(6)In line with the existing definitions in Union sectoral legislation, it is appropriate to provide definitions of all the key concepts of securitisation. In particular, a clear and encompassing definition of securitisation is needed to capture any transaction or scheme whereby the credit risk associated with an exposure or pool of exposures is tranched. An exposure that creates a direct payment obligation for a transaction or scheme used to finance or operate physical assets should not be considered an exposure to a securitisation, even if the transaction or scheme has payment obligations of different seniority.