On communication and collusion

We study the role of communication within a cartel. Our analysis is carried out in Stigler's (1964) model of repeated oligopoly with secret price cuts. Firms observe neither the prices nor the sales of their rivals. For a fixed discount factor, we identify conditions under which there are equilibria with "cheap talk" that result in near-perfect collusion, whereas all equilibria without such communication are bounded away from this outcome. In our model, communication improves monitoring and leads to higher prices and profits.