Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2020
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Business Zions Bancorporation, National Association and its subsidiaries (collectively “Zions Bancorporation, N.A.,” “the Bank,” “we,” “our,” “us”) together comprise a bank headquartered in Salt Lake City, Utah. We provide a wide range of banking products and related services in 11 Western and Southwestern states through seven separately managed affiliates, as follows: Zions Bank in Utah, Idaho and Wyoming; California Bank & Trust (“CB&T”); Amegy Bank (“Amegy”) in Texas; National Bank of Arizona (“NBAZ”); Nevada State Bank (“NSB”); Vectra Bank Colorado (“Vectra”) in Colorado and New Mexico; and The Commerce Bank of Washington (“TCBW”) which operates under that name in Washington and under The Commerce Bank of Oregon (“TCBO”) in Oregon. Basis of Financial Statement Presentation and Principles of Consolidation The consolidated financial statements include our accounts and those of our majority-owned, consolidated subsidiaries. Unconsolidated investments where we have the ability to exercise significant influence over the operating and financial policies of the respective investee are accounted for using the equity method of accounting. All significant intercompany accounts and transactions have been eliminated in consolidation. Assets held in an agency or fiduciary capacity are not included in the Consolidated Financial Statements. The consolidated financial statements have been prepared in accordance with United States (“U.S.”) generally accepted accounting principles (“GAAP”) and prevailing practices within the financial services industry. References to GAAP, including standards promulgated by the Financial Accounting Standards Board (“FASB”), are made according to sections of the Accounting Standards Codification (“ASC”). Changes to the ASC are made with Accounting Standards Updates (“ASU”) that include consensus issues of the Emerging Issues Task Force. In certain cases, ASUs are issued jointly with International Financial Reporting Standards. In preparing the consolidated financial statements, we are required to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Certain prior year amounts have been reclassified to conform with the current year presentation. These reclassifications did not affect net income or shareholders’ equity. Variable Interest Entities A variable interest entity (“VIE”) is consolidated when a company is the primary beneficiary of the VIE. Current accounting guidance requires continuous analysis on a qualitative rather than a quantitative basis to determine the primary beneficiary of a VIE. At the commencement of our involvement, and periodically thereafter, we consider our consolidation conclusions for all entities with which we are involved. As of December 31, 2020, and 2019, we have no VIEs that have been consolidated in our financial statements. Statement of Cash Flows For purposes of presentation in the consolidated statements of cash flows, “cash and cash equivalents” are defined as those amounts included in cash and due from banks in the consolidated balance sheets. Fair Value Estimates We measure many of our assets and liabilities on a fair value basis. Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. To improve consistency and comparability in fair value measurements, GAAP has established a hierarchy to prioritize the valuation inputs among three levels. We prioritize quoted prices in active markets and minimize reliance on unobservable inputs when possible. When observable market prices are not available, fair value is estimated using modeling techniques such as discounted cash flow analysis. These modeling techniques use assumptions that market participants would consider in pricing the asset or the liability — including assumptions about the risk inherent in a particular valuation technique — the effect of a restriction on the sale or use of an asset, the life of the asset and applicable growth rate, the risk of nonperformance, and other related assumptions. Changes in market conditions may reduce the availability of quoted prices or observable data. When market data is not available, we use valuation techniques requiring professional judgment to estimate the appropriate fair value. See Note 3 of the “Notes to Consolidated Financial Statements” for further information regarding the use of fair value estimates. Security Resell Agreements Security resell agreements represent overnight and term agreements with the majority maturing within 30 days. Due to increased cash reserves and in order to increase yield, we have extended the maturity of some security resell agreements beyond 30 days. As of December 31, 2020, 28% of all security resell agreements have a maturity beyond 30 days but none greater than 50 days. These agreements are generally treated as collateralized financing transactions and are carried at amounts at which the securities were acquired plus accrued interest. Either we, or in some instances third-parties on our behalf, take possession of the underlying securities. The fair value of such securities is monitored throughout the contract term to ensure that asset values remain sufficient to protect against counterparty default. We are permitted by contract to sell or repledge certain securities that we accept as collateral for security resell agreements. If sold, our obligation to return the collateral is recorded as “securities sold, not yet purchased” and included as a liability in “Federal funds and other short-term borrowings.” At December 31, 2020, we held $5.7 billion of securities for which we were permitted by contract to sell or repledge. Security resell agreements averaged $2.1 billion during 2020, and the maximum amount outstanding at any month-end during 2020 was $6.4 billion. Investment Securities We classify our investment securities according to their purpose and holding period. Gains or losses on the sale of securities are recognized using the specific identification method and recorded in noninterest income. Held-to-maturity (“HTM”) debt securities are carried at amortized cost with purchase discounts or premiums accreted or amortized into interest income over the contractual life of the security. We have the intent and ability to hold such securities until maturity. For HTM securities, the ACL is assessed consistent with the approach described in Note 6 for loans carried at amortized cost. Available-for-sale (“AFS”) securities are stated at fair value and generally consist of debt securities held for investment. Unrealized gains and losses of AFS securities, after applicable taxes, are recorded as a component of other comprehensive income (“OCI”). AFS securities in an unrealized loss position are formally reviewed on a quarterly basis for the presence