Abstract: The existing literature is mainly based on the perspective that various factors affecting the motivation or ability of managers to hide negative information, which results in the insufficient response of investors to the negative information, and then influences the stock price crash risk. Based on the overreaction theory of behavioral finance, investors not only under-react to negative news due to the hiding of negative news from the management, but also overreact to positive information due to the rendering of positive information from the management, which in turn affects the risk of stock price crash. With the case of Amarsoft, this study analyzes the main way of positive information rendering and its influence mechanism on stock price crash risk. This study finds that major shareholders tend to render positive information of the company to achieve their own interests by colluding with the seller's analysts to spread propaganda emails and research reports, adjusting the answer of institutional investor research and company announcement. Besides, this study finds that various influencing factors make investors overreact to positive information, which may cause stock prices to exceed their intrinsic value and increase the risk of stock price crash.

Key words: positive information rendering, stock price crash risk, case study