Bei der Besteuerung nicht oder nur begrenzt handelbarer Dienstleistungen (wie z.B. lokale Postdienstleistungen) entfällt der Anpassungsdruck des internationalen Steuerwettbewerbs weitgehend, sodass etwaige Wettbewerbsverzerrungen insbesondere zwischen verschiedenen inländischen...

This paper studies competition in the German market for mobile telecommunications, motivated by recent suggestions that T-Mobile and Vodafone possess a position of collective dominance. Allegedly, their position of joint dominance is secured through a combination of first-mover advantages and...

This paper explores the effects that collusion can have in newspaper markets where firms compete for advertising as well as for readership. We compare three modes of competition: i) competition in the advertising and the reader market, ii) semi-collusion over advertising (with competition in the...

This paper summarizes the peculiarities of online markets and discusses recent antitrust cases related to online markets. Following a brief description of the online markets' characteristics and potential tendencies for concentration the paper first discusses the antitrust allegations and...

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 re-examine the view that a ban on price discrimination in input markets is particularly desirable in the presence of buyer power. This argument crucially depends on an inverse relationship between downstream firms' profits and the uniform input price. Assuming different input efficiencies...

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...