Market equilibrium is at the intersection of the supply and demand curves. At this intersection the quantity supplied equals the quantity demanded. All buyers are able to find sellers and all sellers are able to find buyers. When the price is above the equilibrium price, the quantity supplied will exceed the quantity demanded. The excess supply results in unsold inventories.
Sellers have sales and cut the price to eliminate the inventories.
This continues until the quantity demanded equals the quantity suppplied at the equilibrium price. When the price is below the equilibrium price, the quantity demaneded will exceed the quantity supplied. The excess demand results in a shortage. Buyers will be unable to purchase all that they are willing and able to purchase and will bid the price up. This continues until the shortage is eliminated Markets are efficient in that they maximize the sum of producer and consumer surplus.