UnitedHealth Group named John Rex, formerly of its subsidiary Optum, as Chief Financial Officer in June 2016. Rex replaces David Wichmann, who has been working dual roles as President and CFO since a C-level reorganization in November  2014. Wichmann will stay on as President of the company. UnitedHealth Group includes UnitedHealthcare and Optum, a health services platform, as well as Amil, Brazil’s largest health care company. Prior to joining