Price Variations in a Stock Market with Many Agents

P. Bak, M. Paczuski and Martin Shubik
Additional contact information
P. Bak: Brookhaven National Laboratory
M. Paczuski: Brookhaven National Laboratory

No 1132, Cowles Foundation Discussion Papers from Cowles Foundation for Research in Economics, Yale University

Abstract: Large variations in stock prices happen with sufficient frequency to raise doubts about existing models, which all fail to account for non-Gaussian statistics. We construct simple models of a stock market, and argue that the large variations may be due to a crowd effect, where agents imitate each other's behavior. The variations over different time scales can be related to each other in a systematic way, similar to the Levy stable distribution proposed by Mandelbrot to describe real market indices. In the simplest, least realistic case, exact results for the statistics of the variations are derived by mapping onto a model of diffusing and annihilating particles, which has been solved by quantum field theory methods. When the agents imitate each other and respond to recent market volatility, different scaling behavior is obtained. In this case the statistics of price variations is consistent with empirical observations. The interplay between "rational" traders whose behavior is derived from fundamental analysis of the stock, including dividends, and "noise traders," whose behavior is governed solely by studying the market dynamics, is investigated. When the relative number of rational traders is small, "bubbles" often occur, where the market price moves outside the range justified by fundamental market analysis. When the number of rational traders is large, the market price is generally locked within the price range they define.

Pages: 43 pages
Date: 1996-09
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (7)

Published in Physica A: Statistical Mechanics and its Applications (December 1997), 246(3-4): 430–453

Downloads: (external link)
https://cowles.yale.edu/sites/default/files/files/pub/d11/d1132.pdf (application/pdf)
Our link check indicates that this URL is bad, the error code is: 404 Not Found

Related works:
Journal Article: Price variations in a stock market with many agents (1997)
Working Paper: Price Variations in a Stock Market with Many Agents (1996)
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:cwl:cwldpp:1132

Ordering information: This working paper can be ordered from
Cowles Foundation, Yale University, Box 208281, New Haven, CT 06520-8281 USA
The price is None.

Access Statistics for this paper

More papers in Cowles Foundation Discussion Papers from Cowles Foundation for Research in Economics, Yale University Yale University, Box 208281, New Haven, CT 06520-8281 USA. Contact information at EDIRC.
Bibliographic data for series maintained by Brittany Ladd (cowles@yale.edu).