As soon as 21-year-old Matt Murphy snagged the valuable piece of sports history Tuesday night, his souvenir became taxable income in the eyes of the Internal Revenue Service, according to experts.

That would instantly put Murphy, a college student from Queens, in the highest tax bracket for individual income, where he would face a tax rate of about 35 percent, or about $210,000 on a $600,000 ball.

Even if he does not sell the ball, Murphy would still owe the taxes based on a reasonable estimate of its value, according to Barrie. Capital gains taxes also could be levied in the future as the ball gains value, he said.