Monopoly, natural monopoly, monopsony and price discrimination

Detail

1. What a monopoly is

• A monopoly is a market with one seller of a product that has no close substitutes. Entry barriers (things that stop new firms from coming in) protect it.
• Class 9, The Price Puzzle: a monopoly is a single seller that controls the entire supply of a unique product.
• A monopolist is a price maker. It picks its own price. A competitive firm is a price taker and must accept the market price.
• It restricts output, which means it sells less on purpose, so that it can charge a price above marginal cost (P > MC).
• Marginal cost (MC) is the extra cost of making one more unit.

2. Sources of monopoly (entry barriers)

• Legal or statutory rights, where a law gives one body the sole right to supply.
• Example: Indian Railways.

• Correction to the scaffold: the Post Office Act, 2023 does not give a monopoly over carrying letters. The old Indian Post Office Act, 1898 gave the Centre the "exclusive privilege" of carrying letters by post. The 2023 law replaced it and dropped that privilege. India Post keeps only one exclusive privilege: issuing postage stamps [2]. (NCERT/scaffold: "postal letter monopoly under the Post Office Act 2023".)

• Patents. The law gives an inventor the sole right to make and sell the invention for a fixed period.

• Control of a key resource. One firm owns the only supply of an input.
• Scale economies. A very large firm has such a low average cost that smaller rivals cannot survive. This leads to a natural monopoly (see section 5).

3. Monopoly equilibrium

• Marginal revenue (MR) is the extra revenue from selling one more unit.
• A monopolist must lower its price to sell more. So MR < P.

• With linear demand P = a − bQ, MR = a − 2bQ. The MR line has twice the slope of the demand line.

• Rule 1: produce the output where MR = MC.

• Rule 2: charge the highest price the demand curve allows at that output. This gives P > MC.
• Result: compared with perfect competition, output is lower and price is higher. The lost gains from trade are the deadweight loss (DWL), a loss to society that nobody gains.
• Consumer surplus (CS) is the buyer's maximum willingness to pay minus the price actually paid. Producer surplus (PS) is the price minus MC.

Worked example. Demand P = 100 − Q, MC = 20.

	Competition (P = MC)	Monopoly (MR = MC)
Output	80	40 (MR = 100 − 2Q = 20)
Price	20	60
Consumer surplus	½ × 80 × 80 = 3,200	½ × 40 × 40 = 800
Producer surplus	0	(60 − 20) × 40 = 1,600
Total surplus	3,200	2,400 → DWL = 800

• How to read the table:
• Consumers lose 2,400 of surplus (3,200 → 800).
• 1,600 of that moves to the monopolist as profit. This is a transfer, not a loss to society.

• The other 800 simply disappears. That 800 is the DWL = ½ × (80 − 40) × (60 − 20).

• Lerner index, a measure of market power: L = (P − MC) / P = 1 / |e|. Here e is the price elasticity of demand, which shows how strongly buyers react to a price change.

• In the example: L = (60 − 20) / 60 = 0.67.
• Check with elasticity at Q = 40: |e| = (ΔQ/ΔP) × (P/Q) = 1 × 60/40 = 1.5, so 1/1.5 = 0.67 ✔.
• Under perfect competition P = MC, so L = 0.
• A monopolist always produces on the elastic part of demand (|e| > 1), because MR is negative where |e| < 1.

4. Costs of monopoly beyond DWL

• X-inefficiency (Harvey Leibenstein, 1966) means a firm that faces no competition stops trying to keep its costs as low as possible.
• Examples: overstaffing, slack management, poor upkeep.

• Its costs end up above the lowest possible cost. This waste comes on top of the DWL.

• Other costs (Class 9): higher prices, poorer quality and restricted supply. That is why government keeps prices and supply in check.

• Regulators named in Class 9:
• RBI (banking);
• SEBI (securities markets);
• TRAI (telecom);

• Central Consumer Protection Authority (CCPA) (unfair trade practices and misleading advertisements).

• Other sector regulators:

• CERC (central) and SERCs (states) for electricity;
• AERA (airport tariffs, 2008);
• PNGRB (petroleum pipelines and city gas distribution, 2006).

5. Competition law in India — the economy-wide check on monopoly power

• Competition Act, 2002. Parliament enacted it on 13 January 2003. The Competition Commission of India (CCI) was set up with effect from 14 October 2003 [3].
• Section 4 bans abuse of a dominant position. Being dominant is legal; misusing that position is not [4].

• One banned abuse is predatory pricing: selling below the cost of production in order to reduce competition or drive competitors out [4].

• Case example: CCI found the BCCI guilty of abusing its dominant position. BCCI had used restrictions to block others from organising professional domestic cricket leagues. CCI fined it ₹52.24 crore [3].