of impairment. If we have an intent to sell an identified security, or it is more likely than not we will be required to sell the security before recovery of its amortized cost basis, then we recognize an impairment equal to any existing allowance written off against the security. If we do not have the intent to sell a security, and it is more likely than not that we will not be required to sell a security prior to recovery of its amortized cost basis, then we determine whether there is any impairment attributable to credit-related factors. The process, methodology, and factors considered to evaluate securities for impairment are described further in Note 5. Trading securities are stated at fair value and consist of securities acquired for short-term appreciation or other trading purposes. Realized and unrealized gains and losses are recorded in trading income, which is included in “Capital Markets and Foreign Exchange.” The fair values of investment securities, as estimated under current accounting guidance, are described in Note 3. Leases As a lessee, when we enter a lease contract, we classify and account for the lease as either a finance lease or an operating lease, depending on the terms and conditions of the lease. A finance lease is recorded as an asset and a liability, and the asset is generally depreciated over the lease term. The lease liability is reduced as lease payments are made. An operating lease is recorded as a right-of-use (“ROU”) asset and operating lease liability. These balance sheet items are reduced as lease payments are made. Lease payments are expensed over the lease term; they are recorded as rent expense and are recognized on a straight-line basis. Lease-related assets are reviewed for impairment on an on-going basis. The lease term is the non-cancelable period that we have the right to use the leased asset. This term begins on the commencement date of the lease and incorporates options to extend or renew the lease when it is reasonably certain that we will exercise these options. Loans Loans are reported at the principal amount outstanding, net of unearned income, unamortized purchase premiums and discounts, and net deferred loan fees and costs, which are amortized to interest income over the life of the loan using the interest method. Interest income is recognized on an accrual basis. At the time of origination, we determine whether loans will be held for investment or held for sale. We may subsequently change our intent to hold loans for investment and reclassify them as held for sale. Loans held for sale are carried at the lower of aggregate cost or fair value. A valuation allowance is recorded when cost exceeds fair value based on reviews at the time of reclassification and periodically thereafter. Gains and losses are recorded in noninterest income based on the difference between sales proceeds and carrying value. We evaluate loans throughout their lives for signs of credit deterioration, which may impact the loan’s status, and potentially impact our accounting for that loan. Loan status categories include past due as to contractual payments, nonaccrual, and restructured, including troubled debt restructurings (“TDRs”). Our accounting policies for these loan statuses and our estimation of the related allowance for loan and lease losses (“ALLL”) are described further in Note 6. In the ordinary course of business, we transfer portions of loans under participation agreements to manage credit risk and our portfolio concentration. We evaluate the loan participations to determine if they meet the appropriate accounting guidance to qualify as sales. Certain purchased loans require separate accounting procedures that are also described in Note 6. Allowance for Credit Losses The allowance for credit losses (“ACL”) includes the ALLL and the reserve for unfunded lending commitments (“RULC”). For periods prior to 2020, the ALLL represented management’s estimate of probable losses believed to be inherent in the loan portfolio at that time, and the RULC was estimated using the same procedures and methodologies as for the ALLL, in addition to assumptions regarding the probability and amount of unfunded commitments being drawn. On January 1, 2020, we adopted ASU 2016-13, Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, and its subsequent updates, often referred to as the Current Expected Credit Loss (“CECL”) model. CECL changes how the ACL is measured for loans and for additional financial assets, including HTM securities. Under CECL, the ACL will represent our estimate of current expected credit losses over the contractual term of the loan and lease portfolio and unfunded lending commitments as of the balance sheet date. The ACL for debt securities is estimated separately from loans. Further discussion of our estimation process for the ACL is included in Note 6. Other Noninterest-bearing Investments These investments include investments in private equity funds — referred to in this document as private equity investments (“PEIs”) — venture capital securities, securities acquired for various debt and regulatory requirements, bank-owned life insurance (“BOLI”), and certain other noninterest-bearing investments. See further discussion in Note 3. Certain PEIs and venture capital securities are accounted for under the equity method and some are reported at fair value. Changes in fair value and gains and losses from sales are recognized in noninterest income. The values assigned to the securities where no market quotations exist are based upon available information and may not necessarily represent amounts that will ultimately be realized. Such estimated amounts depend on future circumstances and will not be realized until the individual securities are liquidated. BOLI is accounted for at fair value based on the cash surrender values (“CSVs”) of the general account insurance policies. A third-party service provides these values. Other PEIs, and those acquired for various debt and regulatory requirements, are accounted for at cost less impairment (if any), plus or minus observable price changes from an identical or similar investment of the same issuer, with such changes recognized in income. Periodic reviews are conducted for impairment by comparing carrying values with estimates of fair value determined according to the previous discussion. Premises, Equipment and Software, Net Premises, equipment, and software are stated at cost, net of accumulated depreciation and amortization. Depreciation, computed primarily on the straight-line method, is charged to operations over the estimated useful lives of the properties, generally 25 to 40 years for buildings, three to 10 years for furniture and equipment, and three to 10 years for software, including capitalized costs related to our technology initiatives. Leasehold