L'impact des annonces de notation de crédit sur les valeurs européennes : une comparaison avant et pendant la crise de 2008

This paper focuses on differences of reaction of common stock returns to rating announcements for 231 exchange-listed European companies before and during the 2008 financial crisis. These ratings were announced by Standard & Poor?s from July 1 2005 to December 31 2008. The empirical analysis conducted from an event study by type of credit rating announcement shows that these announcements have an almost immediate impact on the stock returns. Depending on the nature of the announcement, we observe that investors construe differently the information content of ratings, especially when it comes to positive announcements. Robustness analysis confirms that rating agencies decisions have little impact on investors in times of crisis. Classification JEL: G14, G24.