UNIVERSITÀ DEGLI STUDI DI PADOVA
Dipartimento di Scienze Economiche “Marco Fanno”
THE STATE AID GAME
STEPHEN MARTIN
Purdue University
PAOLA VALBONESI
Università di Padova
July 2006
“MARCO FANNO” WORKING PAPER N.24
The State Aid Game∗
Stephen Martin
Department of Economics
Purdue University
403 West State Street
West Lafayette, Indiana 47907-2056, USA
smartin@purdue.edu
Paola Valbonesi
Dipartimento di Scienze Economiche
Universita’ degli Studi di Padova
Via del Santo 33
35100 Padova, Italia
paola.valbonesi@unipd.it
July 2006
Abstract
We present a model of the impact of state aid on equilibrium market
structure and on market performance in an integrating market when the
process of integration is driven by consumer inertia. In a partial equilibrium
model, it is an equilibrium for governments to grant state aid, even though
this reduces common market welfare.
SAG0606.tex
Key words: state aid, exit, market integration.
JEL codes: F15, L11, L53
∗
We are grateful to David Collie for comments on a much earlier version of this paper, and
for comments received at the University of Bern, the University of Padua, at the Jornadas de
Economía Industrial, Bilbao, Michigan State University, and the University of Salerno. Responsibility for errors is our own.
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . .
2 Market Integration and Market Structure . . . . . . . . .
2.1 Pre-integration market structure . . . . . . . . . . .
2.2 Post-integration market structure . . . . . . . . . .
3 Integrated Market Monopoly . . . . . . . . . . . . . . . .
3.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.1 Demand . . . . . . . . . . . . . . . . . . . .
3.1.2 Technology . . . . . . . . . . . . . . . . . .
3.1.3 Pre-integration market structure . . . . . . .
3.1.4 Post-integration market structure . . . . . .
3.1.5 Integration and payoffs . . . . . . . . . . . .
3.2 No State Aid . . . . . . . . . . . . . . . . . . . . .
3.2.1 Equilibrium withdrawal integration levels . .
3.2.2 Welfare . . . . . . . . . . . . . . . . . . . .
3.3 State Aid . . . . . . . . . . . . . . . . . . . . . . .
3.3.1 By Country 1 . . . . . . . . . . . . . . . . .
3.3.2 By Both Countries . . . . . . . . . . . . . .
3.3.3 Welfare flows in the fully-integrated market
3.3.4 Simulations and discounted welfare values .
4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1 Proof of Proposition 1 . . . . . . . . . . . . . . . .
5.2 Welfare . . . . . . . . . . . . . . . . . . . . . . . .
5.2.1 Integration levels 0 to ιd1 . . . . . . . . . . .
5.2.2 Integration levels ιd1 to 1 . . . . . . . . . . .
5.2.3 Fully integrated market . . . . . . . . . . . .
5.2.4 Discounted values . . . . . . . . . . . . . . .
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1. Introduction
Despite the prohibition of state aid that distorts competition contained in Article 87(1) of the Treaty establishing the European Community,1 the mandatory
and discretionary exceptions to this prohibition contained in Articles 87(2) and
87(3), and the requirement of Article 88 that the European Commission constantly review systems of state aid, state aid has been an enduring feature of the
EC economic landscape. Although state aid has decreased since the end of the
1990s, in 2002 state aid overall in the fifteen member states amounted to around
€49 billion, representing about 0.56 per cent of EU GDP. In relative terms, aid
ranged from 0.25 per cent of GDP in the United Kingdom to 1.28 per cent in
Finland. State aid policy seems certain to remain the subject of controversy as
the accession of less economically-developed Member States shifts the standards
for permissibility of aid throughout the Community.2
The increased competition that accompanies market integration is expected
to improve market performance by reducing firms’ abilities to hold price above
marginal cost and by eliminating waste (reducing X-inefficiency).3 It is less commonly noted4 that the increase in rivalry that comes with market integration may,
and in general will, result in the exit of less efficient firms. Indeed, such exit, and
the concomitant concentration of production in the hands of a smaller number
of more efficient firms, is one source of improved performance in the integrated
market.
There is a large policy-oriented literature on European Union state aid policy.5
1
Article 87(1) provides that “any aid granted by a Member State or through State resources
in any form whatsoever which distorts or threatens to distort competition by favouring certain
undertakings or the production of certain goods shall, in so far as it affects trade between Member
States, be incompatible with the common market.” Article 88(2) provides that incompatible
aid is to be altered or abolished.
2
See, for example, Ricard (2005). The 10 new members of the European Union devote a
larger percentage of their GDP per capita to state subsidies to business than do the 15 older
member states (respectively about 1.35% of new member versus 0.45% of the older member
states in the period 2002-04). In absolute terms, the new member states granted €6,274 billion
aid compared with €42,717 billion for the EU-15 in the period 2002-04 (EU State Aid Scoreboard,
Spring 2006, p.11).
3
See, for example, Vickers (1995), Nickell (1996), and Hay and Liu (1997).
4
See, however, Symeonidis’ (2000) discussion of the impact on market structure of an unanticipated toughening of UK competition policy.
5
For references, see Martin and Evans (1991), Martin and Valbonesi (2000), and Friederiszick
et al. (2005).
3
Formal treatments are rare. Collie (2000, 2003), in what is the work most closely
related to the present discussion of which we are aware, models of the impact
of state aid on market performance in an integrated market. In this paper, in
addition to examining the impact of state aid on market performance, we examine
the transition period in the run-up to full integration and also consider the impact
of state aid on market structure.
The analysis presented in this paper is based on the observation that the
economics of equilibrium market structure in an integrating market has elements in
common with the analysis of exit from a declining industry.6 This insight develops
from the analysis of the demand curves characterized by consumer inertia – a
preference for the product of domestic producers that persists for a limited period
even after formal barriers to trade have been eliminated. In such markets, and
in absence of government intervention, shifts in the residual demand curves facing
individual firms in imperfectly competitive integrating markets dictate a reduction
in the equilibrium number of firms. We show that state aid, by frustrating such
reductions, neutralizes an efficiency effect of competition in an integrated market,
and blocks the way to realization of an efficient specialization of production and
division of labor in the common market.
Aid granted by a single country may increase its own net social welfare, although in so doing it reduces common market net social welfare. Aid by several
member states can result in a outcome that reduces net social welfare in all member states, and therefore of necessity in the common market.
That market integration may induce exit, absent state aid, is without doubt.
An example from the early history of EU market integration is that of the Belgian
coal industry in the European Coal and Steel Community. Belgian costs were so
high that coal suppliers in the Ruhr would have been able to undersell Belgian
mines in Belgium without engaging in freight absorption (Lister, 1960, p. 296;
Meade et al., 1962, p. 292). The history of EU competition policy is replete
with examples of Member States granting aid to their firms that was generally
recognized as contrary to treaty provisions by all parties involved except the legal
representatives of the aid-granting member states, who argued in defense of the
aid before the European Court of Justice.
In contrast to the general literature on subsidies, which relies mainly on models
similar to those found in the strategic trade, tax competition and rent-seeking
literatures,7 our model develops the idea that the incentive to supply state aid is
6
7
See Ghemawat and Nalebuff (1985, 1990) and the literature stemming therefrom.
See Martin and Valbonesi (2006, forthcoming) for a survey.
