Supported by the positive accounting approach, the objective of this research was to determine whether the accounting information has become more relevant after the promulgation of Law 11.638/07. To answer the research question, it was used a sample composed by 50 public Brazilian companies before (2005-2007) and after (2008-2010) the adoption of IFRS. This is a hypothetical-deductive study with quantitative approach. The dependent variable of research is the annual return measured from the closing price of the shares. It has as independent variables the EBITDA per share, earnings per share, book value per share and revenues per share. It was developed eight research hypotheses, and 4 for common shares (ON) and 4 for preferred shares (PN). ...