Price discrimination

Topic: Market Structures, Market Failure and Competition · NCERT: Beyond NCERT

Meaning

Price discrimination means a seller charges different buyers different prices for the same product, and the gap in price is not due to any difference in cost.

It matters because it shows how a firm with market power (the ability to set its own price) can earn more profit. The same tool can also help the poor, as with student fares and cheap power for farmers, or it can be used to exploit buyers, as with personalised online pricing. In third-degree discrimination, the price in each market follows the Lerner index rule: (P − MC) / P = 1 / |e|. Here P is price, MC is marginal cost (the extra cost of making one more unit) and e is the price elasticity of demand (how strongly buyers react to a price change). So the market with the lower |e| gets the higher price.

Explanation

Conditions needed

A firm can price-discriminate only when all four conditions hold:

1. The seller has market power. A price taker, such as a firm in perfect competition, must accept the market price, so it cannot charge different prices.
2. The markets can be kept apart. The seller must be able to tell groups apart, for example by ID cards, time of booking or location.
3. The groups have different price elasticities. The higher price goes to the less elastic group, the group that reacts less to price.
4. There is no resale (no arbitrage). A buyer who gets the low price must not be able to resell to someone charged the high price. If resale is possible, the high-price market collapses.

Three degrees of price discrimination

Degree	How it works	Effect on buyers and society	Indian example
First (perfect)	Each buyer pays their maximum willingness to pay	Seller takes all consumer surplus (CS = 0). Output rises to the competitive level, so there is no deadweight loss (DWL)	Personalised or algorithmic online pricing
Second	Price changes with quantity or version. Buyers sort themselves by picking a plan	Seller never needs to know who is who	Data packs, bulk discounts, tiered subscription plans
Third	Different prices for identifiable groups	Less elastic group pays more	Student and senior citizen fares, railway classes, electricity cross-subsidy tariffs

• Consumer surplus (CS) is the most a buyer is willing to pay minus the price they actually pay.
• Deadweight loss (DWL) is the gain from trade that is lost because output falls below the efficient level. Nobody receives it.
• Why first degree has no DWL:
• A single-price monopolist sells less on purpose so that it can keep the price high.
• A perfect discriminator loses nothing by selling one more unit to a low-value buyer, because it does not have to cut the price for everyone else.

• So it keeps selling until price = MC, which is the competitive output. Efficiency is full, but all the gain goes to the seller.

• Example (demand P = 100 − Q, MC = 20): under competition, output is 80 and CS = 3,200. A single-price monopolist sells 40, and the DWL is 800. A perfect discriminator sells 80, like competition, but takes the whole 3,200 as profit, and CS falls to 0.

Worked example: third degree

MC = 20. Market A (business travellers): P = 100 − Q. Market B (students): P = 60 − Q.

• Market A: MR = 100 − 2Q = 20 → Q = 40, P = 60, |e| = 60/40 = 1.5 (less elastic).
• Market B: MR = 60 − 2Q = 20 → Q = 20, P = 40, |e| = 40/20 = 2 (more elastic).

• MR (marginal revenue) is the extra revenue from selling one more unit. The firm sets MR = MC in each market separately.

• Lerner check: A: (60 − 20)/60 = 0.67 = 1/1.5. B: (40 − 20)/40 = 0.5 = 1/2. The less elastic market has more market power and a higher price.

• Profit with discrimination: (60 − 20) × 40 + (40 − 20) × 20 = 1,600 + 400 = 2,000.
• Profit with a single price: combined demand Q = 160 − 2P, so MR = 80 − Q = 20 → Q = 60, P = 50. Profit = 30 × 60 = 1,800.
• Lesson: discrimination raises profit from 1,800 to 2,000, and the less elastic group (business travellers) pays more.

