Thiel v The Commissioner of Taxation

The case before the High Court of Australia concerned an appeal by Mr Thiel against an assessment issued by the Commissioner of Taxation. Mr Thiel, a resident of Switzerland with no permanent establishment in Australia, had purchased units in a unit trust through a Perth broker. These units were subsequently acquired by a company in consideration for shares in that company, which was then listed on the stock exchange. Mr Thiel then instructed his broker to sell these shares over a period of time. The Commissioner assessed the profits from these sales, and the dispute centred on whether these profits were taxable in Australia, particularly in light of the Australia-Switzerland double tax agreement.

The primary legal issue before the Court was the interpretation of the phrase "enterprise of one contracting State" as used in the relevant double tax agreement. Specifically, the Court had to determine whether this phrase imposed a limitation requiring an enterprise to be understood as engaging in activities of a repetitive, business-like nature. The appellant argued that the profits derived from his share transactions constituted an "adventure in the nature of trade" and that such an adventure fell within the scope of profits of an enterprise for the purposes of the treaty. The Court also considered whether the profits were taxable under Australian domestic tax law, with reference to section 26AAA and section 25A(1) of the Income Tax Assessment Act 1936.

The appellant contended that the profits from his share sales amounted to an adventure in the nature of trade, which he argued should be considered as profits of an enterprise for the purposes of the Australia-Switzerland double tax agreement. The agreement itself provided methods for avoiding double taxation, including the elimination of the source country's entitlement to tax, as exemplified by Article 8(1) of the Treaty. The Court was required to interpret the scope of "enterprise" within this treaty context, considering whether it encompassed isolated transactions or required a more sustained business activity. The majority of judges in the Supreme Court of Western Australia and the Full Federal Court had previously found the profits to be taxable, potentially under section 25A(1) of the Act.