20. Securitization: External- Ratings-Based Approach (SEC- ERBA)
No: 44047144 Date(g): 27/12/2022 | Date(h): 4/6/1444 Status: In-Force External-Ratings-Based Approach (SEC-ERBA)
20.1 For securitization exposures that are externally rated, or for which an inferred rating is available, risk-weighted assets under the securitization external ratings- based approach (SEC-ERBA) will be determined by multiplying securitization exposure amounts (as defined in 18.19) by the appropriate risk weights as determined by 19.2 to 19.7, provided that the operational criteria in 20.8 to 20.10 are met.108
20.2 For exposures with short-term ratings, or when an inferred rating based on a short-term rating is available, the following risk weights in table 28 below will apply:
ERBA risk weights for short-term ratings Table 28 External credit assessment A-1/P-1 A-2/P-2 A-3/P-3 All other ratings Risk weight 15% 50% 100% 1250% 20.3 For exposures with long-term ratings, or when an inferred rating based on a long-term rating is available, the risk weights depend on
(1) The external rating grade or an available inferred rating;
(2) The seniority of the position;
(3) The tranche maturity; and
(4) In the case of non-senior tranches, the tranche thickness.
20.4 Specifically, for exposures with long-term ratings, risk weights will be determined according to Table 29 and will be adjusted for tranche maturity (calculated according to 18.22 and 18.23), and tranche thickness for non-senior tranches according to 20.5.
ERBA risk weights for long-term ratings Table 29 Rating Senior tranche Non-senior (thin) tranche Tranche maturity (MT) Tranche maturity (MT) 1 year 5 years 1 year 5 years AAA 15% 20% 15% 70% AA+ 15% 30% 15% 90% AA 25% 40% 30% 120% AA- 30% 45% 40% 140% A+ 40% 50% 60% 160% A 50% 65% 80% 180% A- 60% 70% 120% 210% BBB+ 75% 90% 170% 260% BBB 90% 105% 220% 310% BBB- 120% 140% 330% 420% BB+ 140% 160% 470% 580% BB 160% 180% 620% 760% BB- 200% 225% 750% 860% B+ 250% 280% 900% 950% B 310% 340% 1050% 1050% B- 380% 420% 1130% 1130% CCC+/CCC/CCC- 460% 505% 1250% 1250% Below CCC- 1250% 1250% 1250% 1250% 20.5 The risk weight assigned to a securitization exposure when applying the SEC-ERBA is calculated as follows:
(1) To account for tranche maturity, banks shall use linear interpolation between the risk weights for one and five years.
(2) To account for tranche thickness, banks shall calculate the risk weight for non- senior tranches as follows, where T equals tranche thickness, and is measured a minus A, as defined, respectively, in 22.15 and 22.14:
Risk weight = (risk weight from table after adjusting for maturity) x (1 - min(T,50%))
20.6 In the case of market risk hedges such as currency or interest rate swaps, the risk weight will be inferred from a securitization exposure that is pari passu to the swaps or, if such an exposure does not exist, from the next subordinated tranche.
20.7 The resulting risk weight is subject to a floor risk weight of 15%. In addition, the resulting risk weight should never be lower than the risk weight corresponding to a senior tranche of the same securitization with the same rating and maturity.
108 The rating designations used in Tables 28 and 29 are for illustrative purposes only and do not indicate any preference for, or endorsement of, any particular external assessment system.
Operational Requirements for Use of External Credit Assessments
20.8 The following operational criteria concerning the use of external credit assessments apply in the securitization framework:
(1) To be eligible for risk-weighting purposes, the external credit assessment must take into account and reflect the entire amount of credit risk exposure the bank has with regard to all payments owed to it. For example, if a bank is owed both principal and interest, the assessment must fully take into account and reflect the credit risk associated with timely repayment of both principal and interest.
(2) The external credit assessments must be from an eligible external credit assessment institution (ECAI) as recognized by SAMA in accordance with SAMA Circular No. BCS 242, Date: 11 April 2007 (Mapping of Credit Assessment Ratings Provided by Eligible External Credit Assessment Institution to Determine Risk Weighted Exposures) as outlined in chapter 8 with the following exception. In contrast with 8.3 (3), an eligible credit assessment, procedures, methodologies, assumptions and the key elements underlying the assessments must be publicly available, on a non-selective basis and free of charge.109 In other words, a rating must be published in an accessible form and included in the ECAI’s transition matrix. Also, loss and cash flow analysis as well as sensitivity of ratings to changes in the underlying rating assumptions should be publicly available. Consequently, ratings that are made available only to the parties to a transaction do not satisfy this requirement.
(3) Eligible ECAIs must have a demonstrated expertise in assessing securitizations, which may be evidenced by strong market acceptance.
(4) Where two or more eligible ECAIs can be used and these assess the credit risk of the same securitization exposure differently, paragraph 8.8 will apply.
