Revocation of retained EU law Transitional amendments Amendments to the Markets in Financial Instruments Regulation (MiFIR) and the European Market Infrastructure Regulation (EMIR) Wholesale capital markets regulation
UK capital markets are regulated under the framework that the UK inherited from the EU: the MiFID II framework (with ‘MiFID’ standing for ‘Markets in Financial Instruments Directive’). The MiFID II framework has been, where necessary, brought into UK law and amended to address deficiencies resulting from the UK’s withdrawal from the EU.
	The cornerstone of the MiFID II framework is an EU Directive known as MiFID II. 1 Being an EU Directive, MiFID II required transposition into national law across EU states. Responsibility for transposition into UK law was essentially divided between HM Treasury and the FCA: the FCA made changes to its Handbook (for example, to introduce new rules on the categorisation of clients of regulated entities), and HM Treasury dealt with the changes that had to be made to UK legislation (for example, it updated the Regulated Activities Order 2 to include new regulated activities). Although MiFID II itself was not brought into UK law, those UK-issued rules and legislation which were used to transpose it still reflect the content of that Directive.
	The other central piece of legislation in the MiFID II framework is MiFIR. Being an EU Regulation, MIFIR applies directly across EU states. MiFIR is one of the parts of the framework that was brought into UK law; this means there is now a UK version of MiFIR, which is currently treated much like UK primary legislation. In its UK version, MiFIR applies to investment firms, credit institutions and market operators with a registered or head office in the UK. 3 In this UK version, the FCA inherited functions that had belonged to the European Securities and Markets Authority (ESMA) and the European Banking Authority (EBA) under the EU version.
	A number of MiFID II and MiFIR provisions had required supplementing via delegated acts or technical standards (including regulatory technical standards (RTS)). Like MiFIR, the resulting Commission Delegated Regulations were brought into UK law but, differently from MiFIR, they are treated much like, respectively, UK subordinate legislation and regulators’ rules.
	Changes to the regulation of wholesale financial markets will involve amendment of the UK version of MiFIR. Because of the interplay between rules and legislation making up the MiFID II framework, most of these changes will also involve amendment of UK-issued law transposing MiFID II (especially the MiFI Regulations 4 ), FCA and PRA rules, and the UK versions of Commission Delegated Regulations. Many of these additional amendments will be effected other than through the Act: for example, changes to certain Commission Delegated Regulations will be effected by the FCA through powers the FCA already has.