The issuer of the debt that is “insured” by a credit derivative. In other words, it is the institution (known as a name) that issued the so-called reference asset (debt security) that is covered by a credit derivative (for credit protection), such as a credit default swap (CDS).  It is the entity against which payments under the credit default insurance are calculated- so that the protection buyer pays to the protection seller on a regular basis (in the form of CDS premiums).