A bond rating is a score assigned to a bond that indicates its credit quality and the likelihood of default. Ratings are provided by agencies like Moody's, Standard & Poor's, and Fitch, which evaluate the issuer's financial health and ability to meet its debt obligations. Higher ratings suggest lower risk, while lower ratings indicate higher risk. Investors use bond ratings to make informed decisions about purchasing bonds. A bond rated as AAA is considered very safe, while a bond rated as C is seen as highly speculative. These ratings help investors assess potential returns against the risks involved.