10. The long-run industry supply curve is the industry supply curve given sufficient time for entry into and exit from the industry. In the long-run market equilibrium—given by the intersection of the long -run industry supply curve and the demand curve—no producer has an incentive to enter or exit. The long -run industry supply curve is often horizontal. It may slope upward if there is limited supply of an input, resulting in increasing costs across the industry. It may even slope downward, the case of decreasing costs across the industry. But it is always more elastic than the short -run industry supply curve.