If price is originally at P1 in the picture below, only Q1 will be sold because this is all that buyers will purchase, even though sellers are willing to sell more, Q2. The difference Q2 - Q1 is called a surplus. In this situation the buyers are in equilibrium because they can buy all they want to buy at the going price. However, the sellers are not in equilibrium and will compete among themselves to get rid of the surplus. Some sellers will be willing to offer their product at a lower price. Buyers are always willing to move down the demand curve, so there is a tendency to move downward toward market equilibrium in the picture below.