• Aucun résultat trouvé

Learning and Collusion in New Markets with Uncertain Entry Costs∗

N/A
N/A
Protected

Academic year: 2022

Partager "Learning and Collusion in New Markets with Uncertain Entry Costs∗"

Copied!
28
0
0

Texte intégral

(1)

Learning and Collusion in New Markets with Uncertain Entry Costs

Francis Bloch

Ecole Polytechnique

Simona Fabrizi

Massey University

and

Steffen Lippert

University of Otago

August 17, 2011

Abstract

This paper analyzes an entry timing game with uncertain entry costs. Two firms receive costless signals about the cost of a new project and must decide when to invest. We characterize the equilibrium of the investment timing game with private values, private and public signals. We show that competition leads the two firms to invest too early and analyze collusion schemes whereby one firm prevents the other firm from entering the market. We show that, in the efficient collusion scheme, the active firm must transfer a large part of the surplus to the inactive firm in order to limit preemption.

JEL Classification Codes: C63, C71, C72, D82, D83, O32 Keywords: Learning; Preemption; Innovation ; New Markets ; Entry Costs ; Collusion ; Private Information

We are grateful to seminar participants at Erasmus University, Queen Mary, the Paris

School of Economics for helpful comments. We want to thank particularly Rossella Argen-

ziano, Nisvan Erkal, Emeric Henry, Hodaka Morita and Francisco Ruiz Aliseda for their

help and support.

(2)

1 Introduction

The development of new products and processes, the access to new markets are characterized by a high degree of uncertainty. Firms engage in long research process and accumulate information about the cost and benefits of the project before actually investing in new products or entering new markets. Project selection is often very fierce, and very few projects end up being implemented. For example, in the pharmaceutical industry, only a very small fraction of the molecules which are tested end up being patented.

A realistic description of investment in new products and markets must allow for learning about the cost and benefit of the investment.

When different firms or research teams compete to enter a new market, the dynamics of learning and competition may become very complex. Signals received by competitors may transmit information about the profitability of the market, affecting the incentives to acquire information and the speed of investment in the project. A further distinction exists between situations where information received by competitors is made public or kept private.

In the first case, information becomes a public good, resulting possibly in free-riding and low levels of information acquisition. In the second case, participants in the race must control the diffusion of information that their actions convey to their opponents, resulting in complex investment dynamics.

In particular, private information may lead to preemption and accelerate the race between the competitors.

In this paper, our objective is to better understand the interplay between learning and preemption in entry timing games, and to study simple mecha- nisms of collusion between firms. We contrast the outcome of an entry game among firms which cooperate in project selection, and between competitors with public and private information. We consider a simple compensating pay- ment cooperation mechanism, whereby one of the two firms pays the other team to stay out of the market, and show when this compensating payment enables firms to reach the collusive outcome.

Our analysis is motivated by situations where firms are engaged in inno- vation races to launch a new product, and upon success, one of the two teams is acquired by the other so that a single firm extracts the monopoly profit of the innovation. For example in the late 1990s and early 2000s, the computer industry saw an acquisition frenzy in which firms were bought out even before they had an initial success. After acquiring a Switch maker in 1993 (switches were the main competition to their core business, routers), Cisco acquired 69 companies between 1995 and 2000 (more than eleven companies per year).

Many of these acquisitions were early stage acquisitions that turned out not

(3)

to be viable. Cisco often did not learn about their targets: They bought out potential competitors early, before knowing whether or not their own R&D strategy is better. Subsequently, Cisco switched to an acquisition strategy, in which it acquired fewer, but more mature companies, after learning about their potential. 2

Similarly, threatened by looming patent expiry for blockbuster drugs as well as by competition from generics, and facing a declining product pipeline due to low in-house R&D productivity, big pharmaceutical com- panies have recently been acquiring biotechnology companies. For example, in 2009 Hoffmann-La Roche acquired the biotech company Genentech for nearly $47bn. Merck & Co. purchased a follow-on biologics platform from Insmed in 2010. However, contrary to Cisco in the 1990s and early 2000s, these pharmaceutical companies did these acquisitions in order to access their targets’ existing early-stage successes. This seems to suggest that competing teams sometimes wait until there is a success signal in early phases of the R&D process and then purchase their potential competitor.

On the other hand, in the pharmaceutical industry, companies at times engage in what to outside observers seems wasteful investment: Several phar- maceutical companies target the same biological mechanism with different molecules, leading to several drugs with the same therapeutic indications. 3 The phenomenon is called “me-too” drugs, and the presumption is that, after they see a competitor succeed with a particular mechanism, pharmaceutical companies engage in imitation and invest in finding a different molecule that target this mechanism. However, contrary to this commonly held belief, DiMasi and Faden (2011) show that many “me-too” drugs are not the re- sult of one company imitating another, but of parallel research targeting the same mechanism, with no one knowing which drugs will work until they have cleared their regulatory trials, often in rapid succession. 4 In these cases, it seems firms fail to cooperate and instead invest in competition with each other.

We construct a model of entry where firms initially ignore the fixed cost of entry. They gradually acquire signals about the entry cost through research

2

Between 2001 and 2003, they only acquired 10 companies.

3

For example, in the U.S., more than six anti-cholesterol drugs on the market, from Crestor to Zocor, are frequently advertised on television. The market for male sexual enhancements started with Pfizer Inc.s Viagra and now includes two other drugs, Cialis marketed by Eli Lilly and Co. and Levitra, which is sold by a partnership of GlaxoSmithK- line and Bayer Pharmaceuticals Corp.

4

See DiMasi and Faden (2011); and Economist article entitled “Me too! Me too!” (Apr

17, 2007; http://www.economist.com/blogs/freeexchange/2007/04/me_too_me_too).

