Notes to Condensed Consolidated Financial Statements (Unaudited)

Note 1 - Basis of Presentation of Interim Period Statements

The accompanying condensed consolidated financial statements are unaudited and have been prepared by Barrett Business Services, Inc. (“BBSI”, the “Company”, “our” or “we”), pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and note disclosures typically included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, the condensed consolidated financial statements include all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of the results for the interim periods presented. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results may differ from such estimates and assumptions. The condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s 2015 Annual Report on Form 10-K at pages F1 – F62. The results of operations for an interim period are not necessarily indicative of the results of operations for a full year.

Revenue recognition

We recognize professional employer (PEO) service and staffing service revenue as services are rendered by our workforce. PEO services are normally used by organizations to satisfy ongoing needs related to the management of human capital and are governed by the terms of a client services agreement which covers all employees at a particular work site. Our client services agreements have a minimum term of one year, are renewable on an annual basis and typically require 30 days’ written notice to cancel or terminate the contract by either party. In addition, our client services agreements provide for immediate termination upon any default of the client regardless of when notice is given.

We report PEO revenues on a net basis because we are not the primary obligor for the services provided by our clients to their customers pursuant to our client services agreements. We reduce these service fee revenues by the amounts invoiced to our clients for direct payroll expenses such as salaries, wages, health insurance, employee out-of-pocket expenses incurred incidental to employment, and safety incentives. Safety incentives represent cash incentives paid to certain client companies for maintaining safe-work practices and minimizing workplace injuries. The safety incentive is based on a percentage of annual payroll and is paid annually to clients who meet predetermined workers’ compensation claims cost objectives.

Cost of revenues

Our cost of revenues for staffing services includes direct payroll costs, employer payroll related taxes, employee benefits, and workers’ compensation costs. Our cost of revenues for PEO services includes only employer payroll related taxes and workers’ compensation costs. Direct payroll costs represent the gross payroll earned by staffing services employees based on salary or hourly wages. Payroll taxes and employee benefits consist of the employer’s portion of Social Security and Medicare taxes, federal and state unemployment taxes, and staffing services employee reimbursements for materials, supplies and other expenses, which are paid by our customer. Workers’ compensation costs consist primarily

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Note 1 - Basis of Presentation of Interim Period Statements (Continued)

of the costs associated with our workers’ compensation program, including claims reserves, claims administration fees, legal fees, medical cost containment (MCC) expense, state administrative agency fees, third-party broker commissions, risk manager payroll, and excess insurance premiums for catastrophic injuries. We maintain separate workers’ compensation insurance policies for employees working in states where the Company is not self-insured, including California.

Cash and cash equivalents

We consider non-restricted short-term investments, which are highly liquid, readily convertible into cash, and have maturities at acquisition of less than three months, to be cash equivalents for purposes of the consolidated statements of cash flows. A substantial portion of the Company’s cash and cash equivalents is invested in tax-exempt money market funds managed by the Company’s principal bank. The Company maintains cash balances in bank accounts that normally exceed FDIC insured limits. The Company has not experienced any losses related to its cash concentration.

Marketable securities

As of June 30, 2016, the Company’s marketable securities consisted of municipal bonds, corporate bonds, and money market funds. We classify our marketable securities as trading or available-for-sale. The Company had no trading marketable securities at June 30, 2016 and December 31, 2015. The Company classifies money market funds, municipal bonds, and corporate bonds as available for sale. They are reported at fair value with unrealized gains and losses, net of taxes, shown as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Management considers available evidence in evaluating potential impairment of investments, including the duration and extent to which fair value is less than cost and the Company’s ability and intent to hold the investments. Realized gains and losses on sales of restricted marketable securities are included in other income (expense) as other, net in our condensed consolidated statements of operations. In the event a loss is determined to be other-than-temporary, the loss will be recognized in the condensed consolidated statements of operations.

