The system of rating securities was originated by John Moody in 1909. The purpose of Moody's ratings is to provide investors with a simple system of gradation by which future relative creditworthiness of securities may be gauged.
Gradations of creditworthiness are indicated by rating symbols, with each symbol representing a group in which the credit characteristics are broadly the same. There are nine symbols as shown below, from that used to designate least credit risk to that denoting greatest credit risk:
Aaa Aa A Baa Ba B Caa Ca C
Moody's appends numerical modifiers 1, 2, and 3 to each generic rating classification from Aa through Caa.
Click here to view Moody's Rating Symbols and Definitions
Absence of a Rating
Where no rating has been assigned or where a rating has been withdrawn, it may be for reasons unrelated to the creditworthiness of the issue.
Should no rating be assigned, the reason may be one of the following:
1. An application was not received or accepted.
2. The issue or issuer belongs to a group of securities or entities that are not rated as a matter of policy.
3. There is a lack of essential data pertaining to the issue or issuer.
4. The issue was privately placed, in which case the rating is not published in Moody's publications.
Withdrawal may occur if new and material circumstances arise, the effects of which preclude satisfactory analysis; if there is no longer available reasonable up-to-date data to permit a judgment to be formed; if a bond is called for redemption; or for other reasons.
Changes in Rating
The credit quality of most issuers and their obligations is not fixed and steady over a period of time, but tends to undergo change. For this reason changes in ratings occur so as to reflect variations in the intrinsic relative position of issuers and their obligations.
A change in rating may thus occur at any time in the case of an individual issue. Such rating change should serve notice that Moody's observes some alteration in creditworthiness, or that the previous rating did not fully reflect the quality of the bond as now seen. While because of their very nature, changes are to be expected more frequently among bonds of lower ratings than among bonds of higher ratings. Nevertheless, the user of bond ratings should keep close and constant check on all ratings — both high and low — to be able to note promptly any signs of change in status that may occur.
Limitations to Uses of Ratings*
Obligations carrying the same rating are not claimed to be of absolutely equal credit quality. In a broad sense, they are alike in position, but since there are a limited number of rating classes used in grading thousands of bonds, the symbols cannot reflect the same shadings of risk which actually exist.
As ratings are designed exclusively for the purpose of grading obligations according to their credit quality, they should not be used alone as a basis for investment operations. For example, they have no value in forecasting the direction of future trends of market price. Market price movements in bonds are influenced not only by the credit quality of individual issues but also by changes in money rates and general economic trends, as well as by the length of maturity, etc. During its life even the highest rated bond may have wide price movements, while its high rating status remains unchanged.
The matter of market price has no bearing whatsoever on the determination of ratings, which are not to be construed as recommendations with respect to "attractiveness". The attractiveness of a given bond may depend on its yield, its maturity date or other factors for which the investor may search, as well as on its credit quality, the only characteristic to which the rating refers.
Since ratings involve judgements about the future, on the one hand, and since they are used by investors as a means of protection, on the other, the effort is made when assigning ratings to look at "worst" possibilities in the "visible" future, rather than solely at the past record and the status of the present. Therefore, investors using the rating should not expect to find in them a reflection of statistical factors alone, since they are an appraisal of long-term risks, including the recognition of many non-statistical factors.
Though ratings may be used by the banking authorities to classify bonds in their bank examination procedure, Moody's ratings are not made with these bank regulations in mind. Moody's Investors Service's own judgement as to the desirability or non-desirability of a bond for bank investment purposes is not indicated by Moody's ratings.
Moody's ratings represent the opinion of Moody's Investors Service as to the relative creditworthiness of securities. As such, they should be used in conjunction with the descriptions and statistics appearing in Moody's publications. Reference should be made to these statements for information regarding the issuer. Moody's ratings are not commercial credit ratings. In no case is default or receivership to be imputed unless expressly stated.
*As set forth more fully on the copyright, credit ratings are, and must be construed solely as, statements of opinion and not statements of fact or recommendations to purchase, sell or hold any securities. Each rating or other opinion must be weighed solely as one factor in any investment decision made by or on behalf of any user of the information, and each such user must accordingly make its own study and evaluation of each security and of each issuer and guarantor of, and each provider of credit support for, each security that it may consider purchasing, selling or holding.