Sandy forgets that OPEC also has something to do with oil prices; adjusting production to keep prices within a range. Saudi Arabia and Iran, with the two largest production companies, Saudi Aramco and NIOC, along with the Emirates and Kuwait, are the OPEC members that control in that group (Venezuela has quit).

Exxon Mobil, with decreasing reserves, buys much of the oil that it refines. It does share ownership of some important refining companies, but shares this market with other biggies. It prefers to invest, and let others control, a change in policy that has taken place.
Many changes in rank and importance in the past five years.

World Petroleum Liquids Production- 2006
1. Saudi Aramco 11035 (thousands bbls/day)
2. NIOC (Iran)   4049
3. Pemex (Mexico) 3710
4. PDV (Venezuela) 2650
5. KPC (Kuwait) 2643
6. BP (British Petroleum) 2562
7. Exxon Mobil 2523
8. PetroChina 2270
9. Shell 2093
10. Sonotrach (Algeria) 1934 (Seldom mentioned, but widespread interests)
Seven of those ten are state-owned, and all have a share in refineries.
Source: "Energy Intelligence Research," 2007 ed.

The largest corporations, as economic entities: Wal-Mart, British Petroleum, Exxon Mobil, and Royal Dutch Shell in that order. All three oil companies make much of their profit in refining and manufacturing. PetroChina soon will surpass Exxon Mobil and British Petroleum.

A mistake in my previous post- ENI, the Italian company, has made peace with Venezuela, and plans to invest $4B in new fields.