Risk weight
The Risk Weights are defined in MAR22.34.
They may be provided in the input files for each tranche.
Otherwise the SEC-ERBA risk weights are determined for the tranche as specified in CRE42.
The risk weights are looked up from the SEC-ERBA risk weights store.
They are looked up by Rating, Rating Type and Seniority.
For non-senior tranches the Attachment Point and Detachment Point are used to determine the tranche thickness.