Table 5.1 mirrors the four major categories of sector frameworks and their features.

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Table 5.1 Market Structure Characteristics

Free enattempt and exit | Barriers to entry | No entry | |

Perfect competition is on one finish of the market framework spectrum, through numerous firms. The word, “numerous” has special definition in this conmessage. In a perfectly competitive market, each firm is so little relative to the sector that it cannot affect the price of the great. Each perfectly competitive firm is a price taker. As such, plenty of firms suggests that each firm is so tiny that it is a price taker.

Monopoly is the other too much of the sector structure spectrum, via a solitary firm. Monopolies have monopoly power, or the capacity to adjust the price of the good. Monopoly power is additionally called market power, and is measured by the Lerner Index.

This chapter defines and defines 2 intermediary sector structures: monopolistic competition and oligopoly.

**Monopolistic Competition** = A sector structure defined by a identified product and also freedom of entry and also leave.

Monopolistically Competitive firms have one characteristic that is favor a syndicate (a differentiated product offers market power), and one characteristic that is choose a competitive firm (freedom of entry and also exit). This create of sector framework is prevalent in market-based economic situations, and a expedition to the grocery save reveals big numbers of differentiated products: toothpaste, laundry soap, breakfast cereal, and also so on.

Next, we specify the market framework **oligopoly**.

**Oligopoly** = A industry framework defined by obstacles to enattempt and a few firms.

Oligopoly is a fascinating sector structure as a result of interaction and interdependency in between oligopolistic firms. What one firm does affects the other firms in the oligopoly.

Due to the fact that monopolistic competition and oligopoly are intermediary industry frameworks, the following area will certainly testimonial the properties and also characteristics of perfect competition and also monopoly. These features will carry out the defining characteristics of monopolistic competition and also oligopoly.

*5.1.2 Review of Perfect Competition*

The perfectly competitive market has actually 4 characteristics:

(1) Homogenous product,

(2) Large variety of buyers and also sellers (numerous firms),

(3) Freedom of entry and also departure, and

(4) Perfect indevelopment.

The possibility of enattempt and also departure of firms occurs in the lengthy run, considering that the variety of firms is resolved in the short run.

An equilibrium is characterized as a point wright here tbelow is no tendency to readjust. The principle of equilibrium have the right to be extended to include the brief run and lengthy run.

**Brief Run Equilibrium** = A point from which tright here is no tendency to readjust (a steady state), and also a fixed variety of firms.

**Long Run Equilibrium** = A allude from which tright here is no tendency to readjust (a secure state), and enattempt and leave of firms.

In the short run, the number of firms is resolved, whereas in the long run, entry and also leave of firms is feasible, based on profit problems. We will compare the short and lengthy run for a competitive firm in Figure 5.1. The two panels in Figure 5.1 are for the firm (left) and market (right), with vastly different systems. This is emphasized by using “q” for the firm’s output level, and also “Q” for the sector output level. The graph mirrors both short run and also lengthy run equilibria for a perfectly competitive firm and also sector. In short run equilibrium, the firms encounters a high price (PSR), produces amount QSR at PSR = MC, and also earns positive profits πSR.

Figure 5.1 Short Run and also Long Run Equilibria for a Perfectly Competitive Firm

Optimistic profits in the short run (πSR > 0) cause entry of various other firms, as tright here are no barriers to entry in a competitive market. The entry of brand-new firms shifts the supply curve in the market graph from supply SSR to supply SLR. Enattempt will certainly occur till revenues are driven to zero, and long run equilibrium is got to at Q*LR. In the lengthy run, economic profits are equal to zero, so tbelow is no motivation for entry or exit. Each firm is earning precisely what it is worth, the opportunity prices of all resources. In lengthy run equilibrium, revenues are zero (πLR = 0), and also price equates to the minimum average price point (P = min AC = MC). Marginal expenses equal average prices at the minimum average cost point. At the long run price, supply equals demand at price PLR.

