We analyze Bertrand's price competition in a homogenous good market with a fixed cost and an increasing marginal cost (i.e., with variable returns to scale). If the fixed cost is avoidable, we show that the non-subadditivity of the cost function at the output corresponding to the oligopoly...

This paper provides necessary and sufficient conditions for the existence of a pure strategy Bertrand equilibrium in a model of price competition with fixed costs. It unveils an interesting and unexplored relationship between Bertrand competition and natural monopoly. That relationship points...

We extend Armstrong’s result on exclusion in multi-dimensional screening models in two key ways, providing support for the view that this result holds true in a large class of models and is applicable to many different markets. First, we relax the strong technical assumptions he imposed on...