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Microeconomics For Dummies®

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Economics is about many things. On one level, it’s concerned with humanity’s struggle to cope with scarcity and how it leads people to make choices about the things that should have priority. On another level, it’s about the human quest for happiness in an uncertain world, and the ways people have found to achieve it. On yet another level, it’s interested in how societies organise themselves from the bottom up, using markets as a way of trading with each other. But however you look at it, economics is a huge subject!

Microeconomics looks at economics on the smallest scales – individuals, consumers, firms – and uses that picture to build up an understanding of how more complicated parts of the world – markets, industries – work. Microeconomics has become a very big subject too, taking in everything from what kinds of decisions people make to the right way to measure and analyse those decisions. It’s the part of economics that’s like looking through a microscope as small creatures go about their business.

So that’s what microeconomists do. The microscope, though, is a bit unusual. It’s not made of glass but of tools, called models, which are ways of representing the world that you can use to examine real life. They’re not real life itself – making a model of real life that was accurate in every way would be like the perfect global map in a Lewis Carroll story that ended up being the size of the entire world! Instead, models are guides to help you when you need to know what’s going on in a particular situation.

Maybe you’re thinking about starting a business – microeconomics can help with everything from working out how much to pay staff to knowing which markets to avoid. Maybe you’re wondering whether a company is a good place to invest – microeconomics can help you figure out whether the market it’s in would let the firm make profits. Maybe you want to figure out how to get the best price for something you want to sell – microeconomics can help you work out how to auction it to get the highest price. In all these places in life, microeconomics can help you figure out an answer.

With all that, please come and join us as we tell you more of what this book is all about!

About This Book

This book takes you through the most common tools and models that microeconomists use to make sense of a complicated world. The aspects that we cover include the following:

  • What utility is and why microeconomists assume people maximise it.
  • What a firm is and what it does.
  • What happens when firms and consumers interact in a market.
  • Why competition is better than monopoly.
  • How to understand competition between firms, and how the results depend on what type of competition is going on.
  • What happens when some people in a marketplace know more than others.
  • How you can generalise – to some extent – the results from one market to all markets, and how that informs decisions you may make about distributing resources.
  • How you can figure out which options a firm will choose to take when it has competitors who also want to do the best for themselves.
  • How and why markets fail, and some of the things you can do about it.

Foolish Assumptions

Economists often make assumptions – they have to make models when they don’t know exactly how things work in a specific case. Sometimes those assumptions can be foolish – something we learnt from Samuel L. Jackson in The Long Kiss Goodnight and Eric Bogosian in Under Siege 2: Dark Territory! In writing this book, we make some foolish assumptions about you:

Some of or all these assumptions may turn out to be true. Whichever are, we hope that this book chimes with your desire to understand the wild world of microeconomics!

Icons Used in This book

To help you get the most out of this book, we use a few icons to flag up particularly noteworthy items.

tip This icon highlights handy hints for smoothing out your microeconomics journey.

remember Some of the ideas in this book are so important for understanding microeconomics that they need special emphasis – often because they’re easy to get wrong! When you see this icon, you know that the associated text is something economists really want you to understand!

warning The world is full of pitfalls for the unwary. Here we stress areas for which you need to watch out.

jargonbuster Economists use technical terms to speak to each other – it’s just shorthand usually, so that no one needs to go through pages and pages of the same things. When you see this icon, you know that you’re being let into the clubhouse – economics is an inclusive science! – and picking up a piece of lingo that economists use to cut long stories short!

realworld Theories are great, but ultimately economics is about the real world, and the best way to see what microeconomics can do is to see it in action. This icon tells you that you’re getting something from real-life practice to help you get the idea!

Beyond the Book

But wait! There’s more! We’ve not only put together a book that takes in a journey from simple microeconomics to complex models of competition, but also compiled some online bonus bits (at to help you take things further:

  • An online Part of Tens with suggestions for places to take your understanding of microeconomics to the next level – from how to deal with government to how economists test their models.
  • Four online articles with further looks at the bits and pieces of microeconomics – from what ‘economically rational’ means to how you deal with the really long term.
  • A handy e-cheat sheet to keep with you – at least mentally! – at all times.

Where to Go from Here

The great thing about a factual book like this one is that you don’t have to worry about spoilers and can dive straight in anywhere you choose! If you’ve just seen the film Dr. Strangelove and you want to jump further into the wacky world of game theory in Part V, be our guest! If you want to think about why someone wants to break up a monopoly, move straight to Chapter 13 without passing Go! To see how economists think about pollution, check out Chapter 14!

