Table 5.1 shows the 4 significant categories of market structures and their attributes.

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Table 5.1 Market Structure Characteristics

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

Perfect competition is on one finish of the sector structure spectrum, via numerous firms. Words, “numerous” has special meaning in this conmessage. In a perfectly competitive industry, each firm is so little loved one to the sector that it cannot influence the price of the excellent. Each perfectly competitive firm is a price taker. Because of this, many firms indicates that each firm is so tiny that it is a price taker.

Monopoly is the other excessive of the sector structure spectrum, via a solitary firm. Monopolies have monopoly power, or the capability to change the price of the great. Monopoly power is likewise dubbed sector power, and also is measured by the Lerner Index.

This chapter defines and also describes 2 intermediary market structures: monopolistic competition and also oligopoly.

**Monopolistic Competition** = A market structure characterized by a identified product and liberty of entry and also exit.

Monopolistically Competitive firms have actually one characteristic that is favor a syndicate (a identified product gives market power), and one characteristic that is choose a competitive firm (liberty of enattempt and exit). This develop of industry structure is widespread in market-based economic situations, and a expedition to the grocery keep reveals huge numbers of identified products: toothpaste, laundry soap, breakfast grain, and also so on.

Next off, we define the market structure **oligopoly**.

**Oligopoly** = A industry structure identified by obstacles to enattempt and a few firms.

Oligopoly is a fascinating market framework due to interactivity and interdependency in between oligopolistic firms. What one firm does affects the other firms in the oligopoly.

Because monopolistic competition and oligopoly are intermediary industry frameworks, the next area will evaluation the properties and qualities of perfect competition and also monopoly. These features will administer the specifying characteristics of monopolistic competition and also oligopoly.

*5.1.2 Rewatch of Perfect Competition*

The perfectly competitive industry has actually four characteristics:

(1) Homogenous product,

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

(3) Freedom of entry and leave, and

(4) Perfect information.

The opportunity of enattempt and also exit of firms occurs in the long run, given that the number of firms is addressed in the brief run.

An equilibrium is defined as a suggest wbelow tright here is no tendency to readjust. The concept of equilibrium can be extended to encompass the short run and long run.

**Quick Run Equilibrium** = A suggest from which there is no tendency to readjust (a steady state), and also a resolved number of firms.

**Long Run Equilibrium** = A allude from which tbelow is no tendency to change (a stable state), and also enattempt and also leave of firms.

In the brief run, the number of firms is addressed, whereas in the lengthy run, enattempt and departure of firms is possible, based upon profit conditions. We will certainly compare the short and also long run for a competitive firm in Figure 5.1. The two panels in Figure 5.1 are for the firm (left) and also market (right), via vastly different systems. This is emphasized by utilizing “q” for the firm’s output level, and also “Q” for the sector output level. The graph mirrors both brief run and long run equilibria for a perfectly competitive firm and also market. In short run equilibrium, the firms faces a high price (PSR), produces amount QSR at PSR = MC, and earns positive profits πSR.

Figure 5.1 Quick Run and Long Run Equilibria for a Perfectly Competitive Firm

Positive revenues in the brief run (πSR > 0) result in entry of various other firms, as tright here are no obstacles to entry in a competitive sector. The entry of brand-new firms shifts the supply curve in the sector graph from supply SSR to supply SLR. Entry will take place till earnings are propelled to zero, and also long run equilibrium is reached at Q*LR. In the long run, economic earnings are equal to zero, so tbelow is no impetus for entry or leave. Each firm is earning precisely what it is worth, the opportunity costs of all resources. In long run equilibrium, earnings are zero (πLR = 0), and price amounts to the minimum average price point (P = min AC = MC). Marginal expenses equal average costs at the minimum average expense point. At the long run price, supply equates to demand at price PLR.

*5.1.3 Review of Monopoly*

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

Figure 5.2 Monopoly Profit Maximization

Note that long-run profits can exist for a syndicate, because obstacles to enattempt halt any type of potential entrants from joining the market. In the next area, we will explore market structures that lie in between the two extremes of perfect competition and monopoly.

