In the context of a general discussion of consequences where there was an acquisition of control of a corporation incorporated in Canada in 2005 and with a start-up Canadian manufacturing operation in Canada, as well as research and development performed there, but with a shift of its sales and administrative functions to a non-resident location, CRA stated:
Paragraph 4(1)(b) effectively requires a non-resident corporation to allocate its profits between Canada and another country in a manner that reflects the contribution to profits of the activities of each jurisdiction. The Act does not contain a more detailed methodology than paragraph 4(1)(b) of the Act for allocating profits between jurisdictions. However, even if sales are made from the head office, much of the revenue will be allocated to Canada as a result of development and manufacturing operations. You may find useful information for calculating the portion of the income and expenses of the business carried on in Canada in the Commentary on Article 7 of the 2008 OECD Model Tax Convention.