Gates, 59, stepped down as Microsoft’s chief executive officer in 2000 and established, with his wife, the Bill & Melinda Gates Foundation, which fights hunger, disease and poverty in the developing world. The foundation had a total endowment of $43 billion at the end of 2014.
In 2010, Gates joined billionaires including Warren Buffett, chairman of Berkshire Hathaway Inc. and No. 2 on the Bloomberg Billionaires Index, and Oracle Corp. CEO Larry Ellison, in signing the “Giving Pledge,” a vow to give away the majority of his fortune to charity.