Map activities first. Direct sales and branches use the Canadian corporation: it files T2 and, with a US trade or business, Form 1120-F; treaty may limit US tax. A US subsidiary files Form 1120 and pays its own tax; its parent reports the affiliate. A disregarded LLC may require parent Form 1120-F, its own Form 5472, and Canadian affiliate reporting.
Corporations
Direct ownership generally means a Canadian resident reports US rent and gains in both countries. Joint title changes the analysis when funding and state law support it. A US LLC can create a Canada–US tax mismatch without settling estate exposure. Corporate ownership raises separate tax questions, especially when someone uses the property personally.
Individuals · Corporations
A Canadian corporation may need state authority before operating locally through an office, staff or on-site work. Shipping from Canada or accepting orders there usually does not, by itself, require it. Check each state's rule before starting local work. If registration was required, the corporation can owe back fees and penalties and may have to qualify before suing.
Corporations
A US business can sell into Canada without forming a Canadian company, but Canadian activity may still require tax and business registration. For a US corporation, a branch keeps Canadian operations in that corporation and may face branch tax; a Canadian subsidiary files its own return and may withhold on dividends. Partnerships and LLCs need separate classification checks.
Partnerships · Corporations
If you are not a US citizen or resident and work from Canada with no US office or staff, a Canadian corporation usually fits: under the Canada–US treaty, US federal tax reaches its business profits only through a US permanent establishment. A US corporation fits US operations or investors. A US LLC, taxed differently by each country, risks double tax.
Self-employed · Corporations