(5) Where credit risk mitigation (CRM) is provided to specific underlying exposures or the entire pool by an eligible guarantor as defined in chapter 9 and is reflected in the external credit assessment assigned to a securitization exposure(s), the risk weight associated with that external credit assessment should be used. In order to avoid any double-counting, no additional capital recognition is permitted. If the CRM provider is not recognized as an eligible guarantor under chapter 9, the covered securitization exposures should be treated as unrated.
(6) In the situation where a credit risk mitigant solely protects a specific securitization exposure within a given structure (e.g. asset-backed security tranche) and this protection is reflected in the external credit assessment, the bank must treat the exposure as if it is unrated and then apply the CRM treatment outlined in chapter 9 or in the foundation internal ratings-based (IRB) approach of chapters 10 to 16, to recognize the hedge.
(7) A bank is not permitted to use any external credit assessment for risk-weighting purposes where the assessment is at least partly based on unfunded support provided by the bank. For example, if a bank buys asset- backed commercial paper (ABCP) where it provides an unfunded securitization exposure extended to the ABCP programme (e.g. liquidity facility or credit enhancement), and that exposure plays a role in determining the credit assessment on the ABCP, the bank must treat the ABCP as if it were not rated. The bank must continue to hold capital against the other securitization exposures it provides (e.g. against the liquidity facility and/or credit enhancement).
109 Where the eligible credit assessment is not publicly available free of charge, the ECAI should provide an adequate justification, within its own publicly available code of conduct, in accordance with the “comply or explain” nature of the International Organization of Securities Commissions’ Code of Conduct Fundamentals for Credit Rating Agencies.
Operational Requirements for Inferred Ratings
20.9 In accordance with the hierarchy of approaches determined in 18.41 to 18.47, a bank must infer a rating for an unrated position and use the SEC-ERBA provided that the requirements set out in 20.10 are met. These requirements are intended to ensure that the unrated position is pari passu or senior in all respects to an externally-rated securitization exposure termed the “reference securitization exposure”.
20.10 The following operational requirements must be satisfied to recognize inferred ratings:
(1) The reference securitization exposure (e.g. asset-backed security) must rank pari passu or be subordinate in all respects to the unrated securitization exposure. Credit enhancements, if any, must be taken into account when assessing the relative subordination of the unrated exposure and the reference securitization exposure. For example, if the reference securitization exposure benefits from any third-party guarantees or other credit enhancements that are not available to the unrated exposure, then the latter may not be assigned an inferred rating based on the reference securitization exposure.
(2) The maturity of the reference securitization exposure must be equal to or longer than that of the unrated exposure.
(3) On an ongoing basis, any inferred rating must be updated continuously to reflect any subordination of the unrated position or changes in the external rating of the reference securitization exposure.
(4) The external rating of the reference securitization exposure must satisfy the general requirements for recognition of external ratings as delineated in 20.8.
Alternative Capital Treatment for Term STC Securitizations and Short- Term STC Securitizations Meeting the STC Criteria for Capital Purposes
20.11 Securitization transactions that are assessed as simple, transparent and comparable (STC)-compliant for capital purposes as defined in 18.67 can be subject to capital requirements under the securitization framework, taking into account that, when the SEC-ERBA is used, 20.12, 20.13, and 20.14 are applicable instead of 20.2, 20.4 and 20.7 respectively.
20.12 For exposures with short-term ratings, or when an inferred rating based on a short-term rating is available, the following risk weights in table 30 below will apply:
ERBA STC risk weights for short-term ratings Table 30 External credit assessment A-1/P-1 A-2/P-2 A-3/P-3 All other ratings Risk weight 10% 30% 60% 1250% 20.13 For exposures with long-term ratings, risk weights will be determined according to Table 31 and will be adjusted for tranche maturity (calculated according to 18.22 and 18.23), and tranche thickness for non-senior tranches according to 20.5 and 20.6.
ERBA STC risk weights for long-term ratings Table 31 Rating Senior tranche Non-senior (thin) tranche Tranche maturity (MT) Tranche maturity (MT) 1 year 5 years 1 year 5 years AAA 10% 10% 15% 40% AA+ 10% 15% 15% 55% AA 15% 20% 15% 70% AA- 15% 25% 25% 80% A+ 20% 30% 35% 95% A 30% 40% 60% 135% A- 35% 40% 95% 170% BBB+ 45% 55% 150% 225% BBB 55% 65% 180% 255% BBB- 70% 85% 270% 345% BB+ 120% 135% 405% 500% BB 135% 155% 535% 655% BB- 170% 195% 645% 740% B+ 225% 250% 810% 855% B 280% 305% 945% 945% B- 340% 380% 1015% 1015% CCC+/CCC/CCC- 415% 455% 1250% 1250% Below CCC- 1250% 1250% 1250% 1250% 20.14 The resulting risk weight is subject to a floor risk weight of 10% for senior tranches, and 15% for non-senior tranches.