Strategic Buyers and Privately Observed Prices

A model of repeated price competition with large buyers is analyzed. The sellers are allowed to offer different prices to different buyers and the buyers act strategically. The set of subgame perfect Equilibria is investigated under public and private monitoring. With public monitoring the equilibrium set with large buyers expands relative to the standard model where each buyer is small and behaves myopically. With private monitoring, where prices are not observable to the competing sellers, the set of equilibrium payoffs shrinks . In the finitely repeated game with private monitoring, all sales are made by the efficient seller. In the infinitely repeated game this result is preserved as long as the sellers condition their prices on the public history. In contrast to the finite horizon game, the set of pure strategy equilibria expands if the sellers are allowed to condition their own past prices. Comparisons are drawn to Markovian equilibria of similar dynamic games

Explicit vs Tacit Collusion:The Effects of Firm Numbers and Asymmetries

In an infinitely repeated game where firms with (possibly asymmetric) capacity constraints can make secret price cuts, we analyse the incentives for explicit collusion when firms can alternatively collude tacitly. Tacit collusion can involve price wars on the equilibrium path. Explicit collusion involves firms secretly sharing their private information to avoid such price wars, but this is illegal and runs the risk of sanctions. We find that, in contrast to the conventional wisdom but consistent with some empirical evidence, illegal cartels are least likely to arise in markets with a few symmetric firms, because tacit collusion is relatively more appealing in such markets. We discuss the implications for anti-cartel enforcement policy

Strategic buyers and privately observed prices

A model of finitely repeated price competition between two sellers with differentiated goods and a large buyer is analyzed. The set of pure strategy sequential equilibria is investigated under public and private monitoring. With private monitoring, i.e., when prices are not observable to the competing sellers, all sales are made by the better seller and the set of repeated game equilibrium payoffs coincides with the stage game subgame perfect equilibrium payoffs. This is in sharp contrast to the game with perfect monitoring where the folk theorem obtains. Journal of Economic Literature Classification Numbers: C72, D43