The scenario matrix analysis involves specifying a fixed range of changes in the option portfolio's risk factors and calculating changes in the value of the option portfolio at various points along this 'grid' or 'matrix'. For the purpose of calculating the capital charge, the bank will revalue the option portfolio using matrices for simultaneous changes in the option's underlying rate or price and in the volatility of that rate or price. A different matrix is set up for each individual underlying as defined in Section CA-8.3 above. As an alternative, in respect of interest rate options, banks which are significant traders in such options are permitted to base the calculation on a minimum of six sets of time-bands. When using this alternative method, not more than three of the time-bands as defined in Chapter CA-4 should be combined into any one set.