Opinion of the European Central Bank of 11 October 2017 on a proposal for a regulation of the European Parliament and of the Council amending Regulation (EU) No 648/2012 as regards the clearing obligation, the suspension of the clearing obligation, the reporting requirements, the risk-mitigation techniques for OTC derivatives contracts not cleared by a central counterparty, the registration and supervision of trade repositories and the requirements for trade repositories (CON/2017/42)