| AAA | 'AAA' rated entities and instruments demonstrate exceptional credit quality and lowest expectation of default risk. |
| AA | 'AA' rated entities and instruments demonstrate very high credit quality with a very low default risk. |
| A | 'A' rated entities and instruments demonstrate high credit quality with a low default risk. |
| BBB | 'BBB' rated entities and instruments demonstrate medium credit quality with a moderate default risk. |
| BB | 'BB' rated entities and instruments demonstrate speculative credit quality with a slightly increased default risk. |
| B | 'B' rated entities and instruments demonstrate highly speculative credit quality with an increased default risk. |
| CCC | 'CCC' entities and instruments demonstrate very low credit quality with a high default risk. |
| CC | 'CC' rated entities and instruments demonstrate very low credit quality and an event of default is very likely. |
| C | 'C' rated entities and instruments demonstrate the lowest credit quality and an event of default is imminent. |
| D/SD | 'D' rated entities and instruments have defaulted, as defined by NCR. 'SD' (selective default) rated entities have only defaulted on certain debt obligations. |
| Plus (+) and minus (-) | Rating categories from 'AA' to 'B' are modified by a plus (+) or a minus (-), where required, to show their relative position within the rating category. |