主管:中国科学院
主办:中国优选法统筹法与经济数学研究会
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Chinese Journal of Management Science ›› 2023, Vol. 31 ›› Issue (10): 1-11.doi: 10.16381/j.cnki.issn1003-207x.2020.0779

   

Does Margin Trading System Reduce the Degree of Information Asymmetry in Stock Trading? ————Evidence from the Chinese Stock Market

Ming-tao WANG,Qian LI()   

  1. School of Finance,Shanghai University of Finance and Economics,Shanghai 200433,China
  • Received:2020-04-30 Revised:2023-01-23 Online:2023-10-15 Published:2023-11-03
  • Contact: Qian LI E-mail:14669841@qq.com

Abstract:

Since advantage information holders can benefit by using private information and adversely select liquidity providers, reducing information asymmetry has always been an active topic in market microstructure research. Based on the high-frequency (1-minute) data of China's A-share market from 2008 to 2019, DID is used and effect model is fixed to look at how margin trading business improves the level of information asymmetry from the perspective of regulation implementation and margin trading.From our results, the following conclusions are drawn. First, from a regulation implementation perspective, research results indicate that, after the implementation of margin trading, the degree of the information asymmetry of underlying stocks decreases. Moreover, after the shares are listed as the subject of margin trading, the degree of information asymmetry for good news decreases year by year, and the degree of information asymmetry for bad news first increases and then decreases. Second, from a margin trading perspective, it is confirmed that an inferior level of information advantage in financing trading reduces the information asymmetry of good news, while a fairly high level of information advantage in short selling increases the information asymmetry of bad news. According to additional research, financing based on public information reduces the degree of information asymmetry in good news transactions of underlying stocks, whereas trading based on unpublished information increases it. On the other hand, both public information-based and private information-based short selling deteriorate the degree of information asymmetry in bad news trading. Finally, the effects of either long or short trading on the information asymmetry level vary across market cycles. The improvement of information asymmetry based on financing is weakened in a bull market but strengthened in a bear market, the deterioration of information asymmetry level based on short trading is strengthened in a bull market but weakened in a bear market.This study is about the effect of margin trading in Chinese stock market. According to existing research, it is found that a significant body of literature focuses on the effects of margin trading on the efficiency of financial market but seldom discuss whether the introduction of long and short trading promotes market fairness or not. This gap is bridged by identifying the effects of margin trading on the information asymmetry level from the perspective of regulation implementation and margin transactions.On the other side, the literature on information asymmetry is another related research field. In Market Microstructure Theory studies, information accuracy, information advantage, and trader characteristics are usually the key research points in earlier studies. However, it is shown that the asymmetry level of good news and bad news differs in financing and short selling, which suggests that distinguishing investor attention to good and bad news would be an interesting direction in market microstructure research.

Key words: margin trading, information asymmetry, information advantage

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