(3)Both the back-testing and the profit and loss attribution test are to be based on data for the 250 business days preceding the reference date for which the respective test is performed. Extraordinary circumstances should thus be recognised where a period of significant cross-border financial market stress, or of a major regime shift, that materially affects institutions across the Union and produces exceptions that do not result from deficiencies in the internal model is fully or partially included in that 250 business days period.