An originating bank must use the methodology and treatment described in paragraphs CA-6.4.32 to CA-6.4.47 for determining if any capital must be held against the investors' interest. For banks applying the IRB approach to securitisation, investors' interest is defined as investors' drawn balances related to securitisation exposures and EAD associated with investors' un-drawn lines related to securitisation exposures. For determining the EAD, the un-drawn balances of securitised exposures would be allocated between the seller's and investors' interests on a pro rata basis, based on the proportions of the seller's and investors' shares of the securitised drawn balances. For IRB purposes, the capital charge attributed to the investors' interest is determined by the product of (a) the investors' interest, (b) the appropriate CCF, and (c) K_IRB.