Their specialists research a business's circumstance and determine a bond ranking for the business. Every ranking service has its own formula for determining risk and its own type of score scale. Generally, rating scales are defined in letter grades, where an AAA rating designates a safe, low-risk bond, and a D ranking designates a high-risk bond.federal government bonds, are generally low-yield bonds. You can depend on getting a payment however that payout will be small. what is a bond personal finance. On the other side of the spectrum, you have what's not-so-affectionately referred to as, which are low-rated, high-risk bonds. In order to entice investors into buying these risky junk bonds, the issuing business promise high yields.