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Chinese Journal of Management Science ›› 2025, Vol. 33 ›› Issue (6): 1-13.doi: 10.16381/j.cnki.issn1003-207x.2022.1247

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Over-reaction, Jump Return and A-share Momentum Strategy

Longbing Xu1,2,3(), Wenbin Wu1   

  1. 1.School of Finance,Shanghai University of Finance and Economics,Shanghai 200433,China
    2.Dishui Lake Advanced Finance Institute,Shanghai University of Finance and Economics,Shanghai 201306,China
    3.School of Finance,Xinjiang University of Finance and Economics,Urumqi 830012,China
  • Received:2022-06-07 Revised:2023-04-17 Online:2025-06-25 Published:2025-07-04
  • Contact: Longbing Xu E-mail:xlb@mail.shufe.edu.cn

Abstract:

Existing literature have proved that the disappearance of momentum effect in A-share market is due to the over-reaction of investors, however such strategy construction through double-sorting that uesd in proving leads to its limited practical feasibility.In this paper it tries to find single indicator which can measure momentum effect, and transform momentum effect to momentum strategy.There are many individual investors in A-share market, which is one of the greatest differences between A-share market and other developed market like U.S. stock market. The researches on abnormal trading behavior in A-share market form stock exchanges have shown that individual investors who prefer short-term trading will exacerbate the intraday herd effect and promote stock prices to jump within the day.Based on this fact, daily return is decomposed into two parts: jump return and non-jump return, with the analysis framework of Lou et al. (2019) and intraday jump test of Jiang and Zhu (2017), and then subsequent analysis is conducted. Jump return is discussed from three perspectives: herd effect, fundamental information shock, and investor sentiment. The empirical results show that: (1) jump return is significantly correlated with intraday herd effect, while buying herd effect is positively correlated and selling herd effect is negatively correlated; (2) The PEAD phenomenon mainly comes from non-jump return; (3) Jump return is significantly positively correlated with investor sentiment. Based on the above empirical results, it is concluded that the jump return in A-share market mainly reflects the overreaction of investors, which is different from the explanation of risk premium or under-reaction in U.S. stock market.In the horizontal comparison of time series and cross-sectional, jump return can explain other overreaction proxy variables, but not vice versa. After eliminating the jump return, there is a significant monthly momentum effect in A-share market. From 2008 to 2019, the size neutral momentum long-short portfolio based on non-jump return achieved an average monthly return of 0.92% and 1.27% monthly alpha of the CH-3 model.The causes of intraday stock price jump in A-share market are analyzed for the first time, and momentum strategy is constructed with single indicator, that contributes both in the theroy and practice.

Key words: over-reaction, return decomposition, jump return, momentum strategy

CLC Number: