UnitedHealth Group's stock has collapsed nearly 50% in 2025 after a leadership shake-up, surging medical costs, and a DOJ criminal probe into Medicare fraud.

Shares of UnitedHealth Group slumped 6% in premarket trading Thursday on a report that the U.S. Department of Justice is investigating the embattled health insurance provider for possible criminal Medicare fraud.

Stephen Hemsley ran UnitedHealth Group for more than a decade. It's a different company after four years with Andrew Witty in charge.

"Leading the people of UnitedHealth Group has been a tremendous honor as they work every day to improve the health system and they will continue to inspire me," Witty said in a st

Former UnitedHealth Group chief executive officer Stephen Hemsley to replace Andrew Witty. Here's what we know.

UnitedHealth Group CEO Stephen Hemsley, who replaced Andrew Witty, said he has the right strategy in place “for the era ahead.”