Changes in Supply Versus Changes in Quantity Supplied A shift in the supply curve from S0 to S1 represents an increase in supply, because businesses are willing to offer more of the product to consumers at all prices. A shift from S0 to S2 reflects a decrease in supply. A movement along S0 from point a to point c represents an increase in quantity supplied; it results from an increase in the product’s market price from $40 to $80.