improvements are amortized over the terms of the respective leases or the estimated useful lives of the improvements (including any extension options that are reasonably certain to be exercised), whichever is shorter. Premises, equipment and software are evaluated for impairment on a periodic basis. Goodwill and Identifiable Intangible Assets Goodwill and intangible assets deemed to have indefinite lives are not amortized. We subject these assets to annual specified impairment tests as of the beginning of the fourth quarter and more frequently if changing conditions warrant. Business Combinations Business combinations are accounted for under the acquisition method of accounting. Upon initially obtaining control, we recognize 100% of all acquired assets and all assumed liabilities, regardless of the percentage owned. The assets and liabilities are recorded at their estimated fair values, with goodwill being recorded when such fair values are less than the cost of acquisition. Certain transaction and restructuring costs are expensed as incurred. Changes to estimated fair values from a business combination are recognized as an adjustment to goodwill over the measurement period, which cannot exceed one year from the acquisition date. Results of operations of the acquired business are included in our statement of income from the date of acquisition. Other Real Estate Owned Other real estate owned (“OREO”) consists principally of commercial and residential real estate obtained in partial or total satisfaction of loan obligations. Amounts are recorded initially at fair value (less any selling costs) based on property appraisals at the time of transfer and subsequently at the lower of cost or fair value (less any selling costs). Derivative Instruments We use derivative instruments — including interest rate swaps and purchased and sold options such as floors and basis swaps—as part of our overall interest rate risk management strategy. Derivatives are an important tool used in managing our overall asset and liability sensitivities to remain within management’s stated interest rate risk thresholds. Their use allows us to adjust and align our naturally occurring mix of fixed and floating-rate assets and liabilities to manage interest income volatility by synthetically converting variable-rate assets to fixed-rate, or synthetically converting fixed-rate funding instruments to floating-rates. We also execute both interest rate and short-term foreign currency derivative instruments with our commercial banking customers to facilitate their risk management strategies. These derivatives are immediately hedged by offsetting derivatives with third-parties such that we minimize our net risk exposure as a result of such transactions. We record all derivatives at fair value in the balance sheet as either other assets or other liabilities. The accounting for the change in value of a derivative depends on whether or not the transaction has been designated and qualifies for hedge accounting. Derivatives that are not designated as hedges are reported and measured at fair value through earnings. See Note 7 for more information. Derivatives in Designated Accounting Hedge We apply hedge accounting to certain derivatives executed for risk management purposes, primarily interest rate risk. To qualify for hedge accounting, a derivative must be highly effective at reducing the risk associated with the exposure being hedged and the hedging relationship must be formally documented. We primarily use regression analysis to assess the effectiveness of each hedging relationship, unless the hedge qualifies for other methods of assessing effectiveness (e.g., shortcut or critical terms match), both at inception and on an ongoing basis. We designate derivatives as fair value and cash flow hedges for accounting purposes and these hedges can be a significant aspect of our overall interest risk sensitivity management. We may add additional hedging strategies and apply hedge accounting to the strategies as it deems necessary. See Note 7 for more information regarding the accounting for derivatives designated as hedging instruments. Commitments and Letters of Credit In the ordinary course of business, we enter into commitments to extend credit, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded in the financial statements when they become payable. The credit risk associated with these commitments is evaluated in a manner similar to the ALLL. The RULC is presented separately in the balance sheet. Revenue Recognition Service charges and fees on deposit accounts are recognized in accordance with published deposit account agreements for customer accounts or contractual agreements for commercial accounts. Other service charges, commissions, and fees include interchange fees, bank services, and other fees, which are generally recognized at the time of transaction or as the services are performed. Share-based Compensation Share-based compensation generally includes grants of stock options, restricted stock, restricted stock units (“RSUs”), and other awards to employees and nonemployee directors. We recognize compensation expense in the statement of income based on the grant-date value of the associated share-based awards. See further discussion in Note 19. Income Taxes Deferred tax assets (“DTAs”) and liabilities (“DTLs”) are determined based on temporary differences between financial statement asset and liability amounts and their respective tax basis and are measured using enacted tax laws and rates. The effect on DTAs and DTLs of a change in tax rates is recognized in income in the period that includes the enactment date. DTAs are recognized subject to management’s judgment that realization is more likely than not. Unrecognized tax benefits for uncertain tax positions relate primarily to tax credits on technology initiatives. See further discussion in Note 20. Net Earnings Per Common Share Net earnings per common share is based on net earnings applicable to common shareholders, which is net of preferred stock dividends. Basic net earnings per common share is based on the weighted average outstanding common shares during each year. Unvested share-based awards with rights to receive nonforfeitable dividends are considered participating securities and included in the computation of basic earnings per share. Diluted net earnings per common share is based on the weighted average outstanding common shares during each year, including common stock equivalents. Stock options, restricted stock, RSUs, and stock warrants are converted to common stock equivalents using the more dilutive of the treasury stock method or the two-class method. Diluted net earnings per common share excludes common stock equivalents whose effect is antidilutive. See further discussion in Note 21.

