balance Sheets, with changes to the balance charged against noninterest expense.

Land, buildings, leasehold improvements and equipment are stated at cost less accumulated depreciation and amortization. Gains or losses on dispositions are reflected in current operations. Expenditures for improvements and major renewals are capitalized, and ordinary maintenance, repairs and small purchases are charged to “Occupancy” expense in the Consolidated Statements of Income. Depreciation and amortization are computed based on the straight-line method over the estimated useful lives of the various classes of assets.

Capitalized software is stated at cost, less accumulated amortization. Amortization is computed on a straight-line basis and charged to expense over the estimated useful life of the software, which is generally three years. Capitalized software is included in “Premises and equipment, net” in the Consolidated Balance Sheets.

OREO is composed of real estate acquired by the Company through either foreclosure or deed in lieu of foreclosure in satisfaction of debt. At foreclosure, OREO is recorded at fair value less estimated costs to sell. Any fair value adjustments at foreclosure are charged to the allowance, or in the event of a write-up without previous losses charged to the allowance, a credit to earnings is recorded. The fair value of the OREO is based upon a current appraisal or a letter of intent to purchase. Losses that result from the ongoing periodic valuation of these properties are charged to the net cost of operation of OREO in the period in which they are identified. Improvements to OREO are capitalized and holding costs are charged to the net cost of operation of OREO as incurred.

Net assets of companies acquired in a business combination are recorded at fair value at the date of acquisition. Any excess of the purchase price over the fair value of net assets acquired, including identified intangible assets, is recognized as goodwill. Goodwill is reviewed for potential impairment annually, during the third quarter, or, more frequently, if events or circumstances indicate a potential impairment, at the reporting unit level. A reporting unit is an operating segment or one level below an operating segment for which discrete financial information is available and regularly reviewed by management. The Company consists of a single reporting unit. The test for impairment requires the Company to compare the fair value of the reporting unit to its carrying value. If the fair value of the reporting unit is less than its carrying value, the difference is the amount of impairment and goodwill is written down to the fair value of the reporting unit. Prior to completing the impairment test, however, the Company may assess qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. If such an assessment indicates the fair value of the reporting unit is more likely than not greater than its carrying value, then the impairment test need not be completed.

Identified intangible assets are amortized on an accelerated basis over the period benefited. Intangible assets are also evaluated for impairment if events and circumstances indicate a possible impairment. Such evaluation is based on undiscounted cash flow projections. At December 31, 2022, intangible assets included in the Consolidated Balance Sheets principally consisted of CDI with an original estimated life of 10 years.

The Company determines if a lease is present at the inception of an agreement. Operating leases are capitalized at commencement and are discounted using the Company’s FHLB borrowing rate for a similar term borrowing unless the lease defines a rate within the contract. Leases with original terms of less than 12 months are not capitalized. For operating leases existing prior to January 1, 2019, the rate for the remaining lease term as of January 1, 2019 was used. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments arising from the lease. Operating lease right-of-use assets and operating lease liabilities are recognized on the lease commencement date based on the present value of lease payments over the lease term. The lease term includes options to extend or terminate the lease if the Company is reasonably certain that an option will be exercised. See Note 10, “Leases” for additional information on leases.

The provision for income taxes includes current and deferred income tax expense on net income adjusted for temporary and permanent differences such as interest income from state and municipal securities and investments in affordable housing tax credits. Deferred tax assets and liabilities are recognized for the expected future tax consequences of existing temporary differences between the financial reporting and tax reporting basis of assets and liabilities using enacted tax laws and rates. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. On a quarterly basis, management evaluates deferred tax assets to determine if these tax benefits are expected to be realized in future periods. This determination is based on facts and circumstances, including the Company’s current and future tax outlook. To the extent a deferred tax asset is no longer considered “more likely than not” to be realized, a valuation allowance is established.

We recognize the tax benefit from uncertain tax positions only if it is more likely than not that the tax positions will be sustained on examination by the tax authorities, based on the technical merits of the position. The tax benefit is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. We recognize interest and penalties related to unrecognized tax benefits in “Provision for income taxes” in the Consolidated Statements of Income.

