The tail-end volume ratio factor is negatively correlated with the stock's future returns, which means that stocks with a higher proportion of tail-end volume tend to have lower future returns. This phenomenon may be attributed to the following points: 1. Tail-end speculative behavior: The tail-end period may be full of speculative behavior, and some investors may try to influence the stock price by trading before the close. This irrational trading behavior may cause the stock price to deviate from its intrinsic value; 2. Differences between informed and uninformed traders: Uninformed traders such as retail investors may be more inclined to trade in the tail-end to avoid intraday fluctuations due to their low risk tolerance. Informed traders such as institutional investors may be more inclined to trade in the morning due to their information advantage. This difference in trading behavior may lead to information asymmetry in the tail-end period, thereby affecting the rationality of stock prices. Therefore, the tail-end volume ratio can be used as an indicator to measure market sentiment and investor behavior, which helps to capture potential abnormal signals in the market. In practical applications, this factor is often used in combination with other factors to improve the effectiveness of stock selection strategies.