NEW YORK, April 11 (Reuters) -

Sam Bankman-Fried, facing the prospect of spending much of

his adult life behind bars, on Thursday appealed his conviction

and 25-year prison sentence for stealing $8 billion from

customers of the now-bankrupt FTX cryptocurrency exchange he

founded.

Defense lawyer Marc Mukasey had announced plans for the

appeal to the Manhattan-based 2nd U.S. Circuit Court of Appeals

during Bankman-Fried's March 28 sentencing hearing. The

32-year-old former billionaire crypto wunderkind was convicted

in November on seven counts of fraud and conspiracy in what

federal prosecutors have called one of the biggest financial

frauds in U.S. history.

Bankman-Fried's appeal could take years. He faces steep

odds, with his lawyers needing to persuade the 2nd Circuit - and

potentially the U.S. Supreme Court - that U.S. District Judge

Lewis Kaplan made significant errors that deprived Bankman-Fried

of his legal rights and made the trial unfair.

The sentence imposed by Kaplan was shorter than the 40- to

50-year term that prosecutors had recommended but longer than

the 5-1/4 years or fewer that Mukasey had suggested.

Bankman-Fried's sentencing put an exclamation point on his

downfall from an entrepreneur whose meteoric rise prompted

adulation, reverence and jealousy from some quarters into the

biggest trophy for U.S. prosecutors in their crackdown on

excesses in the cryptocurrency markets.

The Massachusetts Institute of Technology graduate rode a

boom in the values of bitcoin and other digital assets to a $26

billion net worth before he turned 30, Forbes magazine

estimated.

Bankman-Fried also became a major political donor and an

advocate of effective altruism, a movement that encourages

talented young people to focus on earning money and giving it

away to worthy causes.

His wealth evaporated when Bahamas-based FTX declared

bankruptcy on Nov. 11, 2022, following a wave of withdrawals by

customers panicking over reports that Bankman-Fried commingled

their assets with Alameda Research, a crypto-focused hedge fund

he also controlled.

The next month, Bankman-Fried was arrested in the Bahamas

and extradited to the United States.

'BAD DECISIONS'

Three former close associates testified as prosecution

witnesses against Bankman-Fried, saying he ordered them to use

FTX funds to pay Alameda's debts, make political donations and

buy luxury real estate in the Bahamas. They pleaded guilty to

fraud and are awaiting sentencing.

Bankman-Fried testified in his own defense, acknowledging he

made mistakes managing risk but denying he stole money.

"I made a series of bad decisions," Bankman-Fried said at

his sentencing hearing. "They weren't selfish decisions. They

weren't selfless decisions. They were bad decisions."

His lawyers have complained that prosecutors worked too

closely with FTX's bankruptcy estate, and asked it to hand over

only information that would help their case.

During the sentencing hearing, Mukasey told Kaplan that the

judge should ignore the prosecution's claim that FTX customers

had lost $8 billion because, he said, customers would likely be

made whole eventually. Kaplan dismissed that as speculative, and

said Bankman-Fried lied by testifying he did not know until

shortly before FTX's collapse that Alameda had spent large sums

of customer money.

"He was viewing the cost of getting caught, discounted by

probability or improbability, against the gain of getting away

without getting caught, given the probabilities. That was the

game," Kaplan said of Bankman-Fried.

Earlier on Thursday, Bankman-Fried's former lawyer Mark

Cohen questioned the disparity between Bankman-Fried's sentence

and rival exchange Binance's founder Changpeng Zhao's maximum

18-month sentence for violating an anti-money laundering law.

Zhao pleaded guilty in connection with a $4.3 billion

settlement for Binance and is due to be sentenced on April 30.

Authorities said Binance failed to report more than 100,000

suspicious transactions with U.S.-designated terrorist groups

including Hamas, al Qaeda and Islamic State.

"These are very different outcomes," Cohen, who represented

Bankman-Fried at his trial, said at a conference hosted by the

New York City Bar. "Can you square them from a policy point of

view? I would suggest it's very hard."

Nicolas Roos, one of prosecutors in the Bankman-Fried case,

said at the conference that the two cases involved very

different conduct. Zhao also acknowledged wrongdoing and

traveled voluntarily to the United States to face the charges.