Restricted marketable securities

At June 30, 2016, restricted marketable securities consisted of money market funds, certificates of deposit, U.S. Treasuries, corporate bonds, and municipal bonds with maturities generally from 180 days to two years. At June 30, 2016, the approximate fair value of restricted marketable securities equaled their approximate amortized cost. Restricted marketable securities have been categorized as available-for-sale. They are reported at fair value with unrealized gains and losses, net of taxes, shown as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Realized gains and losses on sales of restricted marketable securities are included in other income (expense) as other, net in our condensed consolidated statements of operations. In the event a loss is determined to be other-than-temporary, the loss will be recognized in the condensed consolidated statements of operations.

Allowance for doubtful accounts

The Company had an allowance for doubtful accounts of $258,000 and $268,000 at June 30, 2016 and December 31, 2015, respectively. We make estimates of the collectability of our accounts receivable for services provided to our customers. Management analyzes historical bad debts, customer concentrations, customer credit-worthiness, current economic trends and changes in customers’ payment trends when evaluating the adequacy of the allowance for doubtful accounts. If the financial condition of our customers deteriorates, resulting in an impairment of their ability to make payments, additional allowances may be required.

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Note 1 - Basis of Presentation of Interim Period Statements (Continued)

Workers’ compensation claims liabilities

Our workers’ compensation claims liabilities do not represent an exact calculation of liability but rather management’s best estimate, utilizing actuarial expertise and projection techniques, at a given reporting date. The estimated liability for open workers’ compensation claims is based on an evaluation of information provided by our internal claims adjusters and our third-party administrators for workers’ compensation claims, coupled with an actuarial estimate of future adverse cost development with respect to reported claims and incurred but not reported claims (together, IBNR). At June 30, 2016 and December 31, 2015, workers’ compensation claims liabilities included case reserve estimates for reported losses, plus additional amounts for estimated future adverse cost development of IBNR claims, MCC and legal costs, and unallocated loss adjustment expenses, including future administrative fees to be paid to third-party service providers. These estimates are reviewed at least quarterly and adjustments to estimated liabilities are reflected in current operating results as they become known.

The process of arriving at an estimate of unpaid claims and claims adjustment expense involves a high degree of judgment and is affected by both internal and external events, including changes in claims handling practices, changes in reserve estimation procedures, changes in individuals involved in the reserve estimation process, inflation, trends in the litigation and settlement of pending claims, and legislative changes.

Our estimates are based on informed judgment, derived from individual experience and expertise applied to multiple sets of data and analyses. We consider significant facts and circumstances known both at the time that loss reserves are initially established and as new facts and circumstances become known. Due to the inherent uncertainty underlying loss reserve estimates, the expenses incurred through final resolution of our liability for our workers’ compensation claims will likely vary from the related loss reserves at the reporting date. Therefore, as specific claims are paid out in the future, actual paid losses may be materially different from our current loss reserves.

The Company’s independent actuary provides management with an estimate of the current and long-term portions of our total workers’ compensation claims, which is an important factor in our process for estimating workers’ compensation claims liabilities. The current portion represents the independent actuary’s best estimate of payments the Company will make related to workers’ compensation claims over the ensuing twelve months. The Company will also pay out a portion of claims first incurred in the ensuing twelve months during that twelve-month period. The long-term portion represents the independent actuary’s best estimate of payments the Company will make related to workers’ compensation claims more than twelve months in the future.

A basic premise in most actuarial analyses is that historical data and past patterns demonstrated in the incurred and paid historical data form a reasonable basis upon which to project future outcomes, absent a material change. Significant structural changes to the available data can materially impact the reserve estimation process. To the extent a material change affecting the ultimate claim liability becomes known, such change is quantified to the extent possible through an analysis of internal Company data and, if available and when appropriate, external data. Nonetheless, actuaries exercise a considerable degree of judgment in the evaluation of these factors and the need for such actuarial judgment is more pronounced when faced with material uncertainties.