5.2 Monopolistic CompetitionMonopolistic competition is a industry structure characterized by free enattempt and also departure, choose competition, and also identified commodities, favor monopoly. Differentiated commodities provide each firm via some market power. Advertising and also marketing of each individual product provide uniqueness that causes the demand curve of each excellent to be downward sloping. Free entry indicates that each firm competes via other firms and also profits are equal to zero on long run equilibrium. If a monopolistically competitive firm is earning positive economic earnings, entry will happen until economic profits are equal to zero.

*5.2.1 Monopolistic Competition in the Brief and Long Runs*

The demand also curve of a monopolistically competitive firm is downward sloping, indicating that the firm has actually a level of sector power. Market power derives from product differentiation, since each firm produces a various product. Each excellent has actually many cshed substitutes, so industry power is limited: if the price is boosted too a lot, consumers will certainly transition to competitors’ products.

Figure 5.3 Monopolistic Competition in the Short Run and also Long Run

Quick and also lengthy run equilibria for the monopolistically competitive firm are shown in Figure 5.3. The demand curve encountering the firm is downward sloping, but relatively elastic due to the availcapacity of close substitutes. The brief run equilibrium shows up in the left hand also panel, and also is practically similar to the monopoly graph. The only difference is that for a monopolistically competitive firm, the demand is reasonably elastic, or level. Otherwise, the brief run profit-maximizing solution is the exact same as a syndicate. The firm sets marginal revenue equal to marginal price, produces output level q*SR and charges price PSR. The profit level is shown by the shaded rectangle π.

The lengthy run equilibrium is presented in the appropriate hand also panel. Enattempt of various other firms occurs till profits are equal to zero; total profits are equal to total expenses. Therefore, the demand curve is tangent to the average expense curve at the optimal lengthy run quantity, q*LR. The long run profit-maximizing amount is found wright here marginal revenue equates to marginal expense, which also occurs at q*LR.

*5.2.2 Economic Efficiency and also Monopolistic Competition*

Tbelow are two resources of inefficiency in monopolistic competition. First, dead weight loss (DWL) due to monopoly power: price is greater than marginal expense (P > MC). Second, excess capacity: the equilibrium quantity is smaller than the lowest cost quantity at the minimum suggest on the average cost curve (q*LR minAC). These two resources of ineffectiveness have the right to be seen in Figure 5.4.

Figure 5.4 Comparikid of Efficiency for Competition and Monopolistic Competition

First, tright here is dead weight loss (DWL) as a result of sector power: the price is higher than marginal expense in long run equilibrium. In the ideal hand panel of Figure 5.4, the price at the long run equilibrium quantity is PLR, and marginal expense is lower: PLR > MC. This causes dead weight loss to society, considering that the competitive equilibrium would be at a larger quantity wbelow P = MC. Total dead weight loss is the shaded location beneath the demand also curve and over the MC curve in figure 5.4.

The second source of ineffectiveness connected with monopolistic competition is excess capacity. This can also be seen in the right hand panel of Figure 5.4, wbelow the long run equilibrium amount is lower than the amount where average costs are lowest (qminAC). Therefore, the firm can develop at a lower cost by boosting output to the level wright here average costs are minimized.

Given these two inefficiencies associated with monopolistic competition, some individuals and teams have actually dubbed for federal government intervention. Regulation can be supplied to mitigate or get rid of the inefficiencies by rerelocating product differentiation. This would result in a single product rather of a large variety of cshed substitutes.

Regulation is probably not an excellent solution to the inefficiencies of monopolistic competition, for 2 reasons. First, the market power of a typical firm in the majority of monopolistically competitive sectors is small. Each monopolistically competitive market has actually many firms that create sufficiently substitutable commodities to provide enough competition to result in fairly low levels of industry power. If the firms have small levels of sector power, then the deadweight loss and also excess capacity inefficiencies are likely to be small.

2nd, the advantage offered by monopolistic competition is product diversity. The acquire from product diversity can be large, as consumers are willing to pay for different characteristics and also attributes. As such, the get from product diversity is most likely to outweigh the expenses of ineffectiveness. Evidence for this case can be watched in market-based economic situations, wbelow there is a substantial amount of product diversity.

