Abstract: Due to the increasing investment opportunities of enterprises, share pledge has also attracted more and more attention from enterprises and investors. When there are capital requirements for controlling shareholders of listed companies, with low cost, strong liquidity and high efficiency, share pledge has become one of the preferred financing methods for controlling shareholders. However, this is not without risk. Because of the uncertainty of the value of the pledge equity and the immaturity of the securities market, once the stock market environment changes, such as abnormal or continuous fluctuations in stock prices, if the controlling shareholder fails to make up the value of the pledge in time, controlling shareholders will be forced to liquidate or even transfer control, thus triggering the risk of corporate governance. In the face of frequent incidents of default in the capital market, how will listed companies with share pledge reduce the risk of pledge is worth studying.
In this paper,the main problems of this study are divided into two aspects. First,compared with other enterprises, whether controlling shareholders are more likely to have market value management after share pledge. Second, after the occurrence of share pledge, whether controlling shareholders adopt equity incentive to manage market capitalization. The initial sample is selected from all listed companies in Shanghai and Shenzhen Stock Exchange from 2012 to 2016. In order to ensure the integrity and continuity of data, the financial industry, St, *st and outliers and missing values are excluded. 12829 sample data are obtained, while all statistics are from the CSMAR database, whose raw data were processed.
In this paper, the relationship between equity pledge and market value management is analyzed through OLS multiple regression model. Then, by simultaneous equations, we examine the transmission mechanism between share pledge, equity incentive and market value management among the three are examined.
The empirical results in this paper show that, first, the coefficient between market value management and share pledge is positive, which has a significant positive correlation at 1% significant level. Compared with companies without share pledge, controlling shareholders are more likely to carry out market value management to avoid abnormal fluctuation of stock price after pledge. Second, The coefficient between market value management and share pledge is positive and has a significant positive correlation at 1% level; the correlation coefficient between equity incentive and share pledge is positive and has a significant positive correlation at 1% level; the regression of the last three variables in one equation is also positively correlated with the level of 1%. This indicates that the mediation effect is valid.
The research contributions of this paper are embodied in the following three aspects:first, taking share pledge as explanatory variable, and using market value management as explanatory variable, the direct correlation between the two, enriching the research on the motivation of market value management is studied; secondly, taking event behavior-economic-consequences as research paradigm, and taking equity incentive as an intermediary variable, the transmission mechanism between share pledge, equity incentive and market value management among the three is explored; thirdly, the understanding of investors on the share pledge is deepened, which is of reference significance for the government and regulatory departments to formulate relevant policies.

Key words: share pledge, market value management, equity incentive