信息不对称有两种类型，第一种是逆向选择，即隐藏信息的问题。在我们所研究的问题中体现为公司管理者比外部投资者更了解公司的状况。由于逆向选择的存在，至少会产生两方面的问题：第一，管理人员可能利用自己所拥有的内部信息进行某些私下交易为自己谋利，而牺牲了外部投资 There are two types of information asymmetry, the first is the reverse selection, that is, the problem of hiding information. Among the problems we have studied is that corporate managers know the company better than external investors. Due to the existence of adverse selection, there are at least two problems. First, managers may use some of the internal information they own to make some private transactions for their own benefit at the expense of external investment