Internal Risk Based Approach -- Evolutionary Approaches to Regulatory Capital Charge for Operational Risk --

Since the Basel Committee proposed an explicit capital charge in its consultation paper issued in June 1999, various approaches to measuring operational risk have been developed by both the industry and supervisors. Among them was the Internal Risk Based (IRB) approach, in which individual banks' internal loss data would be effectively taken into account while the structure of the scheme would be kept relatively simple and comparable compared to the structure of "full model" type approaches. IRB approach can bridge the gap between a basic approach and a more advanced approach, providing a clear and evolutionary path that leads banks to more sophisticated approaches on a business line by business line basis. The purpose of this paper is to explain the structure of the IRB approach and its application to regulatory capital calculation. Of course, the authors of the paper fully recognize that the IRB approach is still under development. Until now, the Bank of Japan has conducted research on operational risk measurement along with a series of dialogues with the industry. In writing this paper, the authors tried to incorporate the industry's view toward regulatory capital for operational risk, while emphasizing simplicity, comparability, and objectivity from the supervisors' point of view.