Causal Evidence of Antitrust Damages in the Car Manufacturers’ Cartel in Spain

This paper estimates the causal impact on vehicle prices of an automobile manufacturers' cartel that operated in Spain from 2006 to 2013. To do so, we construct a novel dataset containing manufacturers' recommended retail prices for Spain and several unaffected European Union countries over the period 2000-2011. Exploiting variation in the timing of cartel entry across brands, we apply a difference-in-differences approach controlling for sales volume, scrappage schemes, and fixed effects. Our estimates show that the cartel increased prices in Spain by approximately 9.3% on average during the infringement period. Robustness checks confirm the consistency of the findings: the parallel trends assumption holds, results remain stable with alternative control groups, and placebo tests yield no significant effects. These findings contribute to the limited empirical literature on causal estimation of cartel overcharges and provide policyrelevant insights on the transmission of upstream collusion to final consumer prices.