On the corporate front, Facebook ( FB), the social networking giant, posted an in-line quarterly profit after Thursday's closing bell that failed to impress Wall Street. The company didn't provide an outlook and the stock dropped nearly 12% on the day, hitting new all-time lows for its brief time as a public company. Amazon.com ( AMZN), the online retailer, delivered mixed second-quarter results after the market closed Thursday. The Seattle-based company reported a profit of $7 million, or 1 cent a share, on revenue of $12.83 billion. The latest results included a net loss of $65 million related to the acquisition and integration of Kiva Systems. Analysts were expecting second-quarter earnings of 2 cents a share on revenue of $12.88 billion. The stock gained nearly 8% on the day. Starbucks ( SBUX) shares dropped more than 9% after the coffee chain operator reported below-consensus third-quarter earnings, and fourth quarter and full-year outlook. Green Dot ( GDOT) shares plunged 61% after the bank holding company posted a 1.5% decline in earnings and worsening margins. Barclays ( BCS) said Friday the U.K.'s financial regulator has started a probe of four current and former senior employees, including the bank's finance chief. The issue involves the "sufficiency of disclosure" in relation to fees paid when Barclays conducted an emergency €7.3 billion capital increase with Middle Eastern investors in 2008, according to The Wall Street Journal. The U.K. bank last month reached a settlement with U.K. and U.S. regulators after it admitted to trying to manipulate the London interbank offered rate. Barclays also announced first-half profit on Friday that exceeded forecasts, and shares added 9%.