Berkshire Hathaway's $1.6 billion stake in UnitedHealth Group is helping to lift the Dow Jones Industrial Average to a new record as investors pile into healthcare sector funds.

UnitedHealth Group Inc. shares jumped after funds piled into the company, which has been hampered by a federal probe into its business practices and weakening results.

Shares of UnitedHealth Group surged nearly 14% on Friday after billionaire Warren Buffett's Berkshire Hathaway bought 5 million shares of the company, providing a shot in the arm for investors who think the health conglomerate will turn around under its new CEO.