We extend a market model of Kyle (1984) to a multi-period mar- ket model in which market makers are imperfectly competitive. When there are only a finite number of market makers who try to maximize their expected profits, Kyle's λ, price sensitivity to the order ow, is higher than that of Kyle (1985), who assumes perfect competition among risk-neutral market makers. We show that in a multi-period
... [Show full abstract] setting, the price movement has a negative serial correlation as Roll (1984) and Glosten and Milgrom (1985).