On prices’ cyclical behaviour in oligopolistic markets

We revisit the discussion about the relationship between price's cyclical features, implicit collusion and the demand level in an oligopoly supergame where a positive shock may hit demand and disrupt collusion. The novel feature of our model consists in characterising the post-shock noncooperative price and comparing it against the cartel price played in the last period of the collusive path, to single out the conditions for procyclicality to arise both in the short and in the long-run. This poses an issue in terms of an antitrust agency's ability to draw well defined conclusions on the firms’ behaviour after the occurrence of the shock, with particular reference for the litigation phase after a cartel breakdown.