4
endogenously created by the very process of market integration. To highlight the
issues involved, we first examine (in Section 2) the impact of market integration on
equilibrium market structure for the case of integration of two identical markets
in which all firms have access to the same technology. In Section 3 we relax
the assumption of identical technologies, outline conditions under which market
integration implies that less-efficient firms leave the market, and evaluate the
welfare impact of market integration. In Section 3.3 we turn to the impact of
state aid on market performance and outline the economic case for control of state
aid. We conclude and draw policy implications in Section 4. Proofs are given in
the Appendix.
2. Market Integration and Market Structure
Consider a situation in which two countries, each home to a Cournot oligopoly
with inverse demand equation
pi = a − bQi ,
(2.1)
c (q) = F + cq.
(2.2)
for i = 1, 2, form a common market.8 Firms in both countries produce with a cost
function that exhibits fixed cost and constant marginal cost:
In this section, for simplicity, we ignore the fact that the number of firms must
be an integer, and ask how market integration affects the equilibrium number of
firms.
2.1. Pre-integration market structure
We work with a continuous time model. In what is a standard analysis of Cournot
oligopoly with linear inverse demand and constant marginal cost, a typical firm
(of a total n) in one of the pre-integration component markets noncooperatively
picks its own output rate to maximize its payoff per unit time,
!#
"
Ã
n
X
π i = a − c − b qi +
qi − F.
qj
(2.3)
j6=i
8
The slope parameter b can be normalized to some convenient value (usually taken to be 1)
by appropriate redefinition of the units in which output is measured. Having normalized b for
a single-country market, the slope of the integrated-market inverse demand curve cannot then
be normalized again. With this in mind, we write the slope parameter explicitly in (2.1).
5
The first-order condition for profit maximization is
Ã
!
n
X
a − c − b qi +
qj = bqi ,
(2.4)
j6=i
and this implies that the firm’s equilibrium payoff is rate proportional to the
square of its equilibrium output,
π i = bqi2 − F.
(2.5)
(2.4) is also, implicitly, the equation of firm i’s best response function. Since
the model is symmetric, all firms produce the same equilibrium output rate. (2.4)
implies that this equilibrium output rate is
q∗ =
1 a−c
,
n+1 b
(2.6)
where the asterisk denotes an equilibrium value for the component market. (2.5)
then implies that the equilibrium payoff rate per firm in the component market is
¶2
µ
1 a−c
∗
− F.
(2.7)
π =b
n+1 b
The equilibrium market structure is the number of firms, n∗ , that makes the
Nash-Cournot equilibrium payoff rate (2.7) equal to zero:
a−c
n∗ = qb
F
b
− 1.
(2.8)
The numerator of the fraction on the left, a−c
, is the quantity that would be
b
demanded in either of the component markets if price were equal to marginal cost;
it is one measure of market size. The denominator is the square root of fixed
cost, normalized by the slope of the inverse demand curve. (2.8) therefore says
that the equilibrium number of firms in a Cournot market is larger, the larger is
the market and the smaller is fixed cost.
2.2. Post-integration market structure
In the fully integrated market, firms cannot price discriminate based on nationality. In one perspective, this may be regarded as a definition of market integration.
6
n∗
1
2
3
4
5
6
7
8
m∗
[m] 2n∗ − [m]
1.83
1
1
3.24
3
1
4.66
4
2
6.07
6
2
7.49
7
3
8.89
8
4
10.31 10
4
11.73 11
5
Table 2.1: Pre-integration equilibrium number of firms per country n∗ , postintegration equilibrium number of firms m∗ , equilibrium integer number of postintegration firms [m], and 2n∗ − [m].
Nationality-based price discrimination may also be prohibited by competition policy, as indeed it is in the European Union. The equation of the inverse demand
curve in the integrated market is
1
p = a − bQ.
2
(2.9)
Going through the same steps as for the single market (alternatively, substituting b/2 for b in (2.8)), the equilibrium number of firms in the integrated market
m∗ satisfies
√ a−c
√
m∗ + 1 = 2 qb = 2 (n∗ + 1) .
(2.10)
F
b
The ratio (m∗ + 1) / (n∗ + 1) equals the square root of the number of equallysized markets that integrate to form a single market – in this case, two. m∗ > n∗ ,
but m∗ < 2n∗ . The equilibrium number of firms in the integrated market exceeds
the equilibrium number of firms in a single component market, but is less than
the total number of firms in all component markets before integration. Table 2.1
shows the relation between n∗ and m∗ for small values of n∗ .
It is worth emphasizing that even though market integration leads to a reduction in the number of firms, it means an improvement in market performance.
Pre-integration long-run equilibrium price (by definition, equal to the average cost
of producing equilibrium output) is
√
(2.11)
p (n∗ ) = c + bF .
7
After integration, each surviving firm produces more output, reducing average
fixed cost. Post-equilibrium long-run equilibrium price is
1 √
p (m∗ ) = c + √ bF < p (n∗ ) .
2
(2.12)
Integration not only economizes on fixed cost but also reduces price, thereby
increasing consumer surplus.
3. Integrated Market Monopoly
3.1. Setup
Our model is of two countries that integrate their markets for a single product.
For simplicity, we assume quantity-setting behavior with identical linear demands
in each pre-integration market and fixed cost, constant marginal cost technologies,
with as well as a lump-sum entry fee. We consider the simplest possible case, with
each pre-integration market a monopoly and the post-integration market also a
monopoly.9 Realization of the efficiency results that flow from integration then
requires the exit of one of the pre-integration firms. It is this integration-induced
change in market structure that creates an incentive for one country to grant its
firm state aid, and this, in turn, may make a joint policy to control state aid an
attractive proposition.
3.1.1. Demand
(2.1) is the equation of the pre-integration inverse demand curve in country i,
i = 1, 2, and (2.9) is the equation of the inverse demand curve in the fullyintegrated market. We assume that there is a continuous well-behaved integration
function ι (t), with
0 ≤ ι (t) ≤ 1
(3.1)
ι (0) = 0
ι0 (t) > 0
ι (T ) = 1.
(3.2)
9
It is common in both the declining markets literature and the strategic trade policy literature
to consider the case of one firm in each country. Rather than simply assume that these are the
pre-integration market structures, we explicitly specify the conditions on demand and technology
for the configurations we consider to be equilibrium outcomes. The results obtained here
generalize to the case of pre- and post-integration oligopoly, at the expense of increasing the
complexity of the algebra.
8
A time period of length T is required to complete the integration process. At
time t during the integration period, a fraction ι (t) of consumers in each market
are “in” the integrated market and these consumers consider either supplier a
potential source of supply. The complementary fraction 1 − ι (t) of consumers in
each country consider only their domestic supplier a potential source of supply.
The higher is ι, the smaller is the fraction of consumers still buying only on the
pre-integration national market and the more integrated is the common market.
The equation of the inverse demand curve facing each firm is then a weighted
average of the national pre-integration demand curve and the full-integration residual demand curve,
¸
∙
a − pi (t)
a − pi (t)
qi (t) = [1 − ι (t)]
+ ι (t) 2
− qj (t) ,
(3.3)
b
b
for i, j = 1, 2 and j 6= i. In what follows, we suppress the time argument where
this is possible without confusion. It will then be natural simply to write of
“integration level ι.”10
In the “exit from declining markets literature” (Ghemawat and Nalebuff 1985,
1990; Brainard, 1994; others), it is typical to assume that demand declines monotonically to zero over time in a well-behaved way. The assumptions we make about
the integration function correspond to such declining demand assumptions, and
are rooted in assumptions about consumer behavior. Scitovsky (1950), Waterson
(2003), search models of imperfectly competitive markets, and the literature on
consumer switching costs all emphasize the importance of consumer behavior for
market performance. The European Commission, in its First Report on Competition Policy, referred (1972, p. 14) to “differences in the habits of consumers” as
one reason for persistent price differences across member states in the Common
Market. The formulation given by (3.3) describes a particular kind of demand
inertia as a way of modelling the demand side of the integration process.
