Seventeen more U.S. billionaires agreed to give away at least 50 percent of their wealth to charities under the "The Giving Pledge" on Thursday.
The pledge was created by Bill Gates and Warren Buffet in August and originally had 40 wealthy members. New member Carl Icahn, a hedge fund manager, wrote in his pledge letter that he was planning to give away the majority of his assets, said Hedgefund.net.
Facebook co-founders Mark Zuckerberg and Dustin Moskovitz also made pledges to give away at least half their fortune to charity. Zuckerberg said that the pledge was an opportunity to "see the impact of our philanthropic efforts," according to Reuters.