Mr. Skilling and Ken Lay became public symbols of executive wrongdoing and financial malfeasance after the tech and telecom boom of the late 1990s turned to bust. Enron was at the center of a wave of corporate accounting scandals that emerged out of the stock market collapse. The executives, along with other prominent businessmen like Bernard Ebbers of WorldCom and John Rigas of Adelphia, were convicted by juries and received lengthy prison terms for, among other crimes, lying to their investors about the health of their companies. After the Enron and WorldCom collapses in late 2001 punctuated the end of the historic bull market, the Bush White House took an aggressive stance on prosecuting white-collar crime. Since his 2006 conviction on charges of securities fraud, conspiracy and insider trading, Mr. Skilling has served jail time in federal prisons in Minnesota and now Colorado. He and his legal team have waged an aggressive appeal, repeatedly seeking to overturn his conviction on various grounds.