In a Hotelling model, Schultz (2005) obtains a comparable effect by allowing
for two classes of consumers, those who are informed of the prices of both suppliers and those who are informed of the price of only one supplier. Schultz’s
transparency parameter, the fraction of consumers informed of both prices, corresponds conceptually to our integration parameter, although the details of the
models are quite different. Reinhard Selten has explored the impact of demand
10
The formulation adopted here is a general one. If the integration process is linear, we would
have ι (t) = t/T . Alternatively, the integration process might follow the kind of logistic pattern
that is common in diffusion models.
9
inertia on market performance in experimental markets. Consumer heterogeneity
is one of the standard explanations for equilibrium price heterogeneity, and the
two groups of consumers in our markets may be thought of as “shoppers” (buying
in the integrated market) and “nonshoppers) (buying only in the nonintegrated
market).
Inverting (3.3), the inverse demand equation facing firm i at integration level
ι is
qi + ιqj
,
(3.4)
pi = a − b
1+ι
for i, j = 1, 2 and i 6= j.
(3.4) bears a family resemblance to the Bowley (1924) specification for the inverse demand equation of one variety of a differentiated product group. We ought
to expect, therefore, that a partially integrated market for a homogeneous product behaves in some ways like a completely integrated market for a differentiated
product.
3.1.2. Technology
The firm in country i produces with constant marginal cost c per unit and fixed
cost Fi (per unit of time). The cost function of a firm in country i for a flow of
output at rate q per unit time interval is thus
ci (qi ) = Fi + cqi ,
(3.5)
for i = 1, 2
Without loss of generality, we assume that the country 2 firm has the lowest
fixed cost:
F2 < F1 .
(3.6)
Empirically, it is known that there are persistent cost differences across plants
(Roberts and Supina, 1996, 1997). Country-specific differences in cost (which for
simplicity we treat as differences in fixed cost) might reflect locational differences
or, for natural resource industries, differences in the quality of mineral deposits.
3.1.3. Pre-integration market structure
Monopoly profit and value If a single firm supplies country i, it picks its
output to maximize its instantaneous payoff
π i = (a − c − bqi ) qi − Fi .
10
(3.7)
In the usual way, monopoly output, the flow rate of profit, and value are
qim =
a−c
2b
2
πim = bqim
− Fi
Vim =
πim
.
r
(3.8)
Duopoly profit and value If a second firm enters, and market i is a Cournot
duopoly, then duopoly outputs, the flow rates of profit, and values are
qid =
a−c
3b
2
πid = bqid
− Fi
Vid2 =
πid
.
r
(3.9)
Pre-integration natural monopoly The conditions for the equilibrium number of firms in the pre-integration market to be one are
Vim ≥ 0, Vid2 < 0.
(3.10)
These inequalities both hold if
1
<
3
p
Fi /b
a−c
b
1
≤ .
2
(3.11)
(3.11) characterizes the range of parameter values for which the equilibrium
number of firms in each of the pre-integration markets is one. The numerator
of the central fraction is the square root of fixed cost, scaled by the slope of the
inverse demand curve. The denominator is, as noted in discussion of equation
(2.8), a measure of market size. Hence (3.11) can be given the interpretation
that the equilibrium number of firms is one if fixed cost is small enough, relative
to market size, that it is profitable for one firm to supply the market, but large
enough, relative to market size, that it is not profitable for two firms to supply
the market.
3.1.4. Post-integration market structure
We assume that (3.11) holds, and thus that before integration, the equilibrium
market structure has each country supplied by a single firm. By abuse of notation,
we will use the subscript i to indicate both country i and the pre-integration home
firm that supplied country i.
It is intuitive that if (3.11) holds, so that each firm makes a profit as a monopolist in its own national market, each firm would also make a profit as a monopolist
in the fully integrated market (that is, facing the inverse demand (2.9)).
11
Firm i’s payoff function in the fully integrated duopoly market is
¸
∙
1
π i = a − c − b (qi + qj ) qi − Fi , i, j = 1, 2, i 6= j.
2
(3.12)
The first-order condition to maximize π i (this is also, implicitly, the equation
of firm i’s best response function) is
1
a − c − b (2qi + qj ) ≡ 0,
2
(3.13)
from which
1
1
a − c − b (qi + qj ) ≡ bqi ,
(3.14a)
2
2
so that when the first-order condition holds, and in particular in Nash-Cournot
equilibrium, firm i’s payoff is
1
π i = bqi2 − Fi , i = 1, 2.
2
(3.15)
Equilibrium outputs, found by solving the system of equations formed by the
two first-order conditions, are identical (given that assumption that firms have
identical marginal costs),
a−c
qd = 2
(3.16)
3b
per firm.
Then from (3.15), equilibrium flow payoffs when integration is complete are
µ
µ
¶2
¶2
1
a−c
2
a−c
πi = b 2
− Fi = b
− Fi .
(3.17)
2
3b
9
b
Rearranging terms, π i ≥ 0 and both firms are profitable (at least, do not make
losses) in the full-integration market if fixed costs are not too large relative to
market size:
p
√
Fi /b
2
,
(3.18)
≤
a−c
3
b
for i = 1, 2.
In contrast, both firms would be unprofitable in a post-integration duopoly if
p
√
Fi /b
2
< a−c
(3.19)
3
b
12
for i = 1, 2. Combining (3.11) and (3.19), each pre-integration market is a natural
monopoly, as is the post-integration market, if
p
√
Fi /b
2
1
< a−c ≤ ,
(3.20)
3
2
b
for i = 1, 2.
We assume that demand and technology parameters satisfy (3.20).
3.1.5. Integration and payoffs
(3.4) is the inverse demand equation facing firm i if both firms are in operation
at integration level ι, 0 ≤ ι ≤ 1. Firm i’s profit is
¶
µ
qi + ιqj
qi − Fi ,
(3.21)
πi = a − c − b
1+ι
for i, j = 1, 2 and j 6= i.
Rearranging terms, the first-order condition to maximize (3.21) is
2qi + ιqj = (1 + ι)
a−c
b
(3.22)
and this implies that firm i’s equilibrium payoff is
πi =
b 2
q − Fi .
1+ι i
(3.23)
By symmetry, equilibrium output levels are the same, and at integration level
ι, equilibrium output per firm is
qd =
1+ιa−c
.
2+ι b
(3.24)
In the “declining industry” literature, the driving assumption is that the demand curve moves continuously toward the origin. Substituting i = 1, qj = qd in
(3.4) and rearranging terms shows that firm 1’s residual inverse demand equation
at integration level ι is
p1 = c +
q1
2
(a − c) − b
.
2+ι
1+ι
13
(3.25)
As integration goes forward, the price-axis intercept of firm 1’s residual inverse
demand curve falls, and the inverse demand curve becomes flatter, with slope
changing continuously from −b for ι = 0 to − 21 b for ι = 1.
