This paper studies the behavior of buyers confronting an incumbent monopolist and a potential market entrant in a repeated trade situation. In the experiment, buyers have two possibilities to demand lower prices in future trade periods. First, they can withhold demand. Second, they can voluntarily pay a higher price to the entrant in order to encourage future re-entry. Both these forms of buyer behavior occur in the experiment. They are less frequent when the number of buyers is large as opposed to small. A control treatment tests to what extent such behavior can be attributed to strategic motives.