Chicago-area business activity unexpectedly increased at a faster rate in the month of February, according to a report released by the Institute for Supply Management - Chicago on Thursday, with the business barometer rising to its highest level since March of 2012.

The report said the Chicago business barometer rose to 56.8 in February from 55.6 in January, with a reading above 50 indicating an increase in business activity. The increase came as a surprise to economists, who had expected the barometer to edge down to 54.1.