AAA-rated bonds have a high degree of creditworthiness because their issuers are easily able to meet financial commitments and have the lowest risk of default.The highest ratings that may be assigned to an issuer's bonds by any of the major credit rating agencies.Rating agencies use the letters "AAA" to identify bonds with the highest credit quality, while Moody's uses the similar "AAA" to signify a bond's top-tier credit rating.