Mark Armstrong, Oxford University

"Consumer information and the limits of competition"


This paper studies competition between firms when consumers observe a private signal of their preferences over products. Within the class of signal structures which allow pure-strategy Bertrand equilibria, we derive signal structures which are optimal for firms and those which are optimal for consumers. The firm-optimal signal structure amplifies the underlying product differentiation, thereby relaxing competition, while ensuring that consumers purchase their preferred product, thereby maximizing total welfare. The consumer-optimal structure dampens product differentiation, which intensifies competition, but induces some consumers with weak preferences over products to purchase their less-preferred product.

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