Shares of Apple traded lower on Friday after Bernstein Research questioned whether a weakening U.S. consumer may make it difficult for the company to beat rising expectations for its second-quarter results. As it has done for 11 consecutive quarters, we expect Apple's reported revenues and earnings to beat its own guidance, it said, though it said that revenue upside could be more limited this quarter.

>> Broker Sees Leaner Profits for Apple in Q2