We consider multiple-principal multiple-agent models of moral hazard: Principals compete through mechanisms in the presence of agents who take unobservable actions. In this context, we provide a rationale for restricting principals to make use of simple mechanisms, which correspond to direct...

In this note we show that the equilibrium characterized by Biais, Martimort and Rochet (Econometrica, 2000) could have been characterized by direct mechanisms even if the Revelation Principle does not apply in their setting. The use of more sophisticated mechanisms, such as menus, was not necessary

This paper examines the role of direct mechanisms in common agency games. We focus on pure strategies and deterministic contracts and show how the introduction of a separability condition on the preferences of the agent is sufficient for the Revelation Principle to hold in in this setting, when...

In common agency games, one cannot characterize all equilibria by considering only direct mechanisms. In an attempt to overcome this difficulty, Peters [Econometrica, 2001] and Martimort and Stole [Econometrica, 2002] identified a class of indirect mechanisms (namely, menus) which are able to...

This note presents a counter-example to Theorems 3 and 4 in Peters (2003, J. Eco. Theory) and suggests that indifference of the single agent with respect to principals' offers plays an important role in the failure of the Revelation Principle in Common Agency games. In addition we provide a new...

In this note we argue that in Common Agency games, the restriction to deterministic menus is crucial. We give an simple example (complete information, no moral hazard) in which an equilibrium is not robust to the introduction of stochastic menus