(4)

and experimentation. We consider here the case of private values, where the profitability of entry differs across firms (as would be the case if uncertainty primarily involves the private cost of investment) and not the case of common values, where the profitability of innovation is the same for all teams (as would be the case if uncertainty primarily involved the value of the new market).

Our model results in project selection. In the cooperative outcome, only the most profitable firm should be allowed to enter. We show that com- petition results in preemption, as the two firms may, for some parameter values, choose to invest too early, before they learn the entry cost whereas it would have been optimal for them to wait until they learn their cost. If signals on entry costs are public, compensating payments can be used to en- force monopolization of the market. If the signals are private, firms do not observe whether their opponent has dropped from the race or not. Hence, over time, if they don’t observe investment by their opponent, teams become more optimistic as they believe that with high probability their opponent has decided not to invest (”no news is good news”). This dynamics of beliefs will eventually lead a firm to invest before it has learned the profitability of the innovation, aggravating preemption and resulting in an inefficient accel- eration of the entry race. Compensating payments can be designed in order to mitigate this preemption effect and lead to market monopolization. We characterize a lower and upper bound on the share of the surplus which is transferred to the firm which drops out of the race, and show that the optimal compensating payment will typically involve a large share of the surplus to be transferred to the trailing firm. However, the compensating payment cannot restore efficiency in all circumstances, and in fact, there exist states where no efficient, budget balanced, individually rational and incentive compatible mechanism can be designed.

Our analysis sheds light on situations of project selection, where two

independent firms run parallel research programs and a third party can en-

force a cooperative scheme to prevent inefficiencies. The third party can for

instance be a venture capitalist or a granting agency running competing re-

search projects, the editor of an academic journal or organizer of a scientific

conference who discovers that two teams of scientists are working on the same

problem. Our analysis suggests that selection should neither occur too early

(before the profitabilities of the projects are known), nor too late (when the

firms have become very optimistic about their prospects given that the other

firm has not entered). It also shows that the share of the surplus transferred

to the firm which is not selected should neither be too large (in which case

the selected firm may have an incentive to delay the research project) nor too

(5)

small (the higher the payoff transferred to the firm which is not selected, the smaller the gap between the payoffs of the leading and trailing firms, which reduces inefficiencies due to excess momentum.)

Our analysis is rooted in the literature on patent races in continuous time

pioneered by Reinganum (1982) and Harris and Vickers (1985). The first ex-

tensions of patent races allowing for symmetric uncertainty are due to Spatt

and Sterbenz (1985), Harris and Vickers (1987) and Choi (1991). Models

of learning in continuous time with public information have been studied by

Keller and Rady (1999) and Keller, Cripps and Rady (2005). Rosenberg,

Solan and Vieille (2007) and Murto and Valimaki (2010) extend the model

to allow for public signals. The model of preemption we consider is for-

mally closely related to Fudenberg and Tirole (1985)’s models of technology

adoption with preemption. Innovation timing games which can result either

in preemption or in waiting games have been studied by Katz and Shapiro

(1987). Hoppe and Lehmann-Grube (2005) propose a general method for

analyzing innovation timing games. Fudenberg and Tirole (1985)’s model

has been extended by Weeds (2002) and Mason and Weeds (2010) to allow

for stochastic values of the technology. However, none of these models allows

for private information. The closest papers to ours are the recent papers

by Hopenhayn and Squintani (2010) on preemption games with private in-

formation and Moscarini and Squintani (2010) on patent races with private

information. Moscarini and Squintani (2010) analyze a common values prob-

lem, where agents learn about the common arrival rate of the innovation. Our

model with common values shares the same characteristics as theirs, albeit

in a much simpler setting, and the results are closely related. Our model

with private values and preemption displays very different results. Hopen-

hayn and Squintani (2011)’s model is much more general than ours but only

covers situations where agents receive positive information over time. In our

model, research teams may either receive positive or negative signals about

the profitability of the research project, so that the results of Hopenhayn and

Squintani (2011) do not directly apply. However, the spirit of the analysis is

very similar, and we outline in the body of the paper the similarities and dif-

ferences between their results and ours. Cooperation among research teams

with private information has been studied in a mechanism design contest

by Gandal and Scotchmer (1993). In ongoing work, Akcigit and Liu (2011)

study cooperation in a patent race with learning and private signals, where

cooperation involves the disclosure of private signals.

(6)

2 The Model

2.1 Firms, new markets and entry costs

We consider two firms which may invest in order to enter a new market, launch a new product or exploit a new process. The monopoly and duopoly profits obtained after investment are fixed and given by π m and π d respec- tively. We suppose that π m > 2π d . The entry cost to the new market is uncertain, and can either take a high or low value, θ i = θ or θ i = θ. We consider the case of private values where costs are independently distributed among the two firms. Assuming that the two values of the cost are equiprob- able, the expected value of the entry cost is θ e = θ+θ 2 for both firms.

During the experimentation phase, each firm receives a costless perfectly informative signal about its cost according to a Poisson process with intensity µ. Hence, the probability that a firm receives a signal during the interval [0, t] is 1 − e −µt . With probability 1 2 the firm learns that it is of high type, and with probability 1 2 , it learns that it is of low type. We assume that the Poisson processes generating signals to the two teams are independent.

In the private values case, independence furthermore means that the signals received by the two teams are independent. In the common values case, the signals which are perfectly informative, are not independent.

We assume that high cost firms never have an incentive to invest, even if they receive monopoly profit. Low cost firms always have an incentive to invest, even if they receive duopoly profit. When entry cost remains unknown, research teams have an incentive to invest as monopolists but not as duopolists. Formally,

Assumption 1

θ ≤ π d ≤ e θ ≤ π m ≤ θ. (1)

2.2 Entry timing and strategies

At any date t = 0, ∆, 2∆, ..., both firms can choose whether to enter the market. (We will analyze situations where the time grid becomes infinitely fine, and ∆ converges to zero.) If team i enters the market, it pays the fixed cost θ i and starts collecting monopoly (or duopoly) profits immediately.

