Abstract: Important shareholders' market behavior has received much attention from securities in theory and practice, because it has not only directly impact on stock prices, but also affect the company's growth, and which is in conflict with the interests of other investors. A-share listed companies which have buying or selling behavior as the sample are used in this paper, growth target is then created through principal component analysis, and multiple regression analysis model of Shareholders' buying or selling behavior and company's growth is constructed. The empirical research the catalysis of the Alignment and the Entrenchment Effect under the multi-factors' combined influence. The empirical result shows that: important shareholders' buying behavior will strengthen the alignment effect and their selling behavior will strengthen the entrenchment effect. What's more, the entrenchment effect is more obvious when the largest shareholders have more shareholding proportion, and the alignment effect is more obvious when the top ten shareholders hold more stock, which reflects the equilibrium relation between equity balance and equity controlling.

Key words: important shareholder, alignment effect, entrenchment effect, market behavior, company's growth