This study tests whether the effect of the free cash flow rate on the stock return rate better indicates the stock market return than the Book-to-Market ratio by using corporate earnings management research. We created a five-factor model based on the three-factor model by Fama and French to test our hypotheses. The model uses 5 factors as the independent variables, which are the free cash flow rate, corporate growth rate, log value of the corporation size, fixed asset rate, and long-term liability rate. This study applies this five-factor model to explain the stock return rate (i.e., the dependent variable). We found that the highest weighted factor in the model was the free cash flow rate, whereas the other factors were secondary. For the process, we applied the panel regression analysis method to examine 491 listed corporations in Taiwan over an 11-year period from 1999 to 2010. The results indicate that the effect of the free cash flow rate on the stock market return rate is significant. Fund managers should choose to invest in companies with a higher free cash flow
rate to improve portfolio performance.