LAS VEGAS — The IRS says it’s still waiting for its cut from Floyd Mayweather Jr. from his nine-figure payday against Manny Pacquiao.

The undefeated boxer nicknamed “Money” owes $22.2 million in taxes from 2015, according to a notice of a federal tax lien filed by the IRS.

The notice shows the balance unpaid as of March 6. The lien was filed with county officials in Las Vegas in April, and the boxing champ last week filed for a temporary reprieve with the U.S. Tax Court.

Still, the boxer, who regularly flaunts his wealth, defended himself on Facebook on Monday, saying his “empire is rock solid” and the IRS “just wants to be part of the ‘Money May’ show.”

“While everyone is counting my money and assuming the worst, these are the facts… Uncle Sam, received $26,000,000.00 from me in 2015! What else could they possibly want?” he wrote in a post with a picture of a handwritten ledger that showed three amounts totaling $26 million. “I’m sure I would have been notified much sooner if there were any real discrepancies right?”

Mayweather’s tax troubles come as he prepares for a boxing match against Irish MMA star Conor McGregor in August in Las Vegas. Mayweather (49-0) will be ending his retirement to face McGregor at T-Mobile Arena.

Depending on pay-per-view sales, both fighters could earn huge purses, though probably not the $200 million or so Mayweather earned for the fight against Manny Pacquiao.

To promote the fight, the men appeared at a news conference Tuesday in Los Angeles, the first of four this week. There has been plenty of trash talk around the fight, and McGregor didn’t miss the opportunity to attack Mayweather.

“Tell that to the tax man,” McGregor said after Mayweather flashed a $100 million check from his fight against Pacquiao.

Mayweather declined to talk about his taxes when asked by -reporters.

“We ain’t even tripping on that,” he said. His tax attorney did not immediately return a request seeking comment.

It’s unclear whether the IRS has tried to withhold on Mayweather’s purse from the fight against McGregor. The agency does not comment on individual cases.

Nevada boxing regulators did not immediately return a request for comment.

The lien for 2015 is just the latest in a series of tax liens filed by the IRS against Mayweather in the last decade.

McGregor does not appear to have any tax issues in Ireland or the United States. Ireland’s tax website did not include him among a list of delinquent taxpayers for 2015, 2016 and the first quarter of 2017. He did not have any cases in U.S. Tax Court or any liens filed against him in Nevada, Massachusetts or New York, the states where he has fought.