Risk and returns around bond rating changes: New evidence from the Spanish Stock Market

摘要

This study analyzes the effect of corporate bond rating changes over stock prices. We explore the effects over excess of returns and systematic risk. Rating changes by Moody´s, Standard and Poor´sor FitchIBCA are analyzed. On an efficient market, these changes will omly have some effect if they contain some new information or if they are associated to a redistribution of dummy approach. Our results indicate that rating downgrades do not cause abnormal returns around the date of the announcement while upgrades cause significantly negative effect.