Among the key S&P sectors, industrials and consumer discretionary lagged, while energy and telecoms finished higher.

Citigroup held small gains after the financial giant posted quarterly earnings that topped expectations . But revenue was slightly lighter than expected. (Read More: Dennis Gartman—Now’s the Time to Buy Banks )

Citigroup's earnings came after Wall Street cheered better-than-expected reports from both JPMorgan and WellsFargo last week.

Several companies, especially in the tech sector, have warned on profits in recent weeks. Negative to positive earnings guidance for the second quarter is 3.3 to 1, the worst since 2008, according to data from Thomson Reuters.

“We’re in that pre-earnings moment of fear when a lot of investors assume a defensive crouch,” said Lawrence Creatura, portfolio manager at Federated Investors. “People appear overly cautious and stocks look somewhat inexpensive…it doesn’t take a lot of good news to propel stocks higher because investors appear to be braced for such incredible headwinds.”