Screening for A-Shares After a Prior-Day Opening Limit-Down Signal

Summary

This A-share screening rule combines a current amplitude threshold with a prior-day signal involving the 9:15 matched price and limit-down conditions. It also excludes Beijing-listed shares and, in the final version, ST-designated stocks. The article describes the setup as a way to consider volatility and market sentiment, and its sample code proposes ranking candidates by stock popularity.

The post offers formula references and code examples, but no tested results or explanation of how the signal performed. It warns that the rule omits broader market and industry conditions and may overfit technical inputs, limiting its usefulness across market regimes. Suggested refinements include adding fundamental and technical factors, applying risk controls such as stop levels, and evaluating the screen through backtesting. The examples are presented as references that may require adaptation, so they do not establish a reliable trading strategy.

Key ideas

• The screen combines an amplitude threshold with a prior-day opening matched-price and limit-down condition.
• It excludes Beijing-listed A-shares and, in the final rule, ST stocks.
• The example ranks selected stocks by a popularity measure, but the post reports no empirical results.
• The author warns that technical-only screening may overfit and ignores market-wide and sector conditions.
• Backtesting, additional factors, and risk controls are proposed as ways to refine the rule.

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.