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 blue-chip Dow Jones ended higher after hitting an intraday record high on Friday, as UnitedHealth’s shares jumped after Berkshire Hathaway raised its stake, but other Wall Street indexes slipped as mixed data clouded the Federal Reserve’s next monetary policy move.