In markets where product quality is important, more than one characteristic is usually necessary for producers to define product quality. Standard theory maintains that: (i) in a duopoly there will be a quality leader no matter whether the product can incorporate one or two vertical attributes;...

We analyze the competitive effects of quantity discounts in an asymmetric duopoly. We find that for a sizeable set of parameter values, quantity discounts harm the smaller firm and reduce consumers' surplus. They can even decrease social welfare, i.e. the sum of producers' and consumers'...