The purpose of this article is to empirically test the hypothesis that stock market operators use the information contained in published accounting statements in their process of evaluating the performance of listed firms. In particular, we want to know to what extent performance and market indicators can explain the abnormal performance of listed financial securities. After a review of the literature on the usefulness of financial information in the market valuation of listed companies (section I), the research methodology (section II) will be discussed and the empirical results (section III).