US billionaires pledge 50% of their wealth to charity
Microsoft founder Bill Gates started the campaign along with investor Warren Buffet
Thirty-eight US billionaires have pledged at least 50% of their wealth to charity through a campaign started by investor Warren Buffet and Microsoft founder Bill Gates.
They include Mayor Michael Bloomberg, CNN founder Ted Turner and entertainment executive Barry Diller.
"The Giving Pledge" lists all the families and individuals who have committed to the project.
The site says the pledge is a "moral commitment" not a "legal contract".