The Institute for Supply Management's factory index fell to its lowest level in three months, falling to 53.2 percent in May from last month's 54.9 percent, according to the group's report. Anything above 50 percent represents growth in manufacturing output, but May's numbers are still lower than the 55.5 percent gain estimated by economists polled by Bloomberg.
"We have a little bit of a normalization in May of manufacturing output and sentiment after a big unwind of the winter weakness in April," said Guy Lebas, managing director of fixed income strategy at Janney Montgomery Scott LLC in Philadelphia.
The index of production and new orders both fell to 55. 2 percent and 53.3 percent respectively. The employment gauge also fell to 51.9 percent from 54.7 percent.
Respondents to the Institute for Supply Management's survey said that the industry had concerns regarding raw materials pricing, and supply tightness and shortages. The index numbers showed that manufacturing grew for its 12th consecutive month but at a very modest rate.
Manufacturers are facing a tough time as the global economy is taking longer to recover than most expected. But gains made in housing have helped manufacturing companies generate sales in segments ranging from building equipment to appliances such as washers and cooking ranges.