Multi-contracting practices prevail in many organizations be they public (governments) or private (markets). This article surveys the literature on common agency, a major example of such multi-contracting settings. I first highlight some specific features of common agency games that distinguish them from centralized contracting. Then, I review the tools needed to describe allocations which are implementable as common agency equilibria. Economic examples are used to characterize equilibria under both complete and asymmetric information. Particular focus is put on the multiplicity problem and the (interim) efficiency properties of those equilibria. The comparison of those equilibria with the outcomes achieved under centralized contracting allows us to assess the transaction costs of multi-contracting. I also argue that, in some specific contexts, common agency may implement the optimal outcome that would be achieved under centralized contracting if collusion between agents were an issue. More generally, common agency might outperform centralized contracting when either collusion or limited commitment matters.

This paper analyses efficient contracts for digital content, focusing on the music industry. It contributes to the quest for an efficient intellectual property rights environment for information goods. Moreover, it adds an interesting application to the field of behavioural economics. The model is set in a contract theory framework with the copyright holder being the principal and a consumer the agent. We offer three contract cases for analysis: strong copy protection, a strategically low price and voluntary reciprocal contributions. Insights from the economics of information and behavioural economics-- information goods have public goods properties; social preferences are significant among individuals-- are applied to examine the value of a strict copyright enforcement in the digital age. We find that endogenous incomplete contracts based on fair, reciprocal behaviour may achieve a firstbest allocation of information goods, while complete contracts are limited to second-best results.