Known as the perpetrator of what is considered the largest fraud in Wall Street history, a Ponzi scheme that defrauded investors out of billions over at least 20 years, Bernard Madoff began his career as a stockbroker and investment adviser and once was head of the Nasdaq exchange. Along the way, he began the elaborate Ponzi scheme, hiding it alongside his legitimate operations. Eventually reported to authorities by his sons, who claimed no knowledge of the scheme, he pleaded guilty in 2009 to 11 felony counts of fraud and related crimes and admitted losing $50 billion of investors’ money. At age 71, he was sentenced to 150 years in prison. A court-appointed trustee seeking to recover funds for those who were swindled had by mid-2012 recovered just $330 million for victims.