Article

The Social Costs of Side Trading

Andrea Attar, Thomas Mariotti et François Salanié

Résumé

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 a unique 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.

Remplace

Andrea Attar, Thomas Mariotti et François Salanié, « The Social Costs of Side Trading », TSE Working Paper, n° 19-1017, juin 2019, révision octobre 2019.

Référence

Andrea Attar, Thomas Mariotti et François Salanié, « The Social Costs of Side Trading », The Economic Journal, vol. 130, n° 630, août 2020, p. 1608–1622.

Publié dans

The Economic Journal, vol. 130, n° 630, août 2020, p. 1608–1622