Summary of Significant Accounting Policies

Organization

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 West Coast Trust Company, Inc. (“West Coast Trust”). The Bank provides a full range of financial services through 149 branch locations, including 74 in the State of Washington, 59 in Oregon and 16 in Idaho. West Coast 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 West Coast 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 accounting principles generally accepted in the United States of America (“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 allowance for loan and lease losses, business combinations, purchased credit impaired loans, Federal Deposit Insurance Corporation (“FDIC”) loss-sharing asset and goodwill impairment.

The Company has applied its accounting policies and estimation methods consistently in all periods presented in these financial statements (to the periods in which they applied).

Consolidation

The consolidated financial statements of the Company include the accounts of the Corporation and its subsidiaries, including the Bank and West Coast Trust. Intercompany balances and transactions have been eliminated in consolidation.

Cash and cash equivalents

Cash and cash equivalents include cash and due from banks, and interest bearing balances due from correspondent banks and the Federal Reserve Bank. Cash equivalents have a maturity of 90 days or less at the time of purchase.

Securities

Securities are classified based on management’s intention on the date of purchase. All securities are classified as available for sale and are presented at fair value. Unrealized gains or losses on securities available for sale are excluded from net income but are included as separate components of other comprehensive income, net of taxes. Purchase premiums or discounts on securities available for sale 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 is other-than-temporary. Amortized cost includes adjustments made to the cost of an investment for accretion, amortization, collection of cash and previous other-than temporary impairment recognized in earnings. Other-than-temporary impairment exists when it is probable that the Company will be unable to recover the entire amortized cost basis of the security.

In performing the quarterly assessment for debt securities, management considers whether or not the Company expects to recover the entire amortized cost basis of the security. In addition, management also considers whether it is more likely than not that it will not have to sell the security before recovery of its cost basis. If the Company intends to sell a security or it is more likely than not it will be required to sell a security prior to recovery of its cost basis, the entire amount of impairment is recognized in earnings. If the Company does not intend to sell the security or it is not more likely than not it will be required to sell the security prior to recovery of its cost basis, the credit loss component of impairment is recognized in earnings and impairment associated with non-credit factors, such as market liquidity, is recognized in other comprehensive income net of tax. A credit loss is the difference between the cost basis of the security and the present value of cash flows expected to be collected, discounted at the security’s effective interest rate at the date of acquisition. The cost basis of an other-than-temporarily impaired security is written down by the amount of impairment recognized in earnings. The new cost basis is not adjusted for subsequent recoveries in fair value. However, the difference between the new amortized cost basis and the cash flows expected to be collected is accreted as interest income. The total other-than-temporary impairment, if any, is presented in the consolidated statements of income with a reduction for the amount of other-than-temporary impairment that is recognized in other comprehensive income, if any.

Realized gains or losses on sales of securities available for sale are recorded using the specific identification method.

Federal Home Loan Bank Stock

Effective May 31, 2015, the Federal Home Loan Bank of Des Moines (the “FHLB Des Moines”) completed its merger with the Federal Home Loan Bank of Seattle (the “FHLB Seattle”). At closing, the FHLB Seattle merged with and into the FHLB Des Moines, with the FHLB Des Moines surviving the merger as the continuing bank. Also at closing, the Company, a member of the FHLB Seattle, automatically became a member of the FHLB Des Moines. Pursuant to the terms of the merger, each share of the Company’s FHLB Seattle Class B stock was converted into one share of FHLB Des Moines Class B stock.

FHLB Des Moines Class B stock is composed of two sub-classes: membership stock and activity based stock. Membership stock is stock we are required to purchase and hold as a condition of membership in the FHLB Des Moines. The Company’s membership stock purchase requirement is measured as a percentage of our year-end assets, subject to a $10 million cap. Activity based stock is stock we are required to purchase and hold in order to obtain an advance or participate in FHLB Des Moines mortgage programs. Class B stock may be redeemed, subject to certain limitations, on five years’ written notice to the FHLB Des Moines. FHLB Des Moines capital stock is carried at par value because the shares are issued, transferred, redeemed, and repurchased by the FHLB Des Moines at a par value of $100. FHLB Des Moines capital stock is subject to recoverability testing per the Financial Services-Depository and Lending topic of the FASB Accounting Standards Codification (“ASC”).

