Boxing legend Floyd Mayweather doesn't appear to be living up to his "Money" nickname.
Instead, he's struggling to pay his tax debt to the government, suggesting a very practical reason that he agreed to a fight against mixed martial artist Conor McGregor next month.
A petition in tax court asks that the Internal Revenue Service not tack on any more penalties to a 2015 tax liability. Mayweather promises to pay the bill after the Aug. 26 fight, but says he does not have the cash now. He is requesting a three-month agreement as a bridge until he gets his payday.
"Although the taxpayer has substantial assets, those assets are restricted and primarily illiquid. The taxpayer has a significant liquidity event scheduled in about 60 days from which he intends to pay the balance of the 2015 tax liability due and outstanding," Mayweather's petition said, according to a report from Law360. The petition was filed by his attorney, Jeffrey Morse.
Mayweather is coming out of retirement to fight McGregor in Las Vegas and is expected to make at least $100 million and possibly $400 million.
Though Forbes puts Mayweather's net worth at $340 million, the court filing said his assets are "restricted and primarily illiquid." The IRS has rejected the claim, saying that Mayweather has enough to "fully or partially pay the liability." Mayweather's side does not contest that he has the assets, only that he does not currently have the cash on hand.
Morse argued that getting the money together would be "cost-prohibitive" and "a waste of resources." CNBC has reached out to Morse for further comment. The IRS does not comment on individual cases.
Mayweather is a heavy favorite to win the fight, though the odds have come in some recently. Bettors would have to put up $600 to get a $100 profit on Mayweather, and would need $100 to get a $400 profit on McGregor, according to the Odds Shark money line.
WATCH: Avoid these red flags that can trigger a tax audit
