The Giving Pledge
"Created by Bill and Melinda Gates and Warren Buffett, the Giving Pledgecame to life following a series of conversations with philanthropists around the world about how they could collectively set a new standard of generosity among the ultra-wealthy."
https://givingpledge.org/About.aspx
Prince Alwaleed Bin TalalAnd the Giving Pledge
http://tradearabia.com/news/MEDIA_308012.html
Many have made "commitment to philanthropy".
"A COMMITMENT TO PHILANTHROPY
The Giving Pledge is a commitment by the world's wealthiest individuals and families to dedicate the majority of their wealth to giving back."
https://givingpledge.org/Home.aspx