How does a market arrive at equilibrium? Consider the market depicted to the right. Suppose the market price is initially P_A. At this price, the desired quantity demanded is Q_D and the desired quantity supplied is Q_S. Notice that Q_S is far greater than Q_D; firms are willing to sell much more than consumers wish to buy at P_A. If producers actually offer Q_S for sale, a great deal of their product will pile up in inventory or on store shelves. The only way to get rid of this surplus inventory, is for the price to fall.