This fourth progress report complements earlier progress reports by focusing on the readiness of market infrastructure to support OTC derivatives market reforms as the G20’s end-2012 deadline for these reforms approaches. Market infrastructure is in place and can be scaled up, but regulatory uncertainty remains the most significant impediment to further progress and to comprehensive use of market infrastructure. This report also includes a brief update on progress in international policy, national legislation and regulation, and the status of implementation of the four safeguards for a resilient and efficient global framework for central clearing.