Optimal contract orders and relationship-specific investments in vertical organizations

This paper characterizes the optimal contracts issued to suppliers when delivery is subject to disruptions and when they can invest to reduce such a risk. When investment is contractible dual sourcing is generally optimal because it reduces the risk of disruption. The manufacturer (buyer) either issues symmetric contracts or selects one supplier as a major provider who invests while the buffer supplier does not. An increased reliance on single sourcing or on a major supplier is optimal under moral hazard. Indeed, we show that order consolidation increases the manufacturer's profits because it serves as an incentive device in inducing investment.