Some forgotten equilibria of the

This note analyzes the Bertrand duopoly with constant but asym-metric marginal costs on a market with homogenous products. It is shown that there exist some equilibria that are ignored in the litera-ture on IO. In addition, in this setting (perfectly or nearly perfectly) competitive equilibria exist. JEL: D4, L13 The Bertrand duopoly with homogenous products plays an important role in modern industrial organization. Firstly, because of its analytical simplic-ity and the characteristics of the equilibria it is a standard part of modern textbook contents. Secondly, it shows that under some particular conditions even duopolies can induce perfectly competitive results. Thirdly, perhaps due to its comfortable handling it is often used as an essential part in multistage games. ”Bertrand competition is interesting because it depicts a polar case. It represents what we have in mind when we think of sharp small-numbe