This factor is based on the seasonal pattern of stock returns, that is, stocks tend to perform consistently in certain months. By calculating the excess returns for the same month in the past year and the past 2-5 years, this factor aims to capture this seasonal momentum effect. Specifically, if a stock outperformed the market in a certain month in the past, it is likely that the stock will continue to show relative strength in the same calendar month in the future, and vice versa. This factor captures excess return opportunities caused by seasonal factors by measuring the relative return performance of individual stocks relative to the market. It belongs to the category of relative return strategy and can be combined with other factors to construct a multi-factor model.