In the Solidarity Game (Selten and Ockenfels, 1998), two "rich" persons can support a "poor" one. A strong positive correlation between one rich person's solidarity contribution and his expected contribution of the other is observed. This paper investigates the causality behind this correlation....

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...

In Dictator Game experiments where the information status of the recipient varies we find that a certain type of donator tends to reduce his offer when the recipient has incomplete information about the pie size. This result provides new evidence on those approaches on altruism, which assume...

For many people "solidarity" has become a meaningless word used in slogans - too often used without leading to any economic consequences. We show in this paper conditions under which solidarity can be a powerful instrument. In a solidary action, an individual in a group contributes to a series...

In Dictator Game experiments where the information status of the participants varies we find that a certain type of proposer tends to reduce his offers when the recipient has incomplete information about the pie size. We also find that a certain type of recipient tends to reject too small offers...

If a previously unpaid activity (donating blood) is paid then we often observe that this activity is reduced. In this paper, it is hypothesised that the price offered is taken as a proxy for the "market value" of the activity. Depending on how the actor valued the activity previously,...

We analyze vertical structures where a regulated network operator serves n network users, and the network users compete in quantities for customers. We distinguish two cases: (i) none of the network users are related to the network operator (ownership unbundling), (ii) one of the network users...

We propose a model of the European gas market where the risk that Russian deliveries are interrupted is endogenized. While Russia's attempts to buy considerable parts of the European downstream industry have faced strong political opposition, we argue that Russian participation in the downstream...

European and national cartel authorities have required dominant national gas pipelines to auction off certain quantities (typically about 10 % of their sales) to competitors. Do such auctions really improve the competitiveness of the wholesale market? Based on a model where oligopolistic...