Public Gap-Reversion Strategies and Market Efficiency

Summary

The document raises a question about a proposed equity strategy: after an opening gap, absent major news or an unusually large move, prices may return toward the prior close. It asks whether a publicly known version of this gap-reversion idea can produce returns above the market after accounting for risk, and why any apparent relationship might persist if it is widely known.

No answer, data, or trading rules are provided, so the document does not establish that the effect exists or is profitable. It also leaves key research questions open, including how to define gap size, exclude news-driven sessions, choose entry and exit times, and account for transaction costs and market impact. The text is useful as a framing of the tension between a visible historical pattern and competition among traders, but it offers no evidence or method for resolving that tension.

Key ideas

• The proposed setup expects some opening price gaps to reverse toward the prior close.
• The question is whether the pattern can deliver risk-adjusted returns after becoming widely known.
• News and unusually large gaps are suggested as conditions that may change the expected behavior.
• The document presents no evidence, test design, or specific entry and exit rules.
• Costs, market impact, and precise definitions would need to be addressed in any evaluation.

Tags

# Can a publicly known gap trading strategy be profitable and if so why?


# Can a publicly known gap trading strategy be profitable and if so why?












Newbie to this field, please forgive any lacking knowledge...

There is various literature (example) on trading according to strategies which assume that (in the absence of a large gap, or major news) the Dow will return to something approximating yesterday's closing price shortly after the market opens.

Can such a strategy, if publicly known, deliver consistent above market returns for the risk (e.g. as defined by sharpe ratio)? Intuitively I would think that any correlation so obvious/public would be reflected in the price already. If this is not the case then how does it remain so?

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

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