Zions Bancorporation, National Association and its subsidiaries (collectively “Zions Bancorporation, N.A.,” “the Bank,” “we,” “our,” “us”) together comprise a bank headquartered in Salt Lake City, Utah. We provide a wide range of banking products and related services in 11 Western and Southwestern states through seven separately managed affiliates, as follows: Zions Bank in Utah, Idaho and Wyoming; California Bank & Trust (“CB&T”); Amegy Bank (“Amegy”) in Texas; National Bank of Arizona (“NBAZ”); Nevada State Bank (“NSB”); Vectra Bank Colorado (“Vectra”) in Colorado and New Mexico; and The Commerce Bank of Washington (“TCBW”) which operates under that name in Washington and under The Commerce Bank of Oregon (“TCBO”) in Oregon.

The consolidated financial statements include our accounts and those of our majority-owned, consolidated subsidiaries. Unconsolidated investments where we have the ability to exercise significant influence over the operating and financial policies of the respective investee are accounted for using the equity method of accounting. All significant intercompany accounts and transactions have been eliminated in consolidation. Assets held in an agency or fiduciary capacity are not included in the Consolidated Financial Statements.

The consolidated financial statements have been prepared in accordance with United States (“U.S.”) generally accepted accounting principles (“GAAP”) and prevailing practices within the financial services industry. References to GAAP, including standards promulgated by the Financial Accounting Standards Board (“FASB”), are made according to sections of the Accounting Standards Codification (“ASC”). Changes to the ASC are made with Accounting Standards Updates (“ASU”) that include consensus issues of the Emerging Issues Task Force. In certain cases, ASUs are issued jointly with International Financial Reporting Standards.

