John Arnold is one of those billionaires you don't hear much about. He never really sought a lot of glory and attention. But he's getting lots now. He was recently asked to appear in front of a Congressional committee. His Houston-based hedge fund, Centaurus Energy, which manages more than $5 billion in assets, has never returned less than 50 percent in seven years, reports Fortune.

Arnold personally owns a large stake in the fund, which has made him "the second-youngest self-made multi billionaire in the U.S." He got his start as big-time trader at Enron. He started his own fund after that and has never looked back. But his success has been driven by his ability to make massive bets. "The CFTC, however, has vowed to impose trading limits that would target the industry's largest players. That, say observers, could be a dose of kryptonite for the supertrader."  

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