The relative efficiency of ad valorem and unit taxes is analyzed for oligopolistic markets. We provide a simple proof that ad valorem taxes welfare-dominate unit taxes in the short run if production costs are identical across firms. The proof covers a wide range of market conduct and...

We analyze the incidence of ad valorem and unit excise taxes in an oligopolistic industry with differentiated products and price-setting (Bertrand) firms. Both taxes may be passed on to consumers by more than 100 percent, and an increase in the tax rate can increase short run firm profits (and...

We revisit the fundamental issue of market provision of variety associated with Chamberlin, Spence, and Dixit-Stiglitz when firms sell multiple products. Both products and firms are (horizontally) differentiated. We propose a general nested demand framework where consumers first decide upon a...

We describe firm pricing when consumers search passively and follow simple reservation price rules. In stark contrast to other models in the literature, this approach yields equilibrium price dispersion in pure strategies even when firms have the same marginal costs. In equilibrium, lower price...