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Why prediction markets work : The role of information acquisition and endogenous weighting

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  • Siemroth, Christoph

Abstract

In prediction markets, investors trade assets whose values are contingent on the occurrence of future events, like election outcomes. Prediction market prices have been shown to be consistently accurate forecasts of these outcomes, but we don't know why. I formally illustrate an information acquisition explanation. Traders with more wealth to invest have stronger incentives to acquire information about the outcome, thus tend to have better forecasts. Moreover, their trades have larger weight in the market. The interaction implies that a few well-endowed traders can move the asset price toward the true value. One implication for institutions aggregating information is to put more weight on votes of agents with larger stakes, which improves on equal weighting, unless prior distribution accuracy and stakes are negatively related.

Suggested Citation

  • Siemroth, Christoph, 2014. "Why prediction markets work : The role of information acquisition and endogenous weighting," Working Papers 14-02, University of Mannheim, Department of Economics.
  • Handle: RePEc:mnh:wpaper:35257
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    References listed on IDEAS

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    Cited by:

    1. Page, Lionel & Siemroth, Christoph, 2017. "An experimental analysis of information acquisition in prediction markets," Games and Economic Behavior, Elsevier, vol. 101(C), pages 354-378.
    2. Siemroth, Christoph, 2015. "The impossibility of informationally efficient markets when forecasts are self-defeating," Annual Conference 2015 (Muenster): Economic Development - Theory and Policy 113110, Verein für Socialpolitik / German Economic Association.

    More about this item

    Keywords

    Information Acquisition ; Information Aggregation ; Forecasting ; Futures Markets ; Prediction Markets;

    JEL classification:

    • D83 - Microeconomics - - Information, Knowledge, and Uncertainty - - - Search; Learning; Information and Knowledge; Communication; Belief; Unawareness
    • D84 - Microeconomics - - Information, Knowledge, and Uncertainty - - - Expectations; Speculations
    • G10 - Financial Economics - - General Financial Markets - - - General (includes Measurement and Data)

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