The main purpose of the paper is to analyze the consequences of credit rating agencies (CRA) activity on the Chinese stock market. Implementing event studies methodologies, the research measures and tests the impact of CRA’s decisions (downgrades, upgrades, watchlistings…) on the stock returns of Chinese companies listed on both Shanghai and Shenzhen stock markets. Several issues are raised in the background of the observed market reactions. First, the credibility and the role of credit rating agencies on the Chinese stock exchanges is questioned. Especially, a key issue is their ability to provide on the financial markets significant information to investors. Second, in the specific Chinese context, to highlight the differences between national Chinese agencies and international agencies presents also a specific interest.