Most deferred tax adjustments in financial statements help investors - but not always. The ‘economic value’ of deferred tax assets arising from unused tax losses may be significantly less than the balance sheet figure. However, as a consequence, profit forecasts may be understated, potentially leading to an undervaluation by investors. We estimate that if the £24bn deferred tax asset of Vodafone were discounted to an economic value then it would instead be closer to £8bn, but forecast p...