KEY TAKEAWAYS 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.

(Reuters) -The U.S. Justice Department is investigating UnitedHealth Group for potential criminal fraud in its Medicare Advantage business, the Wall Street Journal reported on Wednesday, citing people familiar with the matter. Reuters could not immediately confirm the details of the report.

The Justice Department is investigating UnitedHealth Group for potential Medicare fraud, focusing on its Advantage business practices.