In this paper we argue that two important causes of welfare losses in oligopolistic markets have been neglected. We show that in models where location is endogenous, welfare losses arising from wrong locations or from lack of market coverage may be substantial despite firms competing in prices....

We study the percentage of welfare losses (PWL) yielded by imperfect competition under product differentiation. When demand is linear, if prices, outputs, costs and the number of firms can be observed, PWL is arbitrary in both Cournot and Bertrand equilibria. If in addition, the elasticity of...

In a market for a homogeneous good where firms are identical, compete in quantities and produce with constant returns, the percentage of welfare losses (PWL) is small with as few as five competitors for a class of demand functions which includes linear and isoelastic cases. We study markets with...