Abstract : Credit default swaps (CDSs), initially intended as instruments for hedging and managing credit risk, have been pinpointed during the recent crisis as being detrimental to ﬁ nancial stability. We argue that the impact of credit default swap markets on ﬁ nancial stability crucially depends on clearing mechanisms and capital and liquidity requirements for large protection sellers. In particular, the culprits are not so much speculative or “naked” credit default swaps but inadequate risk management and supervision of protection sellers. When protection sellers are inadequately capitalised, OTC (over-the-counter) CDS markets may act as channels for contagion and systemic risk. On the other hand, a CDS market where all major dealers participate in a central clearing facility with adequate reserves can actually contribute to mitigating systemic risk. In the latter case, a key element is the risk management of the central counterparties, for which we outline some recommendations.