Sentencing of former Enron boss Jeffrey Skilling is due to start later on Monday for his role in the giant fraud that led to the firm's 2001 collapse.
Mr Skilling could be facing 30 years in prison
Skilling, who back in May was found guilty on 19 counts including fraud, conspiracy and insider trading, could receive 20 to 30 years in prison.
The former Enron chief executive was tried and convicted together with the firm's former chairman Kenneth Lay.
Mr Lay has since died and his own convictions have been quashed.
This is because Mr Lay, who died of a heart attack in July, passed away before he was able to appeal against the verdict.
In addition to a long prison sentence, Mr Skilling faces a multi-million dollar fine.
Mr Skilling's lawyer has already asked that his client be allowed to remain free pending appeal, or to at least not have to go to prison before 27 November - after the Thanksgiving holiday.
Kenneth Lay died at his Colorado ranch in July
The scandal at the one-time energy giant left 21,000 people out of work, and shook corporate America, when the firm went bankrupt in 2001 with debts of $31.8bn (£18bn).
Mr Skilling was found to have orchestrated a series of loss-making deals and financial schemes to try and hide debts from investors.
Analysts do not expect him to be shown much leniency.
"I think we're going to see a major-league sentence," said white-collar crime expert Kirby Behre.
Former Enron staff hope this will be the case.
"Jeffrey Skilling just totally destroyed our corporation," said Enron retiree Charles Prestwood.
"He didn't tell us the truth...he was just a bad businessman."
Mr Skilling's sentencing could roll over into Tuesday.