A credit default swap (CDS) is a credit derivative contract between two counterparties, where the “buyer” makes periodic payments to the “seller” in exchange for the right to a payoff if there is a default or “credit event” regarding the failure of a third party. They are very similar to an insurance contract over the possibility of company failure particularly on the bonds and corporate debt of the “reference entity” company which is the subject of the CDS. Unlike insurance, however, there is no limit on the number of times that a company can be covered or subject to a CDS. In return for small payments like insurance premiums the buyer of the CDS could stand to make an enormous windfall profit in the event of the failure of the subject. The recent failure of Lehman Brothers caused a credit event which ultimately led to a 92 cents on the dollar liability on CDSs written on Lehman debt.

Credit default swaps are the most widely traded credit derivative product. The Bank for International Settlements reported the notional amount on outstanding OTC credit default swaps to be $42.6 trillion in June 2007. By the end of 2007 there were an estimated USD 60 trillion worth of Credit Default Swap contracts. In the US alone, the Office of the Comptroller of the Currency reported the notional amount of outstanding credit derivatives from reporting banks to be $16.4 trillion at the end of March, 2008. (To put these numbers in perspective, the CIA World Fact Book estimated the US GDP for 2007 at $13 trillion)/ One large difference between credit default swaps and other types of insurance, is you do not need to own the bond or instrument being insured in order to obtain insurance on it. If the bond fails, then you get paid, provided the bank writing the contract does not fail. Yet the “insurer” of the bond is not regulated on any exchange and the transaction is largely beyond any government regulation. Speculators can make money by purchasing insurance on a company's bonds then short the stock (sell the stock without owning it) of the company in great quantity, causing pressure on the company to either fail or the value of their CDS to rise. If the company fails the returns can be enormous.

There is a massive overhang of speculative positions in CDS – the market is dramatically larger than the corporate debt which it is covering. One can possibly understand the motive for mitigating the risks of corporate failure for those holding the corporate debt of the reference company. However, when CDS amount to several times the debt in existence it is clear that a large number of speculators are gambling over company failure rather than seeking to mitigate risk. For Lehman Brothers $150 billion total of debt, $400bn of CDS contracts were in issuance. The $60 trillion market for these weapons of mass destruction has taken gambling to a new and unprecedented level.