Loans

Loans, excluding purchased credit impaired loans are generally carried at the unpaid principal balance, net of premiums, discounts and net deferred loan fees. Net deferred loan fees include nonrefundable loan origination fees less direct loan origination costs. Net deferred loan fees, premiums and 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 amortization is calculated using the interest method 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. Thereafter, interest collected on the loan is accounted for on the cash collection or cost recovery method until qualifying for return to accrual status. Generally, a loan may be returned to accrual status when the delinquent principal and interest are brought current in accordance with the terms of the loan agreement for a minimum period of six months and future payments are reasonably assured.

Impaired loans—Loans are considered impaired when based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement or when a loan has been modified in a troubled debt restructuring. The assessment for impairment occurs when and while such loans are designated as classified per the Company’s internal risk rating system or when and while such loans are on nonaccrual. All nonaccrual loans greater than $500,000 and all troubled debt restructured loans are considered impaired and analyzed individually on a quarterly basis. Classified loans with an outstanding balance greater than $500,000 are evaluated for potential impairment on a quarterly basis.

When a loan with unique risk characteristics has been identified as being impaired, the amount of impairment will be measured by the Company using discounted cash flows, except when it is determined that the remaining source of repayment for the loan is the operation or liquidation of the underlying collateral. In these cases, the current fair value of the collateral, reduced by costs to sell, will be used in place of discounted cash flows. As a final alternative, the observable market price of the debt may be used to assess impairment. Predominantly, the Company uses the fair value of collateral approach based upon a reliable valuation.

When the measurement of the impaired loan is less than the recorded amount of the loan, an impairment is recognized by recording a charge-off to the allowance for loan and lease losses or by designating a specific reserve. The Company’s policy is to record cash receipts received on impaired loans first as reductions to principal and then to interest income.

Restructured Loans—A loan is classified as a troubled debt restructuring 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.

Purchased Credit Impaired Loans (“PCI Loans”)—Loans acquired with evidence of credit deterioration since origination for which it is probable that all contractually required payments will not be collected are accounted for under ASC 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality. In addition, because of the significant discounts associated with certain of the acquired loan portfolios, the Company elected to account for those certain acquired loans under ASC 310-30.

In situations where such loans have similar risk characteristics, loans are aggregated into pools to estimate cash flows. A pool is accounted for as a single asset with a single interest rate, cumulative loss rate and cash flow expectation. Expected cash flows at the acquisition date in excess of the fair value of loans are considered to be accretable yield, which is recognized as interest income over the life of the loan pool using a level yield method if the timing and amount of the future cash flows of the pool is reasonably estimable. Subsequent to the acquisition date, any increases in cash flow over those expected at purchase date in excess of fair value are recorded as interest income prospectively. Any subsequent decreases in cash flow over those expected at purchase date due to credit deterioration are recognized by recording an allowance for losses on purchased credit impaired loans. Any disposals of loans, including sales of loans, payments in full or foreclosures result in the removal of the loan from the loan pool at the carrying amount.

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 17 in the Notes to Consolidated Financial Statements.

Allowance for Loan and Lease Losses

The Company accounts for the credit risk associated with lending activities through its allowance for loan and lease losses and provision for loan and lease losses. The provision is the expense recognized in the consolidated statements of income to adjust the allowance to the levels deemed appropriate by management, as determined through application of the Company’s allowance methodology procedures. The provision for loan and lease losses reflects management’s judgment of the adequacy of the allowance for loan and lease losses. Loan and lease losses are charged against the allowance when management believes the collectability of a loan balance is unlikely. Subsequent recoveries, if any, are credited to the allowance.

The allowance for loan and lease losses is evaluated on a regular basis by management and is based upon management’s periodic review of the collectability of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, and estimated value of any underlying collateral and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available.

The allowance consists of general, specific, and unallocated components. The general component covers loans not specifically measured for impairment and is based on historical loss experience adjusted for qualitative factors. The specific component relates to loans that are impaired. For impaired loans an allowance is established when the discounted cash flows (or collateral value or observable market price) of the impaired loan is lower than the carrying value of that loan. The unallocated allowance provides for other credit losses inherent in the Company’s loan portfolio that may not have been contemplated in the general and specific components of the allowance. This unallocated amount generally comprises less than 5% of the allowance. The unallocated amount is reviewed periodically based on trends in credit losses, the results of credit reviews and overall economic trends.

