Bond ratings gauge a bond issuer’s financial ability to repay its promised principal and interest payments. Bond ratings are based on an analysis of the issuer’s financial condition and creditworthiness. In essence, the higher the rating, the more likely it is that a bondholder will receive his or her principal again when the bond matures.
Credit rating agencies assess the risks of certain bonds, issuing grades that reflect the issuer’s ability to meet the promised principal and interest payments. The best-known independent rating services are Standard & Poor’s, Moody’s Investors Service, and Fitch Ratings. The following are the rating scales for each agency, ranging from the highest quality to the lowest (and possibly default). They are rated in descending alphabetic order from A to D.