(4)From 30 March 2019, UK CSDs will be ‘third-country CSDs’ and, as such, may only provide notary and central maintenance services in relation to financial instruments constituted under the law of a Member State if they are recognised by the European Securities and Markets Authority (‘ESMA’) in accordance with Article 25 of Regulation (EU) No 909/2014. In the absence of the recognition of UK CSDs, Union issuers may not use UK CSDs to record transferable securities constituted under such laws in book-entry form in a CSD as required by Article 3 of Regulation (EU) No 909/2014. That situation may result in temporary challenges for issuers to fulfil their legal obligations. As announced in the Contingency Action Plan, it is therefore necessary that, in that exceptional situation, the legal and supervisory arrangements governing UK CSDs are determined as equivalent for a strictly limited period of time and under specific conditions so that those CSDs may continue to provide notary and maintenance services in the Union.