(52)To enhance the proportionality within the quantitative requirements, insurance and reinsurance undertakings should be granted the possibility to calculate the capital requirement for immaterial risks in the standard formula with a simplified approach for a period of no more than three years. Such a simplified approach should allow undertakings to estimate the capital requirement for an immaterial risk on the basis of an appropriate volume measure which varies over time. That approach should be based on common rules and subject to common criteria for the identification of immaterial risks.