Chapter 15: Monopoly

Welcome to Last Minute Lecture.

This free chapter overview is designed to help students review and understand key concepts.

These summaries supplement not replace the original textbook and may not be redistributed or resold.

For complete coverage, always consult the official text.

Okay, let's try and unpack this.

Imagine trying to get your hands on an operating system for your computer, right?

And you find that basically one company, maybe like Microsoft Windows, pretty much controls the whole market.

Now, this isn't just about having fewer choices when you go to buy something.

It's a fundamental economic reality.

We call it a monopoly.

So today we're doing a deep dive into chapter 15 of Manki's Principles of Microeconomics.

It's all about monopoly.

Our mission here is to get a really solid grasp on, you know, what exactly defines a monopoly?

How do these, well, these really powerful firms make their decisions about what to produce and what price to charge?

And what are the consequences for society?

You know, the bigger picture.

And maybe what can governments actually do about it?

And you'll see pretty quickly a monopoly is just fundamentally different from the competitive firms we might be used to talking about.

A competitive firm, remember, is a price taker.

It just has to accept whatever the market price is.

But a monopoly, nope, it's a price maker.

And that one difference, it changes absolutely everything.

It really does.

That ability to actually set the price, it just alters the whole game.

I mean, everything from how they cover their costs to, well, the economic well -being of society as a whole, we're going to explore some of those, maybe subtle ways monopolies affect our daily lives.

Sometimes we don't even notice it.

We'll figure out why a company, say like Microsoft, might charge, you know, $100 for Windows, but probably not $1 ,000.

There are still limits.

Exactly.

So let's get right to the basics.

Why do monopolies even pop up in the first place?

Okay, the core definition.

A monopoly is the sole seller of a product, and crucially, a product with no close substitutes.

That no close substitutes bit is super important.

If there were good alternatives, the monopoly wouldn't last long.

So the fundamental reason they exist comes down to what economists call barriers to entry.

Without these roadblocks, new companies would just jump in and compete away those extra profits.

That's the key, barriers to entry.

And the chapter points out three main kinds.

First up is monopoly resources.

This is pretty straightforward.

A single firm owns a key resource that you absolutely need to produce the good.

Think about like a tiny town in the desert with only one working well, the owner of that well, they've got a monopoly on water there.

Or, historically, you had debiers with diamonds they used to control something like 80 % of the world's rough diamond production.

Huge market power.

Although it's worth noting, the chapter mentions this kind of resource monopoly is actually pretty rare today, especially in big global economies.

Resources tend to be more spread out now.

Okay, so owning the only well is one way.

What's the second barrier?

The second one is government regulation.

Sometimes the government itself creates the monopoly.

It does this by granting exclusive rights to sell a good or service to just one firm.

Think about patent laws.

A pharmaceutical company discovers a new drug, they get a patent, usually for 20 years, giving them the exclusive right to make and sell it.

Or copyright laws for, say, a novelist.

They get the exclusive right to print and sell their book.

Oh, okay.

And this is where it gets really interesting, right?

Because these laws, they create monopolies on purpose, which leads to higher prices, higher profits, sure.

But they also give really crucial incentives.

I mean, why would a drug company spend billions on R &D if anyone could just copy their new drug immediately?

Or why would authors write books?

So it's this trade off, this balancing act between the costs of monopoly and the benefits of innovation and creativity.

Exactly.

It's a deliberate policy choice with pros and cons.

Now, the third source of barriers is a bit different.

It arises from the production process itself.

This leads to what's called a natural monopoly.

This happens when a single firm can supply the entire market for a good or service at a lower cost than two or more firms could.

Okay, how does that work?

It typically happens when there are significant economies of scale over the relevant range of output.

Remember, economies of scale.

That's when the average total cost falls as the quantity of output increases.

So if that average cost curve just keeps going down and down as you produce more and more, then one single large firm can produce any given amount at the lowest possible cost.

Right, I see.

So if you tried to split production, say, between two firms, each one would produce less.

