In
economics
Economics () is the social science that studies the production, distribution, and consumption of goods and services.
Economics focuses on the behaviour and interactions of economic agents and how economies work. Microeconomics anal ...
, a monopsony is a
market structure
Market structure, in economics, depicts how firms are differentiated and categorised based on the types of goods they sell (homogeneous/heterogeneous) and how their operations are affected by external factors and elements. Market structure makes it ...
in which a single buyer substantially controls the market as the major purchaser of goods and services offered by many would-be sellers. The
microeconomic
Microeconomics is a branch of mainstream economics that studies the behavior of individuals and firms in making decisions regarding the allocation of scarce resources and the interactions among these individuals and firms. Microeconomics fo ...
theory of monopsony assumes a single entity to have market power over all sellers as the only purchaser of a good or service. This is a similar power to that of a
monopolist
A monopoly (from Greek el, μόνος, mónos, single, alone, label=none and el, πωλεῖν, pōleîn, to sell, label=none), as described by Irving Fisher, is a market with the "absence of competition", creating a situation where a speci ...
, which can influence the price for its buyers in a
monopoly
A monopoly (from Greek language, Greek el, μόνος, mónos, single, alone, label=none and el, πωλεῖν, pōleîn, to sell, label=none), as described by Irving Fisher, is a market with the "absence of competition", creating a situati ...
, where multiple buyers have only one seller of a good or service available to purchase from.
History
Monopsony theory was developed by economist
Joan Robinson
Joan Violet Robinson (''née'' Maurice; 31 October 1903 – 5 August 1983) was a British economist well known for her wide-ranging contributions to economic theory. She was a central figure in what became known as post-Keynesian economics.
...
in her book ''The Economics of Imperfect Competition'' (1933).
Economists use the term "monopsony power" in a manner similar to "monopoly power", as a shorthand reference for a scenario in which there is one dominant power in the buying relationship, so that power is able to set prices to maximize profits not subject to competitive constraints. Monopsony power exists when one buyer faces little competition from other buyers for that labour or good, so they are able to set wages or prices for the labour or goods they are buying at a level lower than would be the case in a competitive market. In economic literature the term "monopsony" is predominantly used when referring to labour markets,
however could be applied to any industry, good or service where a buyer has market power over all sellers.
A classic theoretical example is a
mining town
A mining community, also known as a mining town or a mining camp, is a community that houses miners. Mining communities are usually created around a mine or a quarry.
Historic mining communities
Australia
* Ballarat, Victoria
* Be ...
, where the company that owns the mine is able to set wages low since they face no competition from other employers in hiring workers, because they are the only employer in the town, and geographic isolation or obstacles prevent workers from seeking employment in other locations. Other more current examples may include school districts where teachers have little mobility across districts. In such cases the district faces little competition from other schools in hiring teachers, giving the district increased power when negotiating employment terms. Alternative terms are
oligopsony
An oligopsony (from Greek ὀλίγοι (''oligoi'') "few" and ὀψωνία (''opsōnia'') "purchase") is a market form in which the number of buyers is small while the number of sellers in theory could be large. This typically happens in a mark ...
or monopsonistic competition.
Etymology
The term "monopsony" (from
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
μόνος (''mónos'') "single" and ὀψωνία (''opsōnía'') "purchase")
was first introduced by
Joan Robinson
Joan Violet Robinson (''née'' Maurice; 31 October 1903 – 5 August 1983) was a British economist well known for her wide-ranging contributions to economic theory. She was a central figure in what became known as post-Keynesian economics.
...
in her influential
book, ''The Economics of Imperfect Competition'', published in 1933. Robinson credited classics scholar
Bertrand Hallward at
the University of Cambridge
, mottoeng = Literal: From here, light and sacred draughts.
Non literal: From this place, we gain enlightenment and precious knowledge.
, established =
, other_name = The Chancellor, Masters and Schola ...
with coining the term.
Static monopsony in a labour market
![Monopsony-static-partial-equilibrium](https://upload.wikimedia.org/wikipedia/commons/c/cb/Monopsony-static-partial-equilibrium.svg)
The standard textbook monopsony model of a labour market is a static
partial equilibrium
In economics, partial equilibrium is a condition of economic equilibrium which analyzes only a single market, ''ceteris paribus'' (everything else remaining constant) except for the one change at a time being analyzed. In general equilibrium ana ...
model with just one employer who pays the same wage to all the workers.
