ISM now says U.S. manufacturers grew faster in May Posted:Mon, 02 Jun 2014 16:54:53 GMT WASHINGTON (MarketWatch) - U.S. manufacturers grew in May at the fastest pace of 2014, according to an ISM survey updated Monday after the firm that produces the index admitted an error. The Institute for Supply Management's manufacturing index rose to 55.4% in May - the highest level so far this year - from 54.9% in April, according to press reports. Using faulty seasonal-adjustment data, ISM originally said its index had dropped to 53.2% last month, a decline that surprised investors. The corrected ISM reading for May is close to the 55.8% forecast of economists polled by MarketWatch. Seventeen of the 18 industries tracked by ISM reported growth last month.