Sovereign rating can be defined as an assessment of the relative likelihood that a Government will default on its obligations. Although the first rating assigned to Brazil dates from 1986, the importance of sovereign rating increased as from 1994, by which time brady bonds were issued and begun to be actively traded. In theory, the role of credit rating would be to add new information to the market, and therefore, their analyses would influence market behaviour; however, several financial market observers have criticized them for just reacting to completely available information. This study therefore analyses the impacts of sovereign rating changes announcements on c-bond spreads. We analysed how c-bond spreads respond to the agencies´ announcements of changes in their sovereign risk assessments and our analyses indicate that the ratings changes do influence c-bond spreads, most significantly in downgrades events.