Edgeworth's taxation paradox when firms engage in cost-reducing investment

This study examines whether and when Edgeworth's taxation paradox, that taxation decreases the equilibrium price, occurs in a free-entry Cournot oligopoly with cost-reducing investment. In contrast to the fact that no paradox occurs in the short-run equilibrium, the paradox can occur in the long-run equilibrium, in which the number of firms is endogenous. However, the conditions under which the paradox occurs are restrictive when there is no investment. By incorporating cost-reducing investments into the model, we demonstrate that the paradox is likely to occur under less restrictive conditions, irrespective of whether the tax is specific or ad valorem.