We propose a framework for analyzing transformations of demand. Such transformations frequently stem from changes in the dispersion of consumers` valuations, which lead to rotations of the demand curve. In a wide variety of settings, profits are a U-shaped function of dispersion. A high level of...

Firms selling multiple quality-differentiated products frequently alter theirproduct lines when a competitor enters the market. We present a model of multiproductmonopoly and duopoly using a general “upgrades” approach that yields a powerfulanalytical framework. We provide a simple...