Eur. Phys. J. B 20, 493-501
From market games to real-world markets
P. Jefferies1, M.L. Hart1, P.M. Hui2 and N.F. Johnson11 Department of Physics, Oxford University, Parks Rd, Oxford, OX13PU, UK
2 Physics Department, Chinese University of Hong Kong, Shatin, Hong Kong, PR China
p.jefferies@physics.ox.ac.uk
(Received 30 August 2000)
Abstract
This paper uses the development of multi-agent market models to present a unified approach to the joint questions of how financial
market movements may be simulated, predicted, and hedged against.
We first present the results of agent-based market simulations in which traders equipped with simple buy/sell strategies and
limited information compete in speculatory trading. We examine the effect of different market clearing mechanisms and show
that implementation of a simple Walrasian auction leads to unstable market dynamics. We then show that a more realistic out-of-equilibrium
clearing process leads to dynamics that closely resemble real financial movements, with fat-tailed price increments, clustered
volatility and high volume autocorrelation.
We then show that replacing the `synthetic' price history used by these simulations with data taken from real financial time-series
leads to the remarkable result that the agents can collectively learn to identify moments in the market where profit is attainable.
Hence on real financial data, the system as a whole can perform better than random.
We then employ the formalism of Bouchaud in conjunction with agent based models to show that in general risk cannot be eliminated
from trading with these models. We also show that, in the presence of transaction costs, the risk of option writing is greatly
increased. This risk, and the costs, can however be reduced through the use of a delta-hedging strategy with modified, time-dependent
volatility structure.
01.30.Cc - Conference proceedings.
05.45.Tp - Time series analysis .
05.65.+b - Self-organized systems.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001



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