Firms have to manage their debt level, which are revealed by their credit rating, if they want to pursue an internationalization strategy. These companies need to manage their debt level in order to maintain their rating. The analysis of 402 rating changes announced by Standard and Poor’s for 182 European multinational companies reveals on average an asymmetric reaction of the stock market : a decrease in stock prices following downgrades but no reaction following upgrades. However, individual reactions are strongly negative in half the downgrade cases and null or positive for the other half. Results are symmetric for upgrades.