Abstract: The credit rating system aims to provide investors with real and effective information to improve the market′s “information asymmetry” and thus improve the trading efficiency of the market. However, under the “Issuer” payment model, the authenticity of the rating is questionable. Based on the credit bond transaction data from 2010 to 2017, this report examines the rating results of the credit rating agencies,finding credit rating agencies have “Pro-cyclical” behavior when they are rating. That is, the rating agencies have a positive “impulse” of overestimating the subjects during the economic boom period,and this behavior is especially obvious in the samples of state-owned enterprises, the samples in the period of rapid growth and the samples which have strong debt repayment abilities; the oligopolistic competition in the rating market and the “rated purchase” behavior of low-rated entities may be an important reason for the rating agencies to overestimate the rating. Therefore, in order to ensure the authenticity of credit rating, the key method is to eliminate the incentive distortion mechanism of rating agencies, improve the constraint of comprehensive credit mechanism on the behavior of rating agencies, and increase the transparency of rating system.

Key words: credit rating agencies, Pro-cyclical;rating overestimation;rating purchase