Expenditure related to exempt income under Rule 8D is computed through a direct-plus-presumptive investment-based formula. Rule 8D prescribes the method for determining expenditure relating to income not includible in total income where the Assessing Officer is not satisfied with the assessee's claim of expenditure or its claim that no expenditure has been incurred. The present computation covers direct expenditure attributable to such income together with one per cent of the annual average of the monthly averages of the opening and closing balances of investments from which exempt income arises, subject to the ceiling that the total cannot exceed the expenditure claimed by the assessee.