Abstract:    On February 17, 2023, the China Securities Regulatory Commission (CSRC) officially issued relevant institutional rules for the full implementation of the stock issuance registration system, which marked the basic finalization of the registration system arrangement, and China′s securities market officially entered the era of registration system. At present, the academic community has not reached a unified conclusion on the relationship between information transparency and stock price synchronization. The research conclusions vary greatly under different national conditions, different institutional backgrounds and different degrees of market efficiency. The majority view is that the opaque information environment reduces the ability of stock prices to absorb information about the heterogeneity of companies; when the heterogeneity of individual stocks is weakened, their trend tends to follow the trend of the broader market, that is, the stock price synchronization is high. However, some scholars believe that high information transparency does not necessarily mean low stock price synchronization. It depends on the effectiveness of information in the market. In summary, the correlation between corporate transparency and stock price synchronization is affected by the efficiency of the capital market and the quality of market information. Under the registration system, the information quality and efficiency of the capital market have improved to a certain extent, so it is particularly necessary to re-examine the relationship between information transparency and stock price synchronization. We introduced internal control audit as a moderating variable into this study. As a key institutional arrangement for maintaining market order, internal control audit is of great significance to the stable and healthy development of the capital market. It seems that the registration system reform and internal control audit can play a "synergistic effect" in the process of listing supervision.In this paper, the data of A-share listed companies in Shanghai and Shenzhen from 2015 to 2021 were selected as samples, and the relationship between corporate transparency and stock price synchronization was empirically tested by using the individual fixed-effect model and group regression method. It was found that: (1) under the registration system, the negative correlation between corporate transparency and stock price synchronization is stronger, high-quality internal control audit can strengthen the marginal contribution of corporate information transparency to stock price synchronization, and registration system reform and internal control audit can play a "synergistic effect" in the process of listing supervision; (2) the degree of uncertainty of the external environment will not affect the efficiency of stock price absorption of heterogeneous information, but the influence of endogenous factors of enterprise nature still exists, that is, the ability of stock prices to absorb heterogeneous information in non-state-owned enterprises is stronger than that of state-owned enterprises; (3) the digital transformation of enterprises also promotes the improvement of information transparency and the absorption of heterogeneous information by stock prices, which can positively adjust the synchronization of corporate transparency and stock prices, reflecting the role of technological progress in promoting modern corporate governance and capital market development.Compared with the existing literature, the contributions of this paper are as follows: (1) firstly, the relationship between corporate transparency and stock price synchronization was explored in the context of registration system reform, which will provide empirical evidence for the "information efficiency" school; (2) secondly, internal control audit was introduced as a regulating variable, and the "synergistic effect" of the registration system reform and internal control audit was explored in coping with pre-listing and post-listing risks; (3) finally, the heterogeneity test was conducted and the impact mechanism was tested to further analyze the synchronization of corporate transparency and stock price, which will increase the depth of research on the impact mechanism of the information transparency and stock price synchronization.

Key words: registration system reform, corporate transparency, internal control audit, stock price synchronization