More businesses in the Chicago region were expanding in December than at any time in the past 16 months. That's according to the The Institute for Supply Management-Chicago's Business Barometer.

The business activity index rose to 60 percent from 56.1 percent in November. It's the highest reading since August 2008 and was stronger than many forecasts.

Readings above 50 percent indicate expansion, and below 50 percent indicate contraction, suggesting business activity is increasing.

The national Institute for Supply Management manufacturing index will be released Monday, and the ISM non-manufacturing index a week from today.