Item 6. SELECTED FINANCIAL DATA

On November 2, 2018, CME Group completed its acquisition of NEX Group plc (NEX). The following data includes the financial results of NEX beginning November 3, 2018.

In the first quarter of 2018, the company adopted the Financial Accounting Standards Board's (FASB) standards update on changes to the presentation of certain components of defined benefit pension costs. Under previous accounting guidance, the components of pension costs were aggregated for reporting in the financial statements within compensation and benefits expense on the consolidated statements of income. The amendments in the update require that the service cost component is reported in the same line as other compensation costs, whereas the other components of net benefit cost are required to be presented on the consolidated statements of income separately from the service cost component. The company has included the other components within non-operating income (expense). This update was adopted as of January 1, 2018 with retrospective application to the earliest period presented, as if the new accounting policy was in effect during those periods. The change in accounting policy has been reflected in the following table.

The following table presents key statistical information on the volume of contracts traded, expressed in round turn trades. All amounts exclude our interest rate swaps and credit default swaps contracts as well as volume data for BrokerTec and EBS.