Berkshire Hathaway’s portfolio added six new stocks, including the three new secret stocks. Warren Buffett was a net seller of stocks for the eleventh straight quarter.

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.

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

The big surprise was a brand new, $1.6 billion stake in UnitedHealth, accumulated entirely during the second quarter.

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

Berkshire Hathaway revealed four new investments Thursday in steelmaker Nucor, insurer UnitedHealth and two of the nation's biggest homebuilders — Lennar and DR Horton — but it's not clear if the investments are big enough to ensure that legendary investor Warren Buffett handled them.