When US billionaires Bill Gates and Warren Buffett held a banquet in China a few years ago to urge fellow tycoons to donate their fortunes to charity, some of their intended targets didn't bother to turn up. The no-shows sparked a fierce debate on social media: are China's super rich really so stingy? By some measures, they are. Total charitable giving in China stands at just 4% of levels in the US or Europe, according to the United Nations Development Programme. Chinese charities have been hit by scandal, and there is widespread mistrust of the private wealth on which much of the giving depends.