Allowance for Loan Losses on Purchased Credit Impaired Loans

The Company updates its cash flow projections for purchased credit impaired loans accounted for under ASC 310-30 on a quarterly basis. Assumptions utilized in this process include projections related to probability of default, loss severity, prepayment and recovery lag. Projections related to probability of default and prepayment are calculated utilizing a loan migration analysis. The loan migration analysis is a matrix of probability that is used to estimate the probability of a loan pool transitioning into a particular delinquency state given its delinquency state at the remeasurement date. Loss severity factors are based upon either actual charge-off data within the loan pools or industry averages, and recovery lags are based upon the collateral within the loan pools.

Any decreases in expected cash flows after the acquisition date and subsequent measurement periods are recognized by recording a provision for loan losses. See Purchased Credit Impaired Loans for further discussion.

Allowance for Unfunded Commitments and Letters of Credit

The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to these unfunded credit facilities. The determination of the adequacy of the allowance is based on periodic evaluations of the unfunded credit facilities including an assessment of the probability of commitment usage, credit risk factors for loans outstanding to these same customers, and the terms and expiration dates of the unfunded credit facilities. The allowance for unfunded commitments is included in other liabilities on the consolidated balance sheets, with changes to the balance charged against noninterest expense.

Premises and Equipment

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 operating expenses. Depreciation and amortization are computed based on the straight-line method over the estimated useful lives of the various classes of assets. The ranges of useful lives for the principal classes of assets are as follows:



Buildings and building improvements	5 to 39 years
Leasehold improvements	Term of lease or useful life, whichever is shorter
Furniture, fixtures and equipment	3 to 7 years
Vehicles	5 years
Computer software	3 to 5 years

Software

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.

Other Real Estate Owned (“OREO”)

OREO is composed of real estate acquired in satisfaction of loans. Properties acquired by foreclosure or deed in lieu of foreclosure are transferred to OREO and are recorded at fair value less estimated costs to sell at the date of transfer of the property. The fair value of the OREO property is based upon current appraisal. If the carrying value exceeds the fair value at the time of the transfer, the difference is charged to the allowance for loan and lease losses. 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 the OREO are capitalized and holding costs are charged to the net cost of operation of OREO as incurred.

FDIC Loss-sharing Asset

The acquisition date fair value of the reimbursement the Company expected to receive from the FDIC under loss-sharing agreements was recorded in the FDIC loss-sharing asset on the consolidated balance sheet. Subsequent to initial recognition, the FDIC loss-sharing asset is reviewed quarterly and adjusted for any changes in expected cash flows. These adjustments are measured on the same basis as the related covered assets. Any decrease in expected cash flows for the covered assets due to an increase in expected credit losses will increase the FDIC loss-sharing asset and any increase in expected future cash flows for the covered assets due to a decrease in expected credit losses will decrease the FDIC loss-sharing asset. Changes in the estimated cash flows on covered assets that are immediately recognized in income generally result in a similar immediate adjustment to the loss-sharing asset while changes in expected cash flows on covered assets that are accounted for as an adjustment to yield generally result in adjustments to the amortization or accretion rate for the loss-sharing asset. Increases and decreases to the FDIC loss-sharing asset are recorded as adjustments to noninterest income.

Goodwill and Intangibles

Net assets of companies acquired in purchase transactions are recorded at fair value at the date of acquisition. Identified intangibles are amortized on an accelerated basis over the period benefited. Goodwill is not amortized but is reviewed for potential impairment during the third quarter on an annual basis 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. If the fair value of the reporting unit, including goodwill, is determined to be less than the carrying amount of the reporting unit, a further test is required to measure the amount of impairment. If an impairment loss exists, the carrying amount of goodwill is adjusted to a new cost basis. Subsequent reversal of a previously recognized goodwill impairment loss is prohibited.

Intangible assets are evaluated for impairment if events and circumstances indicate a possible impairment. Such evaluation of other intangible assets is based on undiscounted cash flow projections. At December 31, 2015, intangible assets included on the consolidated balance sheets principally consists of a core deposit intangible amortized using an accelerated method with an original estimated life of 10 years.

