A number of European countries, among them the UK and Spain, have opened up their Directory Enquiry Services (DQs) market to competition. In Spain, both local and foreign firms challenged the incumbent as of April 2003. The latter raised its rivals' costs and forced quality downgrading by...

We present a Hotelling model of price and advertising competition between prescription drugs that differ in quality/side effects. Promotional effort results in the endogenous formation of two consumer groups: brand loyal and non-brand loyal ones. We show that advertising intensities are...