The official business definition of Supply Curve Shifting To The Left is the change in price and quantity supplied when a good or service’s cost of production suddenly increases. Put simply, shifts in the supply curve to the left occur when there is an increase in cost or a decrease in price associated with production. This can cause businesses to produce less of the good or service, as they need to account for higher costs and decreased prices in order to remain profitable. The demand for the good or service then decreases, resulting in an overall reduction in market supply.