*5.1.3 Resee of Monopoly*

The characteristics of monopoly include: (1) one firm, (2) one product, and (3) no entry (Table 5.1). The monopoly solution is displayed in Figure 5.2.

Figure 5.2 Monopoly Profit Maximization

Note that long-run revenues can exist for a syndicate, considering that obstacles to enattempt halt any type of potential entrants from joining the industry. In the following area, we will certainly explore market structures that lie between the 2 extremes of perfect competition and also monopoly.

5.2 Monopolistic CompetitionMonopolistic competition is a sector framework characterized by totally free entry and leave, prefer competition, and identified commodities, favor monopoly. Differentiated commodities carry out each firm through some sector power. Advertising and also marketing of each individual product provide uniqueness that reasons the demand curve of each good to be downward sloping. Free enattempt suggests that each firm competes with other firms and also profits are equal to zero on long run equilibrium. If a monopolistically competitive firm is earning positive financial profits, enattempt will happen till financial revenues are equal to zero.

*5.2.1 Monopolistic Competition in the Quick and Long Runs*

The demand curve of a monopolistically competitive firm is downward sloping, indicating that the firm has a degree of market power. Market power derives from product differentiation, since each firm produces a various product. Each great has many kind of cshed substitutes, so market power is limited: if the price is enhanced too much, consumers will certainly shift to competitors’ commodities.

Figure 5.3 Monopolistic Competition in the Brief Run and Long Run

Quick and lengthy run equilibria for the monopolistically competitive firm are displayed in Figure 5.3. The demand curve encountering the firm is downward sloping, however relatively elastic due to the availability of cshed substitutes. The brief run equilibrium appears in the left hand panel, and also is virtually identical to the monopoly graph. The only distinction is that for a monopolistically competitive firm, the demand also is reasonably elastic, or flat. Otherwise, the short run profit-maximizing solution is the very same as a monopoly. The firm sets marginal revenue equal to marginal price, produces output level q*SR and charges price PSR. The profit level is presented by the shaded rectangle π.

The lengthy run equilibrium is presented in the best hand panel. Entry of various other firms occurs until earnings are equal to zero; total profits are equal to full costs. Thus, the demand curve is tangent to the average cost curve at the optimal lengthy run amount, q*LR. The long run profit-maximizing amount is uncovered wbelow marginal revenue equates to marginal price, which also occurs at q*LR.

*5.2.2 Economic Efficiency and Monopolistic Competition*

Tright here are 2 sources of inperformance in monopolistic competition. First, dead weight loss (DWL) because of monopoly power: price is higher than marginal cost (P > MC). Second, excess capacity: the equilibrium amount is smaller than the lowest expense quantity at the minimum allude on the average expense curve (q*LR minAC). These two resources of inperformance deserve to be watched in Figure 5.4.

Figure 5.4 Comparikid of Efficiency for Competition and also Monopolistic Competition

First, tbelow is dead weight loss (DWL) due to industry power: the price is better than marginal price in lengthy run equilibrium. In the best hand panel of Figure 5.4, the price at the lengthy run equilibrium amount is PLR, and marginal cost is lower: PLR > MC. This causes dead weight loss to culture, considering that the competitive equilibrium would be at a larger amount wright here P = MC. Total dead weight loss is the shaded area beneath the demand also curve and over the MC curve in number 5.4.

The second resource of inperformance associated with monopolistic competition is excess capacity. This deserve to additionally be seen in the appropriate hand panel of Figure 5.4, wbelow the long run equilibrium quantity is lower than the quantity where average prices are lowest (qminAC). As such, the firm could produce at a lower price by boosting output to the level wbelow average expenses are decreased.

Given these 2 inefficiencies associated with monopolistic competition, some people and also groups have actually referred to as for federal government treatment. Regulation can be used to alleviate or get rid of the inefficiencies by rerelocating product differentiation. This would lead to a solitary product rather of a big variety of close substitutes.

