Nelson took over as CEO of UnitedHealthcare in April 2017. Under his leadership, the insurer's revenue hit $163.3 billion in 2017, up 9.9% from the previous year. The company also grew its membership by 1.1 million people. UnitedHealthcare is rolling out initiatives to address social determinants of care, including programs for transportation and housing. Earlier this year, Nelson oversaw UnitedHealthcare's expansion into Chile, Columbia and Peru.