Key Points Warren Buffett's Berkshire Hathaway owns a big stake in Occidental Petroleum. Berkshire is set to buy Occidental's chemical business, OxyChem, for $9.7 billion. While Occidental will use the proceeds to repay debt, Berkshire is expanding its noninsurance portfolio. 10 stocks we like better than Berkshire Hathaway › Just before Warren Buffett retires as the CEO of Berkshire Hathaway (NYSE: BRK.A)(NYSE: BRK.B) later this year, the company has struck its biggest deal in three years. On Oc ...