Economists are fine with choice – trust us, we make a living because people are able to choose! However, if your choice is to start at the beginning, you also get to see how the whole subject unfolds, from simple ideas to more complex levels.

Of course the two approaches aren’t mutually exclusive, and no reason exists why you can’t do both – although obviously at different times!

With that, we wish you bon appétit  !


Adverse selection
A problem caused by asymmetric information where a product is selected only by the people who’ll make worst returns for a supplier – for example, only people with risky lifestyles buying life insurance. The typical effect is that the market fails.
(1) Anyone who acts in an economic model. (2) In the principal–agent model, anyone who acts on behalf of the principal.
Allocative efficiency
When a firm produces up to the point where marginal revenue equals marginal cost. As a result, when firms are allocatively efficient no deadweight loss exists and price equals marginal cost.
Asymmetric information
The condition that exists when one side of a trade knows more than the other – for example, when sellers know more about their product than buyers.
A way of selling where an auctioneer calls out prices and solicits bids from potential buyers. The good being auctioned goes to one buyer – usually the highest bidder.
Average cost
Total cost divided by the number of units of output produced –in other words, total costs per unit.
Backward induction
A method of solving repeated games by starting at the end payoffs and working backwards, eliminating any move that would yield a lower payoff.
Barriers to entry
Anything that significantly raises the cost for a firm of entering a market and thus deters one from entering.
Bertrand oligopoly
A model of oligopoly where competitors react to each other’s decisions on price.
A group of firms acting together to maximise their collective profits. Cartels try to secure monopoly profits for their members and therefore impose deadweight losses on everyone else.
Co-ordination game
A type of game theory model where the best outcome depends on participants being able to co-ordinate their actions. The stag hunt is one such game.
Cournot oligopoly
A model of oligopoly where competitors react to each other’s decisions on quantity.
Deadweight loss
A loss of welfare (producer plus consumer surpluses) that occurs because production isn’t allocative efficient. Deadweight losses are lost to producers and consumers and therefore to society as a whole.
Demand curve
In the supply and demand model, relates the quantity purchased to the price of the good – holding income and tastes constant. It generally slopes downwards:
as price rises, quantity demanded goes down.
Demand function
Any mathematical description of quantity purchased in terms of prices.
In game theory, deterrence strategies are those whose purpose is to deter a rival from taking an action by signalling that the rival’s payoffs will be lower if it does act. The word is often used in terms of preventing a firm from entering a market.
Dominant strategy
A strategy that gives higher payoffs no matter what the opponent does.
Any market supplied by only two firms.
Dutch auction
Where the auctioneer calls out descending prices until a bidder determines that the price is low enough to buy and calls ‘mine’.
English auction
Where the auctioneer starts at a low price and successive rounds of bidding raise the price until only one bidder is left.
A benefit or cost that falls on a third party not included in a transaction. Externalities can be negative – costs – or positive – benefits.
External cost
A cost that falls on a third party. If A and B trade and C, who isn’t involved in the trade, gets burdened with some cost, C is experiencing an external cost.
Factor of production
The basic inputs of a firm – land, labour and capital. The firm combines them using a technology to produce its output.
Fixed cost
Costs that don’t depend on how many units a firm produces. For example, for a football team, the cost of constructing a stadium is a fixed cost, because it costs the same to build no matter how many games are played there.
Game theory
A branch of mathematics looking at what actions participants will take given the payoffs to their actions and other participants’ decisions. The term is used extensively in economics to examine things such as cartels.
General equilibrium
A concept used to define an equilibrium in all markets in an economy. In a general equilibrium, all markets are simultaneously in equilibrium; in a partial equilibrium, only one market is in equilibrium.
Hotelling’s law
An observation that, given competition on brand or product, markets will form an equilibrium where the differences between brands are as small as they can possibly be.
Indifference curve
A utility function that has a constant level of utility along the curve.
A cost curve where the cost is the same at all points along the curve.
A curve that shows all the combinations of inputs that produce the same output at all points along the curve.
Iterated elimination of dominant strategies
A method for solving games by eliminating any strategies that a rational player wouldn’t choose.
Marginal cost
The cost for a firm of adding one extra unit to production.
Marginal revenue
The revenue gained from selling one extra unit of a product.
Marginal social cost
The cost to society as a whole of a firm adding one extra unit of production.
Mixed strategy
A strategy that assigns a probability to each of a set of pure strategies. For instance, a mixed strategy in Rock, Paper Scissors is playing each of rock, paper and scissors one-third of the time.
