According to Tesco's query, the excess return model in the secondary market was proposed by Treynor and Mazuy in 1966 to explain the fund return model. The model divides the fund income into three parts: one is the alpha income brought by the fund manager's stock selection ability. The second is the beta income brought by the market rise. The third is the gamma income brought by the fund manager's timing ability. According to this model, when the risk-free rate of return and the average rate of return of the underlying index are known, the gamma income can be calculated in reverse.