Duopoly output increases as integration goes forward,
∂qd
a−c
1
=
> 0,
2
∂ι
(2 + ι) b
(3.26)
as each firm faces a progressively larger number of consumers who are in the
integrated market.
From (3.23) and (3.26),
µ
¶2
1 ∂π di
a−c
ι
< 0,
(3.27)
=−
b ∂ι
b
(2 + ι)3
and instantaneous profit falls as integration goes forward and the pseudo-product
differentiation described by the inverse demand equation (3.4) falls.
3.2. No State Aid
3.2.1. Equilibrium withdrawal integration levels
Let ιdi be the degree of integration at which firm i’s duopoly profit just equals
zero. ιdi is implicitly defined by
µ
¶2
1+ιa−c
b
b 2
d
q (ι) − Fi =
− Fi ≡ 0.
(3.28)
πi (ι) =
1+ι d
1+ι 2+ι b
By our assumptions about the ranking of fixed costs, (3.6), and (3.27), we know
that the high-fixed cost firm sees its profit go to zero earlier in the integration
process than does the low-fixed cost firm:
ιd1 < ιd2 .
(3.29)
For ι > ιd2 , both firms lose money if both are active.
The relationships that determine equilibrium withdrawal levels are illustrated
in Figure 3.1.11 As integration increases, residual demand curves fall and rotate
11
To minimize visual clutter, residual marginal revenue curves and the marginal cost curve
are omitted from Figure 3.1. However, q1 = 60 is firm 1’s noncooperative duopoly equilibrium
output for integration level ι = 0.5; q2 = 65.8 is firm 2’s noncooperative duopoly equilibrium
output for integration level ι = 0.925.
14
price
1’s residual demand curve, ι = 0.5
...
.
.
.
.
.
.
.
.
.
100 ..........
.... ...
.........
......... ..............
...... . .
90 ..........
....... ...........................
....... ....
. ...........
. 1’s average cost curve
78.4 ............ .............. ........ ........................
.
.........
.
......... .............. ......... ........................
.........
......... ....... ...........
Fully-integrated
market demand curve
.........
......... ..................
.....
.........
.
.
.
.......... ............
.
.
.........
..
... ............................
.........
...
.
...................
2’s average...
.
.
.
.
.
.........
...........•.....
......... ..........
cost curve
..................
..........
.•.....................
.........
. ...................
.........
......... ...............
.....
......... . ...................
................ . . ......................... ................
.
...............
. . . ......................................
...............
. .... .......................................
....... .........
.....................................
.........
....... ........
.........
.
.
.
.
.
.
.
.
.
.
.
.
.
....... .........
.........
2’s residual
....... .........
.........
.
.........
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
demand curve,
........ .........
.........
....... .........
.........
ι = 0.925
.......
.
.
.
.
.....
....
.
quantity
60 65.8
Figure 3.1: Withdrawal integration levels, Cournot duopoly, partially integrated
market. Each residual demand curve is drawn for the other firm producing its
equilibrium output at the indicated integration level. a = 110, c = 10, b = 1, F1 =
2400, F2 = 2250.
in a counterclockwise direction. At integration level ι = 0.5, firm 1’s residual
demand curve is tangent to its average cost curve. For greater integration levels,
firm 1’s duopoly payoff is negative. Firm 2 has smaller fixed cost than firm 1; for
integration level ι = 0.925, firm 2’s average cost curve is tangent to its average
cost curve, and firm 2 as well has a negative duopoly payoff for greater integration
levels.
The subgame perfect equilibrium without state aid is given by Proposition 1,
which is proven in the Appendix.
Proposition 1: It is a subgame perfect equilibrium for firms to compete as NashCournot duopolists from integration level 0 to integration level ιd1 , for firm 1 to
withdraw when integration level ιd1 is reached, and for firm 2 to supply the market
as a monopolist thereafter.
15
As noted in footnote 9, this result generalizes to the case of pre- and postintegration oligopoly.
3.2.2. Welfare
We measure welfare as the sum of consumer surplus and producer surplus (economic profit). For cases in which subsidies are granted, we assume that the
social cost of a euro of aid is one euro. It may well be – particularly in view of
the self-imposed budget constraints of the Stability and Growth Pact – that the
opportunity cost of granting aid to a firm is more than one euro. We say more
about this below. If the welfare cost of a euro of aid is more than a euro, then it
is less likely that the net impact of aid will be beneficial, all else equal.
In equilibrium, from integration level 0 to ιd1 , net social welfare in each country
is the sum of the profit of its home firm and domestic consumer surplus. From
integration level ιd1 to 1, firm 2 is the single supplier of the partially-integrated
market, and from integration level 1 onward, firm 2 is the single supplier of the
fully integrated market.
After integration level ιd1 , firm 2 maximizes profit along its partial-integration
demand curve (with q1 = 0). Flow welfare in country 1 is the consumer surplus
of those of its residents who are in the integrated market and buy from firm 2.
Flow welfare in country 2 is the sum of the consumer surplus of its residents and
the profit of firm 2 (which includes profit on sales made in country 1).
3.3. State Aid
3.3.1. By Country 1
In the spirit of the early strategic trade policy literature, suppose country 1 and
only country 1 can commit to giving its home firm lump-sum aid in the amount
of any losses the home firm might sustain.
The cost to country 1 of this policy is the discounted value of subsidies to firm
1 between integration levels ιd1 and ιd2 .12 With subsidies, firm 1 is guaranteed at
least a normal flow rate of return on investment, and would not exit the market.
The optimal action for firm 2 is then to exit at integration level ιd2 .
12
In principle, an unrealistically farsighted country 1 government might give firm 1 just enough
of a subsidy so that the discounted value of firm 1’s losses between integration levels ιd1 and ιd2
and the discounted value of its monopoly profits from integration level ιd2 onward equal zero,
so that firm 1 would be willing to stay in the market while receiving a lower subsidy than that
discussed in the text.
16
The benefits to country 1 are the (appropriately discounted) economic profits
of firm 1, which includes profit on sales made in country 2, as well as additional
consumer surplus to those country 1 consumers who are not in the integrated
market during the integration period. Unless discount rates are very high, the net
benefit to country 1 will be positive, and granting the subsidy will be privately
beneficial for country 1.
A subsidy by country 1 imposes costs on country 2: the profits that firm
2 would otherwise earn are lost after it exits, and some surplus that country 2
consumers would otherwise enjoy is lost in the partially integrated market.
A subsidy also reduces the overall economic benefit from integration. In the
case considered here, the fully-integrated market is a monopoly. The globallyefficient outcome is that firm 2, which has lower fixed cost, supply the integrated
market. A subsidy granted by country 1 to firm 1 over the interval ιd1 to ιd2
imposes higher fixed cost on the integrated market forever.
3.3.2. By Both Countries
If country 2 can also commit to loss-neutralizing subsidies for its home firm,
it can avoid the losses that would be inflicted by a unilateral country 1 subsidy.
Subsidies would continue forever. Consumers would be better off, but net welfare,
taking subsidies into account, would be reduced, compared with the no-subsidy
case. Further, all potential welfare gains from integration would be lost, since
there would be no saving of fixed cost.
3.3.3. Welfare flows in the fully-integrated market
Table 3.1 gives the general expressions for per-period welfare outcomes in the fullyintegrated market with no subsidies (upper left), with a subsidy by country 1 only
(lower left), and with subsidies by both countries (lower right). If the factor used to
discount future income flows is sufficiently close to one, the qualitative relationship
of these flow values must indicate the qualitative relationship of the corresponding
present discounted values. We first discuss the flow values, then turn our attention
to numerical evaluation of discounted values for specific parameters.
