We study the effect of entry on costs and competition in the Portuguese mobile telephony industry.\ We construct and estimate a model that includes demand, network, and cost equations. The latter accounts for inefficiency and cost reducing effort. Our results suggest that the entry of a third...

We evaluate the impact on market power and efficiency of a series of mergers on three Portuguese non-life insurance markets. We specify and estimate, with a panel of firm-level data, a structural model which includes: preferences, technology, and a market equilibrium condition. Firms' demand...