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Demand shifts and imperfect competition


  • Simon GB Cowan
  • Simon Cowan


The effects of demand shifts on output, price and profits in imperfectly competitive industries with no entry or exit are derived. Four types of demand shift are modelled: additive and multiplicative shifts of the demand and inverse demand functions. Necessary and sufficient conditions for output, price and profits to increase with an outward demand shift are derived for each case. Either output or the price, but not both, may fall with a positive demand shift. Profits may also fall for a Cournot oligopoly. Log-concavity of the direct demand function is sufficient for the standard results to go through.

Suggested Citation

  • Simon GB Cowan & Simon Cowan, 2004. "Demand shifts and imperfect competition," Economics Series Working Papers 188, University of Oxford, Department of Economics.
  • Handle: RePEc:oxf:wpaper:188

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    References listed on IDEAS

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    1. Essaji Azim, 2010. "Trade Liberalization, Standards and Protection," The B.E. Journal of Economic Analysis & Policy, De Gruyter, vol. 10(1), pages 1-21, July.
    2. David, Maia & Nimubona, Alain-Désiré & Sinclair-Desgagné, Bernard, 2011. "Emission taxes and the market for abatement goods and services," Resource and Energy Economics, Elsevier, vol. 33(1), pages 179-191, January.
    3. Bish, Ebru K. & Suwandechochai, Rawee, 2010. "Optimal capacity for substitutable products under operational postponement," European Journal of Operational Research, Elsevier, vol. 207(2), pages 775-783, December.
    4. Ravi Anupindi & Li Jiang, 2008. "Capacity Investment Under Postponement Strategies, Market Competition, and Demand Uncertainty," Management Science, INFORMS, vol. 54(11), pages 1876-1890, November.
    5. Jesse M. Cunha & Giacomo De Giorgi & Seema Jayachandran, 2011. "The Price Effects of Cash Versus In-Kind Transfers," NBER Working Papers 17456, National Bureau of Economic Research, Inc.
    6. Xiabing Zheng & Xiaolong Guo, 2016. "E-retailing of restaurant services: pricing strategies in a competing online environment," Journal of the Operational Research Society, Palgrave Macmillan;The OR Society, vol. 67(11), pages 1408-1418, November.
    7. Özelkan, Ertunga C. & ÇakanyIldIrIm, Metin, 2009. "Reverse bullwhip effect in pricing," European Journal of Operational Research, Elsevier, vol. 192(1), pages 302-312, January.
    8. Wang, Yao-Yu & Wang, Jian-Cai & Shou, Biying, 2013. "Pricing and effort investment for a newsvendor-type product," European Journal of Operational Research, Elsevier, vol. 229(2), pages 422-432.
    9. Yuyue Song & Saibal Ray & Shanling Li, 2008. "Structural Properties of Buyback Contracts for Price-Setting Newsvendors," Manufacturing & Service Operations Management, INFORMS, vol. 10(1), pages 1-18, November.
    10. Han, Sungill & Chung, Chanjin & Suh, Daeseok, 2011. "Generic Advertising in Concentrated and Differentiated Agricultural Markets," 2011 Annual Meeting, July 24-26, 2011, Pittsburgh, Pennsylvania 103739, Agricultural and Applied Economics Association.

    More about this item


    Comparative Statics; Monopoly; Oligopoly; Log-concavity.;

    JEL classification:

    • D42 - Microeconomics - - Market Structure, Pricing, and Design - - - Monopoly
    • L12 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Monopoly; Monopolization Strategies
    • L13 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Oligopoly and Other Imperfect Markets


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