The Influence of Market Size in an Artificial Stock Market: The Approach Based on Genetic Programming

The relationship between competitiveness and market performance has been discussed for a long time. In a competitive economic environment, each firm or individual is unable to influence the market. It has been mentioned in the economics courses that the competitive market is more efficient and has higher social welfare. Therefore, it is the desirable picture economists intend to draw. The concept of competitiveness is related to market size, i.e., the number of market participants. The idea here is that the larger economy contributes to microeconomic heterogeneity, for example, behavior and strategies, profitability and market shares, production technology and efficiency. The importance of economic diversity has been understood. It is a fundamental driving force and an essential property in the economic systems. People who have different perspectives about the future implies that there exits room for the economic activity and they may benefit from their trading behavior. In other words, the higher degree of heterogeneity may provide more opportunities for trading. It is also an important seed of innovation. In this paper, we try to study the influence of market size to market performance in term of market efficiency.