Investments to enter the market are immediately observed by the other firm.

Given Assumption 1, it is a dominant strategy for a high cost firm not

to invest. Hence, the only relevant choices are choices made by a firm which

learns that its cost is low, or by a firm which still ignores its entry cost. A

(7)

strategy specifies, after every possible history, a pair of probabilities with which the firm invests when it learns that its cost is low and when it ignores its cost. We consider perfect equilibrium strategies which maximize the firm’s expected discounted payoff after every possible history.

2.3 Cooperative benchmark

If the two firms cooperate, they either choose to enter immediately, and earn an expected profit of π m − θ, or wait until they identify whether one firm has e a low entry cost, and obtain an expected profit of

V C = µ

2µ + r (π m − θ)(1 + µ 2(µ + r) ).

The optimal cooperative choice depends on the values of the parameters.

Clearly, the incentive to experiment rather than enter immediately is increas- ing in the difference between the costs θ e and θ, and in the intensity of the Poisson process generating signals, µ. It is decreasing in the discount rate r and in the value of the monopoly profit π m . Finally, notice that if a single firm is present on the market, it will only be able to experiment with one of the two research processes, and obtain an expected payoff by experimenting given by

V O = µ

2(µ + r) (π m − θ).

This expected payoff is lower than the expected payoff obtained by two cooperating firms for two reasons. First, by experimenting in parallel, the two firms accelerate the rate at which signals arrive, as the Poisson process generating signals now has intensity 2µ instead of µ. Furthermore, in the private values case we consider, by experimenting on two projects in parallel, the teams draw two independent signals about the costs. In other words, even if the first team receives a signal that it has a high cost, there is a positive probability as the second team receives a signal that it has a low cost and implements the project.

2.4 Leader and follower payoffs

Suppose that one firm (the leader) invests first. In the private values model,

the second firm (the follower) will only follow suit if it learns that its cost is

low. Hence the expected value of the follower is given by

(8)

V F = µ

2(µ + r) (π d − θ).

The leader thus extracts monopoly profit as long as the other firm has not entered, and we compute the value of the leader after investment as:

V L = π m − µ

2(µ + r) (π m − π d )

3 Entry timing

3.1 Entry timing with public signals

We suppose that the signals received by the two firms during the experimen- tation phase are public. We first establish that a firm which learns that its cost is low invests immediately. Depending on the parameters, a firm which has not yet learned its cost will either choose to preempt at zero or to wait until it learns that its cost is low. In the preemption case, both firms invest with positive probability at zero, resulting in coordination failures. In the waiting game, we show that, because the leader’s and follower’s payoffs are independent of time, the equilibrium strategy is for both firms not to en- ter before they learn the value of their costs. Summarizing, we obtain the following characterization of equilibrium.

Proposition 1 In the entry timing game with public information, a firms which learns that its cost is low invests immediately. If V L − e θ > V F , pre- emption occurs and (i) a firm which ignores its cost invests with positive probability at any date t = 0, ∆, ... whenever the other firm has not invested and (ii) a firm invests immediately after it learns that the other firm has a high cost. If V L − θ < V e F , firms do not enter unless they learn that their cost is low.

Proposition 1 shows that the entry timing game is either a preemption

game (when V L − θ > V e F ), or a waiting game (when V L − e θ < V F ). Notice

that V F − V L = V O − π m < V C − π m . Hence, as compared to the cooperative

benchmark, competition results in excess momentum. In the competitive

entry timing game, firms have an incentive to invest too early, before they

learn the true value of their cost.

(9)

3.2 Entry timing with private signals

When signals are private, teams do not learn whether the other team has drawn a bad or good signal about its cost. Each firm holds beliefs γ t (θ) about the cost of the other firm. These beliefs evolve over time given the strategies and the observation of investments. In order to compute the beliefs, we let G(t, τ ) denote the probability that a firm which learns that its cost is low at date τ invests at t ≥ τ, and g (t, τ ) the instantaneous probability that the firm invests at date t. We also let h(t) denote the instantaneous probability that a firm which ignores its cost invests exactly at date t. Using Bayes’ rule, the beliefs at period t are then given by:

γ t (θ) = R t

0 [1 − G(t, τ )]µe −µτ

A(t) ,

γ t (θ) = 1 − e −µt A(t) , γ t (e θ) = 2[e −µt − R t

0 e −µτ h(τ )]

A(t) where

A(t) = Z t

0

[1 − G(t, τ)]µe −µτ dτ + 1 − e −µt + 2[e −µt − Z t

0

e −µτ h(τ )].

We first establish that a firm which learns that its cost is low has an incentive to invest immediately:

Lemma 1 In the entry timing game with private signals, a firms which learns that its cost is low has an incentive to enter immediately.

Lemma 1 enables us to focus attention on situations where beliefs only involve situations where a firm has learned that its cost is high, or ignores its cost. In other words, we now consider beliefs:

γ t (θ) = 0,

γ t (θ) = 1 − e −µt 1 + e −µt − 2 R t

0 e −µτ h(τ) , γ t (e θ) = 2[e −µt − R t

0 e −µτ h(τ )]

1 + e −µt − 2 R t

0 e −µτ h(τ) .

(10)

It is easy to check that γ(t)(θ), increases over time. As t increases, the probability that the competing firm has a high entry cost increases. No news is good news: as time passes, each firm becomes more pessimistic about the cost of the other firm and thus more optimistic about its own prospects. This dynamics of beliefs is the driving force behind the dynamics of the model, as it ensures that firms which ignore their costs will eventually find it profitable to invest because they believe that the other firm has drawn a high cost and will never invest with high probability.

