This paper studies bilateral trade in which the seller makes a hidden investment that influences the buyer's hidden valuation. In general it is impossible to implement both first-best efficient trade and efficient investment using budget-balanced trading mechanisms. The paper fully characterizes...

A principal can observe both the output and input of an agent who works at a job involving multiple tasks. We provide a simple theory that explains why it may be optimal for the principal to use only an output-based incentive contract, even though the principal can monitor the agent's actions...