2.2.4—Individual and market supply

Individual supply is one producer’s schedule; market supply is the horizontal sum of quantities supplied by all producers at each price.

Entry, exit and different costs change market supply; add quantities at the same price.

Sum producer quantities at one price before plotting the market point.

At $5 three firms supply 2, 3 and 4 units, so market supply is 9 units.

Market supply is not the average of firm schedules.