Price Competition and Advertising Signals: Signaling by Competing Senders

Can price and advertising be used by vertically differentiated duopolists to signal qualities to consumers? We show that pure price separation is impossible if the vertical differentiation is small, while adding dissipative advertising ensures the existence of separating equilibria. Two simple, but nonstandard, equilibrium refinements are introduced to deal with the multisender nature of the game, and they are shown to produce a unique separating and a unique pooling profile. Pooling results in a zero-profit Bertrand outcome. Separation gives strictly positive duopoly profits, and dissipative advertising is used by the high-quality firm when products are sufficiently close substitutes. Finally, compared to the complete-information benchmark, the separating prices of both firms are distorted upwards when the degree of vertical differentiation is large, and downwards when it is small.