(42)The Commission should take into account the principle of proportionality in the calculation of the own funds requirements for market risk for institutions with a medium-sized trading book business and calibrate those requirements accordingly. Therefore, institutions with a medium-sized trading book business should be allowed to use a simplified standardised approach to calculate the own funds requirements for market risk, in line with the internationally agreed standards. In addition, the eligibility criteria for identifying institutions with medium-sized trading book business should remain consistent with the criteria for exempting such institutions from the FRTB reporting requirements introduced by Regulation (EU) 2019/876.