Bertrand–Edgeworth model

In microeconomics, the Bertrand–Edgeworth model of price-setting oligopoly explores what happens when firms compete to sell a homogeneous product (a good for which consumers buy only from the cheapest available seller) but face limits on how much they can supply. Unlike in the standard Bertrand competition model, where firms are assumed to meet all demand at their chosen price, the Bertrand–Edgeworth model assumes each firm has a capacity constraint: a fixed maximum output it can sell, regardless of price. This constraint may be physical (as in Edgeworth’s formulation) or may depend on price or other conditions.

A key result of the model is that pure-strategy price equilibria may fail to exist, even with just two firms, because firms have an incentive to undercut competitors' prices until they hit their capacity constraints. As a result, the model can lead to price cycles or the emergence of mixed-strategy equilibria, where firms randomize over prices.