1. Institutions may use an approach for calculating the own funds requirement for the general risk on debt instruments which reflects duration, instead of the approach set out in Article 339, provided that the institution does so on a consistent basis.
2. Under the duration-based approach referred to in paragraph 1, the institution shall take the market value of each fixed-rate debt instrument and hence calculate its yield to maturity, which is implied discount rate for that instrument. In the case of floating-rate instruments, the institution shall take the market value of each instrument and hence calculate its yield on the assumption that the principal is due when the interest rate can next be changed.
D = duration calculated according to the following formula:
R = yield to maturity;
Ct = cash payment in time t;
M = total maturity.