The employer faces an upward-sloping ''labour supply curve''
(as generally contrasted with an infinitely elastic labour supply curve), represented by the ''S'' blue curve in the diagram on the right. This curve relates the wage paid,
, to the level of employment,
, and is denoted as an increasing function
. Total labour costs are given by
. The firm has total revenue
, which increases with
. The firm wants to choose
to maximize profit,
, which is given by:
:
.
At the maximum profit
, so the first-order condition for maximization is
:
where
is the derivative of the function
implying
:
The left-hand side of this expression,
, is the ''
marginal revenue product
Marginal may refer to:
* ''Marginal'' (album), the third album of the Belgian rock band Dead Man Ray, released in 2001
* ''Marginal'' (manga)
* '' El Marginal'', Argentine TV series
* Marginal seat or marginal constituency or marginal, in polit ...
'' of labour (roughly, the extra revenue generated by an extra worker) and is represented by the red ''MRP'' curve in the diagram. The right-hand side is the ''
marginal cost'' of labour (roughly, the extra cost due to an extra worker) and is represented by the green ''MC'' curve in the diagram. Notably, the marginal cost is ''higher'' than the wage
paid to the new worker by the amount
:
.
This is because, by assumption, the firm has to increase the wage paid to all the workers it already employs whenever it hires an extra worker. In the diagram, this leads to an ''MC'' curve that is ''above'' the labour supply curve ''S''.
The first-order condition for maximum profit is then satisfied at point ''A'' of the diagram, where the ''MC'' and ''MRP'' curves intersect. This determines the profit-maximizing employment as ''L'' on the horizontal axis. The corresponding wage ''w'' is then obtained from the supply curve, through point ''M''.
The monopsonistic equilibrium at ''M'' can be contrasted with the equilibrium that would obtain under competitive conditions. Suppose a competitive employer entered the market and offered a wage higher than that at ''M''. Then every employee of the first employer would choose instead to work for the competitor. Moreover, the competitor would gain all the former profits of the first employer, minus a less-than-offsetting amount from the wage increase of the first employer's employees, plus profit arising from additional employees who decided to work in the market because of the wage increase. But the first employer would respond by offering an even higher wage, poaching the new rival's employees, and so forth. As a result, a group of perfectly competitive firms would be forced, through
competition
Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indiv ...
, to intersection ''C'' rather than ''M''. Just as a
monopoly
A monopoly (from Greek language, Greek el, μόνος, mónos, single, alone, label=none and el, πωλεῖν, pōleîn, to sell, label=none), as described by Irving Fisher, is a market with the "absence of competition", creating a situati ...
is thwarted by the competition to win sales, minimizing prices and maximizing output, competition for employees between the employers in this case would maximize both wages and employment.
Welfare implications
![Monopsony-welfare-effects](https://upload.wikimedia.org/wikipedia/commons/8/81/Monopsony-welfare-effects.svg)
The lower employment and wages caused by monopsony power have two distinct effects on the economic welfare of the people involved. Firstly, it redistributes welfare away from workers and to their employer(s).
Secondly, it reduces the aggregate (or social) welfare enjoyed by both groups taken together, as the employers' net gain is smaller than the loss inflicted on workers.
The diagram on the right illustrates both effects, using the standard approach based on the notion of
economic surplus
In mainstream economics, economic surplus, also known as total welfare or total social welfare or Marshallian surplus (after Alfred Marshall), is either of two related quantities:
* Consumer surplus, or consumers' surplus, is the monetary gain ...
. According to this notion, the workers' economic surplus (or net gain from the exchange) is given by the area between the ''S'' curve and the horizontal line corresponding to the wage, up to the employment level. Similarly, the employers' surplus is the area between the horizontal line corresponding to the wage and the ''MRP'' curve, up to the employment level. The ''social'' surplus is then the sum of these two areas.
Following such definitions, the grey rectangle, in the diagram, is the part of the competitive social surplus that has been redistributed from the workers to their employer(s) under monopsony. By contrast, the yellow triangle is the part of the competitive social surplus that has been lost by ''both'' parties, as a result of the monopsonistic restriction of employment.
This is a net social loss and is called ''
deadweight loss
In economics, deadweight loss is the difference in production and consumption of any given product or service including government tax. The presence of deadweight loss is most commonly identified when the quantity produced ''relative'' to the amoun ...
''. It is a measure of the market failure caused by monopsony power, through a wasteful misallocation of resources.
