Feb 21 (Reuters) - The U.S. Justice Department has

launched an investigation into UnitedHealth's ( UNH ) Medicare

billing practices in recent months, the Wall Street Journal

reported on Friday, citing people familiar with the matter.

Shares of the company fell nearly 7% to $466.88 in premarket

trading.

The new civil fraud investigation is examining

UnitedHealth's ( UNH ) practices for recording diagnoses that trigger

extra payments to its Medicare Advantage plans, including at

physician groups the insurance giant owns, the report added.

DoJ and UnitedHealth ( UNH ) did not immediately respond to a Reuters

request for comment.