Banks adopting the foundation IRB (advanced IRB for retail class) approach are required to calculate their capital requirement using these approaches, as well as the capital adequacy regulations issued by CBB dated July 2004 for the time period specified in section CA-A.4. The transition period for adoption of IRB will begin from the publication of this Module. Parallel calculation for banks adopting the foundation IRB approach to credit risk will start in the year beginning year-end 2007.