What are high-yield bonds?
Credit rating agencies, of which Moody's, S&P and Fitch are by far the largest, assess the creditworthiness of individual bonds and of the governments and firms that issue them. The credit ratings they issue reflect the probability of firms or governments being unable to meet their payment obligations. In addition, they factor in the expected loss a creditor faces if the issuer of the debt security should default.
Credit ratings are expressed on a scale, and most market operators use them as guidance in taking their investment decisions. ‘AAA’ is the highest possible credit rating. By contrast, ‘D’ is the lowest, indicating that the issuer is in default, having failed to meet one or more payment obligations. As a firm or government’s creditworthiness remains the same or changes, agencies can from time to time confirm previously issued ratings or upgrade or downgrade their debt securities.
Ratings of BBB- and up are commonly referred to as 'investment-grade', while those of BB+ or lower are known as 'high-yield'. As the latter category carries a higher probability of default, investors demand a higher interest rate in compensation.