This paper collects data from Taiwan Market Observation Post System in Year 2002. In order to meet the statistical requirement by way of collecting enough samples, there are eight events investigated in this paper: CEO changing, asset disposal, investing in China, order obtaining clarifying ns media reports, getting pats, stock dividend and financial forecasting revision. The paper would like to find if these information are useful for investors; however, the results are very disappointed to investors, since investors are hardly to get profits by acquiring these news except the event of order obtaining without concerning transaction costs in the short run.