Ken Lay and Jeffrey Skilling, former executives at Enron, have both been found guilty by a US court for charges relating to fraud and conspiracy.
The two men were heavily involved in the spectacular collapse of the US energy giant in 2001, when it filed for bankruptcy after financial irregularities led to losses of $638 million (£341 million).
The US jury spent six days deliberating in a 15-week trial, with Lay and Skilling found guilty of 34 counts after lying to investors and concealing the company's massive internal financial problems.
However, speaking outside the court in Houston, Texas, Skilling told reporters that he and Lay plan to appeal, with both men facing a lifetime in jail.
"We fought the good fight. Some things work, some things don't. Obviously I am disappointed but that's the way the system works," he said.
With sentencing due at a later date, Skilling is in line for 185 years behinds bars after being found guilty of 19 out of 28 counts, while Lay can expect 45 years in jail after the jury found him guilty of all six fraud and conspiracy charges.
Andrew Fastow, a former chief finance officer at the now defunct US company, pleaded guilty two years ago to his involvement in the scandal and agreed to testify against his former bosses, accepting fines worth $23 million (£12 million) and ten years in prison.
Investors attempted to claim more than $30 billion (£16 billion) in compensation following Enron's collapse.