Commissioner of Taxation v Ryan

The High Court of Australia heard an appeal from the Full Court of the Federal Court of Australia concerning a dispute between the Commissioner of Taxation and the respondent taxpayer, Mrs. Gwenda Ryan. The core of the disagreement revolved around a notice issued by the Commissioner in 1987, which indicated no tax was payable for the 1987 income year, and a subsequent assessment issued in 1994 that sought to amend the initial calculation and impose tax. The taxpayer contended that the 1987 notice constituted a binding assessment under the *Income Tax Assessment Act 1936* (Cth) ("the Act"), and therefore, the Commissioner was precluded by section 170(3) of the Act from issuing an amended assessment that increased her liability.

The legal issues before the High Court were whether the 1987 notice issued by the Commissioner qualified as an "assessment" for the purposes of section 170(3) of the Act, and consequently, whether the subsequent 1994 assessment was unauthorised. A related question was whether any tax became "due and payable" upon the issue of the initial 1987 notice, particularly in light of section 204(1) of the Act which prescribes the timing for tax to become due and payable. The taxpayer argued that having made a full and true disclosure of all material facts, the 1987 notice, which repeatedly referred to itself as an "assessment" and resulted in a refund, effectively finalised her tax liability for that year, and the time limits under section 170(3) had expired.

The High Court allowed the appeal, setting aside the orders of the Federal Court. The Court reasoned that the 1987 notice, despite resulting in zero tax payable and a refund, was indeed an "assessment" within the meaning of the Act. The Court found that the ascertainment of tax payable as zero was a valid assessment, and the repeated use of the term "assessment" in the notice, coupled with its explanatory notes, supported this conclusion. Consequently, the Commissioner was bound by section 170(3) of the Act, which prevents the amendment of an assessment to increase a taxpayer's liability after a certain period has elapsed, provided the taxpayer has made a full and true disclosure of all material facts, which was common ground in this case. The Court therefore concluded that the 1994 assessment was unauthorised.