And because their average cost curve is declining, they'd both end up with higher average costs than the single firm.

Precisely.

The classic example is water distribution.

Think about the massive cost of laying down a network of pipes all across the city.

That's a huge fixed cost.

It's just much cheaper for one company to build and manage that one network than for, say, three companies to each build their own duplicate pipe systems.

That would be incredibly wasteful.

Or, like the chapter mentions, an infrequently used bridge.

Costs a fortune to build.

That's the fixed cost.

But the marginal cost of one more car driving over it is tiny.

It connects back to those Chapter 11 concepts, right?

It's excludable.

You can charge a toll, but maybe not rival in consumption if it's not busy.

Exactly.

And market size plays a role here, too.

That bridge might be a natural monopoly if the town is small.

But if the town grows and suddenly there's tons of traffic, maybe you do need multiple bridges.

So a market could evolve from a natural monopoly towards something more competitive just because it got bigger.

Okay, so we have these barriers, resources, government rules, or the production process itself leading to natural monopolies.

Once a firm has this monopoly position, how do they actually decide what to produce and what price to charge?

This is where things get really different from competition.

Let's recap quickly.

A competitive firm faces that perfectly flat horizontal demand curve.

They're a price taker, but a monopolist.

They are the market.

So they face the entire downward sloping market demand curve.

What does that mean?

It means if they want to sell more, they absolutely have to lower the price.

They can't just sell unlimited amounts at one price.

That demand curve is basically the boundary, the constraint on the monopolist power.

They can pick a point on the curve, like a super high price and a super high quantity.

The market just won't buy that.

So let's talk about their revenue.

MENQ uses table one, the water example, to walk through this.

You have quantity, price,

total revenue, which is just price times quantity,

average revenue, total revenue divided by quantity, which by the way always equals the price.

And then the really important one, marginal revenue.

That's the change in total revenue from selling one more unit.

And here's the absolute key insight.

For a monopolist, that marginal revenue is always less than the price they charge for the good.

Always.

Except for maybe the very first unit.

Right.

And why is that?

It's because of two competing effects when a monopoly sells one more unit.

First, you have the output effect.

You sell more output, Q goes up, so that tends to increase your total revenue.

Good news for the firm.

But second, you have the price effect.

To sell that extra unit, you had to lower the price.

And crucially, you lowered the price not just for that last unit, but for all the units you were already selling.

So P goes down for everything and that tends to decrease total revenue.

Ah, I see.

The competitive firm doesn't have that price effect because they can sell all they want at the market price.

Their individual output doesn't change the market price.

Exactly.

For the monopolist, that price effect is always working against the output effect when they increase sales.

And that's why their marginal revenue is less than the price.

If you visualize it, like in figure three in the chapter, the marginal revenue curve always lies below the demand curve.

It starts at the same point for the first unit, but then it falls faster.

It can even become negative if the price effect outweighs the output effect.

Okay.

So they understand their demand.

They understand their revenue, especially this marginal revenue concept.

How do they maximize profit?

Is the rule different?

Nope.

The fundamental rule is actually the same for all profit maximizing firms, competitive or monopoly.

Produce the quantity where marginal revenue equals marginal costs.

MR equals MC.

Ah, okay.

So the rule's the same, but the outcome must be different because their MR is different.

Precisely.

Here's the critical difference, and figure four illustrates this really well.

First, the monopolist finds the quantity where the MR curve crosses the MC curve.

Let's call that QMAX.

That tells them how much to produce to maximize profit.

Then, and this is the key step, they don't set the price equal to MC.

Instead, they look up from that QMAX quantity to demand curve.

The point on the demand curve directly above QMAX shows the highest price consumers are willing to pay for that specific quantity, and that's the price the monopolist charges.

So because the demand curve is always above the MR curve.

The price they charge will always be greater than the marginal cost at that profit maximizing quantity.

Okay.

Let me summarize that comparison because it's crucial.

For a competitive firm, PMR equals MC, but for a monopoly firm, PMR and MR equals MC.

