Monopolistic competition
What you'll learn
- How to recognise monopolistic competition as a market structure.
- How a firm chooses its profit-maximising price and output.
- Why firms can make supernormal profit or losses in the short run, but usually earn normal profit in the long run.
- How to evaluate the advantages and disadvantages of this market structure.
The basic idea: “many firms, slightly different products”
A market structure means the main features of a market: the number of firms, the strength of competition, barriers to entry, and how much price-setting power firms have.
Monopolistic competition
Monopolistic competition is a market structure with many firms, low barriers to entry and exit, and differentiated products, so each firm has some limited price-setting power.
Typical examples include independent cafés, hairdressers, restaurants, gyms, local estate agents, clothing brands, and takeaway food outlets. They sell products that are similar, but not identical.
A Pret, Costa, independent café and supermarket meal deal all compete for lunch spending — but they are not perfect substitutes. Location, branding, quality, opening hours, loyalty apps and atmosphere all matter.
Key characteristics
A monopolistically competitive market usually has:
- Many firms: each firm is relatively small compared with the whole market.
- Product differentiation: firms make their product seem different from rivals’ products.
- Low barriers to entry and exit: new firms can enter fairly easily if profits look attractive.
- Some price-setting power: firms are not price takers because customers may prefer their specific brand or service.
- Non-price competition: firms compete through branding, quality, advertising, packaging, customer service, convenience or loyalty schemes.
- Limited interdependence: unlike oligopoly, one firm does not usually need to predict a major strategic reaction from all rivals.
Product differentiation
Product differentiation means making a product appear different from competitors’ products, either through real differences, such as quality or ingredients, or perceived differences, such as branding and advertising.
Classifying a high-street café market
- Identify the number of firms: a town may have many cafés and coffee shops, so no single café dominates the whole market.
- Check whether products are identical: coffee is broadly similar, but firms differ by brand, location, seating, service, loyalty rewards and atmosphere.
- Check entry barriers: a new café needs premises, staff and equipment, but entry is much easier than building a national railway network or a new water company.
- Draw the conclusion: the market fits monopolistic competition because there are many firms, differentiated products and low entry barriers.
Do not confuse it with monopoly
“Monopolistic” does not mean there is one firm. It means each firm has a tiny degree of monopoly power over its own differentiated product.
Why the demand curve slopes downwards
In perfect competition, each firm faces a perfectly elastic demand curve because products are identical and firms are price takers.
In monopolistic competition, each firm faces a downward-sloping demand curve. If it raises price, it will lose some customers to close substitutes, but not all customers, because some consumers prefer its brand, location or product features.
Average revenue and marginal revenue
Average revenue (AR) is revenue per unit sold. For a firm, AR is the same as price, so the AR curve is also the firm’s demand curve. Marginal revenue (MR) is the extra revenue gained from selling one more unit.
Because the firm must usually lower price to sell more units, its MR curve lies below AR. The extra unit brings in revenue, but the lower price may also apply to previous units.
Limited market power
A monopolistically competitive firm has some control over price, but demand is usually fairly elastic because there are many close substitutes.
Equilibrium price and output for the firm
For a firm, equilibrium means the price and output where it has no incentive to change its behaviour, given its demand and costs.
The usual A-Level rule is:
MR=MCMR = MCMR=MCMarginal cost
Marginal cost (MC) is the extra cost of producing one more unit of output.
The firm chooses the output where marginal revenue equals marginal cost, then uses the AR/demand curve to find the price consumers will pay for that output.
The diagram technique
To find equilibrium price and output:
- Find where MC intersects MR. This gives profit-maximising output.
- Drop down to the quantity axis to label output, usually QQQ.
- Go vertically up from that output to the AR/demand curve.
- Go horizontally across to the price axis to find price, usually PPP.
- Compare price with average cost (AC) at that output to decide profit or loss.
Average cost
Average cost (AC) is total cost per unit of output. It is calculated as total cost divided by output.
Quantity first, price second
On a cost-revenue diagram, never choose price directly from MC. First find output from MR=MCMR = MCMR=MC, then read price from the AR/demand curve.
Short-run monopolistic competition: profit or loss
The short run is a period in which at least one factor of production is fixed, and firms have not fully entered or exited the market.
In the short run, a monopolistically competitive firm can make:
- Supernormal profit if price is above average cost at the chosen output.
- Normal profit if price equals average cost.
- A loss if price is below average cost.
Normal profit and supernormal profit
Normal profit is the minimum profit needed to keep resources in their current use; it is included in average cost. Supernormal profit is profit above normal profit.
The diagram below shows the short-run cases. In both panels, output is chosen where MC=MRMC = MRMC=MR, then price is read from the AR/demand curve. The profit or loss depends on whether price is above or below AC at that output.
Calculating short-run supernormal profit
- Use the profit-maximising rule: suppose the firm produces 1,000 meals per week where MR=MCMR = MCMR=MC.
- Read price and average cost at that output: price is £8 per meal and AC is £5.50 per meal.
- Find profit per unit: £8 minus £5.50 gives £2.50 supernormal profit per meal.
- Multiply by output:
So supernormal profit is £2.50 multiplied by 1,000, which equals £2,500 per week.
A short-run loss does not always mean instant closure
A firm may continue in the short run if it covers variable costs, but if losses persist in the long run, firms are likely to exit the market.
Long-run monopolistic competition: normal profit
The long run is a period in which all factors of production are variable and firms can enter or leave the market.
