At issue are the ratings handed out primarily by the three largest agencies: Moody's Corp., Fitch Inc. and Standard & Poor's. The ratings serve chiefly to help investors assess the strength of a company or portfolio. But bank regulators also use them, for, among other things, pinpointing areas to focus on in exams and determining permissible securities for a bank to hold. The financial crisis laid bare the flaws of the credit rating agencies, which gave high scores to what proved to be toxic mortgage-backed securities. This raised doubts about the agencies' objectivity in evaluating debt issuers that helped to fund their operations. As a result, the Dodd-Frank law included provisions designed to reduce the government's dependence on ratings, requiring them to come up with different methods for gauging credit strength wherever they now use external ratings. The law gives regulators a year "to remove any reference to or requirement of reliance on credit ratings."