In order to characterize equilibrium strategies, we compute the expected discounted payoff of the leading team which is the first to invest at time t:

V L (t) = γ(t)(θ) + pi m γ(t)(e θ)V L = π m − γ(t)(e θ) µ

2(µ + r) (π m − π d ).

Because γ(t)(e θ) is decreasing over time, the value of the leader is increas- ing over time. As time passes, firms become more optimistic, and the value of the leader increases from V L = V L (0) to π m = lim t∞ V L (t). Notice that the value of the follower, V F , remains independent of time. In order to analyze the equilibrium entry times, we distinguish between three cases: (i) Case 1 when V L − θ > V e F ; (ii) Case 2 when π m − θ e ≥ V F ≥ V L − θ; and (iii) Case 3 e when V F > π m − θ. The three cases are illustrated below: e

Cases 1 and 3 correspond to the preemption and waiting cases in the timing game with public signals. Case 2 exploits the fact that beliefs evolve over time, and describes a new situation which is similar to the preemption game studied by Fudenberg and Tirole (1985). The expected payoff of the leading firm is initially lower than the expected payoff of the following firm, but is increasing over time and eventually becomes higher than the payoff of the following firm. As in Fudenberg and Tirole (1985), the unique subgame perfect equilibrium results in rent equalization. One firm invests at the first time at which the payoff of the leading firm is higher than the payoff of the following team, V L (˜ t) − θ e = V F . Formally,

Theorem 1 In the entry timing game with private signals, a firm which

learns its cost invests immediately. If V L − e θ > V F , preemption occurs at the

beginning of the game and both teams invest with positive probability at time

0. If π m − θ e ≥ V F ≥ V L − θ, in a symmetric equilibrium, rents between the e

leader and the follower are equalized and each firm invests with probability

(11)

Figure 1: Case 1: V L − e θ > V F

1

2 at time t ˜ such that: V L (˜ t) − θ e = V F . If V F > π m − θ, firms do not enter e unless they learn that their cost is low.

Theorem 1 shows that when signals are private, excess momentum due to preemption is higher than when signals are public. When π m − θ e ≥ V F ≥ V L − θ, firms do not invest before learning their cost when signals are public, e but rush to invest at time ˜ t when information about costs are private.This incentive to preempt earlier with private signals than with public signals is different from the result of Hopenhayn and Squintani (2011) who show that preemption is stronger with public signals than with private signals, when new information can only lead to improvements. In their model, publicity of information strengthens competition between agents, and results in higher preemption. In our model, publicity of information reduces competition as firms learn that the other firm is out of the market, and reduces preemption.

We now focus on Case 2 and analyze how the preemption time ˜ t depends on the parameters of the model. The preemption time is implicitly defined as the unique solution to the equation:

π m − µ

2(µ + r) π d − µ

µ + r (π m − π d ) e −µt 1 + e −µt − θ

2 − θr

2(µ + r) = 0. (2)

Implicit differentiation of equation (2) immediately results in the following

comparative statics:

(12)

Figure 2: Case 2: π m − e θ ≥ V F ≥ V L − θ e π m -

π d +

θ +

θ +

r -

µ ?

Table 1: Preemption time ˜ t – Comparative statics

An increase in the monopoly profit π m increases incentives to preempt and

results in a lower preemption time ; conversely, an increase in the duopoly

profit π d reduces incentives to preempt and lengthens preemption time. An

increase in entry costs (both θ and θ) makes entry more costly and results

in longer delays before preemption. When firms become less patient (r in-

creases), preemption time decreases. Changes in the Poisson arrival rate µ

have ambiguous effects, as an increase in µ simultaneously increases the pay-

off of the leader V L (t) and of the follower V F . For small values of µ, (µ close

to zero), the magnitude of the marginal effect of an increase in µ is higher

on the follower payoff than on the leader payoff, so that the preemption time

increases with µ. For large values of µ, (µ close to infinity), the comparison

is reversed, so that the preemption time decreases with µ.

(13)

Figure 3: Case 3: V F > π m − θ e

3.3 Efficiency comparison

We now compare the industry profits in the three r´ egimes of cooperation, competitive entry with public signals and competitive entry with private signals. We distinguish between four parameter regions, depending on the magnitude of the expected entry cost e θ:

1. −e θ > V C − π m : immediate entry in the cooperative r´ egime, and pre- emption at zero in both competitive r´ egimes

2. V C − π m > −e θ > V F − V L : delayed entry in the cooperative r´ egime, and preemption at zero in both competitive r´ egimes

3. V F − V L > −e θ > V F − π m : delayed entry in the cooperative r´ egime and in the competitive r´ egime with public signals, preemption at finite time ˜ t in the competitive r´ egime with private signals

4. V F − π m > −e θ: delayed entry in all r´ egimes.

We define the industry profits when both firms delay their entry until they learn that their cost is low as:

V S = µ

2µ + r [(π m − θ) + µ

2(µ + r) (2π d − 2θ)]

(14)

and the industry profits with preemption at finite time ˜ t as:

V P = (1 − e −(2µ+r)˜ t )[ µ

2µ + r [(π m − θ) + µ

2(µ + r) (2π d − 2θ)]]

− e −(µ+r)˜ t (1 − e −µ ˜ t ) µ

2(µ + r) (π m − θ) + e −(2µ+r)˜ t 2 µ

2(µ + r) (π d − θ)

It is easy to check that V C > V S > V P > 2V F . The following table lists the industry profits under the three r´ egimes in the four parametric configurations:

parameter region cooperative public private

−e θ > V C − π m π m − θ e 2V F 2V F

V C − π m > −e θ > V F − V L V C 2V F 2V F V F − V L > −e θ > V F − π m V C V S V P

V F − π m > −e θ V C V S V S

Table 2: Efficiency comparisons

Table 2 illustrates the three sources of inefficiencies due to competition in our model of entry. First, by competing on the market, the firms forgo the benefits of market monopolization, the difference between monopoly profits, π m and the sum of duopoly profits, 2π d . Second, by competing on the market, the firms pay twice the entry cost θ, whereas in the cooperative benchmark, only one firm enters. Finally – and this is the new element of the model we wish to emphasize– competition results in excess momentum, making firms enter the market before they learn their cost, whereas in the cooperative benchmark, they should wait until they learn their cost before entering.

