Credit default swaps (CDSs) are contracts between buyers and sellers of protection against default. They are a form of debt insurance, or more precisely derivatives contracts that investors buy to either insure against or profit from a default. In this way CDS contracts act as a form of debt insurance in that they provide a means of protection against credit risk. In the aftermath of the global financial crisis, the CDS earned the reputation of a ‘financial weapon of mass destruction’. Why? Is this charge justified? This paper shows that the reality is more complex: CDSs carry benefit as well as costs, and the risks associated with them can be mitigated through prudent supervision.