Markit Economics released final services purchasing managers' index (PMI) for the U.S. on Wednesday. Final U.S. services purchasing managers' index (PMI) fell to 54.3 in December from 56.1 in November, up from the preliminary reading of 53.7. It was the lowest level since January 2015

The index was driven by weaker confidence among clients.

"While the survey data indicate that the economy grew at a reasonably healthy 1.9% annualised clip in the fourth quarter, the weakness seen in the final month of the year raises concerns that growth is losing momentum, possibly quite markedly," Chief Economist at Markit Chris Williamson said.