Markit Economics released its final services purchasing managers' index (PMI) for the U.S. on Monday. The final U.S. services PMI declined to 54.8 in June from 56.2 in May, in line with the preliminary reading.

A reading over 50 indicates expansion in the sector.

The decline was driven by a slowdown in employment and output growth.

The employment subindex decreased to 54.1 in June from 55.5 in May.

"Although still signalling moderate growth in June, the manufacturing and service sector surveys indicate that the rate of economic expansion has slowed markedly since the start of the quarter, when business was boosted by a rebound from weather related weakness. The loss of growth momentum seen in the surveys means GDP growth could slacken off again in the third quarter and hiring could likewise ease off," Markit Economics Chief Economist Chris Williamson noted.