Impacts of credit rating changes on stock returns

Abstract

This paper studies the impact of credit ratings issued by CIC, a Vietnamese local rating agency, on stock returns of listed companies on the Vietnamese stock exchanges in the period of 2007-2010. The findings of the study confirm the assertions of the previous researches by Holthausen and Leftwich (1986), Hand, Holthausen and Leftwich (1992), Chan and Poor (2008). Specifically, CIC’s credit ratings slightly affect the stock prices of the listed firms, an evidence supporting CIC’s role and its rating quality to a certain extent. This paper also confirms semi-strong form of the Vietnamese stock market efficiency.