Abstract: At the early stage of electricity retail market construction, high concentration of ownership is likely to take place and hence the research on collusive pricing behavior of electricity retailers could provide reference for the establishment of reasonable policies. In this paper, the collusive pricing behavior is considered as the strategy choice problem of a “finite population” of electricity retailers under the context of “finite rationality”. The Moran process is introduced into the stochastic evolutionary game model of collusive pricing. Then the effects of key parameters such as collusion coefficient and supply/demand ratio on the collusive pricing strategy of power sales companies are analyzed by virtue of detailed case studies. The results has shown that the success rate of collusive pricing is higher in oligopolistic markets, especially in highly oligopolistic markets; for different types of markets, the collusion coefficient demonstrates different effects on collusive pricing strategies, and furthermore, the impact of random factors in the internal and external market environment on collusive pricing behavior becomes more significant as the market concentration increases; market management agencies should enhance the analysis and research of retail electricity prices and strengthen the supervision of competition effectiveness as well as the information sharing and coordination with anti-monopoly enforcement departments, credit departments and other units.

Key words: electricity retailers, collusive pricing, Moran process, stochastic evolutionary game, absorption probability