In the financial markets, gap phenomena have always been a focus for traders. Typically, the filling of gaps tends to occur the following day, which is the most common scenario. However, the uncertainty of the market can extend the time frame for gap filling to a week or even longer.

It is worth noting that the probability of gap filling decreases over time. The likelihood of filling within a week is relatively low, while cases that fill several months later are even more rare. For example, gaps caused by market fluctuations triggered by significant events last year were not filled until March of this year, which is not a common occurrence.

Based on this probability distribution, when observing the second trading day after a gap occurs, one might consider establishing a moderate short position. However, it is crucial to exercise caution in controlling the position size when implementing this strategy. Overextending the position may introduce unnecessary risk, so maintaining a prudent attitude is a wise choice.

Every trader should develop strategies based on their own risk tolerance and market judgment. While gap filling is a common phenomenon, the complexity of the market means there are no absolute rules to follow. Continuous learning, adapting to market changes, and making decisions based on multiple factors are the keys to long-term success.