Understanding Monopolistic and Oligopolistic Market Structures
Monopolistic Short Run:
Profit: If firms are making profits in the short run, new firms will be attracted to enter the market. Since there are no barriers to entry, they can do it easily. As they enter, they will take business away from existing firms, whose demand curve will start shifting to the left.
Losses: If firms are making losses, some firms in the industry will leave the market. The firms that remain will find that their demand curve starts shifting to the right as they pick up trade from the leaving firms.
Long Run: Firms will end up with normal profit. Each firm is exactly covering its costs, including opportunity costs, and so there is no incentive for firms to leave the industry. Firms outside the industry will not enter since they...