Forty of America’s richest citizens have responded to a campaign by Bill Gates and Warren Buffett to pledge to give more than half their fortunes to charity.
The Giving Pledge was launched in June to encourage billionaires and other wealthy people to make a moral commitment to supporting philanthropic causes and charities.
Michael Bloomberg, the Mayor of New York City, and the director George Lucas, who made the Star Wars films, are among those to have made the pledge.
Each individual will decide which organisations will benefit from their largesse.
Musa Okwonga, press director at the Institute for Philanthropy, welcomed the pledge and hoped it made wealthy givers more comfortable about making their donations public.
But he said the Giving Pledge was likely to have little impact on charities in the UK because 90 per cent of US funding went to US charities.
"There is nothing to say something like this couldn’t happen in the UK, though," said Okwonga. "The billionaire Albert Gubay has recently pledged £1bn here, and social media is making it increasingly easy for projects like this to be put together."
Bea Devlin, head of international at the Charities Aid Foundation, estimated that if every UK billionaire gave more than half of their wealth to charity it would result in an extra £60bn going to good causes.