Kaum eine ordnungspolitische oder regulatorische Frage hat in der deutschen Telekommunikationsbranche wohl in den letzten Jahren für so viel Aufruhr gesorgt, wie die Einführung des neuen §9a in das Telekommunikationsgesetz (TKG). Die neue Vorschrift sieht vor, dass die Bundesnetzagentur...

There is a wide range of magazines, newspapers, TV shows, and websites providing information on products based on product reviews or expert opinions. A natural question is, whether these reviews and expert opinions have effects on product sales. There is a small but growing literature in...

This paper investigates the existence of a possible media bias by analyzing the impact of automobile manufacturer’s advertisements on automobile reviews in a leading German car magazine. By accounting for both endogeneity and sample selection using a two-step procedure, we find a positive...

Platform markets are characterized by the existence of indirect network effects that connect two or more market sides through a platform that internalizes these feedback effects. Conventional instruments of market definitions which consider price levels cannot easily applied in case of two-sided...

This paper examines the causes and effects of mobile number portability (MNP) and provides a survey of its implementation in Europe. We first examine the competitive effects and the costs of introducing MNP. Next, we discuss how to charge for MNP. We argue that a price cap regime starting from...

This paper provides a hedonic price analysis of mobile telephones for the German market. We have assembled data on 302 different handsets from 25 manufacturers over the period from May 1998 to November 2003. While volume has a negative effect on the price of a mobile handset, the number of...