When product quality is unverifiable by third parties, enforceable contracts that condition price upon quality are not feasible. If higher quality is also costly to deliver, moral hazard by sellers flourishes, particularly when procurement is via a competitive auction process. Retainage is a contractual mechanism that presents a solution to the third-party unverifiability problem, by setting aside a portion of the purchase price. After delivery, the buyer has sole discretion over the amount of retainage money that is released to the seller. While generally a feasible contract form to implement, retainage introduces a moral hazard for the buyer. We use laboratory experiments to investigate how and when retainage might be successfully used to facilitate trust and trustworthiness in procurement contracts. We observe that retainage induces a significant improvement in product quality when there are some trustworthy buyers in the population, consistent with a model of fair payment norms that we develop. This improvement is realized at the cost of increased buyer-seller profit inequalities. We also observe that at high levels of retainage, there is a welfare-decreasing market unraveling in which sellers do not bid on contracts. Our results imply that retainage incentives can mitigate the tension between competition and cooperation arising from reverse auctions, but only at appropriate levels of retainage.
Walker, M.J., Katok, E., & Shachat, J. (2020). Trust and trustworthiness in procurement contracts with retainage. ESI Working Paper 20-34. https://digitalcommons.chapman.edu/esi_working_papers/329/