TheStreet. Warren Buffett is arguably the most successful investor of all time. He's amassed an amazingly massive net worth by buying and usually holding stocks for the long haul. Trained under legendary value fund investor Benjamin Graham,

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.

The conglomerate sold Apple shares during the second quarter, though the iPhone maker remains Berkshire’s largest stockholding.

Also notice that although these are six brand-new positions, they add up to about $4 billion, significantly less than the proceeds from the Apple, Bank of America, and T-Mobile sales, which is how Berkshire was still a net seller of stocks for the quarter.

Warren Buffett’s Berkshire Hathaway resumed selling shares of Apple in the second quarter, offloading a stake worth more than $4bn as the billionaire investor continued to cut one of his most profitable trades.

Warren Buffett's top 10 stock holdings in the Berkshire Hathaway portfolio shows a preference to several sectors.

The most significant addition was UnitedHealth Group Inc (NYSE:UNH), with 5,039,564 shares, accounting for 0.61% of the portfolio and a total value of $1.572 billion. The second largest addition to the portfolio was Lamar Advertising Co (NASDAQ:LAMR),

The Oracle of Omaha sent two-thirds of his company's largest investment holding packing in favor of a 7.7% stake in a steadily growing, consumer-facing business.