Gifts as Economic Signals and Social Symbols

Gift-giving has often puzzled economists, especially because efficient gifts-like cash or giving exactly what a person asks for-seem crass or inappropriate. It is shown in a formal game-theoretic model that gifts serve as "signals" of a person's intentions about future investment in a relationship, and inefficient gifts can be better signals. Other explanations for the inefficiency of gift giving are advanced, and some stylized facts about gift-giving practices are described (many of which are consistent with the signaling view of gifts)

Equilibria Under the Probabilistic Serial Rule

The probabilistic serial (PS) rule is a prominent randomized rule for assigning indivisible goods to agents. Although it is well known for its good fairness and welfare properties, it is not strategyproof. In view of this, we address several fundamental questions regarding equilibria under PS. Firstly, we show that Nash deviations under the PS rule can cycle. Despite the possibilities of cycles, we prove that a pure Nash equilibrium is guaranteed to exist under the PS rule. We then show that verifying whether a given profile is a pure Nash equilibrium is coNP-complete, and computing a pure Nash equilibrium is NP-hard. For two agents, we present a linear-time algorithm to compute a pure Nash equilibrium which yields the same assignment as the truthful profile. Finally, we conduct experiments to evaluate the quality of the equilibria that exist under the PS rule, finding that the vast majority of pure Nash equilibria yield social welfare that is at least that of the truthful profile.Comment: arXiv admin note: text overlap with arXiv:1401.6523, this paper supersedes the equilibria section in our previous report arXiv:1401.652

Incentives to Invest in Electronic Coordination: Under- or Overinvestment in Equilibrium?

Do firms have proper incentives to invest in electronic coordination? We discuss this question in an oligopoly model with a local firm and a distant competitor that may reduce transport costs by investing in electronic coordination. In a two-stage game with investment in the first stage and price or quantity competition with differentiated products in the second stage we compare profit maximizing investment with (constrained) welfare maximization by a social planer. Depending on market demand, firm conduct and investment costs either over- or underinvestment may result: The firm will overinvest if the negative impact on its competitor exceeds the gain in consumer surplus. This is shown to be especially likely under quantity competition with (almost) homogenous products.Electronic Markets; Strategic Investments; Transport Costs; Product Differentiation

Social Preferences and Competition

There is a general presumption that social preferences can be ignored if markets are competitive. Market experiments (Smith 1962) and recent theoretical results (Dufwenberg et al. 2008) suggest that competition forces people to behave as if they were purely self-interested. We qualify this view. Social preferences are irrelevant if and only if two conditions are met: separability of preferences and completeness of contracts. These conditions are often plausible, but they fail to hold when uncertainty is important (financial markets) or when incomplete contracts are traded (labor markets). Social preferences can explain many of the anomalies frequently observed on these markets.Social preferences; competition; separability; incomplete contracts; asset markets; labor markets

A bargaining model of financial intermediation

Investment;Bargaining;Financial Institutions

Social Preferences and Competition

There is a general presumption that social preferences can be ignored if markets are competitive. Market experiments (Smith 1962) and recent theoretical results (Dufwenberg et al. 2008) suggest that competition forces people to behave as if they were purely self-interested. We qualify this view. Social preferences are irrelevant if and only if two conditions are met: separability of preferences and completeness of contracts. These conditions are often plausible, but they fail to hold when uncertainty is important (financial markets) or when incomplete contracts are traded (labor markets). Social preferences can explain many of the anomalies frequently observed on these markets.Social preferences; competition; separability; incomplete contracts; asset markets; labor markets

The interdependence between production and allocation

Production;Allocation