Analysis of a rating agency’s credit models

Brattle worked with the Department of Justice (DOJ) in a landmark suit involving whether Standard & Poor’s knowingly published inflated ratings for large mortgage-backed securities that ultimately turned toxic, exacerbating the financial crisis. Brattle worked with the DOJ from the early stages of the case to analyze S&P’s ratings methodology, potential changes to its ratings model inputs, and their impact on investment decisions and financial markets. Brattle consultants advised the DOJ and, separately, worked with testifying experts on both the ratings models and their macroeconomic implications. Our work included rigorous analyses of S&P’s internal documents and models to document the sensitivities of ratings on RMBS and CDOs to alternative assumptions, versions of the model, and the rationale for the qualitative adjustments to the quantitative model results. The case ultimately resulted in a $1.4 billion settlement.