SK Group chairman Chey Tae-won has been sentenced to four years in prison for embezzling company funds.
He was found guilty of using nearly 50 billion won ($US46 million) of group funds for personal investments.
The BBC reports Chey was previously imprisoned in 2003 on charges of accounting fraud.
SK Group is one of the largest conglomerates in South Korea. A spokeswoman said it would appeal against the ruling.