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Note 1 - Basis of Presentation of Interim Period Statements (Continued)

During the three months ended June 30, 2016, the Company reached an agreement to pay its third-party provider of MCC services $9.5 million for all MCC fees on workers’ compensation claims with dates of injury between January 1, 2016 and December 31, 2016. Under this agreement, the Company will make payments for these services totaling $593,250 each quarter starting April 1, 2016 and continuing through January 1, 2020. The agreement limits the maximum amount of claims and services to be provided.

Safety incentives liability

Safety incentives represent cash incentives paid to certain PEO client companies for maintaining safe-work practices and minimizing workplace injuries. The incentive is based on a percentage of annual payroll and is paid annually to customers who meet predetermined workers’ compensation claims cost objectives. Safety incentive payments are made only after closure of all workers’ compensation claims incurred during the customer’s contract period. The safety incentive liability is estimated and accrued each month based upon contract year-to-date payroll and the then current amount of the customer’s estimated workers’ compensation claims reserves as established by us and our third-party administrator and the expected payout as determined by historical incentive payment trends. The Company provided $24.3 million and $21.3 million at June 30, 2016 and December 31, 2015, respectively, as an estimate of the liability for unpaid safety incentives. Safety incentive costs are netted against PEO service revenue in our condensed consolidated statements of operations.

Statements of cash flows

Interest paid during the six months ended June 30, 2016 and 2015 did not materially differ from interest expense. Income taxes received during the six months ended June 30, 2016 and 2015 totaled $1.2 million and $1.1 million, respectively.

Basic and diluted earnings per share

Basic earnings per share are computed based on the weighted average number of common shares outstanding for each year using the treasury method. Diluted earnings per share reflect the potential effects of the exercise of outstanding stock options. Basic and diluted shares outstanding are summarized as follows (in thousands):

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Note 1 - Basis of Presentation of Interim Period Statements (Continued)

Accounting estimates

The preparation of our condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Estimates are used for fair value measurement of all marketable securities, allowance for doubtful accounts, deferred income taxes, carrying values for goodwill and property and equipment, accrued workers’ compensation liabilities and safety incentive liabilities. Actual results may differ from such estimates.

Recent accounting pronouncements

In May 2014, FASB issued ASU No. 2014-09 which provides for a single, principles-based model for revenue recognition that will replace most existing revenue recognition guidance under U.S. GAAP when it becomes effective. The standard permits the use of either the retrospective or cumulative effect transition method. In March and April 2016, the FASB issued ASU 2016-08 Principal versus Agent Considerations (Reporting Revenue Gross versus Net), ASU 2016-10 Identifying Performance Obligations and Licensing, ASU 2016-11 Revenue Recognition and Derivatives and Hedging: Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting, and ASU 2016-12 Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients, which all provide further clarification to be considered when implementing ASU 2014-09. The Company has not yet selected a transition method or determined the effect of the standard on its ongoing financial reporting.

In August 2015, the FASB issued ASU 2015-14 which defers the effective date of ASU 2014-09 by one year. ASU 2014-09 is discussed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. The new guidance is effective for interim and annual reporting periods beginning after December 15, 2017. Early adoption is permitted as of the date of the original effective date, for interim and annual reporting periods beginning after December 15, 2016. The Company is currently evaluating the provisions of ASU 2015-14 and ASU 2014-09.

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Note 2 - Restatement of Previously Issued Condensed Consolidated Financial Statements

On May 25, 2016, the Company filed its Form 10-K for 2015 which included annual consolidated financial statements for the year ended December 31, 2015. Included within the 2015 Form 10-K were the restated consolidated financial statements for the years ended December 31, 2014 and 2013 and related quarters, as well as the quarterly periods ended March 31, 2015 and June 30, 2015.

The following schedules reflect the previously reported and restated financial information as of and for the three and six months ended June 30, 2015.

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