Long-run equilibrium under monopolistic competition and the managerial implications of entry

Monopolistic competition

In monopolistic competition, each of a large number of sellers offers a product a little different from its rivals' (through its brand, packaging, quality, location or after-sales service). That difference gives every seller a small following of its own, and so some say over its price; yet because rivals sell close substitutes, its demand curve, though downward sloping, is fairly elastic. Firms can enter or leave the market freely. Examples (our own): bakeries in a city neighbourhood, tuition centres around a university, and makers of phone covers and chargers.

Long-run equilibrium

Short run. A firm produces where MR = MC. If its price exceeds average cost, it earns supernormal profit.

Adjustment through entry. Because entry is free, supernormal profits attract new firms offering close substitutes. Each existing firm loses some customers, so its demand (AR) curve shifts to the left and becomes more elastic. Entry continues until supernormal profit disappears. (If firms are making losses, some leave, and the demand curves of those remaining shift right, until losses disappear.)

Final position (Chamberlin's tangency solution).

• The firm's demand curve AR is tangent to its long-run average cost (LAC) curve at the equilibrium output OQ.
• MR = LMC at that output, and P = LAC, so the firm earns only normal profit.
• Because the demand curve slopes downward, the tangency lies on the falling part of LAC, to the left of minimum LAC. The firm produces less than the output at minimum average cost: it has excess capacity, and price is above marginal cost.

Diagram. Output on the horizontal axis, price and cost on the vertical axis. U-shaped LAC; the downward-sloping AR curve touches LAC at E (output OQ, price OP); MR cuts LMC vertically below E. The minimum of LAC lies at a larger output OM; QM is the excess capacity.

Managerial implications of the entry of new firms

1. Profits are temporary. Supernormal profit from a good product or location is competed away as imitators enter. A manager should plan on normal returns in the long run and recover investment quickly.
2. Differentiation is the main defence. Brand building, better quality, design, service and location keep the firm's demand curve less elastic and slow the leftward shift. Continuous product innovation restarts the cycle of temporary profits.
3. Rising selling costs. Firms spend more on advertising, promotion and packaging to hold customers, which raises average cost; managers must judge whether each rupee of promotion protects enough demand.
4. Limited pricing power. As demand becomes more elastic, price rises lose more customers; non-price competition (loyalty programmes, convenience, after-sales service) becomes more important than price.
5. Cost control and capacity. With normal profit only and excess capacity, survival depends on keeping costs in line with rivals: using idle capacity (off-peak offers, new products on existing equipment) lowers unit costs.
6. Niche and segment choice. Targeting a segment that newcomers find hard to serve (a speciality, a neighbourhood, a premium tier) protects margins.

Example (our own). When a café chain earns high profits in a Bengaluru neighbourhood, independent cafés open nearby within a year; the chain's footfall per outlet falls, and it responds with a loyalty app, seasonal menus and a delivery tie-up rather than price cuts.

Conclusion

In the long run, free entry pushes each firm to the tangency of its demand curve with LAC: normal profit, a price above marginal cost and excess capacity. For managers, entry means profits must be continually re-earned through differentiation, innovation, efficient use of capacity and careful promotion spending.