Our Consolidated Financial Statements include all of our wholly owned subsidiaries. Intercompany balances and transactions have been eliminated in consolidation. J.B. Hunt Transport Services, Inc. is a parent-level holding company with no significant assets or operations. J.B. Hunt Transport, Inc. is a wholly owned subsidiary of J.B. Hunt Transport Services, Inc. and is the primary operating subsidiary. All other subsidiaries of J.B. Hunt Transport Services, Inc. are minor.

The Consolidated Financial Statements contained in this report have been prepared in conformity with accounting principles generally accepted in the United States of America. The preparation of these statements requires us to make estimates and assumptions that directly affect the amounts reported in such statements and accompanying notes. We evaluate these estimates on an ongoing basis utilizing historical experience, consulting with experts and using other methods we consider reasonable in the particular circumstances. Nevertheless, our actual results may differ significantly from our estimates.

We believe certain accounting policies and estimates are of more significance in our financial statement preparation process than others. We believe the most critical accounting policies and estimates include the economic useful lives and salvage values of our assets, provisions for uncollectible accounts receivable, estimates of exposures under our insurance and claims policies, and estimates for taxes. To the extent that actual, final outcomes are different from our estimates, or that additional facts and circumstances cause us to revise our estimates, our earnings during that accounting period will be affected.

Our trade accounts receivable includes accounts receivable reduced by an allowance for uncollectible accounts and revenue adjustments. Receivables are recorded at amounts billed to customers when loads are delivered or services are performed. The allowance for uncollectible accounts and revenue adjustments is based on historical experience, as well as any known trends or uncertainties related to customer billing and account collectability. The adequacy of our allowance is reviewed quarterly. Balances are charged against the allowance when it is determined the receivable will not be recovered. The allowance for uncollectible accounts and revenue adjustments was $6.6 million and $6.7 million at December 31, 2012 and 2011, respectively.

Our investments consist of marketable equity securities stated at fair value and are designated as either trading securities or available-for-sale securities at the time of purchase based upon the intended holding period. Changes in the fair value of our trading securities are recognized currently in “general and administrative expenses, net of asset dispositions” in our Consolidated Statements of Earnings. Changes in the fair value of our available-for-sale securities are recognized in “accumulated other comprehensive income” on our Consolidated Balance Sheets, unless we determine that an unrealized loss is other-than-temporary. If we determine that an unrealized loss is other-than-temporary, we recognize the loss in earnings. Cost basis is determined using average cost.

Depreciation of property and equipment is calculated on the straight-line method over the estimated useful lives of 4 to 10 years for tractors and 7 to 20 years for trailing equipment, 10 to 40 years for structures and improvements, and 3 to 10 years for furniture and office equipment. Salvage values are typically 10% to 30% of original cost for tractors and trailing equipment and reflect any agreements with tractor suppliers for residual or trade-in values for certain new equipment. We capitalize tires placed in service on new revenue equipment as a part of the equipment cost. Replacement tires and costs for recapping tires are expensed at the time the tires are placed in service. Gains and losses on the sale or other disposition of equipment are recognized at the time of the disposition and are classified in general and administrative expenses, net of asset dispositions.

We recognize revenue based on relative transit time in each reporting period and as other services are provided, with expenses recognized as incurred. Accordingly, a portion of the total revenue that will be billed to the customer once a load is delivered is recognized in each reporting period based on the percentage of the freight pickup and delivery service that has been completed at the end of the reporting period.

We record revenues on the gross basis at amounts charged to our customers because we are the primary obligor, we are a principal in the transaction, we invoice our customers and retain all credit risks, and we maintain discretion over pricing. Additionally, we are responsible for selection of third-party transportation providers to the extent used to satisfy customer freight requirements.

We periodically utilize derivative instruments to manage exposure to changes in interest rates. At inception of a derivative contract, we document relationships between derivative instruments and hedged items, as well as our risk-management objective and strategy for undertaking various derivative transactions, and assess hedge effectiveness. If it is determined that a derivative is not highly effective as a hedge, or if a derivative ceases to be a highly effective hedge, we discontinue hedge accounting prospectively. We had no derivative instruments in place at December 31, 2012 and 2011.

Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as income or expense in the period that includes the enactment date.

We compute basic earnings per share by dividing net earnings available to common stockholders by the actual weighted average number of common shares outstanding for the reporting period. Diluted earnings per share reflect the potential dilution that could occur if holders of unvested restricted and performance share units or options exercised or converted their holdings into common stock. Outstanding unvested restricted share units and stock options represent the dilutive effects on weighted average shares. A reconciliation of the number of shares used in computing basic and diluted earnings per share is shown below (in thousands):

Financial instruments, which potentially subject us to concentrations of credit risk, include trade receivables. For the years ended December 31, 2012, 2011 and 2010, our top 10 customers, based on revenue, accounted for approximately 30%, 32% and 34%, respectively, of our total revenue. Our top 10 customers, based on revenue, accounted for approximately 26% and 27% of our total trade accounts receivable at December 31, 2012 and 2011, respectively. We had no individual customers with revenues greater than 10% of total revenues.

We have share-based compensation plans covering certain employees, including officers and directors. We account for share-based compensation utilizing the fair value recognition provisions of current accounting standards for share-based payments. We currently utilize restricted share units, performance share units and nonstatutory stock options. Issuances of our stock upon restricted share unit and performance share unit vesting or share option exercise are made from treasury stock. Our restricted share unit and performance share unit awards may include both graded-vesting and cliff-vesting awards and therefore vest in increments during the requisite service period or at the end of the requisite service period, as appropriate for each type of vesting. We recognize compensation expense on a straight-line basis over the requisite service periods within each award.

We continually evaluate the carrying value of our assets for events or changes in circumstances that indicate the carrying value may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of an asset to future net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less cost to sell.

We purchase insurance coverage for a portion of expenses related to employee injuries, vehicular collisions, accidents and cargo damage. We are substantially self-insured for loss of and damage to our owned and leased revenue equipment. Certain insurance arrangements include a level of self-insurance (deductible) coverage applicable to each claim. We have umbrella policies to limit our exposure to catastrophic claim costs that are completely insured.

The amounts of self-insurance change from time to time based on measurement dates, policy expiration dates and claim type. For 2010 through 2012, we were self-insured for $500,000 per occurrence for personal injury and property damage and fully insured for substantially all workers’ compensation claims. We have policies in place for 2013 with substantially the same terms as our 2012 policies for personal injury, workers’ compensation, cargo and property damage, with the exception of adding a $100,000 deductible per claim for workers’ compensation.

Our claims accrual policy for all self-insured claims is to recognize a liability at the time of the incident based on our analysis of the nature and severity of the claims and analyses provided by third-party claims administrators, as well as legal, economic and regulatory factors. Our safety and claims personnel work directly with representatives from the insurance companies to continually update the estimated cost of each claim. The ultimate cost of a claim develops over time as additional information regarding the nature, timing and extent of damages claimed becomes available. Accordingly, we use an actuarial method to develop current claim information to derive an estimate of our ultimate claim liability. This process involves the use of loss-development factors based on our historical claims experience and includes a contractual premium adjustment factor, if applicable. In doing so, the recorded liability considers future claims growth and, if applicable, conversion to fully insured status and provides an allowance for incurred-but-not-reported claims. We do not discount our estimated losses. At December 31, 2012 and 2011, we had an accrual of approximately $38 million and $34 million, respectively, for estimated net claims. In addition, we are required to pay certain advanced deposits and monthly premiums. At December 31, 2012 and 2011, we had a prepaid insurance asset of approximately $35 million and $38 million, respectively, which represented prefunded claims and premiums.