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The length of contracts and collusion


  • Green, Richard
  • Le Coq, Chloé


Many commodities (including energy, agricultural products and metals) are sold both on spot markets and through long-term contracts which commit the parties to exchange the commodity in each of a number of spot market periods. This paper shows how the length of contracts affects the possibility of collusion in a repeated price-setting game. Contracts can both help and hinder collusion, because they reduce the size of the spot market, cutting both the immediate gain from defection and the punishment for deviation. Firms can always sustain some collusive price above marginal cost if they sell the right number of contracts, of any duration, whatever their discount factor. As the duration of contracts increases, however, collusion becomes harder to sustain.

Suggested Citation

  • Green, Richard & Le Coq, Chloé, 2010. "The length of contracts and collusion," International Journal of Industrial Organization, Elsevier, vol. 28(1), pages 21-29, January.
  • Handle: RePEc:eee:indorg:v:28:y:2010:i:1:p:21-29

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    References listed on IDEAS

    1. Allaz Blaise & Vila Jean-Luc, 1993. "Cournot Competition, Forward Markets and Efficiency," Journal of Economic Theory, Elsevier, vol. 59(1), pages 1-16, February.
    2. Mahenc, P. & Salanie, F., 2004. "Softening competition through forward trading," Journal of Economic Theory, Elsevier, vol. 116(2), pages 282-293, June.
    3. Margaret E. Slade & Henry Thille, 2006. "Commodity Spot Prices: An Exploratory Assessment of Market Structure and Forward-Trading Effects," Economica, London School of Economics and Political Science, vol. 73(290), pages 229-256, May.
    4. Jean Tirole, 1988. "The Theory of Industrial Organization," MIT Press Books, The MIT Press, edition 1, volume 1, number 0262200716, July.
    5. Ferreira, Jose Luis, 2003. "Strategic interaction between futures and spot markets," Journal of Economic Theory, Elsevier, vol. 108(1), pages 141-151, January.
    6. Liski, Matti & Montero, Juan-Pablo, 2006. "Forward trading and collusion in oligopoly," Journal of Economic Theory, Elsevier, vol. 131(1), pages 212-230, November.
    7. Abreu, Dilip, 1986. "Extremal equilibria of oligopolistic supergames," Journal of Economic Theory, Elsevier, vol. 39(1), pages 191-225, June.
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    Cited by:

    1. de Frutos, María-Ángeles & Fabra, Natalia, 2012. "How to allocate forward contracts: The case of electricity markets," European Economic Review, Elsevier, vol. 56(3), pages 451-469.
    2. de Frutos, Maria-Angeles & Fabra, Natalia, 2008. "On the Impact of Forward Contract Obligations in Multi-Unit Auctions," CEPR Discussion Papers 6756, C.E.P.R. Discussion Papers.
    3. James Bushnell, 2007. "Oligopoly equilibria in electricity contract markets," Journal of Regulatory Economics, Springer, vol. 32(3), pages 225-245, December.
    4. Fiuza de Bragança, Gabriel Godofredo & Daglish, Toby, 2016. "Can market power in the electricity spot market translate into market power in the hedge market?," Energy Economics, Elsevier, vol. 58(C), pages 11-26.
    5. Di Cosmo, Valeria & Lynch, Muireann Á., 2016. "Competition and the single electricity market: Which lessons for Ireland?," Utilities Policy, Elsevier, vol. 41(C), pages 40-47.
    6. Christian Redl & Derek Bunn, 2013. "Determinants of the premium in forward contracts," Journal of Regulatory Economics, Springer, vol. 43(1), pages 90-111, January.
    7. Russell Pittman & Vanessa Yanhua Zhang, 2008. "Electricity Restructuring in China: The Elusive Quest for Competition," EAG Discussions Papers 200805, Department of Justice, Antitrust Division.
    8. Baldursson , Fridrik M. & von der Fehr, Nils-Henrik, 2007. "Vertical Integration and Long-Term Contracts in Risky Markets," Memorandum 01/2007, Oslo University, Department of Economics.
    9. Paulo Cesar Coutinho & Andre Rossi de Oliveira, 2013. "Trading Forward in the Brazilian Electricity Market," International Journal of Energy Economics and Policy, Econjournals, vol. 3(3), pages 272-287.
    10. repec:aen:journl:ej38-si1-acemoglu is not listed on IDEAS
    11. Anne Neumann & Sophia Rüster & Christian von Hirschhausen, 2015. "Long-Term Contracts in the Natural Gas Industry: Literature Survey and Data on 426 Contracts (1965-2014)," Data Documentation 77, DIW Berlin, German Institute for Economic Research.
    12. Petrella, Andrea & Sapio, Alessandro, 2012. "Assessing the impact of forward trading, retail liberalization, and white certificates on the Italian wholesale electricity prices," Energy Policy, Elsevier, vol. 40(C), pages 307-317.
    13. Aichele, Markus F., 2014. "Forward trading and collusion of firms in volatile markets," University of Tuebingen Working Papers in Economics and Finance 75, University of Tuebingen, Faculty of Economics and Social Sciences.


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