Legendary Las Vegas figures can be found winning big all over the city, but legendary sports betting icon Billy Walters would like to forget his recent history, now that he has been ordered by a federal judge to pay a $25.4 million penalty for insider trading.

Billy Walters

Billy Walters was convicted in April of insider trading on a massive scale, but the $25 million he was ordered to pay this week may just be the tip of the iceberg compared to his actual profits. (Image: CNBC)

Walters was convicted in April of profiting from illegal trades on Dean Foods stock, using information provided by ex-Dean Foods chairman Tom Davis.

In July, the 71-year-old Walters was sentenced to five years in prison by Judge Kevin Castel, who called him “a cheater and a criminal, and not a very clever one.”

On Wednesday, the same judge said he would impose the $25.4 million fine, up from an earlier $10 million, because this was the amount that could be definitively traced to Walters’ illegal trades. That figure is believed to be the tip of the iceberg, however, with prosecutors earlier putting the number at “at least $43 million.”

Mickelson Entangled

Davis testified against his former friend as part of a plea bargain, claiming that he became a “virtual conduit of information,” sharing company secrets communicated to Walters via prepaid cell phones, which the pair referred to as their “bat phones.”

He claimed that the nature of their relationship changed after Walters leant him almost $1 million. “[After that] I became indebted to him,” he said. “He became more demanding of information.”

Pro-golfer Phil Mickelson was also embroiled in the case, having made $1 million on Dean Foods trades after receiving tips from Walters. Mickelson was not included of any crime and was not called to appear in court. He swiftly repaid the $1 million.

Walters Appeals but Bail Denied

Walters has appealed his conviction, but his request to remain free on bail while the appeal is being considered was turned down last week. He is due to begin his sentence on October 10.

Walter’s lawyers will argue that the trial was tainted by a series of leaks of sensitive information about the investigation, made by an FBI agent to the press in 2014. They will also claim, as they did throughout the trial, that Davis was an unreliable witness who “wrongfully implicated Walters only after he got caught stealing from a charity and cheating on his taxes.”

Davis admitted in court that he embezzled funds from a charity for battered women which he largely spent on gambling and prostitutes. He also confessed that he told Walters the money he borrowed from him would be used to refinance a Dallas bank, but in fact Davis blew it on gambling, including $200,000 on a single hand of blackjack.