Monopolistic competition
A type of market structure with free entry and exit and where competitors each attempt to make their brand different. It yields some welfare losses, which have to be set against gains from product diversity.
A market served by only one firm. In competition law and policy, it means a firm is able to set higher than cost prices over the medium term.
Moral hazard
A condition in markets that have asymmetric information where someone takes more risks because she knows that someone else will take on the costs of those risks – for instance, leaving your door unlocked because you have generous insurance.
Nash equilibrium
In game theory, any outcome where each party is doing the best it can do, given that other parties are doing the same. At a Nash equilibrium, no party has an incentive to change its strategy.
A market served by few firms, and with some barriers to entry and exit. Firms in an oligopoly interact strategically given each other’s decisions.
Pareto efficiency
A distribution where making one party better off without making another party worse off is impossible.
Partial equilibrium
An equilibrium where supply and demand are equal in a particular market, as opposed to general equilibrium where they’re equal in all markets.
The benefit or loss computed at the end of a game in game theory.
Perfect competition
A type of market structure where a large number of producers are making the same product and have perfect information. The result is that price gets bargained down to marginal cost and no firm can influence price on its own.
Pooled equilibrium
Where two populations have different characteristics, a pooled equilibrium is the equilibrium you get when the two markets are taken together and summed.
Prisoners’ Dilemma
A game theory model where two participants are unable to communicate and as a result make an individually best decision that isn’t as good for the whole.
Productive efficiency
Productive efficiency happens when firms are producing for the lowest possible cost, at the minimum of the long-run average cost curve.
What’s left over after all relevant costs have been taken away from a firm’s revenue.
Pure strategy
A strategy chosen on its payoffs alone, and not on the probability of using it. A pure strategy is a complete specification of how a given player will play the game, as opposed to a mixed strategy, which needs you to know how probable it is that a player will use any given strategy.
Reaction function
A mathematical description of what one firm will do in an oligopoly in reaction to its competitor’s decision.
Separating equilibrium
The equilibrium that you get when you look at different types in the population – for instance high and low productivity workers – as distinct groups. In a separating equilibrium, the two populations have some way of demonstrating their difference from each other, whereas in a pooled equilibrium they don’t.
A game theory term for a move that tells other players something that they aren’t able to discern directly.
Stackelberg oligopoly
A model of an oligopoly where one firm is the leader and able to take the reaction of other firms into account when making its decisions. A Stackelberg oligopoly produces more than a Cournot oligopoly at a slightly lower cost.
Stag hunt
A type of co-ordination game with two Nash equilibria, one that maximises payoff and one that minimises risk.
A set of moves that a player will follow in a game, which must be complete and cover every possible outcome in the game, even if that outcome won’t happen.
Sunk costs
Costs that are unrecoverable after being incurred.
Supply curve
A curve in supply and demand analysis that tells you how much the relevant industry will make as price changes.
Supply and demand
A model microeconomists use to look at prices and quantities in a market. The equilibrium in the model is where supply equals demand, which is where the supply and demand curves cross.
Switching cost
The cost for a firm of a consumer changing from one product to another, for example in switching from one type of word processor to another. Switching costs may come from the sunk cost of learning how to use a product, from having to give up complements or from loss of opportunities to trade with other consumers.
Any method for transforming inputs into outputs, most often used to describe the mix of capital and labour a firm chooses.
Tragedy of the Commons
A situation where a common resource is overexploited because no one owns it.
Transactions costs
The costs of a firm using a market, in terms of searching for people to deal with, making a bargain with others and enforcing a deal when made.
Trust game
A type of game theory model where player 1 has to decide whether to trust player 2, and if she does, player 2 has to decide whether or not to betray that trust.
Utility function
A mathematical description of the utility a consumer gains from performing an action. Utility functions depend on consumers’ preferences.
Variable cost
A cost that depends on the number of units a firm produces.
Vickrey auction
A type of auction where the highest or lowest bidder gets a good for the price last bid by the second-highest or lowest bidder. Vickrey auctions are designed to avoid the incentive to overbid.
A measure of the total utility gained across all consumers and producers. In a partial equilibrium model, it’s the sum of consumer and producer surplus. In a general equilibrium model, it’s the sum of all utility gained by all agents in the model.

Part I

Getting Started with Microeconomics


webextra For Dummies can help to get you started with lots of subjects. Visit to discover more and do more with For Dummies books.

