This Practice Note considers the impact of the UK’s withdrawal from the EU on the supervision of central counterparties (CCPs), trade repositories, and central securities depositories (CSDs) in the UK, including the temporary recognition regime and run-off regime for non-UK CCPs, the temporary registration regime and conversion regime for UK trade repositories, and the transitional regime for non-UK CSDs, as well as the temporary designation regime for settlement finality. The European Union (Withdrawal) Act 2018, as amended by the European Union (Withdrawal Agreement) Act 2020, makes provision for the ratification and implementation in domestic law of the Withdrawal Agreement between the UK and the EU. The Withdrawal Agreement sets out the arrangements for the UK’s withdrawal from the EU. It includes a transition period (or, to use the UK government’s phraseology, an ‘implementation period’) beginning on 31 January 2020 and ending on 31 December 2020 (IP completion day). During the implementation period, the UK was treated, for most purposes, as if it were still an EU Member State with access to EU markets