The Board of Directors of UnitedHealth Group has named Sir Andrew Witty as chief executive officer, succeeding David S. Wichmann, who retires after successfully guiding the company through a period of growth and innovation and the deeply challenging onset of the COVID-19 pandemic. He will rejoin the UnitedHealth Group Board of Directors and becomes CEO immediately, with Wichmann continuing in a transition period through March 2021.Witty, Chief Financial Officer John Rex, and Dirk McMahon, as the new president and chief operating officer, will constitute the company’s Chief Executive Office. McMahon has served as CEO of UnitedHealthcare since June 2019. Prior to this role, McMahon was president and chief operating officer, Optum. McMahon has served in a number of leadership positions across the enterprise since joining the company in 2003, including CEO, OptumRx, overseeing UnitedHealth Group's pharmacy benefit management programs, along with various management positions in information technology, operations and finance. Before joining UnitedHealth Group, McMahon was head of airport operations worldwide for Northwest Airlines. As executive vice president and CFO of UnitedHealth Group since June 2016, Rex has an expansive operating, growth and finance portfolio. He joined the company in 2012 as executive vice president and CFO of Optum. Prior to that, Rex was a leading equity research analyst, served as a strategy and operational consultant, and practiced as a certified public accountant across several health care sectors.