4 Market foreclosure and cooperation

In this section, we analyze cooperation mechanisms which would allow the firms to reach the cooperative outcome. We focus attention on compensating payment schemes which are paid by one firm in order to compensate the other firm for not entering the market. Compensating payment schemes could be implemented at three different points in time:

• ex ante: payments are made before the firms learn their entry cost

(15)

• at the interim stage: payments are made by one firm after it learns its cost, when it ignores the cost of the other firm

• ex post: payments are made after the costs of both firms are common knowledge.

The best timing of compensating payments depends on the specific para- metric configuration. If −e θ > V C − π m , compensating payments should be made ex ante in order to prevent inefficiencies due to market competition and duplication of entry costs. If V C − π m > −e θ, the cooperative benchmark is reached when one of the two firms learns that its cost is low and we argue that the best timing for compensating payments is the interim stage. At the ex ante stage, if one of the firm pays the other firm to leave the market, it still needs to run the other firm’s project in order to select the project with the lowest cost. This requires ongoing cooperation on the part of the managers of the firm which has been bought off, and agency problems will arise, which may limit the gains from cooperation. When signals are public, cooperation may happen at the ex post stage, with compensating payments being paid to the follower firm only when it learns that its cost is low. When signals are private and firms cannot credibly convey information about their entry cost, ex post compensating payments can only be made after the follower firm has entered the market. In that case, the entry cost of the follower firm has been sunk, so that it becomes impossible to alleviate the duplication of entry costs with payments at the ex post stage.

We now concentrate our attention to compensating payments made at the interim stage when V C − π m > −e θ and signals are private. First note that compensating payments should satisfy individual rationality and incentive compatibility. Hence the utility obtained by the leader after the compensat- ing payment is paid at date t, U L (t) and the utility obtained by the follower U F (t) should satisfy the following two conditions:

U L (t) ≥ V L (t), (3)

U F (t) ≥ V F (4)

The first inequality stems from the individual rationality constraint of the

leader, who may choose to forgo the compensating payment. The second

inequality results from the follower’s incentive compatibility and individual

rationality constraint. As the leader cannot verify information about the

follower’s type, he ignores whether the follower has received a high cost signal

or not, and must pay the follower the fixed payment V F corresponding to a

(16)

firm ignoring its cost. As compensating payments are budget balanced, the sum of utilities received by the leader and follower must exactly equal the monopoly profit:

U L (t) + U F (t) = π m (5)

Given inequalities (3), (4) and equation (5), a necessary condition for the existence of a budget balanced, individually rational and incentive compatible transfer scheme is

V L (t) + V F ≥ π m .

As V L (t) is increasing, V L (0) < π m − V F and V L (∞) > π m − V F , there exists a unique date t , such that no budget balanced individually rational compen- sating payments exist if the first firm enters at date t ≥ t . This remark captures the following simple intuition. As time passes, firms become more optimistic about their prospects. If a firm enters at a late date, it will expect the other firm to have left the race and will not be willing to compensate the other firm at the level V F , which is the minimal level at which a firm which ignores its cost is willing to leave the race. Furthermore, this remark shows that there is no efficient, budget balanced and individually rational co- operation mechanism. To see this, consider a realization of the signals where no firm has learned its cost before t . Either the mechanism prescribes that one of the team invests before t , and the mechanism is inefficient because it will result in a high cost team investing with positive probability, or the mechanism prescribes to wait until one of the firm has learned it has a low cost, and the mechanism is inefficient because there is no budget balanced, individually rational compensating payment which prevents the other firm from entering the race.

We now consider the following problem: How should compensating pay- ments be designed in order to guarantee that, whenever one firm learns that it has a low cost before t , it is chosen to be the only firm operating on the market?

Proposition 2 A differentiable compensating payment scheme U F (t) imple- ments the cooperative benchmark when a firm learns that it has a low cost before t if and only if for all t < t ,

π m − θ < e 2U F (t) < 2r + µ

r + µ π m + U F 0 (t)

r + µ

(17)

Proposition 2 shows that efficient compensating payment schemes must be balanced to satisfy two requirements. First, the payment to the follower must be large enough to prevent early entry by firms which ignore their costs.

Second, the payment to the follower should not be too large, in order to give incentives to a firm which learns that its cost is low to enter immediately.

These two requirements provide an upper and a lower bound on the expected payoffs of the follower and leader firm and show that the cooperative surplus must be shared in a balanced way between the two firms.

In order to provide additional intuition, we specialize the model by as- suming that the compensating payment scheme assigns a fixed bargaining power to the leader and the follower firm, so that

U L (t) = V L (t) + α(π m V L (t) − V F ), U F (t) = V F + (1 − α)(π m − V L (t) − V F ),

We observe that U L (t) is increasing and U F (t) decreasing over time. The following graph illustrates these mappings for α = 0 and α = 1. It displays the maximal time t at which compensating payments can be implemented, shows that payoffs are independent of time if all of the bargaining power is given to the leader and that the gap between the payoff of the leader and follower is increasing in α

The cooperative benchmark can be implemented when a firm learns that it has a low cost before t if and only if

2V F ≥ π m − θ, e (6)

2V F + 2(1 − α)(π m − V L − V F ) ≤ 2r + µ

r + µ π m − V L 0 (0)

r + µ . (7) These conditions put a lower bound (but no upper bound) on the share of the bargaining surplus accruing to the leader. Notice that if the first condition (6) fails, it is impossible to guarantee that no early preemption occurs before t . In that situation, the value of α can be manipulated in order to increase preemption time. By reducing α, and giving a larger share of the surplus to the follower, the mechanism designer reduces incentives to preempt and increases the value of ˜ t. 5 The optimal compensating payment

5

The fact that giving a prize to the loser of a contest may be efficient, as it reduces

the gap between the winner and the loser and minimizes wasteful expenditures, has long

(18)

Figure 4: Expected utilities with compensating payments mechanism is thus given by the lowest value of α for which condition (7) holds.

