DANBURY, Conn. (AP) -- Caroline Ellison, a former top executive in Sam Bankman-Fried 's fallen FTX cryptocurrency empire, began her two-year prison sentence Thursday for her role in a fraud that cost investors, lenders and customers billions of dollars.

Ellison, 30, reported to the federal prison in Danbury, Connecticut, according to the Federal Bureau of Prisons. She had pleaded guilty and testified extensively against Bankman-Fried, her former boyfriend, before he was convicted and sentenced to 25 years in prison.

Ellison could have faced decades in prison herself, but both the judge and prosecutors said she deserved credit for her cooperation. At her sentencing hearing in New York in September, she tearfully apologized and said she was "deeply ashamed."

Ellison was chief executive at Alameda Research, a cryptocurrency hedge fund controlled by Bankman-Fried. FTX was one of the world's most popular cryptocurrency exchanges, known for its Superbowl TV ad and its extensive lobbying campaign in Washington, before it collapsed in 2022.

U.S. prosecutors accused Bankman-Fried and other top executives of looting customer accounts on the exchange to make risky investments, make millions of dollars of illegal political donations, bribe Chinese officials and buy luxury real estate in the Caribbean.