Although our management uses these non-GAAP financial measures for operational decision making and considers these financial measures to be useful for analysts and investors, we recognize that there are a number of limitations related to such measures. In particular, it should be noted that several of these measures exclude some costs, particularly share-based compensation, that are recurring. In addition, the components of the costs that we exclude in our calculation of the measures described above may differ from the components that our peer companies exclude when they report their results of operations.
Below, we describe why we make particular adjustments to certain US GAAP financial measures:
We believe that it may be useful for investors and analysts to review certain measures both in accordance with US GAAP and net of the effect of TAC, which we view as comparable to sales commissions but, unlike sales commissions, are not deducted from US GAAP revenues. By presenting revenue, adjusted EBITDA margin and adjusted net income margin net of TAC, we believe that investors and analysts are able to obtain a clearer picture of our business without the impact of the revenues we share with our partners.
SBC is a significant expense item, and an important part of our compensation and incentive programs. As it is a non-cash charge, however, and highly dependent on our share price at the time of equity award grants, we believe that it is useful for investors and analysts to see certain financial measures excluding the impact of these charges in order to obtain a clear picture of our operating performance.
We may incur expenses in connection with acquisitions that are not indicative of our recurring core operating performance. In particular, we are required under US GAAP to accrue as expense the contingent compensation that may be payable to certain employees in connection with our acquisition of the mobile software business of SPB Software in November 2011. The maximum aggregate amount of such contingent compensation is $14.1 million, payable on the achievement of certain milestones and the continued employment of the sellers, $7.1 million of which was paid in November 2012 and $4.1 million of which was paid in February 2013; the remaining $2.9 million is payable in November 2013 upon the satisfaction of defined milestones. We have eliminated this acquisition-related expense from adjusted EBITDA and adjusted net income to provide management and investors a tool for comparing on a period-to-period basis our operating performance in the ordinary course of operations.