New Delhi, May 15 -- Shares of UnitedHealth Group plunged to a five-year low on Thursday on the New York Stock Exchange after reports of a probe against the company.

The shares of UnitedHealth Group plunged over 19 per cent to hit the low of $248.88 per share.

Here is why UnitedHealth Group stock is falling today.

The Wall Street Journal in a recent report citing unnamed individuals stated that the US Department of Justice was investigating UnitedHealth Group for potential Medicare fraud.

The report added that the Department of Justice has had a probe into the company's Medicare Advantage business since at least last summer.

Hours later, UnitedHealth released a statement, denying the allegations made in the report.

"We have not been...