There has been major contest over the taxation of business income. Questions are twofold: the factual one of defining the boundaries of the business activity. Second, that of determining whether a particular gain comes within the ambit of ‘business’. Recent NZ cases have sought to apply the guiding principle - that it is not the size of the gain but the source of it that determines the taxation consequences. Logically, this principle should apply to specialist businesses such as those dealing with banking and insurance. However, the NZ Commissioner has, until 10 years ago, argued that it is the size rather than the source of the gain that is the determining criterion. And since the questions of what is the scope of the particular business activity and whether the particular gain has arisen in the course of such activity are purely factual ones, they are to be guided by the facts of each case. This article concludes that the decisions are indeed based on their particular facts. Further, it investigates how important it is for the taxpayer to ponder the strategy that is to underpin the particular business. The evidence of such strategy being in place and having the practical effect of guiding the decision making of the taxpayer company’s business activities are highly significant in determining the taxation consequences of such decision making. The consistency with which such corporate strategy or policy is formulated and implemented tends to determine their taxation consequences.