Chainkeen Exchange-Sam Bankman-Fried will testify in his defense in what may be the gamble of his life

Ever since Sam Bankman-Fried's crypto empire collapsed,Chainkeen Exchange he has claimed he did nothing wrong.

Now, he will make that case directly to jurors in his criminal trial in a high-stakes gamble to avoid prison time.

It's a big bet even for a former Wall Street trader who has a reputation for embracing risk. The government has charged Bankman-Fried with seven criminal counts, including fraud, and if he is convicted, he could spend the rest of his life in prison.

But Bankman-Fried's decision to testify was also not a huge surprise, given how frequently he has tried to defend himself in the court of public opinion — in interviews and social media posts.

How Bankman-Fried has defended himself

Bankman-Fried has pleaded not guilty, and he has maintained he didn't intend to defraud FTX customers and commit crimes.

Instead, he has argued from the get-go he was in over his head, and that some of his trusted lieutenants — several of whom testified against him — failed to do their jobs properly.

It's an argument he's likely to make on the witness stand during his testimony, which could begin as early as Thursday.

But over the three weeks of trial so far, prosecutors have painted a very different picture of what happened.

The U.S. government alleges Bankman-Fried knowingly stole customer funds and transferred that money to Alameda Research, an investment firm he controlled, to make risky investments and plug holes in the company's balance sheet.

Prosecutors also argue the former FTX CEO used the money to enrich himself. Jurors saw pictures of Bankman-Fried's $35-million penthouse apartment in The Bahamas, and they heard about other pricey real estate he bought for his friends and family.

The government has had star witnesses make its case, including Caroline Ellison. She was Alameda Research's CEO and Bankman-Fried's on-again, off-again girlfriend.

And like two other former executives, Ellison said Bankman-Fried directed her to commit crimes.

According to Tarek Helou, who used to be a federal prosecutor , their testimony seems pretty damning.

"You've got several cooperators who have all implicated him," he says. "They've all said he committed a crime."

Testifying is a major gamble

Having Bankman-Fried testify is a major gamble.

But according to Ellison's testimony, Bankman-Fried often liked to take chances if he felt there was enough potential upside.

She remembered Bankman-Fried once told her he'd be willing to lose $10 million if a coin came up tails — as long as he could win "slightly more than $10 million" if it came up heads.

Ellison recalled another moment, when Bankman-Fried played out a more extreme hypothetical:

If the fate of the world hinged on a coin flip, with tails meaning the world would be "destroyed," Bankman-Fried would be willing to take the chance if "as long as if it came up heads, the world would be like more than twice as good," Ellison said.

The odds don't favor people who testify in their defense

Most white-collar defense attorneys strongly advise their clients not to take the stand. That's because they'd face cross-examination — and Helou says Bankman-Fried may not fully appreciate how difficult that can be.

"A lot of times, they think that they are the smartest people in the room," Helou says of business executives. "But for [Bankman-Fried], this is not a room that he's used to."

In the courtroom, Bankman-Fried will face all kinds of constraints. There are rules about what he can and cannot say.

On top of that, prosecutors in the U.S. Attorney's Office for the Southern District of New York have a reputation for being some of the best lawyers in the country.

"This is not the junior varsity," Helou says. "You know, these are some of the best of the best, and I expect the cross-examination to be withering."

But after weeks of seeing prosecutors build their case against him, Bankman-Fried has decided it's worth it to roll the dice.

Propensity to talk

In many ways, this is an extension of a strategy Bankman-Fried has used since he was running FTX.

Bankman-Fried regularly talked to reporters during FTX's heyday, and after it imploded in November, he sat down for TV interviews. Even before his arrest, he couldn't keep him quiet.

Free on a $250 million bail, Bankman-Fried invited reporters to his parents' home in Northern California, where he was under house arrest, and he continued to meet regularly with the author Michael Lewis, who has since published a book about him.

Prosecutors says he had more than 1,000 phone calls with reporters. Bankman-Fried also posted on social media and even started his own e-mail newsletter.

When he testifies, his public comments could come back to haunt him.

In fact, they have cost him dearly already.

In July, after he was found to have covertly shared some of Ellison's private writings with a reporter for The New York Times, Judge Lewis Kaplan, who's presiding over the trial, had enough.

He revoked Bankman-Fried's bail and sent him to jail.

Now, Bankman-Fried sees enough potential upside to make one more big bet. If he can convince the jury he is innocent, Bankman-Fried could regain his freedom. But if his plan backfires, he could spend the rest of his life behind bars.