(a) General requirements for the SSFA. To use the SSFA to determine the risk weight for a securitization exposure, a System institution must have data that enables it to assign accurately the parameters described in paragraph (b) of this section. Data used to assign the parameters described in paragraph (b) of this section must be the most currently available data; if the contract governing the underlying exposures of the securitization require payment on a monthly or quarterly basis, the data used to assign the parameters described in paragraph (b) of this section must be no more than 91 calendar days old. A System institution that does not have the appropriate data to assign the parameters described in paragraph (b) of this section must assign a risk weight of 1,250 percent to the exposure.

(b) SSFA parameters. To calculate the risk weight for a securitization exposure using the SSFA, a System institution must have accurate information on the following five inputs to the SSFA calculation:

(1) KG is the weighted-average (with unpaid principal used as the weight for each exposure) total capital requirement of the underlying exposures calculated using this subpart. KG is expressed as a decimal value between 0 and 1 (that is, an average risk weight of 100 percent represents a value of KG equal to .08).

(2) Parameter W is expressed as a decimal value between 0 and 1. Parameter W is the ratio of the sum of the dollar amounts of any underlying exposures within the securitized pool that meet any of the criteria as set forth in paragraphs (b)(2)(i) through (vi) of this section to the balance, measured in dollars, of underlying exposures:

(i) Ninety (90) days or more past due;

(ii) Subject to a bankruptcy or insolvency proceeding;

(iii) In the process of foreclosure;

(iv) Held as real estate owned;

(v) Has contractually deferred interest payments for 90 days or more, other than principal or interest payments deferred on:

(A) Federally guaranteed student loans, in accordance with the terms of those guarantee programs; or

(B) Consumer loans, including non-federally guaranteed student loans, provided that such payments are deferred pursuant to provisions included in the contract at the time funds are disbursed that provide for periods(s) of deferral that are not initiated based on changes in the creditworthiness of the borrower; or

(vi) Is in default.

(3) Parameter A is the attachment point for the exposure, which represents the threshold at which credit losses will first be allocated to the exposure. Except as provided in §628.42(i) for nth-to-default credit derivatives, parameter A equals the ratio of the current dollar amount of underlying exposures that are subordinated to the exposure of the System institution to the current dollar amount of underlying exposures. Any reserve account funded by the accumulated cash flows from the underlying exposures that is subordinated to the System institution's securitization exposure may be included in the calculation of parameter A to the extent that cash is present in the account. Parameter A is expressed as a decimal value between 0 and 1.

(4) Parameter D is the detachment point for the exposure, which represents the threshold at which credit losses of principal allocated to the exposure would result in a total loss of principal. Except as provided in §628.42(i) for nth-to-default credit derivatives, parameter D equals parameter A plus the ratio of the current dollar amount of the securitization exposures that are pari passu with the exposure (that is, have equal seniority with respect to credit risk) to the current dollar amount of the underlying exposures. Parameter D is expressed as a decimal value between 0 and 1.

(5) A supervisory calibration parameter, p, is equal to 0.5 for securitization exposures that are not resecuritization exposures and equal to 1.5 for resecuritization exposures.

(c) Mechanics of the SSFA. KG and W are used to calculate KA, the augmented value of KG, which reflects the observed credit quality of the underlying pool of exposures. KA is defined in paragraph (d) of this section. The values of parameters A and D, relative to KA determine the risk weight assigned to a securitization exposure as described in paragraph (d) of this section. The risk weight assigned to a securitization exposure, or portion of a securitization exposure, as appropriate, is the larger of the risk weight determined in accordance with this paragraph (d) of this section and a risk weight of 20 percent.

(1) When the detachment point, parameter D, for a securitization exposure is less than or equal to KA, the exposure must be assigned a risk weight of 1,250 percent.

(2) When the attachment point, parameter A, for a securitization exposure is greater than or equal to KA, the System institution must calculate the risk weight in accordance with paragraph (d) of this section.

(3) When A is less than KA and D is greater than KA, the risk weight is a weighted average of 1,250 percent and 1,250 percent times KSSFA calculated in accordance with paragraph (d) of this section. For the purpose of this weighted-average calculation:

(i) The weight assigned to 1,250 percent equals:

(ii) The weight assigned to 1,250 percent times KSSFA equals:

(iii) The risk weight will be set equal to:

(d) SSFA equation.

(1) The System institution must define the following parameters:

KA = (1 − W) × KG × (0.5 × W)

(2) Then the System institution must calculate KSSFA according to the following equation:

(3) The risk weight for the exposure (expressed as a percent) is equal to KSSFA × 1,250.

(e) Gross-up approach—

(1) Applicability. A System institution may apply the gross-up approach set forth in this section instead of the SSFA to determine the risk weight of its securitization exposures, provided that it applies the gross-up approach to all of its securitization exposures, except as otherwise provided for certain securitization exposures in §§628.44 and 628.45.

(2) To use the gross-up approach, a System institution must calculate the following four inputs:

(i) Pro rata share A, which is the par value of the System institution's securitization exposure X as a percent of the par value of the tranche in which the securitization exposure resides Y:

(ii) Enhanced amount B, which is the value of tranches that are more senior to the tranche in which the System institution's securitization resides;

(iii) Exposure amount (carrying value) C of the System institution's securitization exposure calculated under §628.42(c); and

(iv) Risk weight (RW), which is the weighted-average risk weight of underlying exposures in the securitization pool as calculated under this subpart. For example, RW for an asset-backed security with underlying car loans would be 100 percent.

(3) Credit equivalent amount (CEA). The CEA of a securitization exposure under this section equals the sum of:

(i) The exposure amount C of the System institution's securitization exposure; plus

(ii) The pro rata share A multiplied by the enhanced amount B, each calculated in accordance with paragraph (e)(2) of this section:

CEA = C + (A × B)

(4) Risk-weighted assets (RWA). To calculate RWA for a securitization exposure under the gross-up approach, a System institution must apply the RW calculated under paragraph (e)(2) of this section to the CEA calculated in paragraph (e)(3) of this section:

RWA = RW × CEA

(f) Limitations. Notwithstanding any other provision of this section, a System institution must assign a risk weight of not less than 20 percent to a securitization exposure.