In India

• Railways and transport fares: student and senior citizen concessions and different railway classes are third-degree discrimination. ID cards keep the markets apart and stop resale.
• Telecom and digital plans: data packs and tiered subscriptions are second-degree discrimination. Each buyer picks the plan that suits them.
• Electricity cross-subsidy: this is the biggest policy case of third-degree discrimination.
• Cross-subsidy means one group pays more than the cost of supply so that another group can pay less. Here, industry pays more than farmers.
• The Tariff Policy, 2016 aims to keep every consumer category's tariff within ±20% of the average cost of supply. Many states still go beyond this band [3].
• The Draft Electricity (Amendment) Bill, 2025 proposes that cross-subsidies paid by manufacturing enterprises, railways and metro railways be fully ended within five years, and that tariffs reflect the cost of supply [2].

• Tariffs are set by electricity regulators: CERC (central) and SERCs (states).

• Dynamic pricing (Class 9 Goa hotel example): the same room costs ₹1,500 on an off-season weekday, ₹8,000 on a December weekend and ₹25,000 on New Year's Eve. Tariffs are cut by 40% overnight if a group booking is cancelled. Airline fares and ride-hailing surge pricing work the same way.

• Consumer protection: the Central Consumer Protection Authority (CCPA) deals with unfair trade practices. This makes it the relevant body when algorithmic, personalised pricing harms consumers.

Don't confuse with

• Cost-based price differences: if a product costs more to deliver to one buyer (for example, extra transport), charging that buyer more is not price discrimination. Price discrimination needs the same product with the gap not due to cost.
• Predatory pricing: this means selling below the cost of production to reduce competition or drive rivals out. It is banned as an abuse of dominant position under Section 4 of the Competition Act, 2002 [1]. Price discrimination aims to extract more from buyers, not to kill rivals.
• First vs third degree: first degree takes all CS and leaves no DWL. Third degree only splits buyers into groups by elasticity, so some CS and some DWL remain.
• Two-part tariff (natural monopoly remedy): a fixed charge plus a per-unit charge close to MC, as in an electricity bill (fixed/demand charge + energy charge per kWh). It is a tool to cover fixed costs while keeping output efficient. It is not about charging groups different prices according to elasticity.

Prelims Hooks

• Price discrimination needs four conditions: market power, separate markets, different elasticities, no resale. A price taker in perfect competition cannot discriminate.
• In third degree, the higher price goes to the less elastic market, following (P − MC)/P = 1/|e|.
• Trap: first-degree (perfect) discrimination is efficient. Output equals the competitive level and DWL = 0, but CS = 0, because the seller takes all of it.
• Second degree = price varies with quantity or version, and buyers self-select (data packs, bulk discounts). Third degree = identifiable groups (student and senior citizen fares).
• Tariff Policy, 2016: tariffs within ±20% of average cost of supply [3]. Draft Electricity (Amendment) Bill, 2025: end cross-subsidy paid by manufacturing, railways and metro railways within five years [2].
• Predatory pricing (below-cost selling to push out rivals) is banned under Section 4 of the Competition Act, 2002 [1]. Do not mix it up with price discrimination.

Mains Points

• Fair or exploitative?
• Fair side: student and senior citizen fares and electricity cross-subsidies help poorer groups get access to transport and power.

• Exploitative side: algorithmic, personalised pricing moves towards first-degree discrimination. It takes away buyers' surplus and raises consumer-protection concerns (a CCPA issue).

• Electricity cross-subsidy and competitiveness (GS-III, infrastructure):

• Industry and railways pay tariffs above the cost of supply → their costs rise → Indian manufacturing becomes less competitive.
• Policy answer: the ±20% band under the Tariff Policy, 2016 [3], and the proposed five-year phase-out with cost-reflective tariffs under the Draft Electricity (Amendment) Bill, 2025 [2].

• Trade-off: if cross-subsidy ends, support for farmers and poor households must come as direct, visible subsidies from the state budget.

• Efficiency vs equity: discrimination can raise output compared with a single monopoly price. At the extreme (first degree), the DWL disappears. But the gain goes to the seller, not the buyer. Regulators therefore have to weigh total welfare against who gets it.

Related concepts

• Monopoly
• Natural monopoly
• X-inefficiency
• Monopsony
• Oligopsony
• Bilateral monopoly

Read more

• Monopoly, natural monopoly, monopsony and price discrimination