So ultimately, PMC.

That's the core difference in outcome.

And how do we see their actual profit, like on a graph?

Figure five shows this right.

Yep.

Profit is always total revenue minus total cost, or you can write it as price minus average total cost times quantity.

So on the graph, you find the profit maximizing quantity, QMAX.

You find the price on the demand curve and the average total cost ATC on the ATC curve at that quantity.

The difference between P and ATC is the profit per unit.

Multiply that by the quantity QMAX, and you get the total profit, which is shown as that shaded rectangular box in figure five.

Okay.

So find where MRMC to get Q, go up to the demand curve to find P, check if P is above ATC, and boom, profit.

That's the process.

And the chapter gives a great real world case study, monopoly drugs versus generic drugs.

It perfectly illustrates this.

When a drug company has a patent, it's a monopoly.

They find where MRMC set the price high up on the demand curve, well above their marginal cost of actually making the pills.

They earn monopoly profits.

But then the patent expires.

Then competitors jump in with generic versions.

The market becomes competitive, or at least much more competitive.

What happens?

Competition drives the price down, down, down, much closer to the marginal cost of production.

You see this clearly in figure six.

Although the chapter notes something interesting, even after generics appear, the original brand name drug, like Prozac versus generic Phloxetine, can often still charge premium.

Yeah, that's usually down to things like brand loyalty, maybe consumer trust or just habit.

So even with the competition, the original firm might retain some market power, some ability to charge above the generic price, but it's way less than their original monopoly power.

One last technical point from this section.

Why doesn't a monopoly have a supply curve?

Right.

Remember, a supply curve tells you the quantity a firm is willing to supply at given price.

It assumes the firm is a price taker.

But a monopolist isn't a price taker, it's a price maker.

They choose their quantity, where MRMC, in that decision, combined with the demand curve, determines the price simultaneously.

They don't passively respond to a price.

They actively choose a point on the demand curve.

So the concept of a supply curve just doesn't fit.

There's no unique quantity supplied for any given price.

Okay, that makes sense.

So we understand how they operate, how they maximize profit by setting PMC.

But now the really big question, is this actually bad for society?

What's the welfare cost of monopolies?

Right.

To analyze this, we need to bring back our tools of welfare economics,

consumer surplus, and producer surplus, which for the monopolist is just their profit.

Total surplus is the sum of the two.

Now, what would be the ideal socially efficient outcome?

Imagine a benevolent social planner running the show.

They wouldn't care just about the firm's profit.

They'd want to maximize the total benefit to society.

They would want production to continue as long as the value to the marginal buyer, shown by the demand curve, is greater than or equal to the cost to the marginal seller, shown by the marginal cost curve.

Okay, so the planner would produce where the demand curve intersects the marginal cost curve.

Exactly.

That quantity maximizes total surplus.

At that point, price would equal marginal cost.

That's the efficient benchmark.

Figure 7 shows this.

But we just established the monopolist doesn't do that.

They produce less, right?

Where MRNC - Precisely.

The monopolist produces less than the socially efficient quantity.

And because they produce less, they charge a price that is higher than marginal cost.

This gap between the monopolist quantity and the efficient quantity creates a deadweight loss.

You can see it as that triangular area in figure 8 between the demand curve and the MC curve for the units that aren't produced, but should be from society's point of view.

So it represents the loss of potential surplus, trades that would have benefited both consumers and the producer, but just don't happen because the monopolist restricts output to keep prices high.

That's exactly it.

It's a loss of overall economic well -being.

The economic pie shrinks.

And the chapter makes an analogy to taxes here, which is interesting.

A tax also drives a wedge between the price buyers pay and the price sellers receive, causing deadweight loss.

A monopoly price also creates a wedge, but it's between the consumer's willingness to pay the price and the producer's cost, MC.

Right.

Both lead to quantity falling below the efficient level.

The difference is where the surplus goes.

With a tax, the government gets revenue.

With a monopoly, the producer gets extra profit from the higher price.