• Competition (Amendment) Act, 2023 (Act No. 9 of 2023, 11 April 2023):
• Deal value threshold of ₹2,000 crore. A merger now needs CCI approval if the deal is large, even when the target has few assets or little turnover. This is meant to catch "killer acquisitions" in digital markets, where a firm's value lies in its data. The Bill's explanation cites Facebook buying WhatsApp for USD 19 billion while WhatsApp had a net loss of USD 233 million (mid-2014) [5].
• The time limit for CCI to decide on a merger fell from 210 days to 150 days [5].
• Settlement and commitment schemes for faster closure of cases [5][6]:
  • settlement: the firm may pay money to close the case;
  • commitment: the firm promises to change its structure or behaviour.
• A firm appealing to the NCLAT must first deposit 25% of the penalty [5].

• Penalties can now be based on global turnover (worldwide sales), not only Indian turnover. CCI notified the Determination of Monetary Penalty Guidelines, 2024, and the relevant sections came into force on 6 March 2024 [6].

• Digital markets:

• The Committee on Digital Competition Law reported on 12 March 2024. It proposed a draft Digital Competition Bill [7].
• It proposed ex-ante rules, meaning rules set before harm happens. The current Act works ex-post: it punishes after the harm, and in fast digital markets that is often too late [7].
• Big firms would be named Systemically Significant Digital Enterprises (SSDEs). These are providers of search engines, social networks, operating systems and web browsers [7].
• SSDEs could not self-preference (favour their own products), misuse non-public data of business users, or restrict third-party apps [7].
• Proposed penalty cap: 10% of global turnover [7].

6. Natural monopoly

• A natural monopoly is an industry where one firm can supply the whole market more cheaply than two or more firms could.
• The cause is very large fixed costs (costs that do not change with output) and low running costs.

• So average cost (AC) keeps falling over the whole relevant range of output.

• Examples: railway track, power transmission lines, city gas networks, water pipes. Building two parallel networks would waste money.

• The pricing problem:
• When AC is falling, MC lies below AC.
• Efficient pricing (P = MC) gives price < AC, so the firm makes a loss.
• Profit-maximising monopoly pricing avoids the loss but brings back the DWL.

Worked example. TC = 840 + 10Q (fixed cost 840, MC = 10). Demand P = 50 − 0.4Q.

Pricing rule	Output	Price	AC	Result
P = MC (efficient)	100	10	840/100 + 10 = 18.4	Loss = (18.4 − 10) × 100 = 840, the whole fixed cost
P = AC (average-cost pricing)	70	22	840/70 + 10 = 22	Zero economic profit (normal profit only); output below the efficient 100
Two-part tariff	100	fixed charge (e.g. 84 users × ₹10 = 840) + ₹10 per unit	—	Covers all costs and reaches efficient output

• Remedies:
• Average-cost pricing (P = AC). The firm earns only normal profit. Some DWL remains.
• Two-part tariff. A fixed charge pays for the fixed cost. A per-unit charge close to MC pays for use.
  • Example: an electricity bill = fixed/demand charge + energy charge per kWh.
• Price cap (RPI − X). The regulator lets prices rise by inflation (RPI, the retail price index) minus an efficiency factor X.
  • Example: inflation 5%, X = 2% → price may rise only 3%. The firm keeps any extra savings it makes, so it has a reason to cut costs.

• Public ownership. The State runs the network itself, as with Indian Railways track.

• Recent Indian reform direction:

• The Draft Electricity (Amendment) Bill, 2025 would let one discom (electricity distribution company) supply power over another discom's network. Discoms must give open, non-discriminatory access to their networks, with charges set by the SERC [8].
• The idea: keep the wires as a natural monopoly, but allow competition in selling the power.

7. Price discrimination

• Price discrimination means charging different buyers different prices for the same product, where the difference is not due to cost.

Degree	How it works	Indian example
First (perfect)	Each buyer pays their maximum willingness to pay. The seller takes all consumer surplus. Output = competitive level, so no DWL, but CS = 0	Personalised or algorithmic online pricing
Second	Price varies with quantity or version. Buyers sort themselves by choosing a plan	Data packs, bulk discounts, tiered subscription plans
Third	Different prices for identifiable groups	Student and senior citizen fares, railway classes, electricity cross-subsidy tariffs (industry pays more than farmers)

• Conditions for price discrimination: 1. The seller has market power. A price taker cannot discriminate. 2. The markets can be kept separate (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 one that reacts less to price. 4. No resale (no arbitrage). A buyer who gets a low price cannot resell to someone charged a high price.

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).
• Profit with discrimination: (60 − 20) × 40 + (40 − 20) × 20 = 1,600 + 400 = 2,000.
• Single price: combined demand is Q = 160 − 2P, so MR = 80 − Q = 20 → Q = 60, P = 50.

• Profit = 30 × 60 = 1,800.

• Lesson: discrimination raises profit (1,800 → 2,000), and the less elastic group pays more.

