Monopolistic Competition (Price and Output Determination)

1) Meaning: what is monopolistic competition?

Monopolistic competition is a market structure with:

• many firms
• product differentiation
• free entry and exit (in the long run, typically)
• each firm has some market power because its product is differentiated.

Examples (real-world approximate):

• restaurants, salons,
• branded consumer goods,
• retail clothing, cafes.

Firms compete through price and non-price competition (branding, advertising, service quality, location).

2) Key features (high-yield)

1. Many sellers: each is small relative to the total market.
2. Differentiated product: each firm faces a downward sloping demand curve for its own variety.
3. Free entry/exit: long-run profits are competed away.
4. Independent decision-making: no strategic interdependence as strong as oligopoly.
5. Selling costs: advertising and marketing are common.

CUET distinction:

• Like monopoly: downward sloping demand curve for each firm.
• Like perfect competition: many firms and free entry/exit → long-run normal profit.

3) Demand, AR and MR for the firm

Because products are differentiated:

• Each firm faces a downward sloping demand curve.
• Thus:
  • AR = demand curve
  • MR lies below AR (as in monopoly)

So the firm chooses output where:

and then chooses price from demand curve.

4) Short-run equilibrium

Short run: fixed number of firms. A monopolistically competitive firm can earn:

• supernormal profit,
• normal profit,
• or loss, depending on demand position relative to cost curves.

Profit condition at optimal $Q^*$:

• If $P^* > AC(Q^*)$: profit
• If $P^* = AC(Q^*)$: normal profit
• If $P^* < AC(Q^*)$: loss

5) Long-run equilibrium: entry and exit

5.1 Entry when profits exist

If firms earn positive economic profit:

• new firms enter because there are no strong barriers.
• Entry increases product varieties and draws some consumers away from existing firms.
• Each existing firm’s demand curve shifts left (and becomes more elastic).

5.2 Exit when losses exist

If firms incur losses:

• some exit; remaining firms face higher demand.