Berkshire Hathaway keeps piling into Occidental stock. Should you follow Warren Buffett's lead?Over the past several quarters, Warren Buffett and his team at Berkshire Hathaway have reduced many of their holdings, including selling shares of Apple and Bank of America. However, one stock the conglomerate can't stop buying lately is Occidental Petroleum (OXY -0.59%).In the second quarter, Berkshire Hathaway purchased 7.3 million shares in the oil and gas producer, bringing its total stake to 255.3 million, wo ...