We anlayze Varian's (1980) Model of Sales, and show that when the number of uninformed consumers increases, prices become less competitive for all consumers. Thus, the influx of uninformed consumers generates a negative externality increasing the prices paid by informed consumers.

We analyze Varian's (1980) Model of Sales, and show that when the number of uninformed consumers increases, prices become less competitive for all consumers. Thus, the influx of uninformed consumers generates a negative externality increasing prices paid by informed consumers.