The Company’s capital structure includes common shares, restricted common share awards and common share options. Restricted common share awards granted prior to the 2018 equity incentive plan participate in dividends declared on common shares at the same rate as common shares. These restricted common share awards are considered participating securities under the EPS topic of the FASB ASC.

The Company calculates EPS using the two-class method. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to common shareholders but does not require the presentation of basic and diluted EPS for securities other than common shares. Under the two-class method, basic EPS is computed by dividing earnings allocated to common shareholders by the weighted average number of common shares outstanding for the period. Earnings allocated to common shareholders represents net income reduced by earnings allocated to participating securities. Diluted EPS is computed in the same manner as basic EPS except that the denominator is increased to include the number of additional common shares that would have been outstanding if certain shares issuable upon exercise of common share options were included unless those additional shares would have been anti-dilutive. For the diluted EPS computation, the treasury stock method is applied and compared to the two-class method and whichever method results in a more dilutive impact is utilized to calculate diluted EPS.

The Company accounts for stock options and stock awards in accordance with the Compensation—Stock Compensation topic of the FASB ASC. Authoritative guidance requires the Company to measure the cost of employee services received in exchange for an award of equity instruments, such as stock options or stock awards, based on the fair value of the award on the grant date. This cost must be recognized in the Consolidated Statements of Income over the vesting period of the award.

The Company issues RSAs and RSUs which generally vest over a three- or four-year period. RSA and RSU time-based awards vest ratably over their vesting period while RSA and RSU performance-based awards cliff vest. Recipients of RSAs have voting rights while recipients of RSUs do not. Pursuant to our equity incentive plan approved in 2018, the holder accrues dividends, which are paid out when the RSAs vest or when the RSUs vest and the common shares are issued. The fair value of time-based and performance-based awards are equal to the fair market value of the Company’s common stock on the grant date. The fair value of market-based performance awards are estimated on the date of grant using the Monte Carlo simulation model.

In accordance with the Derivatives and Hedging topic of the FASB ASC, the Company recognizes derivatives as assets or liabilities on the Consolidated Balance Sheets at their fair value. The Company periodically enters into interest rate contracts with customers and offsetting contracts with third parties. As these interest rate contracts are not designated as hedges under the Derivatives and Hedging topic of the FASB ASC, the changes in fair value of these instruments are recognized immediately in earnings. The Company also enters into forward contracts to sell residential mortgage loans to broker/dealers at specific prices and dates in order to hedge the interest rate risk in its portfolio of mortgage loans held for sale and its residential loan commitments. The commitments to originate mortgage loans held for sale and the related forward delivery contracts are considered derivatives.

As part of the Company’s overall interest rate risk management, the Company used an interest rate collar with a notional amount of $500.0 million to mitigate interest rate risk. This collar was designated and qualified as a cash flow hedge. Gains and losses were recorded in accumulated other comprehensive income to the extent the hedge was effective. Gains and losses were reclassified from accumulated other comprehensive income to earnings in the period the hedged transaction affected earnings and was included in the same income statement line item that the hedged transaction was recorded. In October 2020, the interest rate collar was terminated. See Note 17. “Derivatives and Balance Sheet Offsetting” for additional information.

Revenue in the scope of Topic 606, Revenue from Contracts with Customers is measured based on the consideration specified in the contract with a customer and excludes amounts collected on behalf of third parties. The vast majority of the Company’s revenue is specifically outside the scope of Topic 606. For in-scope revenue, the following is a description of principal activities, separated by the timing of revenue recognition from which the Company generates its revenue from contracts with customers.

a.Revenue earned at a point in time - Examples of revenue earned at a point in time are ATM transaction fees, wire transfer fees, overdraft fees, interchange fees and foreign exchange transaction fees. Revenue is primarily based on the number and type of transactions and is generally derived from transactional information accumulated by our systems and is recognized immediately as the transactions occur or upon providing the service to complete the customer’s transaction. The Company is the principal in each of these contracts, with the exception of interchange fees, in which case we are acting as the agent and record revenue net of expenses paid to the principal.

b.Revenue earned over time - The Company earns revenue from contracts with customers in a variety of ways where the revenue is earned over a period of time - generally monthly. Examples of this type of revenue are deposit account maintenance fees, investment advisory fees, merchant revenue and safe deposit box fees. Revenue is generally derived from transactional information accumulated by our systems or those of third-parties and is recognized as the related transactions occur or services are rendered to the customer.

