Markit Economics released its preliminary services purchasing managers' index (PMI) for the U.S. on Wednesday. The U.S. preliminary services purchasing managers' index (PMI) climbed to 56.5 in November from 54.8 in October. It was the highest level since April.

Analysts had expected the index to rise to 55.0.

A reading above 50 indicates expansion in economic activity.

The increase was driven by a new business growth.

"The US economy is showing further robust economic growth in the fourth quarter, with the pace of expansion picking up in November. The upturn in the flash PMI brings the surveys up to a level indicative of 2.3% annualised GDP growth in November, up from 1.8% in October," Markit Chief Economist Chris Williamson.