If country 1 alone grants a subsidy, its welfare must increase, and that of
country 2 decrease, compared with the no-subsidy outcome: a subsidy by country
1 alone shifts monopoly profit from country 2 to country 1, and leaves consumer
surplus unchanged.
17
No
Subsidy
Total
Subsidy
Total
No subsidy
¡ ¢
Subsidy
2
0 + 81 b a−c
b
¡ ¢2
¡ ¢2
1
b a−c
− F2 + 81 b a−c
2
b
b
¡ a−c ¢2
3
b
−
F
2
¡ a−c4¢2 b
¡ ¢2
1
1
b b
− F1 + 8 b a−c
2
b
¡ a−c ¢2
1
0 + 8b b
¡ a−c ¢2
3
b
− F1
4
b
0 + 92 b
0+
2
b
9
¡ a−c ¢2
b
¡ a−c ¢2
8
b
9
+
+
b
¡ a−c ¢2
b
h
h
2
b
9
2
b
9
¡ a−c ¢2
b
− F1
b
− F2
¡ a−c ¢2
− F1 − F2
i
i
Table 3.1: Alternative welfare outcomes per period, fully-integrated market: the
general case. Rows and upper entries in each cell refer to country 1, columns
and lower entry in each cell refer to country 2. Elements in each sum are firm
value, discounted consumer surplus, and subsidy (where applicable). See text for
definition of parameters.
If country 2 also grants a subsidy, the profit of its firm falls from 0 to less than
zero, and the subsidy just matches the amount of the loss. Country 2 consumer
surplus increases, as the common market is a duopoly rather than a monopoly.
The change in country 2 welfare if it matches country 1’s subsidy policy is
µ
µ
µ
µ
¶2
¶2
¶2
¶2
2
2
1
23
a−c
a−c
a−c
a−c
b
− F2 + b
− b
= b
− F2 . (3.30)
9
b
9
b
8
b
72
b
The first two terms on the left are firm 2’s (negative) payoff in the fully-integrated
duopoly market, which in absolute value is the flow subsidy paid by country 2.
The third term on the left is country 2 resident consumer surplus in the fullyintegrated duopoly market. The fourth term is country 2 resident consumer
surplus in the fully-integrated monopoly market.
Given our assumptions about the relationship between fixed costs and market
size, (3.20), this difference is positive. Thus country 1 increases its welfare if it
alone grants a subsidy, and if country 1 grants a subsidy, then country 2 increases
its welfare by granting a subsidy to its own firm.
The change in country 1 flow welfare between the two-subsidy and the nosubsidy case is
" µ
µ
µ
¶2
¶2
¶2 #
2
a−c
a−c
a−c
1
2
,
(3.31)
b
− F1 + b
− b
9
b
9
b
8
b
18
No subsidy
Subsidy
No
0 + 1250 = 1250
Subsidy 2750 + 1250 = 4000
Total
5250
Subsidy 2600 + 1250 = 3850 0 + 2222.2 − 177.8 = 2044. 4
0 + 1250 = 1250
0 + 2222.2 − 27.8 = 2194. 4
Total
5100
4238.8
Table 3.2: Alternative welfare outcomes per period, fully-integrated market. Rows
and upper entries in each cell refer to country 1, columns and lower entry in each
cell refer to country 2. Elements in each sum are firm value, discounted consumer
surplus, and subsidies (where applicable). a = 110, c = 10, b = 1, F1 = 2400,
F2 = 2250.
where the first term (losses of the subsidized firm 1) is negative and the term in
braces (change in consumer surplus between duopoly and monopoly) is positive.
Combining terms, (3.31) is
µ
¶2
23
a−c
b
− F1 ,
72
b
(3.32)
and once again this is positive, as for (3.20).
One can also show that “common market” flow welfare falls moving from the
no-subsidy to the country 1-subsidy only case, and falls again moving to the twosubsidy case. Thus the noncooperative equilibrium if national governments act to
maximize national welfare flows in the fully-integrated market is that both countries grant subsidies. The country that is home to the high-cost firm increases its
national welfare by initiating a subsidy game, even if the other country follows suit
and even though common market welfare would be greater without any subsidies.
3.3.4. Simulations and discounted welfare values
Table 3.2 illustrates the general results of Table 3.1 for specific parameter values.
It shows, as does Table 3.1, that considering per-period welfare outcomes in the
fully-integrated market, the equilibrium outcome is for both countries to subsidize,
even though this reduces common market welfare.
One might wonder, however, if this result could be upset if the appropriately
discounted welfare values during the integration period are taken into account.
19
No subsidy
Subsidy
No
521.59 + 13379.8 = 13901.4
Subsidy 7933.6 + 14148.3 = 22081.9
Total
35983.3
Subsidy 3079.87 + 15475.1 − 112.94 = 18442 521.59 + 16432.9 − 286.56 = 16667.9
1760.11 + 15466.9 = 17227
1760.11 + 16432.9 − 25.08 = 18167.9
Total
35669
34835.9
Table 3.3: Alternative welfare outcomes, linear integration function. Rows and
upper entries in each cell refer to country 1, columns and lower entry in each cell
refer to country 2. Elements in each sum are firm value, discounted consumer
surplus, and (where applicable) discounted subsidy. a = 110, c = 10, b = 1,
r = 1/10, F1 = 2400, F2 = 2250, T = 25.
The integral expressions for welfare during the integration period (these are derived in the Appendix) lack closed-form solutions, and must be evaluated numerically. Simulation results suggest that the results of Table 3.1 and Table 3.2 are
quite general (as they must be, if the interest rate used to discount future income
is sufficiently close to zero).
Table 3.3 gives present-discounted welfare values for the parameterization of
Table 3.2 of the model for a 25-year integration period and a linear integration
function.13 The pre-integration rates of profit and consumer surplus are 100 and
1250 per year in country 1, 250 and 1250 per year in country 2, respectively.
Integration thus improves welfare in both countries. The gain in country 1 is
minimal – 13901 versus a capitalized 10 (1350) = 13500. The value of firm 1,
which goes out of business, is sharply reduced by integration.14 In country 1, it
is consumers who benefit from integration (in the absence of subsidies).
If country 1 alone grants a subsidy, it improves its own welfare at the expense
of country 2. Country 2 consumers, some of whom purchase from a duopoly for a
13
The numerical results reported here were generated by Mathematica programs and checked
using the version of Maple that is part of Scientific Workplace. The Mathematica programs are
available from the authors on request.
14
In the model considered here, the owners of the firm that goes out of business shift the
firm’s assets to other markets, where they earn at least a normal rate of return. In practice,
appeals for state aid are often rationalized by assertions that capital investments (non-human
and human) are partially or wholly sunk, and cannot more to other markets. Analysis of this
aspect of the market integration question requires explicit consideration of input choices, and is
the subject of ongoing research.
