Paragraph 3 of Article XXIX-A of the Canada-US tax treaty (Treaty) can extend treaty benefits to a US resident that is not otherwise a qualifying person under the Treaty with respect to certain income derived from Canada. Such income must be derived in connection with, or be incidental to, the active conduct of a trade or business (other than certain investment businesses) carried on in the US by the US resident, or a person related to the US resident, and the US trade or business must be “substantial” in relation to the activity carried on in Canada giving rise to the income. In 2014-0549621C6, the CRA disclosed four cases where the CRA ruled that the US business was substantial in relation to the Canadian activities. In one of these cases, the ratio of US assets and revenues to the Canadian assets and revenues was 0.5 to 1, and the ratio of US employees to the Canadian employees was 0.1 to 1.