10. Michael Bloomberg, 76, Bloomberg LP, $50 B
Special envoy to the United Nations for climate change Michael Bloomberg dresses the medias at the One Planet Summit, in Boulogne-Billancourt, near Paris, France, Tuesday, Dec. 12, 2017. World leaders, investment funds and energy magnates promised to devote new money and technology to slow global warming at a summit in Paris that President Emmanuel Macron hopes will rev up the Paris climate accord that U.S. President Donald Trump has rejected. (AP Photo/Christophe Ena)