We develop a market model which explains how prices react to short-run demand variations when the number of active price-setting firms is held fixed on its long-run level. We assume that for each firm the average production cost function is U-shaped, that customers are imperfectly informed about...

This paper investigates price setting when firms produce with increasing returns and customers are imperfectly informed about prices but customers can search. It is shown that there exists a unique randomization equilibrium where each customer is offered a random price by each firm known to him....