NEW YORK, USA: As dozens of U.S. billionaires pledge their fortunes to charity and the country struggles to shake off recession, philanthropy is a growing status symbol of the rich, experts say.

Being wealthy may no longer be about how many properties or fast cars a millionaire owns – it could be about how much money they are giving away – bringing hope to charities that Warren Buffett and Bill Gates' philanthropic push inspires others.

"It will be something that's very important to the wealthy – to be able to say: 'I give my money away as much as I spend it in all these other exciting ways'," said Stacy Palmer, editor of the Chronicle of Philanthropy.

"Clearly pressure on the elite is high right now to say that they are giving money away and that will make it trendy," she said. "People who have enough money to give away but maybe haven't thought about that ... those folks will want to do what Warren Buffett and Bill Gates are doing."

Investor Buffett and Microsoft founder Gates are urging American billionaires to give away at least half their wealth during their lifetime or upon their death by signing the Giving Pledge, which so far has 40 members.

While experts in philanthropy say recognition is not a key motivation for people to give, some say it would not be a bad thing if philanthropy became a greater badge of honor among the rich.

"It would be naive to think that nobody cares about the attention because otherwise there wouldn't be any names on buildings," said Patrick Rooney, executive director of the Center on Philanthropy at Indiana University.

"But it would not be a terrible thing if philanthropy became a more important status symbol than the car you drive or the street address and how many square feet you live in or how many residences you own," he said.

Based on Forbes magazine's estimates of the wealth of the 40 members of the Giving Pledge, at least $150 billion could be given away. Gates and Buffett are the second and third richest people in the world, behind Mexican tycoon Carlos Slim, with fortunes of $53 billion and $47 billion respectively.