Using Earnings Surprises to Capture Post-Announcement Drift in A-Shares
Summary
This research note studies post-earnings-announcement drift in Chinese A-shares: stocks reporting results above expectations may continue to earn positive abnormal returns, while those below expectations may lag. It estimates expected net profit and revenue with seasonal random-walk models, with and without a drift term, then standardizes the surprises into four measures: SUE0, SUE1, SUR0, and SUR1.
The reported event studies find post-announcement drift across all four measures, with net-profit surprises associated with stronger cumulative abnormal returns than revenue surprises. Returns remain significant for roughly three to four months, though the note says abnormal performance is already present before announcements. In stock selection, the industry- and market-cap-neutral SUE0 measure has a positive average RankIC and long-short returns, and the authors report that the factor retains selection power after controlling for other factor groups. Replacing a growth factor with an earnings-surprise factor also reportedly improves an index-enhancement portfolio's results without material changes in risk measures. These are study-specific historical findings, not guarantees; the authors cite model failure and extreme market conditions as risks.
Key ideas
- Seasonal random-walk forecasts can provide a benchmark for measuring unexpected profit and revenue.
- Standardized earnings surprise measures can be constructed with or without a drift term.
- The reported A-share event studies find post-announcement abnormal returns lasting several months.
- Net-profit surprise measures show stronger cumulative abnormal returns than revenue surprise measures in the study.
- Earnings-surprise signals overlap substantially with growth factors, but reportedly retain independent stock-selection value.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.