Credit rating scale helps in evaluating the credit worthiness of a debtor. There are different types of credit rating scale and you can gain knowledge about them. What do letter ratings indicate? Can credit ratings be used for investment purposes? Do credit ratings change? What do you need to know about credit rating scale? Aaa – The obligations are of the highest quality with the lowest level of credit risk Aa - The obligations are of high quality with the low level of credit risk A - The obligations are medium quality with the low level of credit risk Baa - The obligations are medium quality with moderate credit risk Ba - The obligations are speculative with substantial credit risk B - The obligations are speculative with high credit risk Caa - The obligations are of poor standing with substantial credit risk Ca - The obligations are highly speculative and may default on payments C - The obligations are lowest rated P1 – There is a superior ability to pay the s