The Social Costs of Side Trading
研究了在存在消费者与企业间侧交易时，计划者无法阻止双边交易对资源配置的影响，发现逆向选择和侧交易严重限制了可行交易，导致效率损失和再分配能力丧失，对保险和金融市场有启示。
Abstract We study resource allocation under private information when the planner cannot prevent bilateral side trading between consumers and firms. Adverse selection and side trading severely restrict feasible trades: each marginal quantity must be fairly priced given the consumer types who purchase it. The resulting social costs are twofold. First, second-best efficiency and robustness to side trading are in general irreconcilable requirements. Second, there actually exists only one budget-feasible allocation robust to side trading, which deprives the planner from any capacity to redistribute resources between different types of consumers. We discuss the relevance of our results for insurance and financial markets.