Eleven billionaires have added their names to the effort by Bill Gates and Warren Buffett to donate half their fortunes to charity, bringing the total to 92.
The newest members of the club include Netflix chief executive Reed Hastings, Intel cofounder Gordon Moore, and Charles Bronfman, the Canadian-born former head of Seagram.
The Giving Pledge was launched in 2010 by Microsoft mogul Gates and investment guru Buffett who want to convince the richest people in the country to give 50 per cent or more of their fortune to charity.
The group includes CNN founder Ted Turner, New York Mayor Michael Bloomberg, Oracle cofounder Larry Ellison and film director George Lucas.
"We've said from the beginning that this is a long-term effort, so it's exciting to see continued progress over the last two years," said Gates, who is co-chairman of the Bill & Melinda Gates Foundation.
The newest members also include Manoj Bhargava, Indian-born founder of 5-hour Energy; and Dan Gilbert, founder of Quicken Loans and majority owner of the Cleveland Cavaliers basketball team.
Also pledging were Peter Lewis, chairman of Progressive Insurance; Jonathan Nelson, founder of Providence Equity Partners; Jorge Perez, chairman and CEO of The Related Group; Albert Lee Ueltschi, founder of FlightSafety International; and Symphony Technology Group founder Romesh Wadhwani.
New pledges also came from Claire Tow, co-founder one of a major cable television company, and husband Leonard Tow, the CEO of New Century Holdings.
Forbes magazine says there are 95 mainland Chinese billionaires, and 37 in Hong Kong. None have signed Giving Pledge.