Buffett owned UnitedHealth shares before selling his stake in 2010, though his Berkshire Hathaway recently acquired shares.

The investment comes as UnitedHealth faces soaring medical costs, federal investigations, the fallout of the killing of a top executive and a cyberattack last year.

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.

Warren Buffett's Berkshire Hathaway increased its holdings in UnitedHealth Group stock, and also added positions in D.R. Horton, Lamar Advertising, and Nucor.

Top political and market headlines this weekend include stock trades by lawmakers, Trump's tech export tax, and calls for Fed action after weak job data.

Warren Buffett's modus operandi is to wait for price dislocations to present themselves. In a historically pricey stock market, locating value has been virtually impossible. Yet, with UnitedHealth Group stock losing more than half its value since the midpoint of April, a rare price dislocation has emerged.

UNH stock soared after Warren Buffett’s Berkshire Hathaway revealed it bought shares of the healthcare company. Nonetheless, UnitedHealth faces a long list of unresolved issues.