证券欺诈的预期模型

用理性预期模型研究不诚实公司的欺诈行为，并分析证券欺诈的发生概率与监管效率的动态关系．研究发现欺诈行为是证券市场的内生规律，不诚实公司对欺诈被发现的预期是欺诈行为是否发生的关键因素．对国内相关数据的实证研究得到的结论与理论分析一致．我国证券市场的欺诈行为主要聚集在1996年，占总案件量的40．5％，而欺诈案件查处则聚集在2000年，比欺诈聚集期晚4年．证明案件查处时间过晚是导致欺诈行为聚集效应显著的主要原因．

Rational Expectation Model for Securities Frauds

The fraud behaviors of dishonest companies were studied with a rational expectations model to analyze the dynamic relations between the possibility of frauds to happen and the efficiencies of the regulatory authorities. It is found that frauds are a common phenomenon independent of the developing degree of securities markets, and the expectation by the dishonest companies of being found is one of the key factors affecting the happening of frauds. The data from Chinese securities market were taken to verify the arguments, and the result is the same as the theoretic analysis. Frauds in Chinese securities market happened mostly in 1996, accounting for 40.5% of the total. Investigations started in 2000, 4 years later than the happening peak of the frauds, suggesting that the investigations were. too late, which is the main cause for the high rate of frauds to happen within a period.