The gross value of this derivatives market is approximately fifteen times larger than annual global GDP. In moving this market to a standardised open public clearing house environment, any central clearing house will need to guarantee counter-party risk. While most of the positions cancel one another out to leave a smaller net aggregate position, the market is so large that the failure of a participant to meet even a small fraction of market obligations could cause multi-trillion dollar liabilities and losses.
The only logical ultimate guarantor would be US, European, and UK taxpayers.
This "over the counter" (OTC) (which means the market is not conducted on a public exchange) derivatives market is dominated by six financial institutions: Bank of America, Barclays, Citigroup, Deutsche Bank, Goldman Sachs, and JP Morgan. These have already been declared to be "too big to fail" and hence are implicitly assured of government support, apparently irrespective of any greater risk they continue to take on. Their assumption of risk continues to grow at a rapid pace.
No one would ever receive a second bail-out after the revelation of falsified accounts after a first bail-out. They would go to jail. Greece was given a second bail-out after their national accounts were revealed to have been falsified.
A Greek sovereign default would require the performance of some OTC derivatives insurance positions to meet obligations, which would expose some of those institutions to potentially huge liabilities. This is why US, UK and European authorities are determined to prevent Greek default, at apparently any cost. And it is why Greece doesn't need to really care about debt reduction anymore. This might be why Greece has been granted two bail-outs despite falsified national accounts, an outcome otherwise unfathomable.
I thank JSMineset for drawing my attention to CNBC's "EU agrees rules for $700 trillion derivatives market".