In preparing the consolidated financial statements, we are required to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Certain prior year amounts have been reclassified to conform with the current year presentation. These reclassifications did not affect net income or shareholders’ equity.

A variable interest entity (“VIE”) is consolidated when a company is the primary beneficiary of the VIE. Current accounting guidance requires continuous analysis on a qualitative rather than a quantitative basis to determine the primary beneficiary of a VIE. At the commencement of our involvement, and periodically thereafter, we consider our consolidation conclusions for all entities with which we are involved. As of December 31, 2020, and 2019, we have no VIEs that have been consolidated in our financial statements.

We measure many of our assets and liabilities on a fair value basis. Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. To improve consistency and comparability in fair value measurements, GAAP has established a hierarchy to prioritize the valuation inputs among three levels. We prioritize quoted prices in active markets and minimize reliance on unobservable inputs when possible. When observable market prices are not available, fair value is estimated using modeling techniques such as discounted cash flow analysis. These modeling techniques use assumptions that market

participants would consider in pricing the asset or the liability — including assumptions about the risk inherent in a particular valuation technique — the effect of a restriction on the sale or use of an asset, the life of the asset and applicable growth rate, the risk of nonperformance, and other related assumptions. Changes in market conditions may reduce the availability of quoted prices or observable data. When market data is not available, we use valuation techniques requiring professional judgment to estimate the appropriate fair value. See Note 3 of the “Notes to Consolidated Financial Statements” for further information regarding the use of fair value estimates.

Security resell agreements represent overnight and term agreements with the majority maturing within 30 days. Due to increased cash reserves and in order to increase yield, we have extended the maturity of some security resell agreements beyond 30 days. As of December 31, 2020, 28% of all security resell agreements have a maturity beyond 30 days but none greater than 50 days. These agreements are generally treated as collateralized financing transactions and are carried at amounts at which the securities were acquired plus accrued interest. Either we, or in some instances third-parties on our behalf, take possession of the underlying securities. The fair value of such securities is monitored throughout the contract term to ensure that asset values remain sufficient to protect against counterparty default. We are permitted by contract to sell or repledge certain securities that we accept as collateral for security resell agreements. If sold, our obligation to return the collateral is recorded as “securities sold, not yet purchased” and included as a liability in “Federal funds and other short-term borrowings.” At December 31, 2020, we held $5.7 billion of securities for which we were permitted by contract to sell or repledge. Security resell agreements averaged $2.1 billion during 2020, and the maximum amount outstanding at any month-end during 2020 was $6.4 billion.

Held-to-maturity (“HTM”) debt securities are carried at amortized cost with purchase discounts or premiums accreted or amortized into interest income over the contractual life of the security. We have the intent and ability to hold such securities until maturity. For HTM securities, the ACL is assessed consistent with the approach described in Note 6 for loans carried at amortized cost.

Available-for-sale (“AFS”) securities are stated at fair value and generally consist of debt securities held for investment. Unrealized gains and losses of AFS securities, after applicable taxes, are recorded as a component of other comprehensive income (“OCI”). AFS securities in an unrealized loss position are formally reviewed on a quarterly basis for the presence of impairment. If we have an intent to sell an identified security, or it is more likely than not we will be required to sell the security before recovery of its amortized cost basis, then we recognize an impairment equal to any existing allowance written off against the security. If we do not have the intent to sell a security, and it is more likely than not that we will not be required to sell a security prior to recovery of its amortized cost basis, then we determine whether there is any impairment attributable to credit-related factors. The process, methodology, and factors considered to evaluate securities for impairment are described further in Note 5.

