In their merger control, EU and the US have considered symmetric size distribution (cost structure) of firms to be a factor potentially leading to collusion. We show that forbidding mergers leading to symmetric market structures can induce mergers leading to asymmetric market structures with...

Deltas, Salvo and Vasconcelos (2011) develop a model of geographically separated markets with differentiated goods in which collusion (or merger to monopoly), by restricting trade relative to duopolistic competition, is beneficial for society and can be beneficial for consumers. In this chapter,...