1. Topic 11: Market Definition
Antitrust Economics 2013
David S. Evans
University of Chicago, Global Economics Group
Elisa Mariscal
CIDE, Global Economics Group
Topic 11| Part September 2013
Date

2. Overview Part 1 Part 2 Role of Market Definition
General Principles of Market Definition
Hypothetical Monopolist Test
Critical Loss Analysis
Part 2
Overview of Issues in Multisided Platforms
The Case of Additive Prices
Newspaper Markets
One-Sided Biases

3. Key Questions to Think About
Why “market definition” isn’t used by economists outside of their work on competition policy matters.
Why “market definition” is used by courts and competition authorities
Could the courts and competition authorities dispense with market definition?
What is the role of false positives and negatives in market definition analysis, and does it matter whether it is merger or non-merger?

4. Things You Really Need to Know
Relevant market and why it isn’t the same as what laypeople or businesspeople might call a market
Hypothetical monopolist test which is very popular among competition authorities
The SSNIP test which is the name of the standard way of implementing this test.

5. Role of Market Definition

6. Market Definition and Market Power
Market power is important for assessing whether a firm has the incentive and ability to engage in anti-competitive behavior and whether merger will result in an increase in market power
Market power depends on the constraints that a firm faces in increasing the price of a product profitably; these constraints typically involve substitutes in demand and changes in supply by other firms.
The “market” identifies the producers the impose significant constraints on the power or a firm or group of firms to raise price profitably.
Market definition is primarily (perhaps solely) used for the purpose of helping the courts and competition authorities assess dominance/market power.

7. Market Definition and Context
Identifies sets of firms, substitution patterns, and strategic relationships among firms.
Market definition provides a context for examining firm strategies
Market definition limits the discussion of rival products and firms to a manageable group. F
Firms in the market
A, B, C, D, E G H
Firms outside of the market: F, G, H, …

8. Market Definition and Measures
Share = Sales of firm’s product/total sales in the “market”
Courts and competition authorities use “market share” as an indicator of possible “market power” or “dominance” for a firm (or group of firms in the case of collective dominance)
Bigger market results in smaller share
Smaller market results in bigger share
Must make decision on what other products compete in the “market” to calculate the denominator of share.
Other measures of concentration such as the HHI are based on market shares (HHI is sum of the shares, each squared, of all the firms in the market—see below).
“See below”? Meaning we should include the equation – please add in the non green box…

9. Market Definition, the Case Law, and Economics
“A relevant product market comprises all those products and/or services that are regarded as interchangeable or substitutable by the consumer, by reason of the products' characteristics, their prices and their intended use." (EC Notice of Definition of Market)
Market share calculations put equal weight on all products in the market and zero weight on all products outside the market; no economic basis for this and it is obviously wrong.
By putting products outside of the market we lose information which may be valuable and may make errors if the products outside do matter
Economist claim they can analyze economic effects of business practices without defining the market first (is this true?).
Economists see constraints on market power as a continuum rather than having some products “in” the market vs. “outside” the market.

10. Market Definition Sets Hard Boundaries Between Products that are “In” or “Out” of the Market.
Think of the “Hotelling Line” with many ice cream stands on a beach of infinite length. Start with stand in the middle. Market definition would say that there is a definite point at which stands to left or right are not “in the same market” because they don’t impose enough of a constraint.
Out In
Product in question
Continuum of product substitutes—farther away are less substitutable

11. General Principles of Market Definition

12. Identifying Relevant Substitutes by Asking What Would Constrain an Increase in Price
The goal of market definition is to identify the group of products which provide significant and timely competitive constraints to the firm/product as issue.
Demand-side
Supply side
How will marginal customers react?
Will producers of other products divert capacity?
Product market
Would firms in one area supply another?
Will customers buy from other areas?
Geographic market