Regulation is more than likely not a good solution to the inefficiencies of monopolistic competition, for 2 factors. First, the industry power of a typical firm in most monopolistically competitive industries is tiny. Each monopolistically competitive market has actually many kind of firms that produce sufficiently substitutable commodities to provide enough competition to result in fairly low levels of market power. If the firms have actually little levels of sector power, then the deadweight loss and excess capacity inefficiencies are likely to be small.

2nd, the advantage provided by monopolistic competition is product diversity. The obtain from product diversity deserve to be huge, as consumers are willing to pay for different features and also qualities. Therefore, the get from product diversity is most likely to outweigh the expenses of inperformance. Evidence for this claim have the right to be seen in market-based economies, wright here tright here is a vast amount of product diversity.

The next chapter will certainly present and also comment on oligopoly: strategic interactions in between firms!

5.3 Oligopoly ModelsAn oligopoly is characterized as a sector structure through few firms and also obstacles to enattempt.

**Oligopoly** = A industry structure via few firms and also obstacles to enattempt.

Tright here is frequently a high level of competition in between firms, as each firm provides decisions on prices, amounts, and also heralding to maximize profits. Since there are a small variety of firms in an oligopoly, each firm’s profit level depends not only on the firm’s own decisions, but additionally on the decisions of the various other firms in the oligopolistic sector.

*5.3.1 Strategic Interactions*

Each firm have to consider both: (1) various other firms’ reactions to a firm’s very own decisions, and also (2) the own firm’s reactions to the various other firms’ decisions. Thus, there is a continuous interplay in between decisions and also reactions to those decisions by all firms in the sector. Each oligopolist need to take into account these strategic interactions once making decisions. Since all firms in an oligopoly have outcomes that depfinish on the other firms, these strategic interactions are the structure of the research and also understanding of oligopoly.

For example, each auto firm’s industry share counts on the prices and amounts of every one of the various other firms in the sector. If Ford lowers prices relative to other automobile manufacturers, it will boost its sector share at the cost of the various other car providers.

When making decisions that consider the feasible reactions of various other firms, firm supervisors generally assume that the supervisors of competing firms are rational and intelligent. These strategic interactions form the research of game theory, the topic of Chapter 6 listed below. John Nash (1928-2015), an Amerideserve to mathematician, was a pioneer in game theory. Economists and mathematicians usage the principle of a Nash Equilibrium (NE) to define a prevalent outcome in game concept that is typically provided in the research of oligopoly.

** Nash Equilibrium** = An outcome where there is no tendency to change based on each individual selecting a strategy given the strategy of rivals.

In the study of oligopoly, the Nash Equilibrium assumes that each firm makes rational profit-maximizing decisions while holding the actions of rival firms consistent. This assumption is made to simplify oligopoly models, offered the potential for huge complexity of strategic interactions between firms. As an aside, this presumption is one of the interesting themes of the activity photo, “A Beautiful Mind,” starring Rusmarket Crowe as John Nash. The idea of Nash Equilibrium is likewise the structure of the models of oligopoly presented in the following 3 sections: the Cournot, Bertrand also, and also Stackelberg models of oligopoly.

*5.3.2 Cournot Model*

Augustin Cournot (1801-1877), a French mathematician, arisen the first version of oligopoly explored right here. The Cournot model is a model of oligopoly in which firms develop a homogeneous great, assuming that the competitor’s output is addressed once deciding exactly how a lot to develop.

A numerical instance of the Cournot version follows, wright here it is assumed that tright here are 2 similar firms (a duopoly), via output offered by Qi (i=1,2). Thus, complete sector output is equal to: Q = Q1 + Q2. Market demand is a duty of price and also given by Qd = Qd(P), hence the inverse demand also attribute is P = P(Qd). Note that the price counts on the sector output Q, which is the amount of both individual firm’s outputs. In this way, each firm’s output has an affect on the price and revenues of both firms. This is the basis for strategic interaction in the Cournot model: if one firm rises output, it lowers the price dealing with both firms. The inverse demand feature and price feature are offered in Equation 5.1.

