The European Physical Journal B

, Volume 61, Issue 2, pp 241–246

Increasing market efficiency in the stock markets

  • Jae-Suk Yang
  • Wooseop Kwak
  • Taisei Kaizoji
  • In-mook Kim
Interdisciplinary Physics

DOI: 10.1140/epjb/e2008-00050-0

Cite this article as:
Yang, JS., Kwak, W., Kaizoji, T. et al. Eur. Phys. J. B (2008) 61: 241. doi:10.1140/epjb/e2008-00050-0

Abstract.

We study the temporal evolutions of three stock markets; Standard and Poor's 500 index, Nikkei 225 Stock Average, and the Korea Composite Stock Price Index. We observe that the probability density function of the log-return has a fat tail but the tail index has been increasing continuously in recent years. We have also found that the variance of the autocorrelation function, the scaling exponent of the standard deviation, and the statistical complexity decrease, but that the entropy density increases as time goes over time. We introduce a modified microscopic spin model and simulate the model to confirm such increasing and decreasing tendencies in statistical quantities. These findings indicate that these three stock markets are becoming more efficient.

PACS.

89.65.Gh Economics; econophysics, financial markets, business and management 89.70.+c Information theory and communication theory 89.75.Fb Structures and organization in complex systems 

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Copyright information

© EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2008

Authors and Affiliations

  • Jae-Suk Yang
    • 1
  • Wooseop Kwak
    • 1
  • Taisei Kaizoji
    • 2
  • In-mook Kim
    • 1
    • 3
  1. 1.Department of PhysicsKorea UniversitySeoulKorea
  2. 2.Division of Social SciencesInternational Christian UniversityTokyoJapan
  3. 3.School of Physics, Korea Institute for Advanced StudySeoulKorea

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