We report our financial results in accordance with U.S. GAAP. However, management believes that, in order to more fully understand our short-term and long-term financial and operational trends, investors may wish to consider the impact of certain items resulting from our recent acquisition of e2v and U.S. tax reform which have an infrequent or non-recurring impact on operations. Accordingly, we present non-GAAP financial measures as a supplement to the financial measures we present in accordance with GAAP. These non-GAAP financial measures provide management with additional means to understand and evaluate the operating results and trends in our ongoing business by adjusting for certain expenses and other items. Management believes these non-GAAP financial measures provide additional means of evaluating period-over-period operating performance. In addition, management understands that some investors and financial analysts find this information helpful in analyzing our financial and operational performance and comparing this performance to our peers and competitors.

We use the term “adjusted operating income” to refer to GAAP operating income excluding items related to the e2v business acquisition and integration such as expense related to inventory fair value step-up amortization, transaction and integration expenses such as advisory, legal, financial and other fees, stamp duty and other costs. We use the related term “adjusted operating margin” to refer to adjusted operating income as a percentage of revenue.

We use the term “adjusted fully diluted earnings per share” and “adjusted earnings” to refer to GAAP earnings per share excluding items related to the e2v business acquisition and integration such as expense related to inventory fair value step-up amortization, transaction and integration expenses such as advisory, legal, financial and other costs, stamp duty, foreign currency option contract to hedge the e2v purchase price, funds-certain bank bridge facility commitment expense and other costs. We also adjust for any tax impact related to the above items.

Furthermore, for 2017, “adjusted fully diluted earnings per share”, “adjusted earnings” and “adjusted EPS” exclude charges in the fourth quarter of 2017 as a result of the Tax Cuts and Jobs Act enacted on December 22, 2017.

Management excludes the effect of each of the items identified below to arrive at the applicable non-GAAP financial measure referenced above for the reasons set forth below with respect to that item:

• e2v transaction costs, including stamp duty, advisory, legal and other consulting fees and other costs – In connection with our e2v acquisition, we incurred legal, financial, and other advisory fees, stamp duty and other costs, which are part of selling, general and administrative expenses. We exclude these expenses to arrive at our non-GAAP measures because we believe they do not reflect the performance of our ongoing operations.
• e2v inventory fair value step-up amortization expense – In connection with our e2v acquisition, accounting rules require us to adjust various balance sheet accounts, including inventory, to fair value at the time of the acquisition. This expense is part of costs of sales. We exclude the amortization expense relating to the step-up in fair value of our inventory to arrive at our non-GAAP measures as we believe it does not reflect the performance of our ongoing operations.
• e2v funds-certain bank bridge facility commitment expense – In connection with our e2v acquisition, we entered into a £625.0 million bridge credit facility in December 2016 to fund the acquisition and related transaction costs, in order to meet the requirement under the U.K. City Code on Takeovers and Mergers that we have sufficient and certain resources available to fund the consideration for the acquisition. This expense is part of interest expense. In January 2017, we amended our revolving credit agreement to allow us to use that facility to fund part of the consideration in lieu of the bridge credit facility. We exclude the expense associated with the bridge facility to arrive at our non-GAAP measures because we believe it does not reflect the performance of our ongoing operations.
• Foreign currency option contract expense to hedge the e2v purchase price – In connection with our e2v acquisition, we entered into a foreign currency option contract in December 2016 to hedge the e2v purchase price. This expense is part of other expense, net. We exclude this expense to arrive at our non-GAAP measures because we believe it does not reflect the performance of our ongoing operations.
• Tax Cuts and Jobs Act repatriation tax and other impacts – On December 22, 2017, the Tax Cuts and Jobs Act was enacted. The Tax Act significantly revised the U.S. corporate income tax by, among other things, lowering corporate income tax rates, implementing the territorial tax system and imposing a repatriation tax on deemed repatriated earnings of foreign subsidiaries. As a result of the Tax Act, Teledyne incurred estimated charges in the fourth quarter of 2017 primarily due to the repatriation tax and the remeasurement of U.S. deferred tax assets and liabilities.