In this part …

check.png See how microeconomics looks at firms and individuals.

check.png Discover how microeconomics builds on people’s choices.

check.png Understand how consumers choose.

check.png Look at the ways firms make their decisions.

Chapter 1

Discovering Why Microeconomics Is a Big Deal

In This Chapter

arrow Introducing the areas that interest microeconomists

arrow Considering the central roles of decision-making, competition and co-operation

arrow Seeing that markets don’t always work

As we’re sure you know, micro as a prefix often indicates something very small, such as a microchip (a tiny French fry) or a microbrain (your arch enemy’s intellect). Micro can also mean something that isn’t small itself but is used to examine small things, such as a microscope (necessary to see your nemesis’s minuscule brain).

Well, microeconomics is the area of economics that studies the decisions of consumers and producers and how they come together to make markets. It asks how people decide to do what they do and what happens when interests conflict. It also considers how people can improve markets through their actions, the effects of laws and other outside interventions. However you look at it, and despite the name, microeconomics is a huge subject!

Traditionally, people contrasted microeconomics with macroeconomics – the study of national economies and big phenomena such as growth, debt or investments. But over the years, the scope of microeconomics has grown; today economists analyse some parts of what used to be macroeconomics – for instance, negotiations on loans – using microeconomic tools.

remember Microeconomists employ those tools to look at things that form from the bottom up, because markets build on the actions of individual firms and consumers. This approach involves starting with an account of how firms and consumers make decisions and building on that to investigate more complex things that ‘emerge’ from those decisions – such as how a market is structured.

In general, microeconomics works by building models of these situations. Models are mathematical – or graphical – pictures of how the world works given some basic assumptions. Models aren’t reality; they’re a description of something that resembles it. Like an architect’s model of a house, they don’t have to stand up to reality; they just have to provide a feeling for what the world looks like. Microeconomists use additional data to refine the models until they provide a more accurate picture. They also test models against real data to see how well the models work – the answer is usually ‘variably’!

In this chapter we introduce you to microeconomics and its core areas of interest, and we touch on the fact that markets don’t always work.

Peering into the Economics of Smaller Units

Microeconomics is fundamentally about what happens when individuals and firms make decisions. The idea is to think through those decisions and explore their consequences.

What happens – for example – when prices, say of ice cream, go up? Well, on the one hand, people are likely to buy less ice cream. On the other hand, firms may want to make more of it so that they can get more revenue. The result is a lot of unsold ice cream! Then people want to get rid of those stocks to avoid holding onto them, and they probably do that by cutting the price.

tip When does that process stop? At the limit, the only logical place to stop cutting the price is when exactly as much is sold as is made. This point is an equilibrium in the market for ice cream – a place where supply and demand are equal. We discuss equilibria more fully in Chapter 9.

jargonbuster When people talk about market forces, they’re talking about the sum of all these decisions. No vast impersonal power called ‘market forces’ exists, just a lot of smaller entities – consumers and firms – making a lot of simple decisions based on signals that come from prices. That’s really all market forces means.

The way markets work seems so impersonal because every one of the smallest units – small firms and individuals– makes up just a tiny fraction of all the decisions taken. Even the biggest companies or most powerful governments have limitations on their ability to influence the world. Microeconomists take this fact for granted and explore cases where it looks like they’re less limited as exceptions, not the rule!

remember All these smaller units do the best they can, given that ultimately they’re acting with imperfect knowledge of a complicated world. People and firms can’t know exactly how much they’ll be earning next year or exactly how much they’ll sell. They just look for ways of making decisions that give them the best chance of doing the best that they can – which is about all anyone can ask for in an uncertain world!

Making Decisions, Decisions and More Decisions!

remember One word that’s central to microeconomics is ‘decision’. Microeconomics is ultimately about making decisions – whether to buy a house, how much ice cream to make, at what price to sell a bicycle, whether to offer a product to this or that market and so on.

This is one reason why economists centre their models on choice. After all, when you don’t have options to choose from, you can’t take a decision! Deciding to make something or to buy something is the starting point for microeconomics.

To a microeconomist, decisions aren’t right or wrong; instead they’re one of the following:

Of course, a model of decisions needs two sides:

This book presents a few ways that microeconomists look at these decisions. In Chapters 2–8, we use a framework for making the best decision given some kind of constraint – budget, time or whatever else constrains you – to show you how microeconomists look at individuals and firms separately. In Chapters 9–15, the famous supply and demand model shows you how different types of market lead to different results. And in Chapters 16–19, we introduce you to the set of techniques known collectively as game theory, which look at how individuals or firms (or even other entities, such as governments) interact with each other.

