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

D.R. Horton, Lennar, and other home builder stocks were rising Friday after Warren Buffett’s Berkshire Hathaway purchased shares.

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.

What Happened: The undisclosed investments of Berkshire Hathaway have been made public. The company has reportedly invested in steelmaker Nucor NUE +1.07% Get Free Report , homebuilders D.R. Horton DHI +1.30% Get Free Report and Lennar LEN +1.56% Get Free Report , with the total investments amounting to $1.8 billion.

Thanks partly to Bogle, Buffett once won a $1 million bet that a Vanguard S&P index fund would outperform a selection of top hedge funds.

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Given Buffett's concern over the stock market, it makes sense for investors to buy the most conservative stocks in the Berkshire Hathaway portfolio.