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Two plus two equals six: an alternative explanation of why so many goods prices end in nine


  • David Demery
  • Nigel W. Duck



The prevalence of prices ending in 99 cents is explained as the result of rational consumers rounding prices up. Monopolists are shown to be harmed by this practice whereas consumers may gain. The model is compared with two other models: Basu's (1997) model and one which assumes consumers round prices down.

Suggested Citation

  • David Demery & Nigel W. Duck, 2007. "Two plus two equals six: an alternative explanation of why so many goods prices end in nine," Bristol Economics Discussion Papers 07/598, Department of Economics, University of Bristol, UK.
  • Handle: RePEc:bri:uobdis:07/598

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    References listed on IDEAS

    1. Basu, Kaushik, 1997. "Why are so many goods priced to end in nine? And why this practice hurts the producers," Economics Letters, Elsevier, vol. 54(1), pages 41-44, January.
    2. Kaushik Basu, 2006. "Consumer Cognition and Pricing in the Nines in Oligopolistic Markets," Journal of Economics & Management Strategy, Wiley Blackwell, vol. 15(1), pages 125-141, March.
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    More about this item


    Consumer rationality; price perception; pricing;

    JEL classification:

    • A10 - General Economics and Teaching - - General Economics - - - General
    • D40 - Microeconomics - - Market Structure, Pricing, and Design - - - General
    • L12 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - Monopoly; Monopolization Strategies

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