From the researching results, we can see that there are clear cycles (about 275 days) in the data array of daily income rate data of Hong Kong Hang Seng Index and stocks , the time cycles of the stock price and the index present non-linear fractal character, they are a cycling system which is inverse enduring tendency and to be a so called "reback the value".
香港恒生指数收益的日数据和个股收益的日数据序列的实证结果均出现了明显的循环周期(大约是275天)，股价和指数所构成的时间序列均呈现非线性的分形特征，他们是一个属于常被称为是“均值回复”的反持久性的序列系统，这意味着如果一个系统在前一个期间是向上(向下)走的，那么它在下一个期间多半是向下(向上)走，今天的股票价格影响未来股价。
