We propose a methodology for estimating the competition effects from entry when firms sell differentiated products. We first derive precise conditions under which Bresnahan and Reiss' entry threshold ratios (ETRs) can be used to test for the presence and to measure the magnitude of competition...

We study a major new entry in the French mobile telecommunications market, followed by the introduction of fighting brands by the three incumbent firms. Using an empirical oligopoly model with differentiated products, we show that the incumbents' launch of the fighting brands can be rationalized...

Although economically very important, local-service sectors have received little attention in the extensive literature on competitive interactions. Detailed data gathering in these sectors is hard, not only because of the multitude of local players, but also because key service dimensions are...