(5)The approach used in third countries and also taken by trade repositories themselves as they start their businesses should be taken into account. Therefore, to ensure a cost-effective solution for counterparties and to mitigate operational risk for trade repositories, the reporting start date should include phase-in dates for different derivative classes, beginning with the most standardised classes and subsequently extending to the other classes. The derivative contracts which were entered into before, on or after the date of entry into force of Regulation (EU) No 648/2012, that are not outstanding on or after the reporting start date, are not of major relevance for regulatory purposes. They must however be reported under Article 9(1)(a) of Regulation (EU) No 648/2012. To ensure an efficient and proportionate reporting regime in those cases and taking into account the difficulties in reconstructing data of terminated contracts, a longer deadline should be provided for such reporting.