“I’m a little worried about what we’re approaching over the next several weeks,” said Mark Luschini, chief investment strategists at Janney Montgomery Scott on CNBC’s “ Squawk on the Street .” “Over the last 4 to 6 weeks, we’ve seen sequentially slowing economic data points in the U.S., which not indicative of necessarily entering a recession, but not overly encouraging in what is necessary to support elevated equity prices or enough to bid up earnings.”

On the economic front, Midwest business activity slowed in April from the prior month, according to the Chicago ISM. And household income logged its biggest gain in three months , according to the Commerce Department, but consumer spending only edged up 0.3 percent.

The string of mixed economic news follows last week's GDP report that showed U.S. economic growth cooled in the first quarter , bolstering the Federal Reserve's case that interest rates should be kept near zero at least though late 2014.

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