The Chicago Business Barometer, also known as the Chicago PMI, fell to 44 in February from 46 in the prior month.
Economists polled by the Wall Street Journal forecast a 48 reading.
The index is far below the 55.6 reading in November, which was the highest level since May 2022, when business picked up following the end of the UAW auto strike.
The index is produced by the ISM-Chicago with MNI. It is released to subscribers three minutes before its release to the public at 9:45 am Eastern. It is the last of the regional manufacturing indices before the national ISM data for January is released Thursday.
Before the Chicago data was released, the other regional Fed manufacturing surveys for February were looking better, economists said.
Economists expect the national IMF factory index to rise to 49.5% in February from 49.1 in the prior month. It would be the highest level since October 2022, although still in contraction territory for the 16th consecutive month.