The pledge started by Warren Buffett and Bill Gates is The Giving Pledge.
Announced in 2010, the campaign asks wealthy individuals and families to publicly commit to giving at least half of their net worth to philanthropic causes, either during their lifetimes or through their wills. Bill Gates, Melinda French Gates, and Warren Buffett were its founding figures and early recruiters.
The pledge is deliberately a public promise rather than a legally enforceable contract. Participants generally publish personal letters explaining their motivations, which makes the campaign as much about creating a culture of large-scale giving as about collecting money for one central organization. Signatories can choose the charities and causes they support.
It is often confused with the Gates Foundation because Gates and Buffett have collaborated closely in philanthropy. They are separate: the foundation makes grants and runs programs, while The Giving Pledge encourages donors to direct their own wealth to charitable work. The phrase “at least half” also matters—the pledge sets a minimum target, not a requirement to donate exactly 50%.