Symes v. Canada, 94 DTC 6001, [1993] 4 S.C.R. 695, [1994] 1 CTC 40 -- summary under Accounting Principles

Iacobucci J. indicated (p. 6009) that in considering what types of expenses may be deducted under s. 9, it is more appropriate to refer to "well accepted principles of business (or accounting) practice" or to "well accepted principles of commercial trading", rather than to generally accepted accounting principles (which "connotes a degree of control by professional accountants which is inconsistent with a legal test for 'profit' under s. 9(1)".