Technology, industrial, health-care and consumer companies all report earnings in the week ahead and may provide some clues on the extent of the economy's soft patch.
So far the earnings season has been lackluster, and some high-profile warnings have already given investors pause. Wal-Mart said its sales would be weaker than expected next year, and Yum Brands said its sales in China are too difficult to predict because of volatility there.
"The earnings are not good. Companies are giving cautionary guidance," said David Bianco, chief U.S. equity strategist at Deutsche Bank.