Now, is that monopoly profit itself a social cost?

Not necessarily from an efficiency standpoint.

It's mainly a transfer from consumers to the producer.

It doesn't shrink the pie.

It just changes who gets which slice.

So the real problem isn't the profit per se, but the fact that they produce too little.

Yes.

The core inefficiency is the underproduction relative to the social optimum.

That's the deadweight loss, although there's an added potential cost.

If the firm has to spend money just to maintain its monopoly position, maybe lobbying the government, legal battles, then those resources are also wasted from society's perspective.

They aren't creating anything valuable.

Okay.

So monopolies generally lead to inefficiency, but they sometimes use a discrimination.

What's that about?

Price discrimination is selling the exact same good at different prices to different customers, even though the cost of producing it for each customer is the same.

Can any firm do this?

No, absolutely not.

It's impossible in a perfectly competitive market.

Why?

Because competitive firms have zero market power.

If one tried to charge Mrs.

Smith more than Mr.

Jones for the same thing, Mrs.

Smith would just buy from a competitor selling at the market price.

Ah, so you need market power.

You need to be a price maker, at least to some degree.

Exactly.

Only firms with market power, like monopolies, can potentially pull off price discrimination.

The chapter uses this fun little parable about read -a -lot publishing.

They have a new novel, right?

Let's say there are 100 ,000 huge fans willing to pay $30 and maybe 400 ,000 more casual readers only willing to pay $5.

Marginal cost is zero, just to keep it simple.

If read -a -lot sets just one price, what should it be?

Well, at $30, they sell 100k copies.

Revenue is $3 million.

Let's say the author costs $2, so profit is $1.

If they charge $5, they sell to everyone 500k copies.

Revenue is $2 .5 million.

Profit is only $500k.

So with a single price, they choose $30.

But look, those 400 ,000 readers who pay $5 get left out.

That's potential $2 million in lost surplus right there, $400k, $5.

Right.

But what if read -a -lot could somehow separate these markets, maybe sell the $30 version only in, say, Australia, where the fans are, and the $5 version only in the U .S.

where the casual readers are?

Now they can charge $30 in Australia getting $3 man revenue and charge $5 in the U .S.

getting another $2 revenue.

Total revenue is $5.

Profit is now $3, much higher than before.

And everyone gets to read the book.

This sounds kind of like hardcovers and paperbacks, doesn't it?

Sell the expensive hardcover first to the eager fans, then the cheaper paperback later to everyone else.

Exactly like that.

It's a classic form of price discrimination over time.

So this little story teaches us a few things.

One, price discrimination is a rational strategy for a monopolist.

It lets them charge prices closer to each customer's actual willingness to pay, capturing more surplus as profit.

Two, it requires the ability to separate customers based on their willingness to pay.

Geography, age, time of purchase, something must segment the market.

Three, and this is really interesting, market forces like

undermine price discrimination.

What's arbitrage?

Buying low in one market and selling high in another.

Precisely.

If those casual readers in the U .S.

could easily buy the $5 books and resell them to the fans in Australia for, say, $25,

then readalot's $30 price wouldn't hold up.

The ability to prevent arbitrage is key.

And lesson four, maybe the most surprising,

price discrimination can actually increase economic welfare.

How?

Because it can allow mutually beneficial trades to happen that wouldn't happen under a single monopoly price.

In the readalot example with discrimination, all 500 ,000 people got the book.

Without it, only 100 ,000 did.

So more people enjoy the product.

But wait, who gets that extra welfare?

Ah, good question.

In the readalot example, all the increased welfare went to the producer as higher profit.

Consumer surplus didn't necessarily increase for everyone.

And for the high paying group, it might even decrease if the firm gets better at extracting their willingness to pay.

Okay, so let's get a bit more analytical.

What about perfect price discrimination?

That sounds extreme.

It is.

Perfect price discrimination is the theoretical ideal for the monopolist.

They somehow know exactly what each and every customer is willing to pay.

And they charge each one that precise amount for each unit they buy.

