This paper examines the use of market-share thresholds (safe harbors) in evaluating whether a given vertical practice should be challenged. Such thresholds are typically found in vertical restraints guidelines (e.g., the 2000 Guidelines for the European Commission and the 1985 Guidelines for the...

This paper generalizes the frequently used Hotelling model for two-sided markets in order to determine the equilibrium market shares. We show that advertisement levels depend neither on the media price nor on the location of the media firm. An increase in advertising revenues does not change...