ESSAYS IN COMPETITION BETWEEN PRICE COMPARISON SITES AND PRICING BEHAVIORS OF FIRMS ON THE INTERNET By

iAbstract My dissertation consists of three chapters. In the first two chapters, I study entry decisions and competition between price comparison sites on the Internet. In the third chapter, I empirically examine pricing behaviors of firms on two leading price comparison sites — Cnet.shopper.com and Nextag.com. My research is motivated by the fact that price comparison sites are widely used by consumers when they shop online. Moreover, in most online markets, there are multiple price comparison sites. In my first chapter, I study under what kind of circumstance multiple price compar-ison sites coexist in the market, and under what kind of circumstance a monopoly site dominates the market. The Baye and Morgan (2001) (hereafter BM) model, in which the market is served by a single price comparison site (also called an “information gate-keeper”), is the basis of my research. I show that even if each consumer observes price quotations from all price comparison sites, potential entrants do not find it optimal to enter a market monopolized by an incumbent information gatekeeper. Thus, the BM equilibrium is robust when one allows entry into the information market. The resul