Oppenheimer Issues Massive Upgrade To Refining Sector By: Benzinga via Benzinga May 27, 2015 at 08:33 AM EDT Analysts at Oppenheimer said in a new research note that the more than five year outperformance of refining stocks will ... Read More >> Related Stocks: Hollyfrontier Corp Marathon Petroleum Phillips 66 Tesoro Petroleum Co Valero Energy