Addressing how individuals and firms make decisions

Economists look at decisions in a slightly different way from how you might expect. They don’t have a model of all the things that you as a consumer use to inform your decisions. They don’t know, for a start, who you are, or what all your values are. They make no assumptions about gender, ethnicity, sexuality or anything else (though applied economists may test what they know about one population’s decisions against a more general model). They just know that you need to make choices, and explore how you may do so.

Starting simply

remember Economists make the least possible number of assumptions about the decision-making process and ask what you’d do if you only wanted the best possible outcome. Here are the two basic assumptions:

  • The consumer is utility-maximising: She seeks to maximise her utility – that is, the value of her choice (see Chapters 2 and 4 for more details).
  • The firm is profit-maximising: It wants to maximise its profit – see Chapters 3 and 8.

tip These choices don’t necessarily involve selfishness – a utility-maximising consumer can get benefit from helping other people and a profit-maximising firm may want to redistribute surplus profits to charitable causes.

Growing more complex

To begin with, these models are quite simple. If Billy Bob has £10 in his pocket and he wants to decide between having a burrito or a pizza, he’ll get the meal that gives him most utility given that it costs less than £10. Simple!

But later on, the models start to incorporate all kinds of other things, such as budget constraints (which we discuss in Chapter 5): if Billy Bob’s income goes up, will he buy more or less pizza? Or what about the utility gained by other people: if Billy Bob’s friends won’t eat pizza with him (perhaps he chews with his mouth open and makes an unappetising noise), he may get less utility from the pizza. Eventually, even with simple assumptions, models can end up incorporating some pretty complicated reasoning!

When you look at this example from the perspective of the pizza restaurant, things also start off simple: the restaurant just wants to make as much profit as possible, working to reduce its costs to do so. But what if you build in competitors? What about if the shareholders of the pizza company – the firm has grown, adding layer on tasty layer! – have different interests from the managers? What if the managers don’t just want to get costs down, but to keep competitors out? Again, the key is to start from the fewest justifiable assumptions and then build up as you get more familiar with models.

remember Even at the simplest level, models tell you plenty about reality. They can give you an account of how people and companies react to prices, and how this reaction changes as industries get more competitive or as companies get bigger.

Seeing how decisions come together to make markets

Markets are places – real or virtual – where consumers and producers come together to trade. In theory, the trades make both sides better off, though not necessarily to the same extent.

remember Markets co-ordinate people’s desires for stuff with producers’ ability to make stuff, but importantly with no one being in charge of the process! The only thing you need is that both sides respond to a price signal. That’s it!

Microeconomists say that markets are equilibrium-seeking, which means that trading in a market ultimately leads to a point where as much is supplied as consumers demand (and no more or less). The concept of equilibrium is much used in microeconomics, especially in the supply and demand model that we introduce in Chapter 9. This model looks at ‘partial equilibrium’ or the equilibrium in one given market (for example, the market for tinned tuna, or the market for books). It’s also used for a couple of special types of equilibrium:

  • Nash equilibrium: A point where two people or entities are competing for something and arrive – separately – at a point where no one has an incentive to change their behaviour. (We cover this situation in Chapters 16–19.)
  • General equilibrium: An equilibrium state that exists across a whole economy given certain conditions. This is used for the analysis of welfare, and we write about it in Chapter 12.

Of course reality gets very complicated and usually someone – often government, but sometimes private monopolists or property owners – wants to control the price, which is often not desirable. Take a rent control, for instance. Introduce too low a maximum rent and more people want to rent than people who’re willing to put their house up to rent. As a result, setting a rent control at a very low level just creates homelessness – more people trying to rent, but landlords withdrawing their properties from the market because the price is too low for them to bother.

What about if we set the rents at too high a price? Well, if the maximum rent is above the equilibrium in the market, it has no effect because landlords are more willing to rent at that price and so more enter the market. But fewer renters are willing to rent at that price, and so the result is an excess supply of rentable flats. As a result some landlords drop out – those that need the highest level of rent to make a profit – and the price falls until it reaches the market equilibrium again!

tip Controlling prices can have many other consequences too. The price signal isn’t just an absolute number – say a price of £5 – it’s also a relative measure: for example, this car costs more in other things you can do with your money than this sofa. The model of a consumer eventually tells you that the relative price encapsulates consumer preferences. When you affect the relative price, you affect choices everywhere. That’s one reason why economists prefer almost any solution to one that affects relative prices!

