Institutions shall have robust systems in place to validate the accuracy and consistency of their internal models and modelling processes. All material elements of the internal models and the modelling process and validation shall be documented.
The validation and documentation of institutions' internal models and modelling processes shall be subject to the following requirements:
(b) the methods and data used for quantitative validation shall be consistent over time. Changes in estimation and validation methods and changes to data sources and periods covered, shall be documented;
(c) institutions shall regularly compare actual equity returns computed using realised and unrealised gains and losses with modelled estimates. Such comparisons shall make use of historical data that cover as long a period as possible. The institution…