Market makers are required to post a price at which they are willing and able to buy and sell. These prices are commonly referred to as bid and ask prices.
Some MM's don't bother to close out their entries at the end of the day and you will sometimes see the furthest MM that lingers on the bottom 'move' up as the ones above them close out. Again, it is all utterly meaningless when the markets are CLOSED. Don't be mislead by the antics around here.