Major oil companies such as Esso, Shell and BP insist that although they are making money from producing oil, they are not making money from selling it. BBC News Online looks for answers.
Oil companies like to separate the different parts of their business.
One part of their business is a customer of the other. When crude oil is expensive the seller will see a rise in profits while the buyer will see a rise in costs. Take a small independent refinery or petrol station. They would not be able to compete with Shell refineries and petrol station whose prices were subsidised by the profits from Shell's North Sea explorations. This is determined by supply and demand in the crude oil market.