As a lessee, when we enter a lease contract, we classify and account for the lease as either a finance lease or an operating lease, depending on the terms and conditions of the lease. A finance lease is recorded as an asset and a liability, and the asset is generally depreciated over the lease term. The lease liability is reduced as lease payments are made. An operating lease is recorded as a right-of-use (“ROU”) asset and operating lease liability. These balance sheet items are reduced as lease payments are made. Lease payments are expensed over the lease term; they

Loans are reported at the principal amount outstanding, net of unearned income, unamortized purchase premiums and discounts, and net deferred loan fees and costs, which are amortized to interest income over the life of the loan using the interest method. Interest income is recognized on an accrual basis.

At the time of origination, we determine whether loans will be held for investment or held for sale. We may subsequently change our intent to hold loans for investment and reclassify them as held for sale. Loans held for sale are carried at the lower of aggregate cost or fair value. A valuation allowance is recorded when cost exceeds fair value based on reviews at the time of reclassification and periodically thereafter. Gains and losses are recorded in noninterest income based on the difference between sales proceeds and carrying value.

We evaluate loans throughout their lives for signs of credit deterioration, which may impact the loan’s status, and potentially impact our accounting for that loan. Loan status categories include past due as to contractual payments, nonaccrual, and restructured, including troubled debt restructurings (“TDRs”). Our accounting policies for these loan statuses and our estimation of the related allowance for loan and lease losses (“ALLL”) are described further in Note 6.

In the ordinary course of business, we transfer portions of loans under participation agreements to manage credit risk and our portfolio concentration. We evaluate the loan participations to determine if they meet the appropriate accounting guidance to qualify as sales. Certain purchased loans require separate accounting procedures that are also described in Note 6.

The allowance for credit losses (“ACL”) includes the ALLL and the reserve for unfunded lending commitments (“RULC”). For periods prior to 2020, the ALLL represented management’s estimate of probable losses believed to be inherent in the loan portfolio at that time, and the RULC was estimated using the same procedures and methodologies as for the ALLL, in addition to assumptions regarding the probability and amount of unfunded commitments being drawn.

On January 1, 2020, we adopted ASU 2016-13, Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, and its subsequent updates, often referred to as the Current Expected Credit Loss (“CECL”) model. CECL changes how the ACL is measured for loans and for additional financial assets, including HTM securities. Under CECL, the ACL will represent our estimate of current expected credit losses over the contractual term of the loan and lease portfolio and unfunded lending commitments as of the balance sheet date. The ACL for debt securities is estimated separately from loans. Further discussion of our estimation process for the ACL is included in Note 6.

These investments include investments in private equity funds — referred to in this document as private equity investments (“PEIs”) — venture capital securities, securities acquired for various debt and regulatory requirements, bank-owned life insurance (“BOLI”), and certain other noninterest-bearing investments. See further discussion in Note 3.

Certain PEIs and venture capital securities are accounted for under the equity method and some are reported at fair value. Changes in fair value and gains and losses from sales are recognized in noninterest income. The values assigned to the securities where no market quotations exist are based upon available information and may not

Other PEIs, and those acquired for various debt and regulatory requirements, are accounted for at cost less impairment (if any), plus or minus observable price changes from an identical or similar investment of the same issuer, with such changes recognized in income. Periodic reviews are conducted for impairment by comparing carrying values with estimates of fair value determined according to the previous discussion.

Premises, equipment, and software are stated at cost, net of accumulated depreciation and amortization. Depreciation, computed primarily on the straight-line method, is charged to operations over the estimated useful lives of the properties, generally 25 to 40 years for buildings, three to 10 years for furniture and equipment, and three to 10 years for software, including capitalized costs related to our technology initiatives. Leasehold improvements are amortized over the terms of the respective leases or the estimated useful lives of the improvements (including any extension options that are reasonably certain to be exercised), whichever is shorter. Premises, equipment and software are evaluated for impairment on a periodic basis.

