The 2002 prices of suppliers in German call-by-call telephone market are rather dispersed, out-of-phase (uncorrelated), and show systematic down-up movements. In 2004, these prices are less dispersed, more in-phase and show more upwards runs than downs-ups. In both years, we clearly do not...

Models to the issue of altruism which rely on externalities of well-being are rarely used explicitly. In this paper we compare such utility-based approaches with the standard approach on altruism which is based on externalities of income. Testable differences of both types of models are derived...