合同执行与生产效率：来自印度电力合同投标与再谈判的证据

中文摘要

合同执行不力可能降低发展中国家的生产效率。我研究合同执行如何影响印度规模最大的电力项目采购拍卖中的效率。我收集了投标与事后合同再谈判的数据，发现尽管允许投标人将报价与煤炭价格等未来成本挂钩，实行指数化调整，但为应对成本冲击而进行的合同再谈判仍十分普遍。为研究投标策略的异质性，我根据企业是否曾获得政府授予的煤炭特许权，构建了一个新的企业关联度指标。关联企业选择将报价金额中较小的部分与煤炭价格挂钩，并通过这一策略使自身暴露于成本冲击，以诱发再谈判。我使用评分拍卖中的投标结构模型，刻画投标人在成本和再谈判后预期获得的支付金额两方面均存在异质性时的均衡投标。模型估计表明，由于预期到后续再谈判的价值，投标人以低于成本的价格提供电力。我利用该模型模拟严格执行合同情况下的投标与效率。研究发现，合同执行具有促进竞争的作用。在不允许再谈判的情况下，均衡报价将上升至足以覆盖成本的水平，但加成占合同总价值的比例会大幅下降。生产成本也会下降，因为项目将分配给成本较低的投标人，而非那些预期在再谈判中获得更高支付金额的投标人。

Abstract

Weak contract enforcement may reduce the efficiency of production in developing countries. I study how contract enforcement affects efficiency in procurement auctions for the largest power projects in India. I gather data on bidding and ex post contract renegotiation and find that the renegotiation of contracts in response to cost shocks is widespread, despite that bidders are allowed to index their bids to future costs like the price of coal. To study heterogeneity in bidding strategies, I construct a new measure of firm connectedness, based on whether a firm has been awarded coal concessions by the Government. Connected firms choose to index less of the value of their bids to coal prices and, through this strategy, expose themselves to cost shocks to induce renegotiation. I use a structural model of bidding in a scoring auction to characterize equilibrium bidding when bidders are heterogeneous both in cost and in the payments they expect after renegotiation. The model estimates show that bidders offer power below cost due to the expected value of later renegotiation. The model is used to simulate bidding and efficiency with strict contract enforcement. Contract enforcement is found to be pro‐competitive. With no renegotiation, equilibrium bids would rise to cover cost, but markups relative to total contract value fall sharply. Production costs decline, due to projects being allocated to lower‐cost bidders over those who expect larger payments in renegotiation.