from actual results. This may require us to revise our initial estimates which may materially affect our results of operations and financial position in the period the revision is made.

For a given acquisition, we may identify certain pre-acquisition contingencies as of the acquisition date and may extend our review and evaluation of these pre-acquisition contingencies throughout the measurement period (up to one year from the acquisition date) in order to obtain sufficient information to assess whether we include these contingencies as a part of the purchase price allocation and, if so, to determine their estimated amounts.

If we determine that a pre-acquisition contingency (non-income tax related) is probable in nature and estimable as of the acquisition date, we record our best estimate for such a contingency as a part of the preliminary purchase price allocation. We often continue to gather information for and evaluate our pre-acquisition contingencies throughout the measurement period and if we make changes to the amounts recorded or if we identify additional pre-acquisition contingencies during the measurement period, such amounts will be included in the purchase price allocation during the measurement period and, subsequently, in our results of operations.

In addition, uncertain tax positions and tax related valuation allowances assumed in connection with a business combination are initially estimated as of the acquisition date and we reevaluate these items quarterly with any adjustments to our preliminary estimates being recorded to goodwill provided that we are within the measurement period and we continue to collect information in order to determine their estimated values. Subsequent to the measurement period or our final determination of the uncertain tax positions estimated value or tax related valuation allowances, changes to these uncertain tax positions’ and tax related valuation allowances will affect our provision for income taxes in our consolidated statement of operations and could have a material impact on our results of operations and financial position.

Goodwill and Intangible Assets—Impairment Assessments

We review goodwill for impairment annually and whenever events or changes in circumstances indicate its carrying value may not be recoverable in accordance with ASC 350, Intangibles—Goodwill and Other . The provisions of ASC 350 require that a two-step impairment test be performed on goodwill. In the first step, we compare the fair value of each reporting unit to its carrying value. Our reporting units are consistent with the reportable segments identified in Note16 of Notes to Consolidated Financial Statements. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, goodwill is not considered impaired and we are not required to perform further testing. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then we must perform the second step of the impairment test in order to determine the implied fair value of the reporting unit’s goodwill. If the carrying value of a reporting unit’s goodwill