13. Demand-side substitution
Substitution among products provides the main immediate competitive constraint and therefore plays the most important role in market definition in practice
“Average” customers are not necessarily relevant. What matters most is the behavior of “marginal” customers – the ones who are most likely to move between products as a result of price changes and who therefore have biggest impact on revenue changes.
Asymmetric substitution
“Will the average buyers of product A switch to product B?” is not the same question as “Will the average buyers of product B switch to product A?” since neither is necessarily the marginal consumers who matter
Key question is whether many consumers are at the “margin” between using this product or an alternative and would switch following a price increase
Think of the fixed line vs. mobile phone example in terms of asymmetry of substitution…

14. Demand-side substitution and the marginal consumer
F is an “average consumer” of beer (from O to C) O
A,B, C, D are at “the margin” of buying or not buying beer. F A C D B G
G is not a consumer of beer at current prices
The “average” consumer may not switch to a substitute product in response to a small price increase; producer needs to worry about what consumers “at the margin” between buying and not buying the product will do.

15. Supply-side substitution
Would firms quickly switch capacity to producing demand-side substitutes for the product of the firm under investigation in reaction to a price increase of that product?
Relevant when firms can produce a range of different products using the same, or very similar, technologies and assets
For example,
Can the same plants be used to produce different products?
Can competitors utilize their existing marketing and distribution networks for new products?
Geographic market is often important for assessing supply-side substitution
Will firms in distant economic areas increase supply?

16. Standard Steps for Identifying a Relevant Market
The first step is to consider a reference “product” (or “products”)
The “candidate market”
Identify the closest potential substitutes for products in the candidate market
As discussed above, there are two potential sources of substitution
Demand-side substitution
Supply-side substitution
But which substitutes do we consider?

17. Which products to consider as demand and supply substitutes for BMW’s MINI Cooper
Other small cars
Supply of new small cars
Mid-size cars
All cars
All means of transportation
Or maybe buyers of MINI Coopers would switch to scooters or bicycles….

18. Hypothetical Monopolist (SSNIP) Test for Market Definition

19. Hypothetical Monopolist Test
Logic of the test
Is a “market” worth monopolizing?
If yes, then the substitutes outside the “market” must be weak
If no, then the substitutes outside the “market” must prevent the exercise of market power
Thus the group worth monopolizing pulls in all of the relevant substitutes.
Start with the narrowest candidate market and assume that there is a monopoly supplier
Could this hypothetical monopolist profitably impose a “small but significant not-transitory increase in price” (SSNIP) or will too many customers switch to demand-side or supply-side substitutes?
Yes  Candidate Market = Relevant Market
No  Candidate Market < Relevant Market Include the closest substitutes and repeat the test

20. How to proceed? Demand-side then supply-side
Candidate Market
Potential substitute products 1 A B  C  2
Demand-side
A+B+C D X
Would be good to think of a toy example to go through this exercise – any ideas? 3
A+B+C S1 
Supply-side
A+B+C+S1 S2 X

21. Issues Concerning Hypothetical Monopolist Test
Focuses entirely on price and excludes non-price dimensions of competition. Firms may adjust quality and other attributes to compete instead of price and engage in other non-price strategies not considered.
The assumptions and measures may not be correct
The standard Lerner equation doesn’t always apply (e.g. two-sided markets).
Estimates of demand and cost may not be reliable.
Cost of errors that lead to “too narrow” a market is that competitive constraints are completely excluded; cost of errors that led to “too broad” is that if all substitutes are weighted the same then overstates competitive constraints.

22. Hypothetical Monopolist Test Depends on Where One Starts
There is not a unique solution to market definition. The market can depend on where one (arbitrarily perhaps) starts.
Starting with small cars competing with scooters could lead to a different answer than starting with small cars competing with large cars
Large Cars
Scooters
Small cars

23. Relevant Market at End of Analysis
G, H
A, B, C, D, E, F L K I
A…..F is the “relevant market” based on the SSNIP test. C is the firm whose actions we are assessing. G, H, L, and K are firms that the SSNIP test says are outside of the market.

