关键词: PPP, 不完全契约, 公共品负担, 演化博弈, 机会主义行为

Abstract: Considering the situation that government imposes the public goods burden to improve social public welfare and satisfies public demands, investors often take opportunistic behavior to protect their own interests from loss, thus damaging the interests of government and reducing social public welfare. We use evolutionary game theory to analyze the mechanism of investors’ behavior strategies and find that the probability of investors’ opportunistic behavior increases with the intensity of public goods burden, as the government subsidy is lower than a certain level. And the probability decreases with the degree of government subsidies when the public goods burden is below some level, while the effect of subsidy policy fails with intensity of public goods burden beyond a certain level. If occupying more proportion of PPP interests, investors are more inclined to take opportunistic actions. According to the research results, government should strengthen the spirit of contract, improve the regulatory mechanism and enhance the confidence of the private sector in project income not just subsidies.

Key words: PPP, incomplete contract, public goods burden, evolutionary game, opportunistic behavior