Berkshire Hathaway recently filed its second-quarter 13F form, revealing its stock holdings at the end of June.

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.

Berkshire purchases often boost stocks. Shares of the steel maker traded as high as $151.32 on Friday, but closed at $145.48, up 0.8%. The S&P 500 fell 0.3%. The Dow Jones Industrial Average rose 0.1%.

UnitedHealth shares surged Friday after Warren Buffett’s Berkshire Hathaway revealed a stake in the embattled healthcare giant. Monitor these major chart levels.

It might not be Warren Buffett's fault that Berkshire Hathaway stock is down 11% since he revealed he's stepping down as CEO in December.

The cyclically adjusted price-to-earnings (CAPE) ratio is a valuation metric typically used to gauge whether entire stock market indexes are overvalued or undervalued. It was developed by Nobel-winning economist Robert Shiller during the dot-com bubble, so it is sometimes referred to as the Shiller P/E ratio.

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.

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