(5.1) P = 40 – QC(Qi) = 7Qi i = 1,2

Each firm chooses the optimal, profit-maximizing output level given the various other firm’s output. This will result in a Nash Equilibrium, since each firm is holding the behavior of the rival consistent. Firm One maximizes revenues as complies with.

max π1 = TR1 – TC1

max π1 = P(Q)Q1 – C(Q1)

max π1 = <40 – Q>Q1 – 7Q1

max π1 = <40 – Q1 – Q2>Q1 – 7Q1

max π1 = 40Q1 – Q12 – Q2Q1 – 7Q1

∂π1/∂Q1= 40 – 2Q1 – Q2 – 7 = 0

2Q1 = 33 – Q2

Q1* = 16.5 – 0.5Q2

This equation is referred to as the “Reactivity Function” of Firm One. This is as far as the mathematical solution deserve to be streamlined, and also represents the Cournot solution for Firm One. It is a reactivity feature since it explains Firm One’s reaction given the output level of Firm Two. This equation represents the strategic interactions in between the 2 firms, as alters in Firm Two’s output level will result in transforms in Firm One’s response. Firm One’s optimal output level relies on Firm Two’s habits and also decision making. Oligopolists are interassociated in both habits and also outcomes.

The 2 firms are assumed to be similar in this duopoly. Therefore, Firm Two’s reaction attribute will be symmetrical to the Firm One’s reaction attribute (check this by establishing up and also solving the profit-maximization equation for Firm Two):

Q2* = 16.5 – 0.5Q1

The two reactivity attributes can be used to settle for the Cournot-Nash Equilibrium. There are 2 equations and two unknowns (Q1 and Q2), so a numerical solution is found via substitution of one equation into the other.

Q1* = 16.5 – 0.5(16.5 – 0.5Q1)

Q1* = 16.5 – 8.25 + 0.25Q1

Q1* = 8.25 + 0.25Q1

0.75Q1* = 8.25

Q1* = 11

Due to symmetry from the presumption of identical firms:

Qi = 11 i = 1,2Q = 22devices P = 18 USD/unit

Profits for each firm are:

πi = P(Q)Qi – C(Qi) = 18(11) – 7(11) = (18 – 7)11 = 11(11) = 121 USD

This is the Cournot-Nash solution for oligopoly, uncovered by each firm assuming that the other firm holds its output level consistent. The Cournot version deserve to be quickly extended to more than two firms, but the math does gain significantly complex as even more firms are included. Economists utilize the Cournot model bereason is based upon intuitive and realistic presumptions, and the Cournot solution is intermediary between the outcomes of the two extreme market frameworks of perfect competition and monopoly.

This deserve to be watched by addressing the numerical instance for competition, Cournot, and also monopoly models, and comparing the options for each sector structure.

In a competitive sector, free entry outcomes in price equal to marginal expense (P = MC). In the instance of the numerical example, COMPUTER = 7. When this competitive price is substituted into the inverse demand equation, 7 = 40 – Q, or Qc = 33. Profits are found by fixing (P – MC)Q, or πc = (7 – 7)Q = 0. The competitive solution is given in Equation (5.2).

(5.2) Pc = 7 USD/unitQc = 33 unitsπc = 0 USD

The monopoly solution is found by maximizing profits as a single firm.

max πm = TRm – TCm

max πm = P(Qm)Qm – C(Qm)

max πm = <40 – Qm>Qm – 7Qm

max πm = 40Qm – Qm2 – 7Qm

∂πm/∂Qm= 40 – 2Qm – 7 = 0

2Qm = 33

Qm* = 16.5

Pm = 40 – 16.5 = 23.5

πm = (Pm – MCm)Qm = (23.5 – 7)16.5 = 16.5(16.5) = 272.25 USD

The monopoly solution is provided in Equation (5.3).

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(5.3) Pm = 23.5 USD/unit Qm = 16.5 unitsπm = 272.5 USD

The competitive, Cournot, and monopoly remedies can be compared on the exact same graph for the numerical instance (Figure 5.5).