Information disclosure to Cournot duopolists

We show that in a standard symmetric Cournot duopoly with unknown demand, the optimal information disclosure policy of an informed benevolent planner is to fully inform one of the duopolists and disclose no information to the other one. We discuss possible extensions of the result. •A planner looks for the information structure that maximizes duopolists’ surplus.•The optimal policy is to fully inform one of them and say nothing to the other.•The result extends in the oligopoly case but depends on specific assumptions.