The massive payday Floyd Mayweather Jr. is sure to earn for his fight against Conor McGregor comes at a most welcome time.

The all-time great fighter filed a petition on July 5 asking the IRS for a reprieve from 2015 taxes that are still unpaid 15 months later. The 40 year old requested that he pay the outstanding tax bill following what figures to be a nine-figure purse for his August 26 bout against Conor McGregor.

“Although the taxpayer has substantial assets, those assets are restricted and primarily illiquid,” the petition stated, according to the legal website Law360. “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.”

That significant event, of course, is the mega fight against UFC superstar McGregor.

Mayweather (49-0, 26 knockouts) has earned more than $700 million during his illustrious career, and in January, Forbes estimated that his net worth was around $340 million.

It’s unclear how much Mayweather owes the IRS, but the penalty is 0.5 percent for each month taxes are unpaid, which now stands at 15 months and counting.

2015 was the highest-earning campaign of Mayweather’s career. That’s the year “Money” outpointed Manny Pacquiao in a fight that shattered revenue records and earned Mayweather between $200 million and $300 million. Mayweather then fought in September against Andre Berto and earned a guaranteed purse of $32 million.

The former five-division champion hasn’t competed since that win over Berto, but that short-lived retirement comes to a close next month.