20
No subsidy
Subsidy
No
751.43 + 124999 = 125750
Subsidy 238585 + 128307 = 366891
Total
492641
Subsidy 206936 + 134856 − 640.17 = 341151 751.43 + 211965 − 14727.2 = 197989
3208 + 134786 = 137994
3208 + 211965 − 2183.75 = 212989
Total
479146
410978
Table 3.4: Alternative welfare outcomes, linear integration function. Rows and
upper entries in each cell refer to country 1, columns and lower entry in each cell
refer to country 2. Elements in each sum are firm value, discounted consumer
surplus, and (where applicable) discounted subsidy. a = 110, c = 10, b = 1,
r = 1/100, F1 = 2400, F2 = 2250, T = 25.
longer period than without subsidies, are better off if there is a subsidy by country
1. A subsidy by country 1 alone reduces total welfare.
Total welfare is further reduced if both countries grant subsidies. Consumers,
in this case able to purchase from a duopoly ad infinitum, are even better off than
before, but subsidies reduce overall welfare.
But country 1 is unambiguously able to improve its welfare by granting a
subsidy to its firm, even if country 2 adopts a retaliatory subsidy policy. Country
2 is worse off if both countries subsidize than if neither do, but country 2 is better
off granting its own subsidy if (as one would expect for the parameter values of
Table 3.3) country 1 grants a subsidy. It is thus an equilibrium for both countries
to subsidize.
The qualitative nature of the results shown in Table 3.3 are robust. The
parameter values used for Table 3.4 are, with one exception, identical to those
used for Table 3.4; the interest rate used to discount future income is 1/100
for Table 3.4, as opposed to 1/10 for Table 3.3. In Table 3.4 and in Table 3.5
(r = 1/100 with a 100-year integration period), the qualitative relationships of
the welfare values for the different policy combinations match those of Table 3.3 .
This result may be one explanation for the persistence of EU Member State
attempts to grant aid that contravenes the competition policy provisions of the
EC Treaty: this is the noncooperative equilibrium outcome.
Two aspects of the situation, both outside our formal model, may explain
Member State agreement on those Treaty provisions. First is to argue that,
given government budget constraints, the social welfare cost of each euro used to
21
No subsidy
Subsidy
No
2641.4 + 127322 = 129963
Subsidy 159186 + 135399 = 294584
Total
424548
Subsidy 105472 + 150656 − 1428 = 254701 2641.4 + 189128 − 8437 = 183332
10265.5 + 150520 = 160786
10265.5 + 189128 − 1061 = 198332
Total
415486
381664
Table 3.5: Alternative welfare outcomes, linear integration function. Rows and
upper entries in each cell refer to country 1, columns and lower entry in each cell
refer to country 2. Elements in each sum are firm value, discounted consumer
surplus, and (where applicable) discounted subsidy. a = 110, c = 10, b = 1,
r = 1/100, F1 = 2400, F2 = 2250, T = 100.
subsidize a private firm is very likely more than one euro (Neary, 1994; Collie,
2003). Then the welfare gains from subsidizing the home country firm are less
than suggested by Table 3.3.
Second, one may note that for a common market, it is the welfare effects in
all markets, not any one market, that are of interest. In one market, country
1 may better itself at the expense of country 2 by granting aid to home country
firms. In another market, it is country 2 that will come out ahead if both
countries subsidize. Taking all markets into account restores a situation in which
a commitment by both countries not to grant aid, thus maximizing overall welfare,
can be a noncooperative equilibrium.
4. Conclusion
Paradoxically, market integration, which expands the size of the market available
to each firm, has some economic implications in common with those of declining
markets. In both cases, the equilibrium number of firms falls over time. The
result is that it is in the national interest of component markets to grant state aid,
even though such aid reduces or eliminates the economic benefits that flow from
integration. This in turn justifies binding international agreements that eliminate
the national gains that would flow from the granting of state aid.
The observation that EU member states, having agreed to control of state aid,
have a history of granting aid that is regularly found to violate Treaty provisions
invites explanation. One part of such an explanation lies in time inconsistency,
22
as national governments find it convenient to deal with conjunctural crises, especially in the run-up to national elections, with policy choices that will (under the
Treaty) be neutralized, but in the future. Another part of the explanation may
be that penalties have not always been sufficient (it is only relatively recently that
aid found to violate guidelines has been recovered). But another part of the explanation may be that when it is consumer behavior that spreads the integration
process over time, if attention is confined to individual product markets, mutual
granting of subsidies may be an equilibrium outcome, even though this reduces
common market welfare for that product market.
23
5. Appendix
5.1. Proof of Proposition 1
The argument of the proof is, with one difference, that of Brainard (1994, Section
2.A). Brainard derives a subgame perfect equilibrium strategy for his declining
industry model by working backward from times at which either firm would earn
zero profit even as a monopolist. In the model considered here, the analysis works
backward from integration levels at which firms would have zero values playing
mixed withdrawal strategies.
(A) At any point in time, firms play withdrawal probabilities σ 1 and σ 2 , respectively, and compete as Cournot duopolists if both are in the market. Equilibrium
withdrawal strategies vary with time during the integration period and are constant in the fully-integrated market.
If both firms are in the market at time T or any time thereafter, it is a subgame
perfect equilibrium for the firms to play the mixed withdrawal strategies given by
(5.4) below. Equilibrium expected values playing these strategies are zero.
The fully integrated market inverse demand equation is (2.9). If firm i supplies
the integrated market as a monopolist, its profit-maximizing output and payoff
rates are
¶
µ
1
a−c
mI
I
qm =
π i = a − c − bqi qi − Fi .
(5.1)
b
2
If both firms are active in the fully integrated market, flow duopoly profits are
given by (3.23) evaluated for qi = qd .
Let σ i be firm i’s probability of withdrawal at time t ≥ T , if both firms are
in the market. Withdrawal probabilities are constant for any t ≥ T at which
both firms are in the market, since their expected payoffs in different states of the
world are the same at all such times. Withdrawal strategies follow an exponential
distribution; the probability that firm 1 drops out before time t, given that firm
2 has not dropped out, is
1 − e−σ1 t .
With probability density e−(σ1 +σ2 )t dt, neither firm has dropped out at time t,
and firm 1’s payoff is π dI
1 .
With probability density σ 1 e−(σ1 +σ2 )t dt, firm 1 drops out at time t, firm 2 has
not yet dropped out, and firm 1’s value from that point onward is 0.
With probability density σ2 e−(σ1 +σ2 )t dt, firm 2 drops out at time t, firm 1 has
not yet dropped out, and firm 1’s value from that point onward is πmI
1 /r.
24
Integrating over all future time, firm 1’s expected value at time t if both firms
are in the market is
¸
∙
Z ∞
πmI
σ 2 1r + π dI
π mI
1
1
dI
I
−(r+σ 1 +σ2 )t
.
(5.2)
V1 =
e
σ 1 (0) + σ 2
+ π 1 dt =
r
r + σ1 + σ2
0
In the same way, firm 2’s value from anytime t ≥ T at which both firms are
in the market is
π mI
σ 1 1r + πdI
2
I
V2 =
.
(5.3)
r + σ1 + σ2
For firms to be willing to play random strategies, these values must be zero,
yielding
−π dI
−π dI
σ 2 = mI 1 .
(5.4)
σ 1 = mI 2
π 2 /r
π 1 /r
Our assumptions mean that π dI
j < 0, j = 1, 2, so the numerators in (5.4) are
positive. It is reasonable to suppose that duopoly losses are less in magnitude than
the capitalized value of monopoly profit (and this is the case for the specifications
investigated here). Hence the expressions in (5.4) are less than one, and so are
valid withdrawal probabilities.
(B) If both firms are in the market at integration level ιd2 or thereafter, it is a
subgame perfect equilibrium for the firms to play the mixed withdrawal strategies
given by (5.16) below, and thereafter if both firms are in the market to play the
mixed withdrawal strategies given by (5.4). Equilibrium expected values playing
these strategies are zero.
