1. For the purposes of Subsection 3, institutions shall set the attachment point (A) at the threshold at which losses within the pool of underlying exposures would start to be allocated to the relevant securitisation position.
The attachment point (A) shall be expressed as a decimal value between zero and one and shall be equal to the greater of zero and the ratio of the outstanding balance of the pool of underlying exposures in the securitisation minus the outstanding balance of all tranches that rank senior or pari passu to the tranche containing the relevant securitisation position including the exposure itself to the outstanding balance of all the underlying exposures in the securitisation.
2. For the purposes of Subsection 3, institutions shall set the detachment point (D) at the threshold at which losses within the pool of underlying exposures would result in a complete loss of principal for the tranche containing the relevant securitisation position.
The detachment point (D) shall be expressed as a decimal value between zero and one and shall be equal to the greater of zero and the ratio of the outstanding balance of the pool of underlying exposures in the securitisation minus the outstanding balance of all tranches that rank senior to the tranche containing the relevant securitisation position to the outstanding balance of all the underlying exposures in the securitisation.
3. For the purposes of paragraphs 1 and 2, institutions shall treat overcollateralisation and funded reserve accounts as tranches and the assets comprising such reserve accounts as underlying exposures.
4. For the purposes of paragraphs 1 and 2, institutions shall disregard unfunded reserve accounts and assets that do not provide credit enhancement, such as those that only provide liquidity support, currency or interest rate swaps and cash collateral accounts related to those positions in the securitisation. For funded reserve accounts and assets providing credit enhancement, the institution shall only treat as securitisation positions the parts of those accounts or assets that are loss-absorbing.
5. Where two or more positions of the same transaction have different maturities but share pro rata loss allocation, the calculation of the attachment points (A) and the detachment points (D) shall be based on the aggregated outstanding balance of those positions and the resulting attachment points (A) and detachment points (D) shall be the same.