At Berkshire Hathaway’s annual meeting earlier this year, Warren Buffett showed just how much of a fan he is of Apple’s CEO, Tim Cook. “Tim Cook has made Berkshire a lot more than I have made Berkshire,” Buffett said to laughter in the room. It was funny, but considering that Apple is Berkshire’s largest holding, I don’t think it was hyperbole.

As UnitedHealth Group wrangles with a federal investigation, an executive shuffle and a tanking stock price, a bullish ally has emerged: Warren Buffett. The Eden Prairie-based health giant’s stock price jumped more than 10% before trading opened Friday,