Welfare effects of taxation in oligopolistic markets

This paper discusses how marginal costs of public funds are related to various market characteristics under imperfect competition. Under a quite general tax scheme, these costs turn out to be lower the wider the firms' product ranges, the lower the degree of market concentration and the lower the degree of product differentiation. Moreover, marginal costs of taxation are lower in Bertrand markets compared to Cournot markets. In cases when marginal costs of public funds cannot easily be assessed we ask if pass-through rates can provide useful information for policy makers. The market characteristics that we analyze are shown to have opposite effects on pass-through and marginal costs of public funds. It is also demonstrated that the marginal cost of public funds is generally lower for ad valorem taxes than for unit taxes. The main results are based on a linear demand system, but a number of extensions confirm that our main results are reasonably robust.