I study a dynamic principal agent model in which the effort cost of the agent is unknown to the principal. The principal is ambiguity averse, and designs a contract which is robust to the worst case effort cost process. Ambiguity divides the contract into two regions. After sufficiently high...

I study the optimal choice of investment projects in a continuous time moral hazard model with multitasking. While in the first best, projects are invariably chosen by the net present value (NPV) criterion, moral hazard introduces a cutoff for project execution which depends on both a project's...

We prove that under standard Lipschitz and growth conditions, the value function of all optimal control problems for one-dimensional diffusions is twice differentiable, as long as the control space is compact and the volatility is uniformly bounded below, away from zero. Under similar...