The Company recognizes revenue from contracts with customers when it satisfies its performance obligations. The Company’s performance obligations are typically satisfied as services are rendered and our contracts generally do not include multiple performance obligations. As a result, there are no contract balances as payments and services are rendered simultaneously. Payment is generally collected at the time services are rendered, monthly or quarterly. Unsatisfied performance obligations at the report date are not material to our Consolidated Financial Statements.

In certain cases, other parties are involved with providing products and services to our customers. If the Company is principal in the transaction (providing goods or services itself), revenues are reported based on the gross consideration received from the customer and any related expenses are reported gross in noninterest expense. If the Company is an agent in the transaction (arranging for another party to provide goods or services), the Company reports its net fee or commission retained as revenue.

The Company does not adjust the consideration from customers for the effects of a significant financing component if at contract inception the period between when the entity transfers the goods or services and when the customer pays for that good or service will be one year or less.

The Company pays sales commissions to its employees in accordance with certain incentive plans and in connection with obtaining certain contracts with customers. The Company expenses such sales commissions when incurred if the amortization period of the asset the Company otherwise would have recognized is one year or less. Sales commissions are included in compensation and employee benefits expense.

For the Company’s contracts that have an original expected duration of one year or less, the Company has not disclosed the amount of the transaction price allocated to unsatisfied performance obligations as of the end of each reporting period or when the Company expects to recognize this revenue.

In December 2022, the FASB issued ASU 2022-06, Reference Rate Reform (Topic 848) - Deferral of the Sunset Date of Topic 848. The amendments in this ASU defer the sunset date included in ASU 2020-04 to provide temporary, optional expedients related to the accounting for contract modifications and hedging transactions as a result of the global markets’ anticipated transition away from the use of LIBOR and other interbank offered rates to alternative reference rates. Preceding the issuance of ASU 2020-04, which established ASC 848, the United Kingdom’s Financial Conduct Authority (“FCA”) announced that it would no longer need to persuade or compel banks to submit to LIBOR after December 31, 2021. In response, the FASB established a December 31, 2022 expiration date of ASC 848. In March 2021, the FCA announced that the intended cessation date of LIBOR in the United States would be June 30, 2023. Accordingly, ASU 2022-06 defers the expiration date of ASC 848 to December 31, 2024. This ASU was effective immediately and did not have a material impact on the Company’s Consolidated Financial Statements.

In June 2022, the FASB issued ASU 2022-03, Fair Value Measurement (Topic 820) - Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions. The amendments in this ASU clarify that a contractual restriction on the sale of an equity security is not considered part of the unit of account of the equity security and is not considered in measuring fair value. Further, an entity cannot, as a separate unit of account, recognize and measure a contractual sale restriction. Additionally, the amendments require the disclosures for equity securities subject to contractual sale restrictions to include the fair value of equity securities subject to contractual sale restrictions reflected on the balance sheet, the nature and remaining duration of the restrictions and the circumstances that could cause a lapse in the restrictions. The ASU is effective for interim and annual reporting periods beginning after December 15, 2023; early adoption is permitted. The adoption of this ASU is not expected to have a material impact on the Company’s Consolidated Financial Statements.

In March 2022, the FASB issued ASU 2022-02, Financial Instruments - Credit Losses (Topic 326) - Troubled Debt Restructurings and Vintage Disclosures. The amendments in this ASU enhance disclosure requirements for certain loan refinancings and restructurings by creditors when a borrower is experiencing financial difficulty. Additionally, the amendments require the disclosure of current-period gross charge-offs by year of origination for financing receivables and net investments in leases within scope. The ASU is effective for interim and annual reporting periods beginning after December 15, 2022; early adoption is permitted. The adoption of this ASU is not expected to have a material impact on the Company’s Consolidated Financial Statements.