Rating organisations evaluate the credit worthiness of an issuer with respect to debt instruments or its general ability to pay back debt over the specified period of time. The rating is given as an alphanumeric code that represents a graded structure or creditworthiness. Typically the highest credit rating is AAA and the lowest is D (for default). Within the same alphabet class, the rating agency might have different grades like A, AA, and AAA and within the same grade AA+, AA- where the "+" denotes better than AA and "-" indicates the opposite. For short-term instruments of less than one year, the rating symbol would be typically "P" (varies depending on the rating agency).
Fixed Income, Credit Rating