Monopolistic Competition and Oligopoly

Monopolistic Competition: The Market We Live In

If perfect competition is the theoretical ideal and pure monopoly is the extreme case, then monopolistic competition is the market structure we encounter every day. When you choose among dozens of restaurants in your neighborhood, among clothing brands in a shopping mall, among hair salons or coffee shops—you are in a market of monopolistic competition.

This model was first proposed by economist Edward Chamberlin in 1933 in his work “The Theory of Monopolistic Competition” and independently by Joan Robinson in “The Economics of Imperfect Competition” in the same year. Both researchers realized that real markets do not fit either the model of perfect competition or that of pure monopoly.

Features of Monopolistic Competition

Many firms, none dominates. The market operates with enough firms that each can make decisions relatively independently, not worrying about the reaction of any specific competitor. In Moscow, more than 15,000 restaurants and cafes operate—none of them controls a significant share of the market.

Product differentiation. This is the key feature that distinguishes monopolistic competition from perfect competition. Each firm produces a unique variant of a product, differentiated by brand, quality, design, location, atmosphere, or service. Two Italian restaurants side by side are not selling identical products—they have different recipes, interiors, service, atmosphere. This gives each restaurant a small “monopoly power”—the ability to set a price slightly higher than a competitor’s without losing all customers.

Differentiation may be:

• Real — differences in quality, composition, features (for example, shampoos with different formulas).
• Perceived — differences exist mainly in the minds of consumers, created by advertising and branding (for example, aspirin tablets of different brands are chemically identical, but branded ones are sold at a higher price).

Some control over price. Thanks to differentiation, the firm faces a downward-sloping demand curve—it can slightly raise the price without losing all customers. However, demand for its product is relatively elastic, because there are many close substitutes. If your favorite coffee shop raises the price of a cappuccino from 300 to 350 rubles, you might stay—you like their coffee specifically. But if the price rises to 500 rubles, you will likely switch to a competitor across the street.

Free entry and exit. Entry barriers to the market are low. Opening a restaurant, hair salon, or clothing store is possible for nearly any entrepreneur with relatively modest capital. This condition is critically important for long-term equilibrium.

Short-Run Equilibrium: Superprofits Possible

In the short run, a firm in monopolistic competition behaves much like a small monopolist. It maximizes profit where MR = MC, setting the price on the demand curve.

Imagine the coffee shop chain “Aromat” with a unique roasting recipe. In the short-run period:

• The demand curve is downward-sloping, but relatively elastic (many competitors).
• MR lies below AR (as for a monopolist—it needs to lower the price on all units to sell more).
• At MR = MC: optimal quantity Q_s, price P_s on the demand curve.
• If P_s > AC at Q_s, the firm earns superprofits.

Suppose Q_s = 500 cups per day, P_s = 280 rubles, AC = 220 rubles. Superprofit = (280 - 220) × 500 = 30,000 rubles per day.

Long-Run Equilibrium: Superprofits Disappear

Here’s what happens next—and this is one of the most important mechanisms in economics:

Step 1. Other entrepreneurs see that coffee shops are earning superprofits. Since entry barriers are low, they open their own coffee shops with similar but slightly differentiated offerings.

Step 2. With the appearance of new coffee shops, demand for each individual coffee shop’s products falls and becomes more elastic. Customers are spread among a larger number of establishments, and each gets more alternatives.

Step 3. The demand curve for each firm shifts left (demand falls) and becomes flatter (more elastic). The MR curve shifts along with it.

Step 4. The process continues until the demand curve (AR) becomes tangent to the LRAC curve—that is, touches it at exactly one point.

Step 5. At this point of tangency, AR = AC at the optimal volume Q_L. The firm earns only normal profit (superprofit = 0). The incentives for new firms to enter vanish.

In our coffee shop example: after competitors enter, Q may fall to 350 cups, P—to 250 rubles, AC—also to 250 rubles. Superprofits = (250 - 250) × 350 = 0.

Comparison with Perfect Competition: Pros and Cons

Monopolistic competition achieves neither allocative efficiency (P > MC), nor productive efficiency (the firm does not operate at the minimum AC). However, it has an important advantage: variety. Consumers get a wide choice of products, tailored to different tastes and preferences.

The question “what is better—cheaper but monotonous, or a bit more expensive with huge variety?” is a normative one, with no unambiguous answer. Most economists believe the loss of efficiency in monopolistic competition is slight, while the gain in variety is significant.

Oligopoly: The Market of Giants

Oligopoly is perhaps the most interesting and complex market structure, because the behavior of firms in an oligopolistic market depends not only on demand and costs, but also on strategic interaction with competitors.

Features of Oligopoly

A few dominant firms. The industry operates with a small number of large firms, each controlling a significant share of the market. For quantitative assessment of market concentration, the concentration ratio is used: CR4 (share of the four largest firms) or CR8 (share of the eight largest). If CR4 > 40%, the market is usually considered oligopolistic.

