Worth: $68.7 billion
Overall rank: #14
The leader of tech giant Microsoft from 2000-2014, Ballmer joined the company as employee number 30 in 1980. A philanthropist, Ballmer put more than $2 billion into a donor-advised fund with a focus on lifting Americans out of poverty. He and his wife, Connie, invested $25 million in 2020 to fight COVID-19.