for a given period is AssetandLiabilityManagement     defined as the difference between fixed-rate assets and fixed-rate liabili- ties. It can also be calculated as the difference between interest-rate sensi- tive assets and interest-rate sensitive liabilities. Both differences are identical in value when total assets are equal to total liabilities, but will differ when the balance sheet is not balanced. This only occurs intra-day, when, for example, a short position has not been funded yet. The general market practice is to calculate the interest-rate gap as the difference between assets and liabilities. The gap is defined in terms of the maturity period that has been specified for it. The convention for calculating gaps is important for interpretation. The "fixed-rate" gap is the opposite of the "variable-rate" gap when assets and liabilities are equal. They differ when assets and liabilities do not match and there are many reference rates. When there is a deficit, the "fixed-rate gap" is consistent with the assumption that the gap will be funded through liabilities for which the rate is unknown. This fund- ing is then a variable-rate liability and is the banks risk, unless the rate has been locked-in beforehand. The same assumption applies when the banks run a cash surplus position, and the interest rate for any period in the future is unknown. The gap position at a given time bucket is sensi- tive to the interest rate that applies to that period. The gap is calculated for each discrete time bucket, so there is a net exposure for say, 0-1 month, 1-3 months, and so on. Loans and depos- its do not, except at the time of being undertaken, have precise maturi- ties like that, so they are "mapped" to a time bucket in terms of their relative weighting. For example, a $100 million deposit that matures in 20 days time will have most of its balance mapped to the 3-week time bucket, but a smaller amount will also be allocated to the 2-week bucket. Interest-rate risk is measured as the change in present value of the deposit, at each grid point, given a 1 basis point change in the inter- est rate. So a $10 million 1-month CD that was bought at 6.50% will have its present value move upwards if on the next day the 1-month rate moves down by a basis point. The net change in present value for a 1 basis point move is the key measure of interest-rate risk for a banking book and this is what is usu- ally referred to as a "gap report," although strictly speaking it is not. The correct term for such a report is a "PVBP" or "DV01" report, which stand for "present value of a basis point" and "dollar value of an 01 [1 basis point]", respectively. The calculation of interest-rate sensitivity assumes a parallel shift in the yield curve; that is, it assumes that every maturity point along the term structure moves by the same amount (here