The ratings on Irving, Texas-based ExxonMobil Corp. reflect the company's "excellent" business risk profile, based on outstanding competitive positions in all facets of the oil and gas industry, and its "minimal" financial risk profile (as Standard&Poor's Ratings Services' criteria define the terms). ExxonMobil operates in three primary business segments: upstream, downstream, and chemicals. Upstream (its exploration and production unit) contributes the most, by far, to profitability and cash flow. For the first nine months of 2011, the exploration and production (E&P) segment accounted for over 80% of the company's consolidated net income. At year-end 2010, ExxonMobil's proved reserves totaled more than 24 billion barrels of oil equivalent (boe)--the largest among the supermajors (the six largest nonstate-owned oil companies
