Sam Bankman-Fried should spend 40 to 50 years in prison after being convicted of stealing $8 billion from customers of his now-bankrupt FTX cryptocurrency exchange, prosecutors said Friday.

The FTX founder was found guilty on all charges in November related to the collapse of his cryptocurrency exchange in the first of two criminal trials against the former CEO.

A jury in a Manhattan federal court agreed with prosecutors that Bankman-Fried defrauded investors, customers and lenders during the collapse of his crypto empire. 

"Even now, Bankman-Fried refuses to admit what he did was wrong," prosecutors wrote in a sentencing memorandum. "His life in recent years has been one of unmatched greed and hubris; of ambition and rationalization; and courting risk and gambling repeatedly with other people's money."

A spokesman for the former billionaire, Mark Botnick, declined to comment. Bankman-Fried's lawyers told U.S. District Judge Lewis Kaplan a 5¼- to 6½-year prison term would be appropriate. They said FTX clients would get most of their money back and that Bankman-Fried did not set out to steal.