Complex sentence: To determine a bond's rating, a credit rating agency will analyze the accounts of the issuer and the legal agreements attached to the bond to produce what is effectively a forecast of the bond's chance of default, expected loss, or a similar metric.
Split into simpler sentences: To determine a bond's rating, a credit rating agency will analyze the accounts of the issuer and the legal agreements attached to the bond. The resultant credit rating is effectively a forecast reflecting the bond's perceived chance of default, expected loss, or a similar metric.