19. Jack Ma, 53, e-commerce, $39 B
Founder and chairman of Alibaba Jack Ma leaves after signing the memorandums of understanding linked to the investment in the country during a press conference Bangkok, Thailand, Thursday, April 19, 2018. The Chinese e-commerce giant Alibaba has agreed to step up investments in Thailand as competition between online retailers heats up in fast-growing Southeast Asia. (AP Photo/Sakchai Lalit)