Anti-tax groups are seizing on the shock decision by top-ranked boxer Manny Pacquiao to junk plans to fight in Las Vegas or any U.S. city because federal taxes are too high.

The fighter had been planning to challenge Juan Manuel Marquez for a fifth time in September at the MGM Grand in Las Vegas.

But while promoter Bob Arum wanted it to happen, Pacquiao is now calling it a "no go" due to the 39.6 tax hit he would take from the federal government.

Americans for Tax Reform told Secrets, "Pacquiao's concerns lie with the federal income tax. As Nevada is one of the nine states that do not have an income tax, Las Vegas has grown to become the home for major bouts because fighters do not have to worry about the state taking a bite out of their winnings or purse. Unfortunately, Nevada's economic benefit is now overshadowed by the federal income tax rate."

Yahoo! Sports noted that Arum feels his boxer would earn $10 million less fighting in the U.S.

ATR said that "for boxers who stand to earn over $1 million per fight through winnings, pay-per-view revenue shares, fight bonuses, and other forms of taxable income, they will be taxed at the top marginal income tax rate of 39.6 percent. Pacquiao, boxing's second biggest PPV draw, understandably views boxing in America under this tax rate to be a bad business decision."