Former cryptocurrency executive Caroline Ellison was sentenced by a federal judge on Tuesday to two years behind bars for her role in her imprisoned former boyfriend Sam Bankman-Fried's theft of about US$8 billion in customer funds from the now-bankrupt FTX exchange he founded.

US District Judge Lewis Kaplan decided at a sentencing hearing in Manhattan federal court that prison time was warranted for Ellison despite her cooperation with prosecutors.

Ellison, 29, pleaded guilty to seven felony counts of fraud and conspiracy and testified as a prosecution witness in the trial of Bankman-Fried, who was convicted of fraud and other charges last year and is serving a 25-year prison sentence arising from FTX's November 2022 collapse.

The crimes to which she pleaded guilty carried a maximum sentence of 110 years in prison.

Kaplan during the hearing told Ellison she was "gravely culpable in this fraud – there is no doubt about it." But Kaplan said her "remarkable cooperation" represented a "fundamental distinction" between her and Bankman-Fried.

Ellison addressed the judge during the hearing.

"Not a day goes by when I don't think about all the people I hurt," said Ellison, a Stanford University graduate whose parents and two sisters were present in court. "My brain can't even truly comprehend the scale of the harms I've caused. That doesn't mean I don't try."

Prosecutors have called Bankman-Fried's actions one of the biggest financial frauds in US history. Ellison from 2021-2022 ran Alameda Research, a Hong Kong-based cryptocurrency-focused hedge fund Bankman-Fried founded. Ellison said she thought about leaving Alameda many times.

"Every time I thought about it, I heard Sam's voice in my head," Ellison told the judge. "Ignoring that voice in my head and speaking out would have been brave," Ellison said, beginning to choke up and sniffle. "I'm sorry I wasn't brave." (Reuters)