Thiel v. Federal Commissioner of Taxation, 90 A.TC 4717 (HC of A.)

McHugh J. stated (p. 4727):

"Because the interpretation provisions of the Vienna Convention reflect the customary rules for the interpretation of treaties, it is proper to have regard to the terms of the Convention in interpreting the Agreement [between Switzerland and Australia], even though Switzerland is not a party to that Convention"

and went on to make reference to the 1977 OECD Model Convention for the Avoidance of Double Taxation in interpreting a provision of the Agreement.

In January and May 1984 the taxpayer, who was a resident of Switzerland, paid $150,000 to acquire six units in the Energy Research Group Unit Trust, in November 1984 he sold his six units to Energy Research Group Australia Ltd. for $300,000 to be satisfied by the issuance to him of 600,000 ordinary shares of that company, and in 1985, following a listing of the shares on the Australian Stock Exchange, he sold 252,000 of his shares for $566,307. The majority found that the taxpayer's activities constituted an "enterprise" for purposes of Article 7 of the Australia-Switzerland Convention regardless whether they constitued an isolated adventure or the recurring conduct of a business. Accordingly, the profits of this enterprise were exempt from taxation under the Income Tax Assessment Act 1936 (Australia).