Flow duopoly payoffs are
µ
¶2
1+ιa−c
b
d
πi =
− Fi ,
(5.5)
1+ι 2+ι b
and given our assumptions, these payoffs are negative. Note that because ι is a
function of time, so is π di .
If firm j drops out, firm i maximizes profit along the partial-integration demand curve
¯
qi + ιqj ¯¯
qi
pi = a − b
=a−b
.
(5.6)
¯
1 + ι qj =0
1+ι
Firm i maximizes
πm
i (ι)
µ
¶
qi
= a−c−b
qi − Fi .
1+ι
25
(5.7)
The first-order condition is
a−c−b
2qi
≡ 0,
1+ι
(5.8)
so that
qi
qi
≡b
,
1+ι
1+ι
a−c
,
q m ≡ (1 + ι)
2b
and the flow monopoly payoff is
∙
¸2
¶2
µ
a−c
b
a−c
m
(1 + ι)
− Fi = b (1 + ι)
− Fi .
π (ι) =
1+ι
2b
2b
a−c−b
(5.9)
(5.10)
(5.11)
If firm 2 exits at time t, firm 1’s value from the moment of firm 2’s exit is
Z T
π mI
m
V1 (t) =
(5.12)
π m [ι (τ )] e−rτ dτ + e−(T −t) 1 .
r
τ =t
This is the present discounted value of firm 1’s monopoly profit during what is
left of the integration period, plus the discounted value of monopoly output in the
fully integrated market.
Let σ i (t) be the probability that firm i withdraws at time t during the integration period, conditional on not having withdrawn before.15 For notational
convenience, write
Z
t
Σi (t) =
σ i (τ ) dτ .
(5.13)
τ =0
With probability density e−(Σ1 +Σ2 ) dt, neither firm has dropped out at time t,
and firm 1’s payoff is π d1 .
With probability density σ 1 (t) e−(Σ1 +Σ2 ) dt, firm 1 drops out at time t, firm 2
has not yet dropped out, and firm 1’s value from that point onward is 0.
With probability density σ 2 (t) e−(Σ1 +Σ2 ) dt, firm 2 drops out at time t, firm 1
has not yet dropped out, and firm 1’s value from that point onward is V1m (t).
Firm 1’s expected value at time t during the integration period if both firms
are active is
Z ∞
¤
£
d
e−[rτ +Σ1 (τ )+Σ2 (τ )] σ 1 (0) + σ 2 V1m (τ ) + π d1 (τ ) dτ
V1 (t) =
t
15
For a similar formulation in another context, see Fudenberg et al. (1983).
26
=
Z
∞
t
In the same way
V2d
(t) =
£
¤
e−[rτ +Σ1 (τ )+Σ2 (τ )] σ 2 V1m (τ ) + π d1 (τ ) dτ .
Z
t
∞
£
¤
e−[rτ +Σ1 (τ )+Σ2 (τ )] σ 1 V2m (τ ) + π d2 (τ ) dτ .
(5.14)
(5.15)
In order for the firms to be willing to play mixed strategies, these expected
values must be zero, which requires that
σ 1 (ι) =
−π d2 (ι)
V2m (ι)
σ 2 (ι) =
−π d1 (ι)
.
V1m (ι)
(5.16)
Given our assumptions, these are both numbers between zero and one and so are
valid withdrawal probabilities.
(C) Now suppose both firms are in the market at any integration level between ιd1
and ιd2 . Firm 2 will stay in: it will make money up to integration level ιd2 even if
firm 1 stays in, and at worst break even thereafter. Firm 1 will play out, since it
would lose money up to integration level ιd2 and break even thereafter. Suppose
then that both firms are in the market at integration level ιd1 . Firm 1 will play
out, since it will lose money as long as it stays in over integration levels ιd1 to ιd2
and break even thereafter if both firms are in the market at integration level ιd2 .
Firm 2 will stay in, since it will make money over the period ιd1 to ιd2 and break
even thereafter if both firms are in the market at integration level ιd2 .
This completes the proof.
5.2. Welfare
We write lower-case letters to denote flow values, with upper-case letters reserved
for integrals of flow values.
5.2.1. Integration levels 0 to ιd1
Flow profits per firm π di are given by (5.5). The inverse demand curves (3.4) are
implied by an aggregate gross welfare equation
¢
1 b ¡ 2
a (q1 + q2 ) −
(5.17)
q1 + 2ιq1 q2 + q22 .
21+ι
If both firms produce the output qd given by (3.24), (5.17) becomes
2aqd − bqd2 .
27
(5.18)
Taking account of the cost of production, net aggregate welfare under duopoly
during the integration period is
¶2
µ
(1 + ι) (3 + ι) a − c
2
− (F1 + F2 ) , (5.19)
2 (a − c) qd − bqd − (F1 + F2 ) = b
b
(2 + ι)2
with flow net aggregate welfare in country i
wid
1 (1 + ι) (3 + ι)
(ι) = b
2
(2 + ι)2
µ
a−c
b
¶2
− Fi .
(5.20)
Subtracting πdi , from (5.5), from wid (ι), flow consumer surplus in country i during
the integration period if both firms are active is
µ
¶2
1
1+ιa−c
1
d
si (ι) = b
(5.21)
= bqd2 .
2
2+ι b
2
5.2.2. Integration levels ιd1 to 1
In equilibrium, firm 1 drops out at integration level ιd1 . Firm 2 maximizes profit
on the inverse demand equation
p2 = a −
b
q2 .
1+ι
(5.22)
Firm 2’s profit-maximizing output is
qm (ι) = (1 + ι)
a−c
= (1 + ι) qm ,
2b
(5.23)
where by modest abuse of notation we write
qm =
a−c
2b
(5.24)
for pre-integration monopoly output in the component markets. Firm 2’s payoff
is
µ
¶2
a−c
m
π 2 (ι) = (1 + ι) b
− F2 .
(5.25)
2b
Price is
p2 = c +
1
(a − c) .
2
28
Country 1 consumers who are in the country 1 market only buy nothing, and
their surplus welfare is zero.
Country 2 consumers who are in the country 2 market only buy
(1 − ι)
a−p
1a−c
= (1 − ι)
b
2 b
and their surplus welfare is
"
µ
µ
¶2 #
¶2
1
1a−c 1
1a−c
1a−c
− b
= (1 − ι) b
.
(1 − ι) (a − p)
2 b
2
2 b
2
2 b
Consumers (of both countries) who are in the integrated market buy
µ
¶
a−p
a−c
ι2
= ι2
.
b
2b
Their surplus welfare is
"
µ
µ
µ
¶
¶2 #
¶2
a−c
a−c
a−c
1
= ιb
ι (a − p) 2
.
− b (4)
2b
4
2b
2b
Half of this accrues to consumers in each country:
µ
¶2
1
a−c
ιb
.
2
2b
The rate of consumer surplus in country 2 if firm 1 has dropped out of the
market:
sm2
2 (ι) =
µ
µ
µ
¶2
¶2
¶2
a−c
a−c
a−c
1
1
1 2
1
+ι b
= b
= bqm
.
(5.26)
(1 − ι) b
2
2b
2
2b
2
2b
2
Firm 2’s profit rate if firm 1 has dropped out of the market is given by (5.25).