As the diagram suggests, the size of both effects increases with the difference between the marginal revenue product ''MRP'' and the market wage determined on the supply curve ''S''. This difference corresponds to the vertical side of the yellow triangle, and can be expressed as a proportion of the market wage, according to the formula:
:
.
The ratio
has been called the
rate of exploitation, and it can be easily shown that it equals the reciprocal of the elasticity of the labour supply curve faced by the firm. Thus the rate of exploitation is zero under competitive conditions, when this elasticity tends to infinity. Empirical estimates of
by various means are a common feature of the applied literature devoted to the measurement of observed monopsony power.
Finally, it is important to notice that, while the gray-area redistribution effect could be reversed by fiscal policy (i.e., taxing employers and transferring the tax revenue to the workers), this is not so for the yellow-area deadweight loss. The market failure can only be addressed in one of two ways: either by breaking up the monopsony through anti-trust intervention, or by regulating the wage policy of firms. The most common kind of regulation is a binding
minimum wage higher than the monopsonistic wage.
Minimum wage
![Monopsony-minimum-wage](https://upload.wikimedia.org/wikipedia/commons/d/da/Monopsony-minimum-wage.svg)
A binding minimum wage can be introduced either directly by law or through collective bargaining laws requiring union membership. While it is generally agreed that minimum wage price floors reduce employment,
economic literature has yet to form a consensus regarding the effects in the presence of monopsony power.
Some studies have shown that if monopsony power is present within a labour market the effect is reversed and a minimum wage ''could'' increase employment.
This effect is demonstrated in the diagram on the right.
Here the minimum wage is , higher than the monopsonistic . Because of the binding effects of minimum wage and the excess supply of labour (as defined by the monopsony status), the marginal cost of labour for the firm becomes constant (the price of hiring an additional worker rather than the increasing cost as labour becomes more scarce). This means that the firm maximizes profit at the intersection of the new marginal cost line (MC' in the diagram) and Marginal Revenue Product line (the additional revenue for selling one more unit). This is the point where it becomes more expensive to produce an additional item than is earned in revenue from selling that item.
This condition is still inefficient compared to a competitive market. The line segment represented by A-B shows that there are still workers who would like to find a job, but cannot due to the monopsonistic nature of this industry. This would represent the unemployment rate for this industry. This illustrates that there will be deadweight loss in a monopsonistic labour environment regardless of minimum wage levels, however a minimum wage law can increase total employment within the industry.
More generally, a binding minimum wage modifies the form of the supply curve faced by the firm, which becomes:
:
where
is the original supply curve and
is the minimum wage. The new curve has thus a horizontal first branch and a kink at the point
:
as is shown in the diagram by the kinked black curve ''MC' S'' (the black curve to the right of point B). The resulting equilibria (the profit-maximizing choices that rational companies will make) can then fall into one of three classes according to the value taken by the minimum wage, as shown by the following table:
Yet, even when it is sub-optimal, a minimum wage higher than the monopsonistic rate can raises the level of employment anyway. This is a highly remarkable result because it only follows under monopsony. Indeed, under competitive conditions any minimum wage higher than the market rate would actually ''reduce'' employment, according to classical economic models and the consensus of peer-reviewed work.
Thus, spotting the effects on employment of newly introduced minimum wage regulations is among the indirect ways economists use to pin down monopsony power in selected labour markets. This technique was used, for example in a series of studies looking at the American labour market that found monopsonies existed only in several specialized fields such as professional sports and college professors.
Wage discrimination
Just like a monopolist, a monopsonistic employer may find that its profits are maximized if it
''discriminates'' prices. In this case the company pays different wages to different groups of workers (even if their MRP is the same), with lower wages paid to the workers who have a lower elasticity of supply of their labour to the firm.
Researchers have used this fact to explain at least part of the observed wage differentials whereby
women often earn less than men, even after controlling for observed productivity differentials. Robinson's original application of monopsony (1938) was developed to explain wage differentials between equally productive women and men.
Ransom and Oaxaca (2004) found that women's wage elasticity is lower than that of men for employees at a grocery store chain in Missouri, controlling for other factors typically associated with wage determination. Ransom and Lambson (2011) found that female teachers are paid less than male teachers due to differences in labour market mobility constraints facing women and men.
Some authors have argued informally that, while this is so for ''market'' supply, the reverse may somehow be true of the supply to individual firms. In particular, Manning and others have shown that, in the case of the
UK Equal Pay Act, implementation has led to higher employment of women. Since the Act was effectively minimum wage legislation for women, this might perhaps be interpreted as a symptom of monopsonistic discrimination.
