Banks that use the BIS SA shall assign the individual exposures to exposure classes.
In the following exposure classes, external ratings may be used for the risk weighting of the individual exposures:
central governments, central banks and supranational organisations;
public sector entities;
multilateral development banks;
banks;
common institutions;
companies;
special financing vehicles;
foreign covered bonds.
External ratings cannot be used for the following exposure classes:
retail exposures;
domestic Pfandbrief bonds;
direct and indirect mortgage-backed exposures;
subordinated exposures;
defaulted exposures;
equity-like instruments;
other exposures.
FINMA shall issue technical implementing provisions on the definition of exposure classes. It shall base these on the CRE131. It shall designate multilateral development banks to which a risk weight of 0% can be assigned.