Revision: Microeconomic Theory >> Price Output Determination Under Monopoly Economics ISC (Commerce) Class 12 CISCE

Definitions: Monopoly

"A pure monopoly exists when there is only one producer in a market, there are no direct competitors." – Ferguson
"Monopoly is a market situation in which there is a single seller, there is no close substitute for commodity it produces, there are barriers to entry." – Koutsoyiannis

Definitions: Price Discrimination

“Price discrimination exists when the same product is sold at different prices to different buyers.” — Koutsoyiannis
“Price discrimination is the act of selling the same article produced under single control at a different price to the different buyers.” — Mrs. Joan Robinson

Formula

\[\text{Lerner Index}=\frac{P-MC}{P}\]

where $P$ is the price of the product and $MC$ is the marginal cost of producing one more unit.

Key Points: Monopoly

Monopoly is a market structure with one seller, no close substitutes, and barriers to entry.
Main features: single seller, no close substitutes, barriers to entry, price maker, firm = industry, and possible price discrimination.
Types include private, public, legal, natural, simple, discriminating, and voluntary (cartel) monopolies.
Under monopoly, AR is the market demand curve; MR lies below AR because price must fall to sell more.
Equilibrium output is found where MC=MR; price is taken from the AR curve at that output and is usually above MC.
Cost curves (FC, AFC, AVC, AC, MC) have the usual shapes, but MC is not the supply curve in a monopoly.
Price discrimination allows a monopolist to charge different prices by person, place, time, or use.

Key Points: Determination of Price and Equilibrium Under Monopoly

A monopolist is a single seller with no close substitutes and strong entry barriers.
Under monopoly, AR is downward sloping and MR lies below AR; MR is less than AR.
The monopolist is in equilibrium where MR = MC and MC cuts MR from below.
Equilibrium can be found by the TR–TC approach (maximum profit where TR − TC is highest) or the MR–MC approach (intersection of MR and MC).
In the short run, a monopolist may earn supernormal or normal profit or even incur losses but will produce as long as price covers average variable cost.

Key Points: Total Revenue and Total Cost Approach

The profit of a monopolist is the difference between TR and TC, i.e., π = TR − TC.
Under the TR–TC approach, the monopolist chooses that output where the difference TR − TC is maximum.
The TR curve usually starts from the origin, while the TC curve starts above the origin due to fixed costs.
The break-even point is where TR = TC and profit is zero.
The equilibrium output of the monopolist is found where the vertical distance between TR and TC is greatest, which corresponds to the highest point on the TP curve (point E).
The process is called trial-and-error because the firm may test different price–output combinations to discover where profit is highest.

Key Points: Marginal Revenue and Marginal Cost Approach

Monopoly equilibrium occurs when MR = MC and MC cuts MR from below.
In the short run, a monopolist may earn super-normal profit, normal profit, or incur losses.
In the long run, entry is restricted, so super-normal profits may continue.
Equilibrium price and output are fixed where MR = LMC.

Key Points: Monopoly Equilibrium and Laws of Costs

Monopoly prioritizes total profit optimization over charging sky-high prices or maximizing per-unit margins.
Balance of scale benefits vs output/price restrictions—government regulation needed (TRAI monitors telecom monopolies).

Key Points: Price Discrimination or Discriminating Monopoly

Key Points: Price and Output Determination under Discriminating Monopoly

A discriminating monopolist charges different prices in different markets to maximise profit.
Total output is fixed where MC = CMR (ΣMR) and divided so that MR₁ = MR₂ = MC.
Higher price is charged in the market with less elastic demand, and lower price where demand is more elastic.
Monopoly equilibrium occurs where MR₁ = MR₂ = CMR = MC.