the reference entity. If AAA-Bank defaults but Risky Corp. does not, the buyer might need to replace the defaulted CDS at a higher cost. The seller takes the risk that the buyer may default on the contract, depriving the seller of the expected revenue stream. More importantly, a seller normally limits its risk by buying offsetting protection from another party — that is, it hedges its exposure. If the original buyer drops out, the seller squares its position by either unwinding the hedge transaction or by selling a new CDS to a third party. Depending on market conditions, that may be at a lower price than the original CDS and may therefore involve a loss to the seller. In the future, in the event that regulatory reforms require that CDS be traded and settled via a central exchange/clearing house, such as ICE TCC, there will no longer be "counterparty risk", as the risk of the counterparty will be held with the central exchange/clearing house. As is true with other forms of over-the-counter derivatives, CDS might involve liquidity risk. If one or both parties to a CDS contract must post collateral (which is common), there can be margin calls requiring the posting of additional collateral. The required collateral is agreed on by the parties when the CDS is first issued. This margin amount may vary over the life of the CDS contract, if the market price of the CDS contract changes, or the credit rating of one of the parties changes. Many CDS contracts even require payment of an upfront fee (composed of "reset to par" and an "initial coupon."). Another kind of risk for the seller of credit default swaps is jump risk or jump-to-default risk. A seller of a CDS could be collecting monthly premiums with little expectation that the reference entity may default. A default creates a sudden obligation on the protection sellers to pay millions, if not billions, of dollars to protection buyers. This risk is not present in other over-the-counter derivatives. Sources of market data Data about the credit default swaps market is available from three main sources. Data on an annual and semiannual basis is available from the International Swaps and Derivatives Association (ISDA) since 2001 and from the Bank for International Settlements (BIS) since 2004. The Depository Trust & Clearing Corporation (DTCC), through its global repository Trade Information Warehouse (TIW), provides weekly data but