Vertical Integration, Raising Rivals’ Costs and Upstream Collusion

This paper analyzes the impact vertical integration has on upstream collusion when the price of the input is linear. As a first step, the paper derives the collusive equilibrium that requires the lowest discount factor in the infinitely repeated game when one firm is vertically integrated. It turns out this is the joint-profit maximum of the colluding firms. The discount factor needed to sustain this equilibrium is then shown to be unambiguously lower than the one needed for collusion in the separated industry. While the previous literature has found it difficult to reconcile raising-rivals-costs strategies following a vertical merger with equilibrium behavior in the static game, they are subgame perfect in the repeated game studied here.collusion, foreclosure, raising rivals’ costs, vertical integration

An Experimental Test of Strategic Trade Policy

In this experiment, we analyze the model of strategic trade policy proposed by Brander and Spencer (1985). Governments can choose whether or not to subsidize domestic firms. Firms compete in a Cournot duopoly, and they know the subsidy decisions when choosing output. Although the theoretical prediction is that firms are subsidized, it turns out that governments only rarely subsidize in experimental markets. Not subsidizing is rational given our observation that firms do not play according to the subgame perfect equilibrium when subsidies are given.Commercial policy; experimental economics; strategic commitment

The impact of the termination rule on cooperation in a prisoner's dilemma experiment

Cooperation in prisoner's dilemma games can usually be sustained only if the game has an infinite horizon. We analyze to what extent the theoretically crucial distinction of finite vs. infinite-horizon games is reflected in the outcomes of a prisoner's dilemma experiment. We compare three different experimental termination rules in four treatments: a known finite end, an unknown end, and two variants with a random termination rule (with a high and with a low continuation probability, where cooperation can occur in a subgame-perfect equilibrium only with the high probability). We find that the termination rules do not significantly affect average cooperation rates. Specifically, employing a random termination rule does not cause significantly more cooperation compared to a known finite horizon, and the continuation probability does not significantly affect average cooperation rates either. However, the termination rules may influence cooperation over time and end-game behavior. Further, the (expected) length of the game significantly increases cooperation rates. The results suggest that subjects may need at least some learning opportunities (like repetitions of the supergame) before significant backward induction arguments in finitely repeated game have force. --Prisoner's dilemma,Repeated games,Infinite-horizon games,Experimental economics

Signaling in deterministic and stochastic settings

We contrast a standard deterministic signaling game with one where the signal-generating mechanism is stochastic. With stochastic signals a unique equilibrium emerges that involves separation and has intuitive comparative-static properties as the degree of signaling depends on the prior type distribution. With deterministic signals both pooling and separating configurations occur. Laboratory data support the theory: In the stochastic variant, there is more signaling behavior than with deterministic signals, and less frequent types distort their signals relatively more. Moreover, the degree of congruence between equilibrium and subject behavior is greater in stochastic settings compared to deterministic treatments. --experiments,learning,noise,signaling,stochastic environments

Equilibrium Vertical Foreclosure in the Repeated Game

This paper analyzes if vertical foreclosure can emerge as an equilibrium outcome of an infinitely repeated game. Foreclosure is profitable due to a 'raising rival's costs' effect but it is not a Nash equilibrium of the static game. The results are that foreclosure is in fact a subgame perfect Nash equilibrium of the repeated game, and it may facilitate collusion compared to the nonintegrated industry. The possibility of a counter merger of the nonintegrated firms negatively affects the likelihood and profitability of collusive foreclosure.foreclosure, vertical integration, collusion

To commit or not to commit: Endogenous timing in experimental duopoly markets

In this paper, we experimentally investigate the extended game with action commitment of Hamilton and Slutsky (1990). In their duopoly game, firms can choose their quantities in one of two periods before the market clears. If a firm commits to a quantity in period 1 it does not know whether the other firm also commits early. By waiting until period 2, a firm can observe the other firm's period 1 action. Hamilton and Slutsky predict the emergence of endogenous Stackelberg leadership. Our data, however, does not confirm the theory. While Stackelberg equilibria are extremely rare we often observe endogenous Cournot outcomes and sometimes collusive play. This is partly driven by the fact that endogenous Stackelberg followers learn to behave in a reciprocal fashion over time, i.e., they learn to reward cooperation and to punish exploitation.duoploly, endogenous timing, experimental economics

Output Commitment through Product Bundling: Experimental Evidence

We analyze the impact of product bundling in experimental markets. A firm has monopoly power in one market but faces competition by a second firm in another market. We compare treatments where the monopolist can bundle its two products to treatments where it cannot, and we contrast simultaneous and sequential order of moves. Our data indicate support for the theory of product bundling, even though substantial payoff differences between players exist. With bundling and simultaneous moves, the monopolist offers the predicted number of units. When the monopolist is the Stackelberg leader, the predicted equilibrium is better attained with bundling although in theory bundling should not make a difference here. In sum: bundling works as a commitment device that enables the transfer of market power from one market to another.

Stability of the Cournot Process - Experimental Evidence

We report results of experiments designed to test the predictions of the best reply process. In a Cournot oligopoly with four firms, the best reply process should theoretically explode if demand and cost functions are linear. We find, however, no experimental evidence of such instability. Moreover, we find no differences between a market which theoretically should not converge to Nash equilibrium and one which should converge because of inertia. We investigate the power of several learning dynamics to explain this unpredicted stability.best reply process, Cournot oligopoly, learning experiments, imitation

Vertical Integration and Market Foreclosure with Convex Downstream Costs

In a framework with an upstream monopoly and a downstream duopoly, we analyze the impact of convex costs on the downstream level. In constrast to the case of constant marginal costs, vertical integration does not imply complete market foreclosure. While the nonintegrated downstream ¯rm receives a strictly positive amount of the intermediate good, the downstream allocation is ine±cient. However, a parametrized example indicates that competition at the downstream level may increase aggregate welfare.Vertical restraints, commitment

Trial & Error to Collusion - The Discrete Case

In this note we study a very simple trial & error learning process in the context of a Cournot oligopoly. Without any knowledge of the payoff functions players increase, respectively decrease, their quantity by one unit as long as this leads to higher profits. We show that despite the absence of any coordination or punishing device this process converges to a collusive outcome.learning, Cournot oligopoly