Shares of UnitedHealth Group are surging before the market open Friday as Warren Buffett's Berkshire Hathaway disclosed that it recently purchased shares of the beleaguered insurer.

UnitedHealth shares jumped 12 per cent on Friday after Warren Buffett’s Berkshire Hathaway snapped up a stake in the troubled US healthcare group.

UnitedHealth Group ( UNH 12.04%) has been a solid dividend growth stock for years. Generally, its yield has been fairly low, due to the stock's rising value. Even as the healthcare insurance giant has grown its dividend, its yield hasn't been particularly high or noteworthy.

UnitedHealth Group Incorporated (NYSE:UNH) is one of the stocks Jim Cramer shed light on. Cramer showed a slight bit of optimism toward the company as he said: “I think UnitedHealth’s going to work

Stocks were mixed Friday after the University of Michigan’s consumer sentiment index fell from the prior month and ahead of a scheduled summit between President Donald Trump and Russian leader Vladimir Putin.