The S&P mid- and small-cap indexes, alongside the Russell 2000, also fell for the month.

The U.S. economy appeared to stall as it entered the second quarter, with consumers increasing spending only modestly last month and a gauge of business activity in the Midwest falling sharply in April.

Industrial and technology companies, usually linked to economic growth, led declines.

The Institute for Supply Management-Chicago's business barometer, which slowed more than expected in April, is a predictor of a national trend, according to Edward Hemmelgarn, chief investment officer at Shaker Investments in Cleveland.

"If you see worse economic data stocks will not do well," he said. "Small caps are more focused on U.S. data than large caps."

The S&P MidCap 400 index <.MID> fell 0.8 percent while the S&P SmallCap 600 index <.SML> lost 1 percent. The Russell 2000 <.RUT> also dropped 1 percent.

For the month, S&P small caps dropped 1.3 percent and mid caps edged down 0.3 percent, while the Russell 2000 shed 1.6 percent.

It was the first monthly decline for the S&P small caps since last September.

Shares of VeriFone Systems (>> VeriFone Systems Inc) fell 12.5 percent to $47.64 after Deutsche Bank questioned the maker of point-of-sale terminals' organic growth projections and downgraded its stock.

Mid cap Barnes & Noble's (>> Barnes & Noble, Inc.) shares soared 52 percent to $20.75 after Microsoft (>> Microsoft Corporation) said it was investing $300 million in Barnes & Noble's Nook e-reader and college business.

(Reporting by Rodrigo Campos)