Deemed income rule: taxable income set at a minimum proportion of book profit when computed income is lower. If a company's total income is less than thirty per cent of its book profit for the relevant previous year, its taxable total income is deemed to be thirty per cent of that book profit. The profit and loss account must be prepared under Parts II and III of Schedule VI to the Companies Act, 1956, with depreciation calculated on the same method and rates as in the financial statements. Book profit is the net profit per that account adjusted by specified additions (e.g., tax, reserves, provisions, dividends, exempt income related expenses) and reductions (e.g., withdrawals from reserves, certain credited incomes, limited set offs like losses or unabsorbed depreciation, and specified tax exempt profits).