Using a general spatial model with two firms interacting repeatedly, we show that the condition for collusion sustainability is the same under uniform delivered pricing, discriminatory delivered pricing and discriminatory f.o.b. pricing.

The existing literature which analyses the relationship between the product differentiation degree and the sustainability of a collusive agreement on price assumes that firms cannot price discriminate, and concludes that there is a negative relationship between the product differentiation degree...

We show in a game-theoretic model that when quantity-setting firms first choose whether to discriminate or not and then set quantities, the unique equilibrium consists in all firms selling a uniform quantity to all consumers. This sharply contrasts with the case of price-setting firms.