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.

The biggest immediate changes will be that different people will be in control of the company's stock portfolio, and Abel will have power over Berkshire's $344 billion cash hoard. However, portfolio managers Ted Weschler and Todd Combs have been managing more of Berkshire's investments as the years have progressed.

Key Takeaways Warren Buffett's Berkshire Hathaway increased its holdings in UnitedHealth Group stock.A regulatory filing showed Berkshire held 5 million shares in the second quarter.Berkshire also added positions in D.