What was once just an altruistic idea conceived by three people has turned into a global movement among the world’s billionaires. When Bill Gates, Melinda French Gates, and Warren Buffett founded the Giving Pledge in 2010 to mobilize the planet’s wealthiest citizens to solve major issues through donations, they likely hoped their friends and some other philanthropic businesspeople would sign on. But after a recent deluge that saw 14 more billionaires join the ranks, the Giving Pledge now boasts 231 philanthropists from 28 different countries. “I’m inspired to see how the Giving Pledge has grown into a movement of over 230 philanthropists from around the world who are committed to giving away the vast majority of their wealth to address some of the most pressing issues in our society,” French Gates said. The newest members of the club include Tony Xu, the CEO and co-founder of DoorDash, and his wife, Patti Bao, and Ben Silverman, CEO and co-founder of Pinterest, and his wife, Divya Bhaskaran. “I think it’s a commitment of not just money, but it’s a commitment of time to be good,” said Jon Ayers, the former CEO of veterinary services firm IDEXX Laboratories and current chairman of Panthera, which attempts to preserve wildcats and their ecosystems around the world. Together, the new signees are worth an estimated $48.1 billion—with Canva’s co-founders Melanie Perkins and Cliff Obrecht contributing their estimated net worth of $13 billion, and Boem-su Kim, the founder of South Korea’s biggest messaging app, Kakao, adding his estimated net worth of $11.4 billion.