The rate of net social welfare in country 2 if firm 1 has dropped out of the
market is the sum of firm 2’s profit and country 2 consumers’ surplus:
µ
µ
¶2
¶2
a−c
1
b
a−c
2
m2
w2 (ι) = (1 + ι) b
− F2 . (5.27)
− F2 + b
= (3 + 2ι) qm
2b
2
2b
2
29
Flow aggregate welfare and consumer surplus in country 1 if firm 1 has dropped
out of the market:
µ
¶2
a−c
1
1 2
m2
.
(5.28)
s1 (ι) = ι bqm = ι b
2
2
2b
If, in contrast, firm 1 should be the surviving supplier, economic profit during
the integration period goes to firm 1 and it is all country 1 consumers that are in
the market, while a fraction 1 − ι of country 2 consumers are out of the market.
The resulting welfare rates are:
Firm 1’s payoff:
µ
¶2
a−c
m
π 1 (ι) = (1 + ι) b
− F1 .
(5.29)
2b
Country 1 consumer surplus:
1 2
sm1
1 (ι) = bqm .
2
(5.30)
Country 1 net aggregate welfare:
w1m1 (ι) =
b
2
(3 + 2ι) qm
− F1
2
(5.31)
Country 2 net aggregate welfare, which is also the rate of country 2 consumer
surplus, since firm 2 has exited:
1 2
w2m1 (ι) = sm1
2 (ι) = ι bqm
2
(5.32)
5.2.3. Fully integrated market
If one firm supplies the fully integrated market, monopoly output is
I
=
qm
a−c
= 2qm .
b
(5.33)
Monopoly profit is
2
2
πm
i (1) = 2bqm − Fi = 2bqm − Fi .
(5.34)
Consumer surplus in both countries is
2
smi (1) = bqm
,
30
(5.35)
and consumer surplus in each country is half this.
If both firms supply the fully integrated market, flow profits per firm (not
taking account of any subsidies) are
µ
¶2
2a−c
1
d
πi (1) = b
− Fi
2
3 b
8 2
= bqm
− Fi .
(5.36)
9
Given the assumptions we have made about demand and technology, (3.11), flow
profits are negative.
Consumer surplus in the fully integrated market with both firms active is
¶2
µ
16
2a−c
d
(5.37)
= b (qm )2 .
s (1) = b
3 b
9
Half of this accrues to consumers in each component market. Net social welfare
in the integrated market is the sum of profits and consumer surplus; net social
welfare in each component market is the sum of the profit of the home firm and
the surplus of domestic consumers.
5.2.4. Discounted values
No subsidies Firm 1’s equilibrium discounted duopoly payoff from the start
of the integration period (suppressing the functional dependence of ι on time for
notational compactness) is
Π1 =
Z
0
td1
e−rt π d1
µ
a−c
(ι) dt = b
b
¶2 Z
td1
0
e−rt
³
´
1+ι
−rtd1
dt
−
F
1
−
e
(5.38)
1
(2 + ι)2
This is firm 1’s discounted profit from time 0 to time td1 , at which time it exits.
Firm 2’s equilibrium discounted value is
Z td1
Z T
m
−rt d
−rT π i (1)
.
(5.39)
e π 2 (ι) dt +
e−rt π m
(ι)
dt
+
e
Π2 =
2
r
td1
0
This is firm 2’s duopoly profit from time 0 to time td1 , its monopoly profit in the
partially integrated market from time td1 to time T , and its monopoly profit in the
fully-integrated market, all appropriately discounted.
31
Equilibrium discounted consumer surplus, by country, is
S1 =
Z
td1
0
e−rt sd1
(ι) dt +
Z
T
td1
−rT
e−rt sm2
1 (ι) dt + e
1 mi
s
2
(1)
r
#
1 2
1
dt +
bq .
e−rt ιdt + e−rT
e−rt
r
2 m
td1
0
Z ∞
Z T
Z td1
−rt m2
−rt d
e−rt sm2
e s2 (ι) dt +
e s2 (ι) dt +
S2 =
2 (1) dt
" Z
= 4
µ
td1
1+ι
2+ι
¶2
Z
T
td1
0
µ
¶2 Z
T
µ
¶2
Z
1 2 ∞ −rt
1+ι
e dt
e
dt + bqm
2+ι
2
td1
0
#
µ
¶2
td1
1
1
+
ι
1 2
d
= 4
e−rt
bq .
dt + e−rt1
2+ι
r 2 m
0
td1
1
a−c
= b
2
b
" Z
−rt
(5.40)
(5.41)
Net social welfare by country is the sum of profit and consumer surplus by
country.
Subsidy by country 1 The present value of the lump-sum subsidy that allows
country 1 to break even over integration levels ιd1 to ιd2 is the negative of firm 1’s
losses over that interval,
#
"
µ
¶2
Z td2
Z td2
1
+
ι
a
−
c
b
(5.42)
L11 =
− F1 dt,
e−rt πdi (ι) dt =
e−rt
d
d
1+ι 2+ι b
t1
t1
where the superscript “1” indicates that country 1 grants a subsidy.
If firm 1 receives such a subsidy and firm 2 receives no subsidy, firm 1’s discounted payoff is the discounted sum of its duopoly payoffs to time td1 , zero from
time td1 to time td2 (when firm 2 exits), and its monopoly profit thereafter,
Π11
=
Z
td1
=
Z
td1
0
0
−rt
e
e−rt π di
(ι) dt +
"
µ
b
1+ι
Z
td2
−rt
e
(0) dt +
td1
1+ιa−c
2+ι b
Z
T
td2
¶2
#
− F1 dt +
32
−rT
e−rt π m
1 (ι) dt + e
Z
T
td2
πm
1 (1)
r
¤
£
2
e−rt (1 + ι) bqm
− F1 dt
2
− F1
2bqm
.
(5.43)
r
Discounted consumer surplus in country 1 if firm 1 receives the subsidy is
Z td2
1 2
d bq
1
S1 =
e−rt sd1 (ι) dt + e−rt2 2 m .
r
0
+e−rT
Firm 2’s discounted payoff if firm 1 receives the subsidy is
¶2 Z td
µ
Z td2
³
´
2
a−c
−rt 1 + ι
1
−rtd2
−rt d
Π2 =
e
dt − F2 1 − e
. (5.44)
e π 2 (ι) dt = b
b
(2 + ι)2
0
0
Discounted consumer surplus in country 2 if firm 1 receives the subsidy is
Z T
Z td2
1 mi
(1)
−rt m1
−rT 2 s
−rt d
1
S2 =
e s2 (ι) dt + e
e s2 (ι) dt +
.
(5.45)
r
td2
0
Subsidy by both countries The present value of the subsidy by country i is
the negative of the losses of the home country firm,
Z 1
d
12
−rt d
−rT π i (1)
,
(5.46)
Li =
e π i (ι) dt + e
r
tdi
for i = 1, 2.
The present values of firm payoffs are
Z td1
12
Π1 =
e−rt π d1 (ι) dt
(5.47)
0
and
Π12
2
=
Z
0
td2
e−rt π d2 (ι) dt,
(5.48)
respectively.
Discounted consumer surplus in the subsidized duopoly, by country, (see (5.21))
is
Z 1
sd (1)
12
Si =
,
(5.49)
e−rt sdi (ι) dt + e−rT i
r
0
for i = 1, 2.
Net social welfare in each country is the sum of discounted profit and discounted consumer surplus, minus the discounted amount of the subsidy.
33
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