Forms of Market and Price Determination
Forms of Market and Price Determination
This domain compares market structures and shows how price and output are determined. The exam tests features of perfect competition, monopoly, monopolistic competition and oligopoly, the MR = MC equilibrium rule, and concepts such as normal profit, shutdown point and price discrimination.
Core rules
- Perfect competition: many buyers and sellers, homogeneous product, free entry and exit, perfect knowledge, and a horizontal firm demand curve. The firm is a price taker, so P = AR = MR.
- Monopoly: a single seller, no close substitute, strong barriers to entry, and a downward-sloping demand curve. A monopolist is a price maker but cannot set both price and quantity independently.
- Monopolistic competition: many sellers with differentiated products, free entry, and some price-setting power. Oligopoly: a few interdependent firms; price rigidity and strategic behaviour are common.
- Profit is maximum where MR = MC and MC is rising. If P is above AC, supernormal profit; if P = AC, normal profit; if AVC is below P but P is below AC, the firm minimises loss in the short run; if P is below AVC, shut down.
- Price discrimination charges different prices to different buyers for the same product, possible when markets can be separated and resale is prevented.
Worked example
At output 3, MR = ₹10 and MC = ₹6; at output 4, MR = ₹8 and MC = ₹8; at output 5, MR = ₹6 and MC = ₹10. The firm expands to 4 units because each unit up to 4 adds more to revenue than to cost, but stops at 4 because the fifth unit would reduce profit. If price at 4 units is ₹12 and AC is ₹9, profit = (12 − 9) × 4 = ₹12.
Traps
Do not use MR = MC alone without checking that MC is rising. Do not say a monopolist charges the highest possible price; the profit-maximising price depends on demand and cost. Do not draw a downward-sloping demand curve for a perfectly competitive firm. Normal profit is part of cost, not a surplus.