Back in 2010, Bill Gates and Warren Buffett started something called The Giving Pledge, where they promised to give most of their money away to charity throughout their lives.
None of them are all that famous, so you might not know their names. But half of them are here in the U.S., and you probably know their companies . . .
Dagmar Dolby is the widow of the guy who created Dolby surround sound. Nick Hanauer was an early investor in Amazon. Dean Metropoulos used to own Pabst Blue Ribbon. Terry Ragon founded the software company InterSystems . . .
Harry Stine owns Stine Seed, the largest seed company in the U.S. Nathaniel Simons runs the Sea Change Foundation. And investor Robert Smith is the second-wealthiest black person in America after Oprah.
Some of the more famous billionaires have already signed the pledge, including Mark Zuckerberg, George Lucas, Michael Bloomberg, and Elon Musk.
168 people in 21 different countries have now signed it, and almost all of them are billionaires.
All total, they've promised to give almost $400 BILLION to charity.