@phdthesis{Jurgan2009,
  author    = {Jurgan, Jens},
  title     = {Three Essays on Market Concentration and Welfare},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40374},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2009},
  abstract  = {This thesis analyzes the relationship between market concentration and efficiency of the market outcome in a differentiated good context from different points of view. The first chapter introduces the objectives of competition policy and antitrust authorities and outlines the importance of market concentration. Chapter 2 analyzes the relationship between social surplus and market heterogeneity in a differentiated Cournot oligopoly. Market heterogeneity is due to differently efficient firms, each of them producing one variety of a differentiated good. All firms exhibit constant but different marginal costs without fixed costs. Consumers preferences are given by standard quadratic utility originated by Dixit (1979). Since preferences are quasi-linear social surplus is the measure for Pareto-optimality. The main finding is that consumer suprlus as well as producer surplus increase with the variance of marginal costs. The third chapter analyzes the relationship between the cost structure and market concentration measured by the Herfindahl-Hirschman Index. Market concentration increases with the variance of marginal costs as well as the mean of marginal costs. Chapter four analyzes welfare implications of present antitrust enforcement policy on basis of the same theoretical model. European as well as the US Merger Guidelines presume a negative impact of market concentration on the competitiveness of the market and, therefore, on the efficiency of the market outcome. The results of the previous chapters indicate that this assumption is false. The main finding is that post-merger joint profit of the insider increase with the size of the merger. Moreover, there is a negative relationship between the size of the merger and efficiency of the market outcome. Present antitrust enforcement policy increases the disparity of output levels and enforces the removal of the least efficient firm of the market. The welfare gains can be traced back on these two effects. Therefore, neither a minimum of market concentration nor a maximum of product diversity is necessarily welfare enhancing even in absence of fixed costs.},
  subject      = {Konzentration <Wirtschaft>},
  language  = {en}
}