It can. The enterprise must be at least 50 per cent owned by nationals of the treaty country, and ownership is traced through corporate layers rather than stopping at the immediate parent. A non-treaty national holding a third of the holding company reduces the treaty-national share of the U.S. business accordingly.
Nationality is traced through every layer of ownership
Hypothetical example: Solange proposes to hold the American enterprise through her Wickham holding company, which has three shareholders in equal parts: herself, her brother, both Canadian citizens, and a long-standing partner who is a citizen of a country with no treaty. The test is applied by looking through the corporate structure to the nationality of the ultimate individual owners. On these facts two thirds of the holding company is in Canadian hands, so two thirds of the American enterprise is treaty-owned, which clears the 50 per cent floor, though it should be documented rather than assumed.
Change the proportions and the answer changes with it. Two related points are worth recording. Canadian permanent residence does not make a shareholder a Canadian national for this purpose, so the passports, not the PR cards, decide it.
And ownership alone is not enough: Solange must also develop and direct the enterprise, which is a question about control and involvement rather than about percentages.