WorldCom founder Bernie Ebbers has been jailed for 25 years for his leading role in the company’s $11bn (£6.2bn) accounting fraud.
The fraud led to the biggest ever US corporate bankruptcy and the sentence means Ebbers, 63, could spend the rest of his life behind bars.
Ebbers was convicted earlier this year on nine counts of conspiracy, securities fraud and filing false statements with financial regulators.
The WorldCom boss has been ordered to report to a low-security prison in Mississippi, US, by 12 October. Although he is planning an appeal, the government has opposed bail.
Prosecutors had sought an 85 years sentence, based on the size of the fraud and the amount investors had lost as a result of it.
Ebbers recently settled with defrauded investors by giving up most of his personal wealth, worth tens of millions of dollars.
Five other former WorldCom executives await sentence this summer, including chief prosecution witness and ex-WorldCom finance head Scott Sullivan. They all pleaded guilty to fraud.
WorldCom went bankrupt in 2002 and its former operation is now known as MCI.