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The Stock Market Impact Of Bond Rating Changes, Michael Leonard

Honors Projects in Mathematics

This paper examines the impact of a downgrade of a company’s credit rating on its stock price in the days surrounding the downgrade. If we consider this downgrade new information, then a negative impact on the company’s stock price would be expected. However, if we assume that rating agencies use information that investors have already accounted for, then there would be no impact. There could also be an impact, at least temporarily, due to the fact that a ratings downgrade is bad news, even if the reasons for the downgrade have already been priced in. To perform this analysis I …