Calculation of EAD is different under foundation and advanced approach. While under foundation approach (
F-IRB) calculation of EAD is guided by the regulators, under the advanced approach (
A-IRB) banks enjoy greater flexibility on how they calculate EAD.
Foundation approach Under
F-IRB, EAD is calculated taking account of the underlying asset, forward valuation, facility type and commitment details. This value does not take account of guarantees, collateral or security (i.e. ignores Credit Risk Mitigation Techniques with the exception of on-balance sheet netting where the effect of netting is included in Exposure At Default). For on-balance sheet transactions, EAD is identical to the nominal amount of exposure. On-balance sheet netting of loans and deposits of a bank to a corporate counterparty is permitted to reduce the estimate of EAD under certain conditions. For off-balance sheet items, there are two broad types which the IRB approach needs to address: transactions with uncertain future drawdown, such as commitments and
revolving credits, and OTC foreign exchange, interest rate and equity derivative contracts.
Advanced approach Under
A-IRB, the bank itself determines how the appropriate EAD is to be applied to each exposure. A bank using internal EAD estimates for capital purposes might be able to differentiate EAD values on the basis of a wider set of transaction characteristics (e.g. product type) as well as borrower characteristics. These values would be expected to represent a conservative view of long-run averages, although banks would be free to use more conservative estimates. A bank wishing to use its own estimates of EAD will need to demonstrate to its supervisor that it can meet additional minimum requirements pertinent to the integrity and reliability of these estimates. All estimates of EAD should be calculated net of any specific provisions a bank may have raised against an exposure. ==Importance==