Unit Versus Ad Valorem Taxes : The Private Ownership of Monopoly In General Equilibrium

In an earlier paper [Blackorby and Murty; 2007] we showed that if a monopoly sector is imbedded in a general equilibrium framework and profits are taxed at one hundred percent, then unit (specific) taxation and ad valorem taxation are welfare-wise equivalent. In this paper, we consider private ownership of the monopoly sector. Given technical difficulties in making a direct general equilibrium comparison of unit and ad valorem taxation, we adopt a technique due to Guesnerie [1980] and Quinzii [1992] in a somewhat different context of increasing returns and non-convex economies to show that neither ad valorem taxation nor unit taxation Pareto dominates the other; although, generally, the two are not welfare-wise equivalent.