Deductibility rule: expenditure related to exempt income disallowed; assessing officer may determine disallowance by prescribed method. Section 14A prohibits deductions for expenditure incurred in relation to income not forming part of total taxable income; the Assessing Officer may determine the attributable expenditure by a prescribed method if not satisfied with the assessee's claim, and the provision applies even where the exempt income has not accrued, arisen or been received in the relevant previous year but related expenditure was incurred.