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

5.3 Oligopoly ModelsAn oligopoly is identified as a industry structure with few firms and obstacles to entry.

**Oligopoly** = A market structure via few firms and obstacles to entry.

Tright here is frequently a high level of competition between firms, as each firm renders decisions on prices, amounts, and also heralding to maximize earnings. Since tright here are a tiny number of firms in an oligopoly, each firm’s profit level depends not just on the firm’s very own decisions, yet also on the decisions of the various other firms in the oligopolistic sector.

*5.3.1 Strategic Interactions*

Each firm need to take into consideration both: (1) other firms’ reactions to a firm’s very own decisions, and (2) the very own firm’s reactions to the various other firms’ decisions. Hence, there is a consistent interplay between decisions and also reactions to those decisions by all firms in the industry. Each oligopolist must take into account these strategic interactions as soon as making decisions. Because all firms in an oligopoly have actually outcomes that depfinish on the various other firms, these strategic interactions are the foundation of the research and expertise of oligopoly.

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

When making decisions that think about the possible reactions of various other firms, firm managers normally assume that the managers of competing firms are rational and also intelligent. These strategic interactions create the examine of game theory, the topic of Chapter 6 below. John Nash (1928-2015), an American mathematician, was a pioneer in game concept. Economists and mathematicians use the principle of a Nash Equilibrium (NE) to define a prevalent outcome in game concept that is generally used in the research of oligopoly.

** Nash Equilibrium** = An outcome wbelow tbelow is no tendency to readjust based upon each individual picking a strategy provided the strategy of rivals.

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

*5.3.2 Cournot Model*

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

A numerical example of the Cournot design adheres to, where it is assumed that tright here are 2 identical firms (a duopoly), through output provided by Qi (i=1,2). Thus, complete industry output is equal to: Q = Q1 + Q2. Market demand also is a duty of price and provided by Qd = Qd(P), therefore the inverse demand feature is P = P(Qd). Keep in mind that the price relies on the industry output Q, which is the sum of both individual firm’s outputs. In this method, each firm’s output has an affect on the price and earnings of both firms. This is the basis for strategic interaction in the Cournot model: if one firm rises output, it lowers the price encountering both firms. The inverse demand also attribute and expense function are provided 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 certainly cause a Nash Equilibrium, because each firm is holding the actions of the rival consistent. Firm One maximizes profits 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 dubbed the “Reactivity Function” of Firm One. This is as much as the mathematical solution can be simplified, and also represents the Cournot solution for Firm One. It is a reaction function given that it explains Firm One’s reactivity offered the output level of Firm Two. This equation represents the strategic interactions in between the two firms, as changes in Firm Two’s output level will result in alters in Firm One’s response. Firm One’s optimal output level counts on Firm Two’s habits and also decision making. Oligopolists are interconnected in both behavior and also outcomes.

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

Q2* = 16.5 – 0.5Q1

The two reactivity attributes have the right to be used to deal with for the Cournot-Nash Equilibrium. There are 2 equations and 2 unknowns (Q1 and Q2), so a numerical solution is found with 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 symmeattempt from the assumption of similar firms:

Qi = 11 i = 1,2Q = 22systems 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 design deserve to be quickly extfinished to even more than two firms, but the math does get progressively complicated as even more firms are added. Economists utilize the Cournot model because is based upon intuitive and realistic presumptions, and also the Cournot solution is intermediary between the outcomes of the two extreme sector frameworks of perfect competition and also monopoly.

This can be seen by addressing the numerical instance for competition, Cournot, and monopoly models, and also comparing the services for each sector structure.

In a competitive market, complimentary enattempt outcomes in price equal to marginal cost (P = MC). In the case of the numerical example, PC = 7. When this competitive price is substituted right into the inverse demand equation, 7 = 40 – Q, or Qc = 33. Profits are found by addressing (P – MC)Q, or πc = (7 – 7)Q = 0. The competitive solution is provided in Equation (5.2).

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

The monopoly solution is uncovered by maximizing revenues as a solitary 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 also monopoly services have the right to be compared on the same graph for the numerical instance (Figure 5.5).