Dynamic models of monopsony
More recent labor market models of monopsony
have indicated that some monopsonistic power is likely present in otherwise competitive markets. Its cause can be linked to
imperfect information
In economics, perfect information (sometimes referred to as "no hidden information") is a feature of perfect competition. With perfect information in a market, all consumers and producers have complete and instantaneous knowledge of all market pri ...
as a result of search frictions.
This may indicate companies operating under competitive market conditions have some limited discretion to manipulate wage rates without losing employees to competitors that is associated with the search friction in that market (ie how hard it is to find and secure another job). This modern perspective of dynamic monopsony
first proposed by
Allan Manning (2003), also results in an upward sloping labor supply curve, and is more practical as it incorporates multiple employers in a competitive market whilst also allowing for search frictions, and a costly search.
Empirical problems
The simpler explanation of monopsony power in labour markets is barriers to entry on the demand side. Such barriers to entry would result in a limited number of companies competing for labour (oligopsony). If the hypothesis was generally true, one would expect to find that wages decreased as firm size increased or, more accurately, as industry concentration increased. However, numerous statistical studies document significant positive correlations between firm or establishment size and wages. These results are often explained as being the result of cross-industry competition. For example, if there were only one fast food producer, that industry would be very consolidated. The company, however, would be unable to drive down wages via monopsonistic power if it were also competing against retail stores, construction, and other jobs utilizing the same labour skill set. This finding is both intuitive (low-skilled labour can move more fluidly through different industries) and supported by a study of American labor markets which found monopsony effects were limited to professional sports, teaching, and nursing, fields where skill sets limit moving to comparably paid other industries.
However, monopsony power might also be due to circumstances affecting entry of workers on the supply side (like in the referenced case above), directly reducing the elasticity of labour supply to firms. Paramount among these are industry accreditation or licensing fees, regulatory constraints, training or education requirements, and the institutional factors that limit labour mobility between firms, including job protection legislation.
An alternative that has been suggested as a source of monopsony power is worker preferences over job characteristics.
Such job characteristics can include distance from work, type of work, location, the social environment at work, etc. If different workers have different preferences, employers could have local monopsony power over workers that strongly prefer working for them.
Empirical evidence of monopsony power has been relatively limited. In line with the considerations discussed above, but perhaps counter to common intuition, there is no observable monopsony power in low-skilled labour markets in the US.
Though there has been at least one study finding monopsony power in Indonesia due to barriers to entry in developing countries.
Several studies expanding their view for monopsony power have found economic and labor mobility in the US precludes any detectable monopsony effects
with the notable exceptions of professional sports
and (with some disagreement
) nursing.
Both of these industries have highly specialized labor conditions and are generally not substitutable. According to a 2020 review of the existing literature on monopsony in labor markets, there is some evidence of monopsony power in higher income industries due to contractual limitations (non-competes for example) though the author notes that the large majority of economists do not ascribe notable monopsony effects to labor markets.
See also
*
Bilateral monopoly
A bilateral monopoly is a market structure consisting of both a monopoly (a single seller) and a monopsony (a single buyer).
Overview
In a standard monopoly structure, the monopolist sells to multiple buyers with no market power, thereby giving t ...
*
Canadian Wheat Board
The Canadian Wheat Board (french: Commission canadienne du blé, links=no) was a marketing board for wheat and barley in Western Canada. Established by the Parliament of Canada on 5 July 1935, its operation was governed by the Canadian Wheat Bo ...
—a (formerly general, now limited) monopsony in agriculture
*
Captive supply Captive supply is a term for that part of the supply that is not owned by a company
A company, abbreviated as co., is a legal entity representing an association of people, whether natural, legal or a mixture of both, with a specific objectiv ...
*
Market form
Market structure, in economics, depicts how firms are differentiated and categorised based on the types of goods they sell (homogeneous/heterogeneous) and how their operations are affected by external factors and elements. Market structure makes it ...
s
*
Single-payer health care
*
Single desk
A single desk is a monopoly marketer and buyer of a product with multiple suppliers. They were common in markets for agricultural produce.
Single-desk marketing in Australia
Wheat
In Australia, the single desk was the monopoly marketing of wheat ...
References
Further reading
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*Suresh Naidu and Eric A. Posner. 2021.
Labor Monopsony and the Limits of the Law. ''Journal of Human Resources''
External links
*
{{Authority control
*
Market failure
Monopoly (economics)
Imperfect competition