JOLIET, IL - NOVEMBER 01:  An Exxon Mobil Corp. logo is painted on a storage tank at the Exxon Mobil refinery November 1, 2007 in Joliet, Illinois. The oil company reported a bigger-than-expected 10% drop in quarterly net income on lower refining and chemical margins. Getty Images logo Getty Images 25 months ago

JOLIET, IL - NOVEMBER 01: An Exxon Mobil Corp. logo is painted on a storage tank at the Exxon Mobil refinery November 1, 2007 in Joliet, Illinois. The oil company reported a bigger-than-expected 10% drop in quarterly net income on lower refining and chemical margins.