Markets are themselves complex things in reality and vary widely from type to type. For example, financial markets are different in their scope, participants and trading outcomes to labour – jobs – markets. Microeconomists look at all these types of market starting with the simplest model, and then as they get more data on how they differ, they start to incorporate that into the models.

warning The great economist Alfred Marshall was the first to make a key point, though: a big difference exists between the practical results of markets in reality and the simulation that economists use – which he called The Market. When you encounter a type of market you don’t understand, starting to analyse it by using the simulation is a decent idea. If you know more about the market, however, relying on a simple simulation may not work as well!

Understanding the Problems of Competition and Co-operation

Society reaps the benefit of all the things that innovation and production make through two different forces: competition and co-operation.

Many firms following their own interests leads to competition (we discuss perfect competition, which consumers usually love, in Chapter 10 and imperfect competition in Chapter 11). In almost all circumstances competition is a pretty good thing, because it leads to lower costs or more innovation. For example, if only one store operates in your area, it may be able to get away with selling milk for £2 a pint. But with other stores, the competition leads to the price falling.

remember Businesses are competitive in some ways, but they’re also co-operative exercises where people have to work together to achieve common goals. Microeconomics studies co-operation as often as it studies competition, but it starts with competitive models to build the foundations. It moves on from that focus, though, looking at what type of circumstances lead people to choose to co-operate, and where the pitfalls of those situations can lie.

realworld Even businesses that are competitors in one area sometimes form alliances in others – Apple’s relationship with Motorola in the early 2000s being just one example.

Microeconomists are often accused of overselling the benefits of competition, but they also point out that co-operation can be perilous too. When a group of firms with large shares of a relevant market work together, the result is often harmful to the public, as Adam Smith pointed out. Working together in that way is illegal, not surprisingly! Similarly, a trade union where a lot of people work together to get the best bargain with their industry can have negative effects on anyone not a member of that union. Microeconomists go on to investigate all these possibilities.

Realising why authorities regulate competition

At some point, the businesses operating in every market in the world have to deal with the legal structures under which they operate. In general, a lot of basic conduct rules underpin every – legal – market – from ensuring that your product is what you say it is to not exploiting market dominance. If the essential point of microeconomics is that organisation happens with no one in charge, why is this even an issue?

Well, markets in reality aren’t perfect! Sometimes they impose costs upon people who aren’t involved in that particular market. Sometimes setting a floor under the conduct of a given market leads to better behaviour! But perhaps the most interesting reason for regulation is because of what happens when a competitor gets too successful.

When that happens, the firm makes larger profits, which is good for shareholders. But suppose that conditions also mean that no firm can set up as a rival – maybe the costs involved in being in that market are too high or the successful competitor holds the entire supply of a key resource.

remember In general, the idea is that you don’t want someone to get permanent advantage in a way that leads to too many losses for everyone else. At this point, competition law steps in and places restrictions on what a company can and can’t do (see the next section), because the costs of runaway success can be very large indeed!

Considering Competition Law

jargonbuster Competition Law (called antitrust law in the US) is at the very top of things that a society can do to make sure that markets don’t hurt the public good. The purpose is to ensure that if a market isn’t competitive at least the costs can be minimised. Competition law is the last line of defence against the worst kinds of behaviour, preventing the biggest firms from prejudicing competition.

The idea is that, although competition is good, stopping the biggest firms from subverting competition requires eternal vigilance. In practice, it means that part of the legal system switches from treating everyone equally to treating those companies with the biggest market shares differently from smaller ones.

remember Many rules are in place to stop large firms from subverting competition:

  • Limit pricing: Makes it illegal for a large player to drop its prices below cost to deter potential rivals.
  • Merger rules: Prevents a large player from buying out its competitors and ensuring that competition is achieved where possible.
  • Behavioural remedies: Stops the largest competitor from owning a key resource. For instance, if you own a port, you aren’t allowed to offer your own ships preferential prices to dock.

In all these cases, companies are treated differently because everyone recognises that if competition fails, everyone loses out in the long run – getting poorer quality goods at higher prices.

tip Microeconomists examine all these cases with models that compare competitive outcomes to those achieved by non-competitive organisations. In most situations, the intuition microeconomists form is that competition is good. But not always! In some cases, competitive markets just don’t produce a good and in others the diversity of products isn’t as good in a competitive market, and so economists – as a whole – aren’t ideologues about this idea!