Cartel Detection and Collusion Screening: An Empirical Analysis of the London Metal Exchange

Posted by Social Science Research Network

Cartel Detection and Collusion Screening: An Empirical Analysis of the London Metal Exchange – Danilo Samà (LUISS “Guido Carli” University of Rome ; Erasmus Rotterdam University ; Ghent University ; University of Aarhus – School of Business and Social Sciences ; Toulouse School of Economics ; University of Hamburg ; Law & Economics LAB)

ABSTRACT: In order to fight collusive behaviors, the best scenario for competition authorities would be the possibility to analyze detailed information on firms’ costs and prices, being the price-cost margin a robust indicator of market power. However, information on firms’ costs is rarely available. In this context, a fascinating technique to detect data manipulation and rigged prices is offered by an odd phenomenon called Benford’s Law, otherwise known as First-Digit Law, which has been successfully employed to discover the “Libor Scandal” much time before the opening of the cartel settlement procedure. Thus, the main objective of the present paper is to apply a such useful instrument to track the price of the aluminum traded on the London Metal Exchange, following the allegations according to which there would be an aluminum cartel behind. As a result, quick tests such as Benford’s Law can only be helpful to inspect markets where price patterns show signs of collusion. Given the budget constraints to which antitrust watchdogs are commonly subject to, a such price screen could be set up, just exploiting the data available, as warning system to identify cases that require further investigations.