Business combinations are accounted for under the acquisition method of accounting. Upon initially obtaining control, we recognize 100% of all acquired assets and all assumed liabilities, regardless of the percentage owned. The assets and liabilities are recorded at their estimated fair values, with goodwill being recorded when such fair values are less than the cost of acquisition. Certain transaction and restructuring costs are expensed as incurred. Changes to estimated fair values from a business combination are recognized as an adjustment to goodwill over the measurement period, which cannot exceed one year from the acquisition date. Results of operations of the acquired business are included in our statement of income from the date of acquisition.

Other real estate owned (“OREO”) consists principally of commercial and residential real estate obtained in partial or total satisfaction of loan obligations. Amounts are recorded initially at fair value (less any selling costs) based on property appraisals at the time of transfer and subsequently at the lower of cost or fair value (less any selling costs).

We use derivative instruments — including interest rate swaps and purchased and sold options such as floors and basis swaps—as part of our overall interest rate risk management strategy. Derivatives are an important tool used in managing our overall asset and liability sensitivities to remain within management’s stated interest rate risk thresholds. Their use allows us to adjust and align our naturally occurring mix of fixed and floating-rate assets and liabilities to manage interest income volatility by synthetically converting variable-rate assets to fixed-rate, or synthetically converting fixed-rate funding instruments to floating-rates.

We also execute both interest rate and short-term foreign currency derivative instruments with our commercial banking customers to facilitate their risk management strategies. These derivatives are immediately hedged by offsetting derivatives with third-parties such that we minimize our net risk exposure as a result of such transactions. We record all derivatives at fair value in the balance sheet as either other assets or other liabilities. The accounting for the change in value of a derivative depends on whether or not the transaction has been designated and qualifies

We apply hedge accounting to certain derivatives executed for risk management purposes, primarily interest rate risk. To qualify for hedge accounting, a derivative must be highly effective at reducing the risk associated with the exposure being hedged and the hedging relationship must be formally documented. We primarily use regression analysis to assess the effectiveness of each hedging relationship, unless the hedge qualifies for other methods of assessing effectiveness (e.g., shortcut or critical terms match), both at inception and on an ongoing basis. We designate derivatives as fair value and cash flow hedges for accounting purposes and these hedges can be a significant aspect of our overall interest risk sensitivity management. We may add additional hedging strategies and apply hedge accounting to the strategies as it deems necessary. See Note 7 for more information regarding the accounting for derivatives designated as hedging instruments.

In the ordinary course of business, we enter into commitments to extend credit, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded in the financial statements when they become payable. The credit risk associated with these commitments is evaluated in a manner similar to the ALLL. The RULC is presented separately in the balance sheet.

Service charges and fees on deposit accounts are recognized in accordance with published deposit account agreements for customer accounts or contractual agreements for commercial accounts. Other service charges, commissions, and fees include interchange fees, bank services, and other fees, which are generally recognized at the time of transaction or as the services are performed.

Share-based compensation generally includes grants of stock options, restricted stock, restricted stock units (“RSUs”), and other awards to employees and nonemployee directors. We recognize compensation expense in the statement of income based on the grant-date value of the associated share-based awards. See further discussion in Note 19.

Deferred tax assets (“DTAs”) and liabilities (“DTLs”) are determined based on temporary differences between financial statement asset and liability amounts and their respective tax basis and are measured using enacted tax laws and rates. The effect on DTAs and DTLs of a change in tax rates is recognized in income in the period that includes the enactment date. DTAs are recognized subject to management’s judgment that realization is more likely than not. Unrecognized tax benefits for uncertain tax positions relate primarily to tax credits on technology initiatives. See further discussion in Note 20.

Net earnings per common share is based on net earnings applicable to common shareholders, which is net of preferred stock dividends. Basic net earnings per common share is based on the weighted average outstanding common shares during each year. Unvested share-based awards with rights to receive nonforfeitable dividends are considered participating securities and included in the computation of basic earnings per share. Diluted net earnings per common share is based on the weighted average outstanding common shares during each year, including common stock equivalents. Stock options, restricted stock, RSUs, and stock warrants are converted to common stock equivalents using the more dilutive of the treasury stock method or the two-class method. Diluted net earnings per common share excludes common stock equivalents whose effect is antidilutive. See further discussion in Note 21.