B5.5.42 Paragraph 5.5.17(a) requires the estimate of expected credit losses to reflect anunbiased and probability-weighted amount that is determined by evaluating a range of possible outcomes. In practice, this may not need to be a complex analysis. In some cases, relatively simple modelling may be sufficient, without the need for a large number of detailed simulations of scenarios. For example, the average credit losses of a large group of financial instruments with shared
risk characteristics may be a reasonable estimate of the probability-weighted
amount. In other situations, the identification of scenarios that specify the
amount and timing of the cash flows for particular outcomes and the estimated
probability of those outcomes will probably be needed. In those situations, the
expected credit losses shall reflect at least two outcomes in accordance with
paragraph 5.5.18.