Using the reputation concept, this study examines the announcement effect of expansion-type projects in Taiwan Stock Market. We have 170 samples from January 1, 1992 to December 31, 1994. Overall, the result shows positive wealth effect on the announcement date, and the positive wealth effect is clearly associated with the short-term investment group. Accordingly, we suggest that the previous finding of the pay-back method being the popular in practice is explained by the managerial reputation effect and the myopic of investors.