Former SAC portfolio manager Michael Steinberg (center) exits a Manhattan federal court with his attorney after his indictment on securities fraud charges in March. Louis Lanzano/AP hide caption

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Federal Reserve Chairman Ben Bernanke during a news conference in June. Financial markets reacted to comments he made then by selling off bonds and stocks. Alex Wong/Getty Images hide caption

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Mary Jo White, then U.S. Attorney for the Southern District of New York, speaks during a May 2001 press conference following guilty verdicts in the trial of four followers of Osama bin Laden that bombed two U.S. embassies in East Africa in 1998. President Obama intends to nominate White to head the Securities and Exchange Commission. Doug Kanter/AFP/Getty Images hide caption

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Investors and financial analysis firms are increasingly looking at "sentimental analysis" — such as Facebook "likes" and Twitter messages — to gauge a company's social popularity. iStockphoto.com hide caption

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