Examples of oligopolies:

• Global smartphone market: Apple and Samsung together control about 50% of the global market (by revenue—much more).
• Air transportation in Russia: “Aeroflot”, S7, “Ural Airlines” and “Pobeda” carry the overwhelming majority of passengers.
• Global oil market: OPEC+ (Saudi Arabia, Russia, UAE and others) coordinates production volumes.
• Global market for PC operating systems: Microsoft Windows and Apple macOS control more than 95%.
• Auditing services: “The Big Four” (Deloitte, PwC, EY, KPMG) dominate the global audit market.

High entry barriers. Economies of scale, huge R&D and marketing costs, network effects, patents and brands—all this makes entry into the oligopoly market extremely difficult. To create a competitor to Boeing or Airbus is almost impossible: developing a new airplane alone takes 7–10 years and costs $15–25 billion.

Interdependence—key feature. This distinguishes oligopoly from all other structures. When making any strategic decision, a firm must consider the expected reaction of competitors. If Coca-Cola lowers its price, how will Pepsi respond? If Samsung releases a foldable smartphone, what will Apple do? This interdependence makes the behavior of oligopolists much more complex and less predictable than that of firms in other structures.

Game Theory: Tool for Oligopoly Analysis

Game theory—a mathematical discipline studying strategic interaction among rational agents—has become the main tool for analyzing oligopolistic behavior.

The Prisoner’s Dilemma is the most famous game, and it perfectly illustrates the paradox of oligopoly. Imagine two manufacturers, “Alpha” and “Beta”, choosing between a high and low price:

If both firms set a high price (collusion), each earns £10 mln—the best joint outcome. But each has an incentive to “cheat” its partner: if “Alpha” lowers the price while “Beta” keeps it high, “Alpha” earns £12 mln. The problem is that “Beta” reasons exactly the same way. As a result, both choose the low price and earn only £5 mln each. This is a Nash equilibrium—a situation where no player can improve their result by changing their strategy unilaterally.

This paradox explains why oligopolists strive to collude (to earn £10 mln) and simultaneously have incentives to break the collusion (to get £12 mln).

Incentives for Competition vs Incentives for Collusion

Incentives for competition: lowering prices to capture market share, advertising campaigns, innovation and product improvement, assortment expansion.

Incentives for collusion: if firms coordinate actions, industry profit is maximized (as with monopoly). Collusion can take two forms:

Explicit collusion—cartels. A cartel is a formal agreement between firms on prices, production volumes, or market division. The most famous cartel is OPEC (Organization of Petroleum Exporting Countries), founded in 1960. In 1973, OPEC imposed an oil supply embargo and reduced production, causing oil prices to quadruple and a global economic crisis.

Cartels are generally unstable for several reasons:

1. Each member has an incentive to “cheat”—secretly increase production to sell more at the high cartel price.
2. New market entrants can undermine the cartel if entry barriers are not high enough.
3. Differences in costs among cartel members create disagreements about quotas and prices.
4. In most countries, cartels are illegal—antitrust authorities prosecute price collusion.

Example of instability: in 2014–2016 OPEC failed to agree on production cuts amid the growth of US shale oil. Oil prices dropped from $115 to $27 per barrel. Only in 2016, with the OPEC+ format (including Russia), coordination was restored.

Tacit collusion. Firms coordinate actions without a formal agreement, through price leadership: one firm (usually the largest) sets the price, and the others follow. In the banking sector, when the central bank changes the key rate, the largest bank usually is first to announce new lending rates, and the rest quickly match them.

The Kinked Demand Curve Model

This model, proposed by Paul Sweezy in 1939, explains the observed stability of prices in oligopoly markets. The logic is based on the asymmetric reaction of competitors:

If a firm raises the price above the current level, competitors do not follow—why should they? They will lure away the customers of the firm that raised prices. Demand for this firm’s product will sharply drop—the demand curve is elastic above the current price.

If a firm lowers the price below the current level, competitors also lower their prices—they can’t afford to lose customers. The firm attracts only a few additional buyers (due to overall market expansion)—the demand curve is inelastic below the current price.

As a result, the demand curve has a kink at the current price, and the MR curve has a vertical discontinuity at the kink point. Marginal cost can fluctuate within this gap without changing the optimal price—that’s why prices in oligopoly markets often remain stable even when costs change.

Critics of the model note that it does not explain how the current price is set—it only explains why, once established, the price remains stable.

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Price Wars

Although oligopoly markets tend toward stability, sometimes price wars erupt—intense price reductions in which all participants lose profit.

Example: the airline price war in Europe in the 2000s. The emergence of low-cost carriers (Ryanair, EasyJet) forced traditional airlines (Lufthansa, British Airways) to lower prices on European routes. Some routes were sold below cost. Result: several airlines went bankrupt (Swissair, Sabena), but consumers got much cheaper tickets.

Comparison of Four Market Structures: Final Analysis

Understanding the differences among these structures is critically important for managers: the pricing strategy of a coffee shop (monopolistic competition) differs fundamentally from that of an airline (oligopoly) or water utility (natural monopoly). Each structure prescribes its own rules of competitive rivalry.