Calculating RWAs for the portion of the securitisation position benefitting from credit protection

In case of an institution buying credit protection, which approach has to be applied for calculating RWAs for the portion of the securitisation position benefitting from credit protection, if the SEC-SA Approach is used for the portion of the securitisation position not benefitting from credit protection, and the institution is allowed to apply the IRB Approach to the direct exposures to the protection provider? May the institution (buying credit protection) calculate the RWAs for the portion of the securitisation position benefitting from credit protection as a direct exposure to the protection provider using the IRB Approach?

Article 249(6) CRR describes the requirements if a securitisation position benefits from full credit protection or a partial credit protection on a pro-rata basis. Article 249(7) CRR states that “In all cases not covered by paragraph 6, the following requirements shall apply: “(a) the institution providing credit protection shall treat the portion of the position benefiting from credit protection as a securitisation position and shall calculate risk-weighted exposure amounts as if it held that position directly in accordance with Subsection 3, subject to paragraphs 8, 9 and 10; (b) the institution buying credit protection shall calculate risk-weighted exposure amounts for the protected portion of the position referred to in point (a) in accordance with Chapter 4. The institution shall treat the portion of the securitisation position not benefiting from credit protection as a separate securitisation position and shall calculate risk-weighted exposure amounts in accordance with Subsection 3, subject to paragraphs 8, 9 and 10”. In our understanding, Article 249(6) CRR is only applicable if a securitisation position benefits from “full credit protection” or a “partial credit protection on a pro-rata basis”, but our question refers to a situation where the credit protection is partial, but not on a pro-rata basis. Consequently, the institution buying credit protection would apply the requirements of Chapter 4 for the protected portion of the securitisation position. However, in Chapter 4, Article 234 CRR states that “where an institution transfers a part of a loan in one or more tranches, the rules set out in Chapter 5 shall apply”, i.e. the regulation actually refers back to Article 249(7) CRR.