To make or to buy from a common supplier? Strategic considerations and welfare consequences

Consider two downstream firms that each can either produce an input in-house or purchase it from an upstream supplier. We show that depending on the difference between the supplier's and the downstream firms' in-house production costs, outsourcing by both firms could help them achieve a Pareto improvement or leave them trapped in a prisoner's dilemma. Furthermore, we find that two downstream firms may play a chicken game in which each makes a sourcing decision different from its rival if the input supplier is not as efficient as in the previous cases. The welfare implications of various sourcing outcomes are explored.