Investing in a relationship
研究了委托人在与代理人重复关系中投资时，事后讨价还价可能攫取回报的敲竹杠问题，发现投资回报可观察时非正式契约比正式契约更有效，因为投资能改善关系激励；回报不可观察则影响不同。
A principal can make an investment anticipating a repeated relationship with an agent, but the agent may appropriate the returns through ex post bargaining. I study how this holdup problem and efficiency depend on the contracting environment. When investment returns are observable, informal contracts ex post can be more efficient than formal contracts, as they induce higher investment ex ante : the principal invests not only to generate direct returns, but also to improve relational incentives. Unobservability of returns increases the principal's ability to appropriate the returns but reduces her ability to improve incentives. The optimal information structure depends on bargaining power.