The meeting minutes from the Fed's latest policy meeting showed that even as consensus built within the central bank about the likely need to begin pulling back on economic stimulus measures soon, many policymakers wanted more reassurance the employment recovery was on solid ground before a policy retreat.
"Several members judged that a reduction in asset purchases would likely soon be warranted," the minutes said. But they added that "many members indicated that further improvement in the outlook for the labor market would be required before it would be appropriate to slow the pace of asset purchases."
Fed Chairman Ben Bernanke is scheduled to speak shortly after the market close from the National Bureau of Economic Research conference. His topic will be "The First 100 Years: A Century of U.S. Central Banking: Goals, Frameworks, Accountability."
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"There's no reason to think Bernanke is going to be showing his hand right now," said Brian Edmonds, head of interest rates at Cantor Fitzgerald.
In earnings news, Family Dollar soared to top the S&P 500 gainers after the retailer edged past earnings expectations and raised its outlook for the year. Rivals Dollar General and Dollar Tree also rallied.
On the downside, Nabors Industries tumbled to lead the S&P 500 laggards after the oil services provider said its second-quarter profit would fall short of Wall Street estimates, pointing to tougher competition and fewer rentals of its rigs. At least three brokerages slashed their price target on the company.
Yum Brands is slated to post earnings, while Chevron is expected to give an interim update on its results after the closing bell.
Analysts expect S&P 500 earnings to grow 2.6 percent in the second quarter from a year ago, while revenue is forecast to increase 1.5 percent from a year ago, according to the latest data from Thomson Reuters.
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Hewlett-Packard rallied after Citigroup upgraded its rating on the tech giant to "buy" from "sell," pointing to increasing benefits from cost savings in the second half of the year, as well as increasing momentum from HP's services segment.
Best Buy declined after Cleveland Research said the consumer electronics chain's domestic comparable store sales appear to be slowing and that fundamentals remain challenging.
Apple edged lower after a federal judge ruled that the iPhone maker conspired to raise the retail prices of e-books, and said a trial for damages will follow.