A credit rating agency (CRA) is a company that assigns credit ratings for issuers of certain types of debt obligations as well as the debt instruments themselves. In some cases, the servicers of the underlying debt are also given ratings. In most cases, the issuers of securities are companies, special purpose entities, state and local governments, non-profit organizations, or national governments issuing debt-like securities (i.e., bonds) that can be traded on a secondary market. A credit rating for an issuer takes into consideration the issuer's credit worthiness (i.e., its ability to pay back a loan), and affects the interest rate applied to the particular security being issued. (In contrast to CRAs, a company that issues credit scores for individual credit-worthiness is generally called a credit bureau or consumer credit reporting agency.)
Your vote on this answer has already been received
Credit rating is an assessment of the credit worthiness of individuals and corporations. It is based upon the history of borrowing and repayment, as well as the availability of assets and extent of liabilities.
If you want info about surety bond, commercial bonds, contractors bond etc visit http://www.probondins.com/