24. Critical Loss Analysis
Implementing the Hypothetical Monopolist (SSNIP) Test

25. Critical loss analysis is a method for implementing SSNIP test in practice
Step (1)—Profits, output, and sales before the price change for hypothetical monopolist (e.g. products A and B).
Price
Profit = ($20 - $10) x 100 = $1,000
$20
$10 MC
Quantity
100

26. Critical loss analysis is a method for implementing the SSNIP test
Step (2): How many units of sales would have to switch to substitutes to make a 10% price increase just unprofitable? Suppose the answer is slightly more than16.7 (with roughly break even).
Price
$22
$20
$10 MC
Quantity
83.33
100
If fewer than 16.7 units of sales switch than a 10% price increase is profitable

27. Critical Loss Analysis Depends on Customer Switching—an Example of a Calculation
How many customers have to switch to substitutes to make a 10% price increase unprofitable?
Consider this example
Initial price = $20; MC = $10; Profit Margin = $10; Quantity = 100; Profit = $10 x 100 = $1,000
New price = $22; MC = $10; Profit Margin = $12; Quantity = 83.33; Profit = $12 x = $1,000
This implies that:
If sales fall by less than 16.7% the price increase is profitable
Candidate market is the no wider than relevant market (i.e. a smaller market could have a profitable price increase too).
If sales fall by more than 16.7% the price increase is unprofitable
Candidate market is too narrow (one can also say that the true market is even broader than the candidate market).
The “critical loss” is 16.7%--this is the dividing line.

28. Dimplied by critical loss
Critical Loss Analysis is a Method for Implementing the SSNIP Test
Step (3)--Whether actual loss of sales is higher or lower than the critical loss depends on the elasticity of demand which depends on the slope of the demand curve at the initial price (in previous example critical loss corresponds to a “critical” demand elasticity of 1.66; what if the true demand elasticity was 5.75?)
Price
$22
$20
Dmore elastic
$10 MC
Dimplied by critical loss
Dmore inelastic
Quantity
83.33
100
Regression analyses, natural experiments, and internal market studies can help determine actual loss.

29. Critical Loss Analysis is a Method for Implementing the SSNIP Test
To conduct the demand-side portion of the test in practice we need
Marginal costs: data from at least one merging parties (and an assumption that these marginal costs are representative of other players in the market).
Demand elasticities: natural experiments, regression studies, consumer surveys, diversion ratios are all ways to estimate the elasticity of demand.
To conduct the supply-side portion of the test in practice we need
Supply elasticities: change in output of substitute products by firms that aren’t currently producing those products
In practice the supply-side response is usually ignored for critical loss.

30. Monopolized and is therefore too small.
Comparison of Actual Versus Critical Loss Determines if Market is Large Enough to be Monopolized.
Actual loss less than critical
Loss implies that price increase is profitable so assumed “market” can be profitably monopolized. Market is therefore at least this narrow.
Actual loss greater than critical loss Implies price increase is unprofitable so assumed “market” can’t be profitably
Monopolized and is therefore too small.
Critical Loss

31. The Simple Math of Critical Loss Analysis
For an X% price increase, the critical loss is
Where M is the Lerner index (% difference between price and marginal cost)
We can compare the critical loss to the actual loss based on data on elasticity of demand to assess whether a price increase would be profitable
In the previous example the actual loss will be greater than the critical loss if a 10% increase in price leads to a more than 16.7% decline in sales which means in turn that the elasticity demand is greater than 1.66 (in absolute value).
Formal calculation

32. The Simple Math of Critical Loss Analysis—Example
For an 5% price increase with a 50% contribution margin, the critical loss is
Which equals 1/11=roughly 9 percent
We can compare the critical loss to the actual loss based on data on elasticity of demand to assess whether a price increase would be profitable
Suppose the elasticity of demand is 3.0. Then a 5% increase in price would reduce sales by 15%. If correct, we could conclude that the true market is larger.
Suppose the elasticity of demand is 1.5. Then a 5% price increase would reduce sales by 7.5 percent. If correct, we would conclude that the true market is at least this narrow.

33. End of Part 1, Next Class Part 2
Overview of Market Definition
General Principles of Market Definition
Hypothetical Monopolist Test
Critical Loss Analysis
Part 2
Overview of Issues in multisided platforms
The Case of Additive Prices
Newspaper Markets
One-Sided Biases