Moral hazard with non-additive uncertainty: When are actions implementable?

We provide sufficient conditions on the information structure for implementing actions in a moral hazard setting when Agent has non-probabilistic uncertainty. For a finite action space, under three well-known formulations of Agent's ambiguity attitude, contracts that partition the outcome space in two parts, and are piecewise constant on each part, are enough to implement an action. (C) 2018 Elsevier B.V. All rights reserved.