Wow.

What happened then?

Well, two things.

First, all mutually beneficial trades would occur.

The monopolists would keep selling right up to the point where price equals marginal cost, because they can capture all the surplus for each sale.

So output would be the efficient quantity.

No deadweight loss.

No deadweight loss.

That sounds good.

It's efficient in terms of quantity.

Yes.

But, and it's a huge but, all the surplus in the market would go to the monopolist as profit.

Consumer surplus would be exactly zero.

Figure 9B shows this compared to the single price monopoly in 9A.

Okay, so efficient outcome, but maybe not seen as equitable.

And is perfect price discrimination even possible?

Realistically, no.

Firms don't have that perfect information.

What we see in the real world is imperfect price discrimination, where firms divide customers into groups like adult versus child movie tickets, or business versus leisure air travelers.

The welfare effects here are ambiguous.

It could raise total surpluses, lower it, or leave it unchanged compared to a single price monopoly.

It depends on the specifics.

But one thing is certain.

It always increases the monopolist's profit compared to charging a single price.

Otherwise, they wouldn't do it.

In the chapter lists tons of real world examples, right?

Movie tickets, kids, and seniors pay less.

Airline prices charging more for last minute bookings or requiring Saturday stays to separate business leisure.

Discount coupons, people who take the time to clip them are probably more price sensitive.

Financial aid at colleges charging different prices based on ability to pay.

Even quantity discounts, like donuts are cheaper by the dozen.

Your willingness to pay for the 12th donut is probably lower than for the first, so they charge a lower average price for bulk purchases.

All great examples.

And this whole issue even went to the Supreme Court in the Impression Products versus Lexmark International case.

Lexmark sold printer cartridges, sometimes cheaper or broader than in the US.

Impression products bought the cheaper ones overseas, refilled them, and resold them in the US, undercutting Lexmark's US prices.

So Lexmark sued, arguing their patent rights allowed them to control resale and prevent this arbitrage, basically to maintain their international price discrimination.

Exactly.

The core question was, does the first sale of a patented item, even overseas,

exhaust the patent holder's right to control its resale?

This had big implications.

If Lexmark won, companies could more easily maintain different prices in different countries.

If Impression Products won, it would make international price discrimination harder.

The Supreme Court ruled in favor of Impression Products in 2017.

They said,

essentially, yes, the patent rights are exhausted after the first authorized sale, regardless of where it happens.

This makes it harder for companies to use patent law to enforce international price differences.

It potentially helps consumers in richer countries get lower prices via imports, but might lead companies to charge more in poorer countries or not sell at all.

It's complex.

Wow.

Okay.

So given all these issues, the deadweight loss,

the sometimes controversial nature of price discrimination, what can governments actually do about monopolies?

What are the public policy options?

The chapter outlines four main approaches.

Number one is trying to increase competition with antitrust laws.

These are laws designed to prevent monopolies from forming or to break them up if they do.

Think about the government blocking a merger between two competitors, like maybe Coke and Pepsi if they ever tried that, or preventing firms from coordinating in ways that reduce competition.

The U .S.

has laws like the Sherman Act and the Clayton Act for this.

Right.

But applying these laws is tricky.

As we discussed, mergers aren't always bad.

Sometimes they create real efficiencies called synergies that can lower costs and potentially benefit consumers.

Think about maybe bank mergers or airline mergers consolidating routes.

So policymakers have to weigh these potential efficiency gains against the potential harm from reduced competition.

It's often a judgment call, and there's lots of debate about how well regulators do this.

Okay.

Antitrust is one tool.

What's the second approach?

Regulation.

This is very common for natural monopolies, like your local water or electric company.

Since competition isn't feasible, the government doesn't try to break them up.

Instead, it regulates

But setting the price is hard, right?

We talked about this with Figure 10.

If they force the natural monopoly to charge a price equal to marginal cost, PMC, which is the efficient price, the company will lose money.

Because for a natural monopoly, average total cost is always falling, which means marginal cost is below average total cost.

