The Institute for Supply Management released its Chicago purchasing managers' index on Friday. The index plunged to 46.3 in May from 52.3 in April, missing expectations for an increase to 53.0.
A reading above the 50 mark indicates expansion, a reading below 50 indicates contraction.
The drop was driven by a decline in new orders. The new orders index fell to 47.5 in May from 55.1 in April.
The production and employment indexes also showed double-digit declined in percentage terms.