Using the 10 percent figure for Exxon, if they totally eliminated their profit, they would then be selling gas for $3.60 instead of $4.
You're speaking only of "downstream" profit here, that is, the profit from refining and marketing the crude. When the "upstream" cost of crude oil is high, big integrated companies like ExxonMobil, BP, Shell, ChevronTexaco, etc., make huge profits on the crude they produce. Their only concern then is that the price of crude doesn't get driven up so high that it significantly reduces demand. They are always looking for the highest
optimum price they can get, that price at which they net the most profit. This summer's unjustified runup in crude prices, driven by investor speculation, was nothing more than a test of what the world market would support, and at what level that "highest optimum" could be set. My guess is that we've returned to something like that level now, with crude in the $120 per barrel range. Notice how so many people here are ecstatic about that. A year ago, we'd have considered $120 crude an outrage.
caw