Another topic for gas price vs crude oil price (see the other one here): Did you remember that when gas price was rising in the early summer, it was moving at several cents a day, but when it has been declining in the last few weeks, one cent difference can take days or even a week?
Barry L. Ritholtz offers some perspective in his thoughtful blog The Big Picture:
When crude prices rise, all the gas stations raise their prices accordingly -- they have no choice, otherwise they would be losing money on each sale. They all pay (more or less) the same prices for refined gas, and make a relatively small mark up on the fuel they sell. As wholesale prices rise, they pass along the increase.
When the price of Crude eases, however, what forces gasoline prices back down is simply competition. One station lowers prices a few cents, and pulls in more traffic; That forces others to do the same -- until prices gradually work their way back down to the earlier prices (assuming crude returns to its prior price). While the retailers may make a greater profit for a few days, competition eventually forces them back to their original margins.
I found this theory to be pretty convincing. If this is the case, and if the general supply and demand works, I can smell that gas price will be an interesting election topic by October and November.