A gallon of oil can be $3 or $6 depending on whether someone is willing to pay. It can also be $10 but only if people are willing to buy it at $10 if not "prices will come down to match the demand" - another way of saying it would be $9..$8...$7...$6 until it matches a buyer at which point gas is $6.
So stock marked is always meaningless except considering it is so large and consequanetial and so many people have access to it that it will be rational automagically. This is more of a belief that seems to be fairly correct than a rational line of thinking.