Explicit vs. tacit collusion—The impact of communication in oligopoly experiments

We explore the difference between explicit and tacit collusion by investigating the impact communication has in experimental markets. For Bertrand oligopolies with various numbers of firms, we compare pricing behavior with and without the possibility to communicate among firms. We find strong evidence that talking helps to obtain higher profits for any number of firms, however, the gain from communicating is non-monotonic in the number of firms, with medium-sized industries having the largest additional profit from talking. We also find that industries continue to collude successfully after communication is disabled. Communication supports firms in coordinating on collusive pricing schemes, and it is also used for conflict mediation. ► We explore the difference between tacit collusion and explicit collusion in experiments. ► Bertrand oligopolies with various numbers of firms are run with and without communication. ► The conventional wisdom that the fewness of firms facilitates collusion is confirmed. ► However, the gain from explicitly talking is non-monotonic in the number of firms. ► We also find that industries continue to collude successfully after communication is disabled.