Das Internet ist stark durch Wettbewerb zwischen Plattformen geprägt, welche potenzielle Tauschpartner zusammenbringen. Die Konkurrenz zwischen solchen mehrseitigen Plattformen und die Marktkonzentration wird maßgeblich bestimmt durch (1) die Stärke der indirekten Netzeffekte, (2) das Ausmaß...

Katz (1987), DeGraba (1990), and Yoshida (2000) have formulated theories that price discrimination bans in intermediary goods markets tend to have positive effects on allocative, dynamic and productive efficiency, respectively. We show that none of these results is robust vis-à-vis endogenous...

We examine how different pass-through rates, from input- to final consumer prices, and different vertical contracts affect upstream market definition. Our theory model predicts that, under reasonable conditions, higher pass-through rates lead to definitions of larger upstream markets. Data...

This paper analyzes how competition works in mobile telecommuncations markets and, bases on this analysis, we discuss whether regulatory intervention in mobile telephone markets is justified from an economic perspective. Starting point of our analysis is the observation that an evaluation of...