When Did the Stock Market Start to React Less to Downgrades by Moody’s, S&P and Fitch?

Moody’s, S&P and Fitch represent an oligopoly in the credit rating business, accounting for 94 percent of the global market (Candelon et al., 2014) and for about 96.5 percent of all the outstanding ratings in U.S.[1] The three agencies are key players in financial markets as they assess the credit worthiness of almost any debt issuer including governments, firms, municipalities and financial institutions. Moody’s, S&P and Fitch heavily affect corporate financing through ratings assigned to corporate debt. The economic literature has shown that bond ratings are strongly correlated with private bond yields (Hand et al., 1992; Hite and Warga, … Read more