A type of fixed-income security that is not backed by collateral. It is backed only by the creditworthiness of the issuer (issuing entity). Unlike secured debt securities, which depend on the collateral posted, unsecured securities lack an additional layer of protection. However, the higher risk involved entails a bigger risk premium, and consequently a higher potential return.

Examples of unsecured debt securities include commercial paper, unsecured bonds, and debentures. These securities are particularly attractive for investors seeking higher returns compared to those generated by available secured securities.

It is also called an uncovered debt security.