The 64-year-old Missouri native, who served as an officer in the Navy and then as an executive with Exxon Co. U.S.A., suffered a massive heart attack while in Aspen, Colo., late Tuesday, the Houston Chronicle reported.
A federal jury in Houston found Lay guilty in May on six counts of conspiracy to commit securities and wire fraud in a case born from one of the biggest business scandals in U.S. history. His sentencing had been set for this fall.
At its 2001 peak Enron was one of the world's most lucrative energy trading companies, but deceptive accounting sparked a massive sale of Enron stock late that year. That forced the company into bankruptcy and into the arms of federal prosecutors. A number of top executives have been convicted or pled guilty in the subsequent investigations.
Lay is survived by his wife, the former Linda Phillips of Washington, and five children, Robyn, Mark, David, Elizabeth and Beau.