American credit rating agencies are facing greater scrutiny from US Securities and Exchange Commission (SEC).
Under new rules adopted by the commission, the agencies must disclose more information on past ratings to help investors make informed judgements.
The agencies, such as Standard & Poor's, Moody's, and Fitch, give company ratings to determine how safe an investment may be.
The BBC reports they have been criticised for their role in the financial crisis, particularly for failing to spot the size and risk of bad US housing debt.
Earlier this year, credit rating agencies admitted errors were made when assessing some of the financial instruments that have been blamed for the credit crunch.
SEC head Mary Schapiro says investors' reliance on agency ratings "did not serve them well over the last several years".