5 Conclusion

This paper analyzes a model of entry with learning. Two firms contemplate the entry into a new market, or the development of a new product and grad- ually learn about their private entry costs. We show that when signals are public, the model either results in a preemption game or a waiting game, and

been noted in the literature on contests. See Moldovanu and Sela (2008) for a recent

formalization of the problem and the references therein.

(19)

when signals are private, firms which ignore their cost may choose to enter at a finite time, resulting in the same rent equalization phenomenon as in Fu- denberg and Tirole (1985). As opposed to Hopenhayn and Squintani (2011), we find that preemption is greater when signals are private, as firms ignore whether the other firm has left the race or not. As compared to the collusive outcome, the equilibrium of the entry timing game exhibits three sources of inefficiencies: dissipation of the monopoly rent, duplication of entry costs and excess momentum. We analyze how compensating payments by one firm to prevent the other firm from entering the market can be implemented. We observe that collusion can only be effective if the first firm enters sufficiently early, and that compensating payments must allocate a significant share of the surplus to the excluded firm.

The model we consider is one instance of models of competition with

learning which have recently attracted considerable attention in economic

theory. There are two directions in which we would like to continue the anal-

ysis. First, in our model, teams do not choose the intensity of the Poisson

processes generating signals. We believe that a more general model, where

experimentation is endogenously chosen by the two firms is worth investigat-

ing. At a more abstract level, our model is an example of a situation where a

designer chooses a mechanism without knowing when the agents learn their

types. The general problem of mechanism design in a dynamic context where

agents gradually learn their types is the next item in our research agenda.

(20)

References

[1] Akcigit, U. and Liu, Q., 2011, Mechanism Design for Efficient Compet- itive R & D. Work in progress presented at AEA Meetings in Denver.

[2] Choi, J.P., 1991, Dynamic R&D Competition under ‘Hazard Rate’ Un- certainty. The RAND Journal of Economics 22, 596–610.

[3] Cripps, M., Keller, G. and Rady, S., 2005, Strategic Experimentation with Exponential Bandits. Econometrica 73(1), 39–68.

[4] DiMasi, J.A., and Faden, L.D., 2011, Competitiveness in follow-on drug R&D: a race or imitation? Nature Reviews Drug Discovery 10, 23–27.

[5] Fudenberg, D., and Tirole, J., 1985, Preemption and Rent Equalization in the Adoption of New Technology. The Review of Economic Studies 52(3), 383-401.

[6] Gandal, N., and Scotchmer, S., 1993, Coordinating Research through Research Joint Ventures. Journal of Public Economics 51(2), 173–193.

[7] Harris, C. and Vickers, J., 1985, Perfect Equilibrium in a Model of a Race. Review of Economic Studies 52, 193–209.

[8] Harris, C. and Vickers, J., 1987, Racing with Uncertainty. Review of Economic Studies 54, 1–21.

[9] Hopenhayn, H. and Squintani, F., 2011, Preemption Games with Private Information. Forthcoming, Review of Economic Studies.

[10] Hoppe, H.C. and Lehmann Grube, U., 2005, Innovation Timing Games:

A General Framework with Applications, Journal of Economic Theory, 121, 30-50.

[11] Katz, M. and Shapiro, C., 1987, R &D rivalry with licensing or imitation.

American Economic Review 77 (1987), 402420.

[12] Keller, G. and Rady,S., 1999, Optimal Experimentation in a Changing Environment. Review of Economic Studies 66(3), 475–507.

[13] Mason, R., and Weeds, H., 2010, Investment, Uncertainty and Preemp-

tion. International Journal of Industrial Organization 28(3), 278–287.

(21)

[14] Moscarini G. and Squintani, F., 2010, Competitive Experimentation with Private Information: The Survivor’s Curse. Journal of Economic Theory 145(2), 639–660.

[15] Murto, P. and Valimaki, J., 2010, Learning and Information Aggregation in an Exit Game. Forthcoming Review of Economic Studies.

[16] Reinganum, J.F., 1982, A Dynamic Game of R and D: Patent Protection and Competitive Behavior. Econometrica 50, 671–688.

[17] Rosenberg, D., Solan, E., and Vieille, N., 2007, Social Learning in One Armed Bandit Problems. Econometrica 75, 1591–1611.

[18] Spatt, C. and Sterbenz, F., 1985, Learning, Preemption and the Degree of Rivalry. RAND Journal of Economics 16, 85–92.

[19] Weeds, H., 2002, Delay in a Real Options Model of R&D Competition.

The Review of Economic Studies 69(3), 729–747.

(22)

A Proofs

Proof of Proposition 1: We first note that, if both firms learn that their cost is low, they have no incentive to delay their investment and will both invest immediately. Consider then a situation where firm i has learned that its cost is low and firm j has not learned its cost yet. We will show that it is a dominant strategy for firm i to invest immediately. If firm j invests, firm i obtains π d − θ by investing immediately and (1 − r∆)(π d − θ) ,by delaying its investment, and thus prefers to invest immediately. If firm j does not invest, and chooses to invest with probability p at period t + ∆, by delaying its investment until t + ∆, firm i will obtain a payoff:

W (t + ∆) = (1 − r∆)[(1 − µ∆)[(1 − p)V L + pπ d ] +µ∆ π d + π m

2 − θ]

Now

W (t + ∆) − (V L − θ) = −r∆(V L − θ) − µ∆(V L − π d + π m

2 )

−p(1 − r∆)(1 − µ∆)(V L − π d ) + O(∆ 2 ).

