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


  • Samà, Danilo


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 aluminium traded on the London Metal Exchange, following the allegations according to which there would be an aluminium 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.

Suggested Citation

  • Samà, Danilo, 2014. "Cartel Detection and Collusion Screening: An Empirical Analysis of the London Metal Exchange," MPRA Paper 55363, University Library of Munich, Germany.
  • Handle: RePEc:pra:mprapa:55363

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    References listed on IDEAS

    1. Bernhard Rauch & Max Göttsche & Gernot Brähler & Stefan Engel, 2011. "Fact and Fiction in EU‐Governmental Economic Data," German Economic Review, Verein für Socialpolitik, vol. 12(3), pages 243-255, August.
    2. Rosa Abrantes-Metz & Sofia Villas-Boas & George Judge, 2011. "Tracking the Libor rate," Applied Economics Letters, Taylor & Francis Journals, vol. 18(10), pages 893-899.
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    More about this item


    Benford's Law; Cartel Detection; Collusion Screening; Competition Authorities; Data Manipulation; Monopolization; Oligopolistic Markets; Price Fixing; Variance Screen;

    JEL classification:

    • C10 - Mathematical and Quantitative Methods - - Econometric and Statistical Methods and Methodology: General - - - General
    • D40 - Microeconomics - - Market Structure, Pricing, and Design - - - General
    • L13 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Oligopoly and Other Imperfect Markets
    • L41 - Industrial Organization - - Antitrust Issues and Policies - - - Monopolization; Horizontal Anticompetitive Practices

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