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 10 per cent in pre-market trading on Friday after Warren Buffett’s Berkshire Hathaway snapped up a stake in the troubled US healthcare group.

The "vote of confidence" from Buffett validates UnitedHealth's long-term value, but " (the) management needs to regain trust and credibility with investors, and get back to its beat-and-raise reputat...