BALTIMORE ( Stockpickr) -- Warren Buffett has his two favorite stock pickers hard at work this summer, picking up shares of their favorite stocks for Berkshire Hathaway's ( BRK.A, BRK.B) $89 billion portfolio. Buffett's betting big on these names; the question is, are you? >>5 Rocket Stocks to Buy Now Todd Combs and Ted Weschler are former hedge fund managers hand-picked by Warren Buffett to help him manage massive chunks of Berkshire's enormous portfolio. So far, the Oracle of Omaha's lieutenants have been earning their keep: both managers beat the S&P 500 by double digits last year. But while Combs and Weschler have turned out impressive performance, don't accuse them of being creative when it comes to their trades; the seven names Berkshire increased in the second quarter were all add-ons to existing positions. Even though the buying has been cautious, it tells us a whole lot more about the stocks that these guys like than if they'd been buying with both hands. >>5 Toxic Stocks You Should Sell That's why today we're taking a closer look at five conviction buys on Berkshire Hathaway's short list. That word -- conviction -- is an important distinction for the folks poring over Berkshire's latest 13F filings with the SEC.