(4)Since it is not possible to provide for a one-size-fits-all calibration that would be applicable to all transactions, given the variety in the types of underlying portfolios and structures in on-balance-sheet securitisations, it is necessary to set out criteria for setting the levels of the performance-related triggers referred to in Article 26c(5), third subparagraph, of Regulation (EU) 2017/2402. To ensure that there is no significant risk that tranches providing credit enhancement amortise to an extent that there would not be sufficient protection to absorb significant losses occurring at the end of the transaction, those criteria should be set in a prudent manner. For that purpose, the parties to the securitisation should test the effectiveness of the backward-looking triggers in a back-loaded loss distribution scenario taking into account the losses expected over the entire maturity of the transaction at its closing date.