NEW YORK (AP) -- Matt Murphy could become $500,000 richer if he sells Barry Bonds' record-breaking home run ball.
The college student, however, may just want to hang on to it -- even if he's hit with a whopping tax bill.
"Part of me wants to keep it. It's the greatest American sports accomplishment in history," Murphy said Thursday on NBC's "Today Show." "Part of me might want to sell it, but I really am leaning towards keeping it. It's just too valuable, sentimental."
Selling the ball for that amount would instantly put Murphy 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 John Barrie, a tax lawyer with Bryan Cave LLP in New York. Capital gains taxes also could be levied in the future as the ball gains value, he said.
On the other hand, he said, if the ongoing federal investigation into steroid abuse among professional athletes takes a criminal turn for Bonds, the ball's value could go down -- which would likely allow Murphy to claim a loss.
Murphy said he and his friend, Amir Kamal, nearly missed Bonds' historic at-bat because they were getting crab sandwiches at AT&T Park.
"We were back in time," Murphy said. "We hustled."
They attended the game because they had a layover in San Francisco on the way to Australia. A third friend, Ryan Breslin, is the brother of Abigail Breslin, the young actress who received an Oscar nomination for her role in "Little Miss Sunshine," and she's shooting a movie in Australia.
Murphy and Kamal bought Giants tickets about three weeks before the game as they were planning the Australia trip.
"Well, it started off, 'Let's spend the night in San Francisco,' to 'Let's go to a Giants game,' to 'He's getting pretty close, what if?"' Murphy said.
Breslin turned down an invitation to attend the game because he was finishing up classes in Washington, D.C. Is he kicking himself for that decision?
"I absolutely am," he said.
Also feeling pangs of regret must be the San Francisco cab driver who drove Murphy and Kamal from the airport to their hotel. Hoping to get out of the $55 fare, they told the driver that if they caught Bonds' record home run ball, they'd give him a couple thousand dollars.
"He turned me down, man," Murphy said.
Bonds passed Hank Aaron to become the majors' career home run hitter when he hit the 756th of his career into the right-center field seats on Tuesday night against the Washington Nationals. After the ball whizzed past Kamal, he turned around to high-five Murphy, but his friend had disappeared.
The ball "took a lucky bounce," Murphy said, and set off a scrum -- with him at the bottom.
"Longest minute of my life," Murphy said. "I think one gentleman kicked me in the back of the head. There were people on top of people on top of people, which I didn't really understand. The San Francisco Police Department really helped me out by getting there quickly."
Murphy wore the jersey of Mets All-Star shortstop Jose Reyes to the game.
"Just had to represent my home team," he said.
But after making the catch, he asked the grounds crew for some Giants gear, thinking he might face some malice for wearing a Mets jersey.
Murphy declined to reveal where he's keeping the ball, but said it's not coming to Australia with him.
"When I get back, I'm going to sort things out," he said.
AP Writer Marcus Wohlsen contributed to this story.