Income Taxes

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 on state and municipal securities and investments in affordable housing 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.

Advertising

Advertising costs are generally expensed as incurred.

Earnings per Common Share

The Company’s capital structure includes convertible preferred shares, common shares, restricted common shares, common share options, and during portions of 2014 and 2013, warrants to purchase common shares. Restricted common shares participate in dividends declared on common shares at the same rate as common shares. Convertible preferred shares participate in dividends declared on common shares on an “as if converted” basis. Accordingly, the Company calculates earnings per common share (“EPS”) using the two-class method under the Earnings per Share topic of the FASB ASC. 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. Participating securities include nonvested restricted stock awards and preferred stock. Diluted EPS is computed in the same manner as basic earnings per share 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 options and warrants 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.

Share-Based Payment

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 restricted stock awards which generally vest over a four- or five-year period during which time the holder receives dividends and has full voting rights. Restricted stock is valued at the closing price of the Company’s stock on the date of an award.

Derivatives and Hedging Activities

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.

Accounting Pronouncements

During the year ended December 31, 2015, the following Accounting Standards Updates were issued or became effective:

In September 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-16, Simplifying the Accounting for Measurement-Period Adjustments. The amendments in ASU 2015-16 require that the acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amount is determined. The acquirer is required to also record, in the same period’s financial statements, the effect on earnings as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date. In addition, an entity is required to present separately on the face of the income statement or disclose in the notes to the financial statements the portion of the amount recorded in current-period earnings by line item that would have been recorded in previous reporting periods if the adjustment to the provisional amounts had been recognized as of the acquisition date. The amendments in ASU 2015-16 are effective for years beginning after December 15, 2015. Early adoption is permitted for reporting periods for which financial statements have not been issued. The Company early adopted the amendments in ASU 2015-16 in 2015. Adoption of this ASU did not have a material impact on the Company's consolidated financial statements.

In June 2014, the FASB issued ASU 2014-11, Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures. The amendments in ASU 2014-11 change the accounting for repurchase-to-maturity transactions and linked repurchase financings to secured borrowing accounting, which is consistent with accounting for other repurchase agreements. Additionally, the amendment requires new disclosures on transfers accounted for as sales in transactions that are economically similar to repurchase agreements and requires increased transparency on collateral pledged in secured borrowings. The amendments in this update were effective for the first interim or annual period beginning after December 31, 2014, with the exception of the collateral disclosures which were effective for interim periods beginning after March 15, 2015. Adoption of this ASU did not have a material impact on the Company's consolidated financial statements.

In May 2014, FASB issued ASU 2014-09, Revenue from Contracts with Customers. The guidance in this update supersedes the revenue recognition requirements in ASC Topic 605, Revenue Recognition, and most industry-specific guidance throughout the industry topics of the codification. For public companies, this update was to be effective for interim and annual periods beginning after December 15, 2016. However, in August 2015, the FASB issued ASU 2015-14, which delayed the effective date of ASU 2014-09 by one year and permits companies to voluntarily adopt the new standard as of the original effective date. The Company is currently assessing the impact that this guidance will have on its consolidated financial statements, but does not expect the guidance to have a material impact on the Company’s consolidated financial statements.

In April 2014, the FASB issued ASU No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. ASU 2014-08 raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. It is effective for annual periods beginning on or after December 15, 2014. Adoption of this ASU did not have a material impact on the Company's consolidated financial statements.

In January 2014, the FASB issued ASU 2014-04, Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans Upon Foreclosure. The update clarifies when a creditor would be considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan such that all or a portion of the loan would be derecognized and the real estate property recognized. Under the guidance, a consumer loan collateralized by residential real estate should be reclassified to other real estate owned when (1) the creditor obtains legal title to the residential property or (2) the borrower conveys all interest in the property to the creditor to satisfy the loan by completing a deed in lieu of foreclosure or similar agreement. In addition, an entity is required to disclose the amount of residential real estate meeting the conditions above and the recorded investment in consumer mortgage loans secured by residential real estate that are in the process of foreclosure. ASU 2014-04 was effective for annual and interim reporting periods within those annual periods, beginning after December 15, 2014. Adoption of this ASU did not have a material impact on the Company's consolidated financial statements.