Because barriers to entry are low, short-run profit is competed away:
- If existing firms make supernormal profit, new firms enter.
- Entry gives consumers more alternatives.
- Demand for each existing firm’s product falls or becomes more elastic.
- This continues until firms earn normal profit.
If firms are making losses:
- Some firms leave the market.
- Remaining firms face higher demand.
- Losses are reduced until surviving firms earn normal profit.
Long-run outcome
In long-run monopolistic competition, firms usually earn normal profit, because entry and exit remove supernormal profits and persistent losses.
The diagram below shows the long-run equilibrium. The firm still produces where MR=MCMR = MCMR=MC, but the AR curve is tangent to AC, so AR=ACAR = ACAR=AC at the chosen output. That means normal profit only.
Excess capacity
In the long-run diagram, the firm does not produce at the minimum point of AC. It produces at a lower output than the productively efficient level.
Excess capacity
Excess capacity is the gap between the firm’s actual output and the output where average cost is minimised.
This matters because firms in monopolistic competition are usually productively inefficient in the long run: they do not produce at the lowest possible average cost.
Tracing long-run adjustment after profit
- Start with a café earning supernormal profit because its price is above AC at the profit-maximising output.
- Low entry barriers encourage new cafés, food vans or chains to enter the local market.
- Consumers now have more substitutes, so demand for the original café falls.
- The café’s AR curve shifts left until it is tangent to AC.
- At the new long-run equilibrium, price equals average cost, so the café earns normal profit only.
Efficiency in monopolistic competition
Monopolistic competition has mixed efficiency effects.
Allocative efficiency
Allocative efficiency
Allocative efficiency occurs where price equals marginal cost, meaning resources are allocated according to consumers’ willingness to pay.
Monopolistic competition is usually allocatively inefficient. Since the firm has a downward-sloping demand curve, price is above marginal revenue. At the profit-maximising output, MR=MCMR = MCMR=MC, but price is taken from AR, so price is greater than MC.
That means consumers value the last unit more than it costs to produce, so output is lower than the allocatively efficient level.
Productive efficiency
Productive efficiency
Productive efficiency occurs when a firm produces at the lowest point of its average cost curve.
In the long run, monopolistically competitive firms usually have excess capacity, so they are not productively efficient. They produce less than the output where AC is minimised.
Normal profit does not mean zero accounting profit
Normal profit is still profit in everyday language. It means the firm is earning just enough to keep its resources in this market rather than moving elsewhere.
Advantages of monopolistic competition
Monopolistic competition can benefit consumers and the wider economy.
More choice and variety
Product differentiation gives consumers a wider range of goods and services. In a UK city centre, consumers can choose between budget cafés, premium coffee shops, vegan bakeries, fast-food chains and independent restaurants.
This increases consumer welfare because people have different preferences.
Strong non-price competition
Firms may improve quality, customer service, branding, convenience or design. For example, gyms compete through equipment, opening hours, classes, apps and cleanliness, not just membership price.
This can encourage innovation and better consumer experience.
Lower prices than monopoly
Although firms have some market power, there are many substitutes. This limits how far firms can raise prices, especially during a cost-of-living squeeze when consumers become more price sensitive.
Entrepreneurship and flexibility
Low barriers to entry allow new firms to test ideas. This can support small businesses, local employment and innovation, although many start-ups also face high failure rates.
Disadvantages of monopolistic competition
The same features can also create costs.
Inefficiency
Firms are usually neither allocatively nor productively efficient. Price exceeds marginal cost, and output is below the minimum-AC level.
This means consumers may pay higher prices than under perfect competition.
Wasteful advertising and selling costs
Some advertising gives useful information. But some spending may simply shift customers between similar brands without improving the product itself.
Selling costs
Selling costs are costs used to persuade consumers to buy a product, such as advertising, branding, packaging and promotions.
If firms spend heavily on branding to create artificial differentiation, resources may be diverted away from actual product improvement.
Lack of economies of scale
Because there are many relatively small firms, they may not fully exploit economies of scale, which are cost advantages from producing on a larger scale. This can keep average costs higher.
Market saturation and business failure
Low barriers mean entry can be easy, but survival is not guaranteed. Many restaurants, independent retailers and cafés face intense competition, rising rents, wage costs and energy bills.
Overall evaluation
Monopolistic competition is not perfectly efficient, but it often performs better for consumers than monopoly because there is more choice and more competitive pressure.
A strong judgement depends on the market:
- In markets where differentiation reflects genuine quality, convenience or innovation, the benefits of choice may outweigh the efficiency losses.
- In markets where differentiation is mostly persuasive advertising, the disadvantages are stronger.
- If consumers have good information and can switch easily, firms’ market power is limited.
- If branding creates loyalty and switching is weak, firms may charge higher prices for little real improvement.
Balanced judgement
Monopolistic competition sacrifices some efficiency, especially productive and allocative efficiency, but can improve consumer welfare through variety, innovation and non-price competition.
In the exam
- Define the market structure using many firms, differentiated products, low barriers and some price-setting power.
- For diagrams, find output from MR=MCMR = MCMR=MC, then read price from AR, then compare price with AC.
- In evaluation, balance inefficiency against consumer choice, innovation and non-price competition, then make a judgement based on the specific market.
Check yourself
- Why is a monopolistically competitive firm’s demand curve downward sloping but relatively elastic?
- How does entry remove supernormal profit in the long run?
- Why is long-run monopolistic competition usually productively inefficient?
