Por MICHELLE CHAPMANEl director general de UnitedHealth, Andrew Witty, dejará su cargo por razones personales y la aseguradora de salud más grande del país suspendió su

May 13 (UPI) -- UnitedHealth Group announced Tuesday CEO Andrew Witty will step down, citing "personal reasons." Witty will leave the role of CEO and be replaced by Stephen J. Hemsley, effective immediately.

UnitedHealth Group said its Chief Executive Andrew Witty resigned as of Tuesday, and the company suspended its annual forecast due to surging medical costs, sending shares plunging nearly 18% to a four-year low.

UnitedHealth Group surprises investors with what its CEO said was an "unusual and unacceptable" quarterly earnings miss, and lowers its outlook for the full year due to higher-than-expected medical costs, sparking a more than 20% selloff in shares that reverberated across the sector.

"We are grateful for Andrew's stewardship of UnitedHealth Group, especially during some of the most challenging times any company has ever faced," Hemsley said. "The Board and I have greatly valued his leadership and compassion as chief executive and as a director and wish him and his family the best.