Note that

V L − π d + π m

2 = r

2(µ + r) (π m − π d ) > 0,

so that W (t + ∆) − (V L − θ) < 0, establishing that firms invest immediately after they learn that their cost is low.

Next, it is easy to check that a firms invests immediately after it learns that the other firm has high cost if and only if

π m − V O = π m − µ

2(µ + r) (π m − θ) = V L − V F ≥ θ e

Consider the investment game played by the two firms if none of them has invested up to date t and costs are not known:

invest not invest

invest (π d − θ, π e d − θ) e (V L − θ, V e F )

not invest (V F , V L − e θ) (W (t + ∆), W (t + ∆)

(23)

where

W (t+∆) = (1−r∆)[(1−2µ∆)W (t)+2µ∆ V L − θ + V F + max[V 0 , π m − θ] e

4 +O(∆ 2 ).

We first consider a symmetric equilibrium where both firms invest with positive probability p ∈ (0, 1). In that equilibrium,

W (t) = p(π d ) + (1 − p)V L − θ e and

W (t) = pV F + (1 − p)(W (t) + δ) Solving this equation, we find

p = V L − e θ − V F V L − π d ,

showing that an equilibrium with preemption exists if and only if V L −V F ≥ e θ.

Next, we consider a symmetric equilibrium in the waiting game when V L − V F ≤ θ. Notice that, by delaying investment one period, the firm e obtains a payoff:

W (t +∆) = (1− r∆)[(1−2µ∆)(V L − θ)+2µ∆ e V L − θ + V F + π m − θ e

4 +O(∆ 2 ).

Now notice that

V L − θ + V F = π m (µ + 2r) − θ(2 m u + 2r) + 2 md

2(µ + r) .

As π m > 2 p i d ,

π m (µ + 2r) + 2 md > 4π d (µ + r).

Hence,

V L − θ + V F > 2[π d − θ] = 4V F (µ + r)

µ .

As V F > V L − θ, e

(24)

µ

2 (V L − θ + V F + π m − θ) e > µ

2 (V L − θ + V F ),

> 2(µ + r)V F

> 2(µ + r)(V L − θ) e

> (2µ + r)(V L − θ), e

establishing that W (t + ∆) > V L − e θ, so that firms always have an incentive to wait.

Proof of Lemma 1: Suppose that firm i learns that its cost is low at date t.

If firm j invests at t, firm i obtains π d −θ by investing at t and (1−r∆)(π d −θ) by delaying investment. As π d − θ > 0, it has an incentive to invest. If firm j does not invest, and firm i invests at t, it obtains a discounted expected payoff:

W (t) = γ t (θ)π m + γ t (e θ)V L + γ t (θ)π d − θ.

By delaying investment until time t + ∆, the firm will obtain an expected discounted payoff:

W (t + ∆) = e −r∆ ([1 − Z t+∆

t

( Z t+∆

0

g(ρ, τ ) µ

2 e −µτ dτ + e −µρ h(ρ))dρ]

(γ t+∆ (θ)π m + γ t+∆ (e θ)V L + γ t+∆ (θ)π d − θ) +

Z t+∆

t

( Z t+∆

0

g(ρ, τ ) µ

2 e −µτ dτ + e −µρ h(ρ)dρ)(π d − θ)).

For small ∆, we have:

W (t + ∆) = [1 − r∆ − ∆ Z t

0

g(t, τ ) µ

2 e −µτ dτ − e −µt h(t)]W (t) + [π d ( ∂γ t (θ)

dt + π m ∂γ t (θ)

dt + V L ∂γ t (e θ) dt ]∆

+ ∆[

Z t

0

g(t, τ) µ

2 e −µτ dτ − e −µt h(t)](π d − θ).

We compute:

(25)

∂γ t (θ)

dt =

µ

2 e −µt − R t

0 g(t, τ ) µ 2 e −µτ

A(t) − A 0 (t)

A(t) γ t (θ),

∂γ t (θ)

dt =

µ 2 e −µt

A(t) − A 0 (t) A(t) γ t (θ),

∂γ t (e θ)

dt = −µe −µ

t

− e −µt h(t)

A(t) − A 0 (t) A(t) γ t (e θ) Hence

W (t + ∆) − W (t) = −r∆W (t) − ∆ µe −µt

A(t) [V L − π m + π d

2 ]

+ ∆ Z t

0

g(t, τ) µ

2 e −µτ dτ W (t) − π d

A(t) + ∆h(t)e −µt W (t) − π d

A(t) .

Notice that if h(t) = g(t, τ ) = 0, W (t + ∆) − W (t) < 0, so it never pays to delay investment if the other firm does not delay investment.

However, if the other firm delays investment (g(t, τ ) > 0 or h(t) > 0), a firm may benefit from delaying investment, as delaying will enable it to learn the type of the other firm. We now prove that in fact firms will never face a positive incentive to delay investment in order to learn the type of the other firm. To see this, consider now a firm which has not yet learned its cost and contemplates delaying its investment between t and t + ∆. We compute the discounted expected value of leaving at t as:

Y (t) = γ t (θ)π m + γ t (e θ)V L + γ t (θ)π d − θ. e

and the discounted expected value of leaving at t + ∆ as:

(26)

Y (t + ∆) = e −r∆ ([1 − Z t+∆

t

( Z t+∆

0

g(ρ, τ) µ

2 e −µτ dτ) + e −µρ h(ρ)dρ]

[e −µ∆t+∆ (θ)π m + γ t+∆ (e θ)V L + γ t+∆ (θ)π d − θ) e + 1 − e −µ∆

2 (γ t+∆ (θ)π m + γ t+∆ (e θ)V L + γ t+∆ (θ)π d − θ)]

+ ( Z t+∆

t

( Z t+∆

0

g(ρ, τ) µ

2 e −µτ dτ) + e −µρ h(ρ)dρ) [e −µ∆d − e θ) + 1 − e −µ∆

2 (π d − θ)]).

