Berkshire Hathaway invests $1.57B in UnitedHealth (UNH), boosting shares by 10.5%. Discover key insights on its challenges, outlook, and analyst ratings.

The long-running mystery around Warren Buffett’s latest stealth investment is finally over. In Berkshire Hathaway’s (NYSE: BRK.B) newest 13F filing, the Oracle of Omaha revealed a fresh stake in UnitedHealth Group Incorporated (NYSE: UNH).

Warren Buffett's Berkshire Hathaway built a $1.6 billion stake in UnitedHealth last quarter, marking one of its last wagers with the investor as CEO.

Warren Buffett's Berkshire Hathaway has acquired 5 million shares in UnitedHealth Group , a regulatory filing showed on Thursday, sending the health insurer's stock up 7% in extended trading.

The company may be under criminal investigation for alleged irregularities in its Medicare business—but it's been touched by the Warren Buffett effect.

Warren Buffett's mystery stock purchase has sparked speculation and a frenzy. The only certain clue is that it's not a bank, insurer, or consumer products company.

B stake in UnitedHealth Group Incorporated signals a market shift. Click for why I have now upgraded UNH stock to Buy.

One figure from Berkshire Hathaway's latest operating results appears to be a telltale sign of trouble to come for the stock market.