Brexit is likely to lead to the relocation of UK financial services firms to the EU in order to be able to access EU markets, mainly through the EU passport. The same applies to the EU firms intending to be active on the UK markets. The access conditions to the EU markets are numerous and complex, laid down in EU and national legislation and regulation, and applied by the national supervisory authorities. The European Supervisory Authorities or “ESAs” have published elaborate statements, called Opinions, on the detailed access conditions and the way they intend to apply these. The two main objectives are the full application of EU law, and the avoidance of authorizing EU firms that would be “empty boxes” for activity that would in fact be exercised in the UK, and this mainly by delegating activities to another firm. Underlying is a policy of competition between national economies for relocations of EU firms, or of business activities to be developed on the UK financial markets.