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Risk-Sharing and Retrading in Incomplete Markets


  • Piero Gottardi
  • Rohit Rahi


At a competitive equilibrium of an incomplete-markets economy agents’ marginal valuations for the tradable assets are equalized ex-ante. We characterize the finest partition of the state space conditional on which this equality holds for any economy. This leads naturally to a necessary and sufficient condition on information that would lead to retrade, if such information were to become publicly available after the initial round of trade.

Suggested Citation

  • Piero Gottardi & Rohit Rahi, 2012. "Risk-Sharing and Retrading in Incomplete Markets," Economics Working Papers ECO2012/03, European University Institute.
  • Handle: RePEc:eui:euiwps:eco2012/03

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    References listed on IDEAS

    1. Geanakoplos, John & Mas-Colell, Andreu, 1989. "Real indeterminacy with financial assets," Journal of Economic Theory, Elsevier, vol. 47(1), pages 22-38, February.
    2. Lawrence Blume & Tarek Coury & David Easley, 2006. "Information, trade and incomplete markets," Economic Theory, Springer;Society for the Advancement of Economic Theory (SAET), vol. 29(2), pages 379-394, October.
    3. Atsushi Kajii & Antonio Villanacci & Alessandro Citanna, 1998. "Constrained suboptimality in incomplete markets: a general approach and two applications," Economic Theory, Springer;Society for the Advancement of Economic Theory (SAET), vol. 11(3), pages 495-521.
    4. Piero Gottardi & Rohit Rahi, 2014. "Value Of Information In Competitive Economies With Incomplete Markets," International Economic Review, Department of Economics, University of Pennsylvania and Osaka University Institute of Social and Economic Research Association, vol. 55, pages 57-81, February.
    5. Milgrom, Paul & Stokey, Nancy, 1982. "Information, trade and common knowledge," Journal of Economic Theory, Elsevier, vol. 26(1), pages 17-27, February.
    6. Magill, Michael & Shafer, Wayne, 1991. "Incomplete markets," Handbook of Mathematical Economics,in: W. Hildenbrand & H. Sonnenschein (ed.), Handbook of Mathematical Economics, edition 1, volume 4, chapter 30, pages 1523-1614 Elsevier.
    7. Michael Magill & Martine Quinzii, 2002. "Theory of Incomplete Markets, Volume 1," MIT Press Books, The MIT Press, edition 1, volume 1, number 0262632543, January.
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    More about this item


    Competitive Equilibrium; Incomplete Markets; Information; Re-trading;

    JEL classification:

    • D52 - Microeconomics - - General Equilibrium and Disequilibrium - - - Incomplete Markets
    • D80 - Microeconomics - - Information, Knowledge, and Uncertainty - - - General

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