Opinion of the European Central Bank of 22 March 2012 on: (i) a proposal for a directive on markets in financial instruments repealing Directive 2004/39/EC of the European Parliament and of the Council; (ii) a proposal for a regulation on markets in financial instruments and amending Regulation (EMIR) on OTC derivatives, central counterparties and trade repositories; (iii) a proposal for a directive on criminal sanctions for insider dealing and market manipulation; and (iv) a proposal for a regulation on insider dealing and market manipulation (market abuse) (CON/2012/21)