Service-Sector Activity Remained Solid in December

Growth in economic activity across the sprawling U.S. service sector was steady and solid in December, a sign of momentum for the broader economy headed into the new year.

The Institute for Supply Management on Thursday said its index of nonmanufacturing activity was 57.2 in December, unchanged from its November level. A reading over 50 indicates expansion, while a reading below 50 suggests contraction.

Economists surveyed by The Wall Street Journal had expected a December reading of 56.5.

The services-providing side of the U.S. economy has continued to post solid growth in recent years despite choppiness in the manufacturing sector, which had been pressured by a strong dollar and the energy sector's slump. The headline ISM services index has remained above 50 continuously for nearly seven years; the last contractionary reading was in January 2010.

Write to Ben Leubsdorf at ben.leubsdorf@wsj.com