We compute:

Y (t + ∆) − Y (t) = −r∆Y (t) − ∆ µe −µt

A(t) [V L − π m + π d

2 ]

+ ∆ Z t

0

g(t, τ ) µ

2 e −µτ dτ W (t) − π d A(t) + +∆h(t)e −µt W (t) − π d

A(t) + ∆ θ − Y (t)

2 .

Hence,

(Y (t + ∆) − Y (t)) − (W (t + ∆) − W (t)) = r∆(W (t) − Y (t)) + ∆ θ − Y (t)

2 .

As Y (t) < W (t) and θ − Y (t) > 0, Y (t + ∆) − Y (t) > W (t + ∆) − W (t) for all t, ∆. Hence, a firm always has a stronger incentive to wait when it ignores its cost than when it knows that its cost is low. In particular, this implies that whenever g (t) > 0 (so that the firm is indifferent between investing at t and t + ∆ when it knows that its cost is low), than a firm must prefer to wait when it ignores its cost.

Suppose by contradiction that g(t, τ ) > 0 for some t, τ < t and let t = min{τ|g(t, τ ) > 0 for some τ < t} be the earliest date at which one of the firms delays its investment. By the previous argument, at t , a firm which ignores its cost must prefer to wait so that h(t ) = 0. Furthermore, by construction, R t

0 g(t , τ ) µ 2 e −µτ dτ = 0. But, as V Lπ

m

2

d

> 0, this implies

that

(27)

W (t + ∆) − W (t ) < 0,

contradicting the fact that a firm which learns its cost at t has an incentive to delay its investment.

Proof of Theorem 1: As in the proof of Proposition 1, we first note that, if V L − e θ ≥ V F , there exists an equilibrium where both firms preempt with positive probability at time t = 0 and at any time t > 0. Suppose next that V L − θ e ≤ V F and π m − θ e ≥ V F . Then there exists ˜ t > 0 such that V L (˜ t) − e θ = V F . By investing at t < ˜ t, a firm either obtains π d − θ < V e F (if the other firm invests) or V L (t) − θ < V e F (if the other firm does not invest). By investing at time ˜ t, the firm obtains V F . Hence it is a dominated strategy to invest at any time t < ˜ t. At any time t ≥ ˜ t, there is a preemption equilibrium where both firms invest with positive probability p(t) at date t.

At t converges to˜ t, the loss due to coordination failures converges to zero, so that at t = ˜ t, as in Fudenberg and Tirole (1985), rent equalization occurs and both firms receive an expected payoff of V L (˜ t) = V F .

Finally, suppose that π m − e θ < V F . We show that, any time t, the firm has an incentive to wait. If the firm waits one period before investing it will obtain a payoff of V F > π d − θ e if the other team invests. If the other team does not invest, it obtains a payoff of

V L (t) − θ e = γ t (θ)(π d − θ) + e γ t (e θ)(V L − θ) e by investing and

W (t + ∆) = (1 − r∆)W (t) + ∆h(t)e −µt (V F − W (t)) + ∆ mu

2 (V F + V L (t) − θ)

−3∆ mu

2 W (t) + ∆γ t 0 (θ)(π m − V L (t)).

by waiting one period. Now V F > W (t) and γ t 0 (θ) > 0. Furthermore,

V F + V L (t) − θ > V F + V L − θ > 4V F (µ + r)

µ > 4W (t)(µ + r)

µ .

Hence, µ

2 (V F + V L (t) − θ) > (2µ + 2r)W (t) > ( 3

2 µ + r)W (t),

showing that W (t + ∆) > W (t), so that the firm has an incentive to wait.

(28)

Proof of Proposition 2 In order to implement the cooperative benchmark, two conditions must be satisfied: (i) no firm must be willing to enter the market at t < t if it ignores its cost and (ii) a firm which learns that it has a low cost must be willing to enter the market immediately. The first condition will hold as long as :

U F (t) > U L (t) − θ e As U L (t) = π m − U F (t), this results in

2U F (t) > π m − θ. e

For the second condition to hold, we characterize the conditions under which an equilibrium where a firm immediately invests after it observes that its cost is low exists. The discounted expected payoff of investing at period t when the other firm does not invest is:

W (t) = U L (t) − θ,

whereas by waiting one period the firm will obtain a discounted expected payoff of

W (t + ∆) = e −r∆ [(1 − e −µ∆

2 )U F (t + ∆) + e −µ∆

2 U L (t + ∆)]

For ∆ small enough and assuming that utilities are differentiable, W (t + ∆) − W (t) = ∆[(−2r − µ)U L (t) + µU F (t) + U L 0 (t)]

so that the firm has an incentive to enter immediately if and only if:

2U F (t) < 2r + µ

r + µ π m + U F 0 (t)

r + µ .

Références

Documents relatifs

In this paper, we study how air-transportation services are to be structured to minimize their environmental costs or conversely, how environmental objectives are to be embodied in

In order to implement it, the regulator needs to observe the level of ambient pollution and to know the number of agents involved in the problem.. But neither the observation

In this paper we treat the optimum ordering policy with a constant lead time and two kind of order costs depending on time.. The analysis is done

[r]

None of the studies on DR programs, even the most recent (Orans et al., 2010; Chao, 2010), actually have provided theoretical underpinnings for the empirical evidence that

consumers want to avoid transaction costs (the cost of using the market in the sense of Coase, 1937) or learning how to use another firm’s technology. The effect of consumer

Le moment des poids des masses est nul par rapport

Car l’écoulement est irrotationnel.. Ce résultat