Forsyth v Federal Commissioner of Taxation

This case concerned an appeal by a taxpayer to the Supreme Court of New South Wales from an assessment of federal income tax for the year ending 30 June 1916. The taxpayer's income comprised amounts exceeding £7,600 derived from personal exertion and amounts exceeding £6,500 derived from property. The matter was referred to the High Court of Australia for its opinion on the correct method of calculating the tax payable.

The legal issues before the High Court were twofold: first, what were the correct rates of income tax chargeable on the taxpayer's income derived from personal exertion and from property, respectively; and second, what was the total amount of income tax payable by the appellant. The dispute centred on the interpretation of sections 3 and 4 of the Income Tax Act 1915, as amended by the Income Tax Act (No. 2) 1915, particularly concerning how to apply the rates prescribed in the First and Second Schedules to income derived from different sources.

The High Court, in allowing the appeal, reasoned that the amending Act (No. 48 of 1915) mandated a specific method for calculating tax when income comprised both personal exertion and property components. This method required determining the rate that would have been applicable if the taxpayer's total taxable income had been derived exclusively from personal exertion, and applying that rate to the actual income from personal exertion. A similar calculation was to be performed for income from property, using the rate that would have applied if the total taxable income had been derived exclusively from property. The total tax payable was the sum of the tax calculated for each component. The Court found the Commissioner's method of calculating an "average rate" based on the total income to be contrary to the plain meaning of the legislation.

The questions posed to the Court were answered in favour of the appellant. The Court ordered that the tax be calculated according to the appellant's contention, which involved applying the respective rates as determined by the First and Second Schedules to the income derived from personal exertion and property, respectively, after considering the impact of the amending Act.