• Cross-subsidy in electricity (third-degree example):

• The Tariff Policy, 2016 aims to keep every consumer category's tariff within ±20% of the average cost of supply [9].
• Many states still go beyond this band [9].

• The Draft Electricity (Amendment) Bill, 2025 proposes that:

  • cross-subsidies paid by manufacturing enterprises, railways and metro railways be fully eliminated within five years;
  • tariffs reflect the cost of supply [8].

• Dynamic pricing means the price changes over time as demand changes.

• 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.

8. Buyer power: monopsony, oligopsony, bilateral monopoly

• Monopsony is a market with a single buyer. Joan Robinson coined the term in 1933.
• It pushes the price of what it buys (wages, crops) below the competitive level.
• It also buys less than a competitive market would.

• Why: to hire one more worker, the monopsonist must raise the wage for all workers. So its marginal cost of labour is higher than the wage. It therefore hires fewer workers and pays each of them less.

• Worked example. Labour supply: w = 10 + L. Marginal revenue product of labour, the extra revenue one more worker brings in: MRP = 70 − L.

• Competition: 10 + L = 70 − L → L = 30, w = 40.
• Monopsony: the marginal cost of labour = 10 + 2L. Set it equal to MRP: 10 + 2L = 70 − L → L = 20, and the wage from the supply curve = 30.

• Result: 10 fewer jobs and a wage ₹10 lower.

• Indian examples:

• gig workers who face one dominant platform;

• sugar mills in cane "reserved areas", where farmers must sell only to the assigned mill.

• Oligopsony is a market with a few large buyers and many sellers.

• Example: trader cartels in APMC mandis holding down auction prices paid to farmers.

• Bilateral monopoly is a market with one seller facing one buyer.

• The price is not fixed by theory. It falls somewhere between the seller's lowest acceptable price and the buyer's highest, depending on bargaining power.
• Example: one trade union negotiating with one employer.

Prelims Hooks

• Monopoly equilibrium: MR = MC, and P > MC. In the P = 100 − Q, MC = 20 example, DWL = 800.
• Lerner index = (P − MC)/P = 1/|e|. It is 0 under perfect competition. A monopolist never produces where demand is inelastic.
• X-inefficiency was proposed by Leibenstein (1966). Monopsony was coined by Joan Robinson (1933).
• Trap: the Post Office Act, 2023 removed the Centre's exclusive privilege to carry letters. Its only exclusive privilege left is issuing postage stamps [2].
• Natural monopoly: AC falls over the relevant output range, so MC < AC and P = MC means a loss. Remedies: average-cost pricing, two-part tariff, RPI − X cap, public ownership.
• Section 4 of the Competition Act, 2002 bans abuse of dominance, including predatory pricing (selling below cost to eliminate competitors) [4]. CCI was set up on 14 October 2003 [3].
• The Competition (Amendment) Act, 2023 brought in a ₹2,000 crore deal value threshold, cut merger review from 210 to 150 days [5], and allowed penalties on global turnover [6].
• In third-degree price discrimination, the higher price goes to the less elastic market. First-degree discrimination takes all consumer surplus but leaves no DWL.
• Tariff Policy, 2016: tariffs should be within ±20% of the average cost of supply [9].
• Institution–sector pairs: AERA – airport tariffs (2008); PNGRB – pipelines and city gas (2006); CCPA – unfair trade practices.

Mains Points

• Ex-post vs ex-ante competition law. The Competition Act, 2002 punishes abuse only after it happens [4]. Digital markets can "tip" quickly and permanently towards one firm, so the Committee on Digital Competition Law (2024) proposed ex-ante duties for SSDEs [7].

• Trade-off: faster protection for rivals and consumers vs regulatory overreach that could slow innovation and start-up funding.

• Natural monopoly regulation.

• Pricing at P = MC gives efficiency but a loss that needs a subsidy.
• Average-cost pricing and price caps are financially viable but leave some DWL.
• Two-part tariffs and network unbundling (open access to discom wires under the Draft Electricity (Amendment) Bill, 2025 [8]) try to get both efficiency and viability.

• This links to discom losses and power-sector reform (GS-III, infrastructure).

• Price discrimination can be equitable or exploitative.

• Equitable: student and senior citizen fares and electricity cross-subsidies widen access.
• Costs: cross-subsidies raise costs for industry and railways, hurting competitiveness. Hence the ±20% band [9] and the proposed 5-year phase-out for manufacturing and railways [8].

• Exploitative: algorithmic, personalised pricing raises consumer-protection concerns (a CCPA issue).

• Monopsony and farm and labour incomes.

• Cane reserved areas, APMC trader cartels and dominant gig platforms all push prices and wages below competitive levels.
• Policy answers: more buyers (market reform, e-NAM-type platforms), minimum or floor prices, and collective bargaining such as FPOs and worker unions, which creates a bilateral monopoly.