The ratings on ExxonMobil Corp. reflect the company's excellent business risk profile characterized by an outstanding competitive position in all facets of the oil and gas industry as well as its minimal financial risk. Although Irving, Texas-based ExxonMobil operates in many segments of the energy industry, its exploration and production (E&P) unit is by far the most important contributor to profitability and cash flow and drives future growth. ExxonMobil's proved reserves total about 22.7 billion barrels of oil equivalent (boe), giving the company one of the largest resource bases of all national and international oil companies. Factors that mitigate depletion risks are a long reserve life (about 14 years) and a large resource base (estimated at 74 billion boe) from