So PMC would mean PATC, leading to losses.

So what can regulators do then?

Well, they could subsidize the monopolist to their own deadweight losses.

So that's not ideal.

Or more commonly, they might allow the monopoly to charge a price equal to its average total cost,

PATC.

This lets the firm earn zero economic profit, just breaking even.

Okay, that sounds better.

But is it efficient?

Not quite.

Yeah.

PATC is still greater than MC for a natural monopoly.

So you still get some deadweight loss, just less than with the unregulated monopoly price.

Plus, average cost pricing gives the monopoly basically zero incentive to reduce its costs.

If costs go down, the regulator just lowers the price so the firm doesn't benefit.

Okay, third option, public ownership.

Yeah, instead of regulating a private monopoly, the government just runs the monopoly itself.

The U .S.

Postal Service is an example.

Many European countries have publicly owned utilities.

How well does that work, according to economists?

Generally, economists are a bit skeptical.

They tend to argue that private owners have a stronger incentive, the profit motive, to keep costs down and run efficiently, compared to government agencies, which might be influenced by political goals or bureaucratic issues.

Private firms face the discipline of the market, or at least the potential for bankruptcy, in a way government agencies don't.

Alright, so antitrust, regulation, public ownership, what's the last option?

The fourth option is maybe the simplest,

doing nothing.

Just let the monopoly be.

Well, some economists, including the Nobel laureate George Stigler, argue that sometimes the cure can be worse than the disease.

They point out that government intervention isn't perfect either.

Regulation can be flawed, antitrust cases can be costly and uncertain, public ownership can be inefficient.

This is sometimes called political failure.

So the argument goes, if the inefficiency from the monopoly, market failure, isn't that bad, maybe it's better to just live with it than risk making things even worse with imperfect government policies.

So deciding whether to intervene or not involves judging both the economics and the situation.

Exactly.

It requires careful consideration of both market failures and potential government failures.

Okay, let's wrap this up.

We've covered a lot about monopolies.

Maybe quickly summarize the key differences compared to competitive firms.

Table 3 does this well.

Sure, competition.

Many firms, identical products, price takers, PMC, zero long run profit, has a supply curve, no price discrimination.

Monopoly, one from unique product, no close substitutes.

Price maker, PMC, potential for long run profit, no supply curve, can price discriminate.

And both maximize profit where MRMC, that rule stays the same.

Right.

But it's also important to remember, as the chapter concludes, that pure monopoly is rare.

Most firms in the real world have some degree of market power because their products aren't perfectly identical to their competitors.

Think Ford versus Toyota or Ben and Jerry's versus Breyer's ice cream.

They aren't monopolies, but they aren't perfect competitors either.

They face downward sloping demand curves because their products are differentiated.

So monopoly power is more like a matter of degree.

Exactly.

Few firms have substantial monopoly power because most goods do have substitutes, even if they aren't perfect ones.

If Ford raises prices too much, people switch to Toyota or Honda.

So while the monopoly model is crucial for understanding market power, the competitive model is often still a pretty good approximation for analyzing many markets, even if they aren't perfectly competitive in reality.

And there you have it, our deep dive into the really fascinating and sometimes complex world of monopolies, all based on Manki's chapter 15.

We've gone from why they exist, those crucial barriers to entry, through how they uniquely maximize profits by setting price above marginal cost, the deadweight loss that results, the interesting strategy of price discrimination, and finally, how governments might step in.

Yeah.

And maybe a final thought to leave you with.

If most firms really do have some degree of monopoly power because products are differentiated, how often are we actually living in that purely competitive world economists often model?

What does that prevalence of, let's call it monopolistic competition mean for how we should think about our economy, about competition policy, and even about our own choices as consumers in a marketplace full of brands trying to convince us they're unique?

Something to definitely mull over.

We hope this deep dive helped clarify the economics of monopoly and maybe sparked a few aha moments for you.

From everyone here on the deep dive team, thanks so much for joining us.

Keep learning and keep questioning.