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中国管理科学 ›› 2023, Vol. 31 ›› Issue (10): 1-11.doi: 10.16381/j.cnki.issn1003-207x.2020.0779

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融资融券降低了交易中的信息不对称程度吗?

王明涛,李茜()   

  1. 上海财经大学金融学院,上海 200433
  • 收稿日期:2020-04-30 修回日期:2023-01-23 出版日期:2023-10-15 发布日期:2023-11-03
  • 通讯作者: 李茜 E-mail:14669841@qq.com
  • 基金资助:
    国家自然科学基金重大研究计划重点资助项目(91546202)

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

摘要:

降低交易中的信息不对称对维护市场公平具有重要意义。本文以我国融资融券渐进式扩容为背景,采用A股市场1分钟高频交易等数据,利用双重差分和固定效应模型,从制度实施及信用交易本身两个层面对融资融券是否降低了交易中信息不对称程度进行了研究。结果表明,两融制度实施降低了标的股票交易中的信息不对称程度,其中“好消息”的不对称程度逐年下降,“坏消息”的不对称程度先升后降。融资交易降低了标的股票交易中“好消息”的不对称程度,融券交易提高了“坏消息”的不对称程度。进一步研究发现,基于公开(未公开)信息的融资交易降低(提高)了“好消息”的不对称程度,基于公开和未公开信息的融券交易均提高了“坏消息”的不对称程度。牛市、熊市分别减弱和加强了融资交易对信息不对称程度的降低作用,加强和减弱了融券交易对信息不对称程度的提升作用。

关键词: 融资融券, 信息不对称, 信息优势

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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