Moody's Long-term Corporate Obligation Ratings are opinions of the relative credit risk of fixed-income obligations with an original maturity of 1 year or more. The ratings reflect both the likelihood of default and any financial loss suffered in the event of default.
Moody's rating is widely used in the financial world along with S&P Ratings.
The rating scale is as follows:
Moody's Investment Grade: Aaa → Aa1 → Aa2 → Aa3 → A1 → A2 → A3 → Baa1 → Baa2 → Baa3
Moody's Speculative Grade: Ba1 → Ba2 → Ba3 → B1 → B2 → B3 → Caa1 → Caa2 → Caa3 → Ca → C