US Subsidiary or Branch? The Tax Math for Canadian SaaS Companies Expanding South

Every Canadian SaaS company with growing US revenue eventually hits the same question: do we set up a US subsidiary, operate as a branch of the Canadian corporation, or just keep selling cross-border without a US entity at all. The answer changes your tax bill, your liability exposure, and how much of your time goes to US compliance instead of building the product.

This is not a decision to make from a Reddit thread or a generic "incorporate in Delaware" guide written for US founders. The Canada-US Tax Treaty changes the calculation in ways that are specific to Canadian companies, and getting it wrong is expensive to unwind.

Start With the Question That Decides Everything: Do You Have a Permanent Establishment?

Under the Canada-US Tax Treaty, a Canadian corporation is only subject to US federal income tax to the extent it has a permanent establishment, a PE, in the US. The Treaty specifically excludes several common early-stage activities from counting as a PE: maintaining a warehouse used only for storage, advertising in US media, and using independent agents to sell your product, among others.

This matters because a lot of Canadian SaaS companies sell into the US, take US customer payments, and even have a few US-based remote employees, without necessarily creating a PE. If you genuinely have no PE, you may not need a US entity at all yet, just clean documentation of why you do not have one. That documentation is exactly what an investor's due diligence team or the IRS will ask for if the question ever comes up, so do not treat "we probably don't have a PE" as a permanent answer. Revisit it every time your US footprint changes: a US-based sales hire who can sign contracts, a US office lease, or a dependent agent acting on your behalf can all create one.

Once You Have a PE: Subsidiary vs Branch

If you do have, or are about to have, a US PE, the structural choice is between a US subsidiary (a separate Delaware or other state corporation, typically a C-corp) and operating directly as a branch of your Canadian parent.

The Subsidiary Route

A US subsidiary is a separate legal entity. Under the Treaty, owning a US subsidiary is specifically excluded from the definition of a PE for the Canadian parent, which means the Canadian parent itself generally does not need to file a US income tax return just because its subsidiary exists. The subsidiary files its own US corporate return and pays US federal and state tax on its own income.

Dividends paid up from the US subsidiary to the Canadian parent are subject to US withholding tax, reduced under the Treaty, generally to 5% if the Canadian parent owns enough of the subsidiary's voting stock, or 15% otherwise. Management has control over timing here: the company decides when to declare a dividend, which means the withholding cost is somewhat deferrable.

Subsidiaries also give you liability separation. If something goes wrong in the US business, US creditors generally cannot reach into the Canadian parent's assets. For a venture-backed company planning a US-led Series A or a US strategic acquirer down the road, a subsidiary is also simply what US investors expect to see on a cap table.

The Branch Route

A branch is not a separate legal entity. It is an extension of the Canadian corporation operating directly in the US. The Canadian parent files US Form 1120-F to report income attributable to the US branch, and on top of regular US corporate income tax, a branch profits tax applies to the after-tax earnings of the branch.

The US statutory branch profits tax rate is 30%. Under the Canada-US Treaty, that rate is reduced to 5%, and the Treaty exempts a cumulative $500,000 of branch profits from the tax entirely. Branch profits tax is charged as profits are earned, not deferred by a declaration decision the way dividends are, which removes the timing flexibility a subsidiary structure offers.

Branches make more sense when the US operations are expected to run at a loss in the near term, since branch losses can offset the Canadian parent's other income more directly, or for short-term, limited-scope US activity where setting up and maintaining a full US corporate entity is not yet worth the overhead.

Side by Side

Legal structure: Subsidiary — a separate US entity. Branch — an extension of the Canadian parent.
US filing: Subsidiary — files its own US return. Branch — parent files Form 1120-F.
Repatriation tax: Subsidiary — withholding on dividends, 5% to 15% under the Treaty, timing is elective. Branch — branch profits tax, 5% under the Treaty, charged as earned.
Treaty exemption: Subsidiary — not applicable in the same way. Branch — first $500,000 cumulative branch profits exempt.
Liability exposure: Subsidiary — contained within the US entity. Branch — extends to the Canadian parent.
Best fit: Subsidiary — profitable, scaling US operations, US investors expected. Branch — early-stage, loss-making, or limited-scope US activity.

The Part Most Guides Skip: US State Taxes Do Not Follow the Treaty

This is the detail that catches Canadian founders off guard. US states administer their own corporate income, franchise, and sales taxes, and most states do not follow federal tax treaties. A Treaty provision that protects you from US federal tax does not automatically protect you from California's franchise tax or another state's economic nexus rules once you have employees, inventory, or enough sales activity in that state.

Four colleagues reviewing a document together at a table

If you are hiring US-based remote employees, selling into specific states at volume, or storing inventory in a US warehouse, get a state nexus review done alongside your federal structuring decision. This is a separate analysis from the PE question, and skipping it is how companies end up with surprise state tax bills years after the fact.

What We Actually Recommend Before You Incorporate Anything

This is genuinely complex, treaty-dependent territory, and the right answer depends on your specific revenue mix, where your team sits, and your fundraising plans. We are not your US tax counsel, and a decision this structural should involve a cross-border tax advisor and corporate lawyer before you file anything. What we do, as your Canadian finance partner, is make sure your books on the Canadian side are built to support whichever structure you choose: clean intercompany reconciliation, proper transfer pricing documentation if you go the subsidiary route, and reporting that holds up when a US accountant, a Canadian investor, or both ask for it at the same time.

We walked through what that intercompany reconciliation needs to look like ahead of a raise in Scaling to Series A: 5 Accounting Steps for Successful Due Diligence.

Schedule a discovery call if you are planning US expansion in the next 6 to 18 months. The financial infrastructure decisions are much easier to make before the US entity exists than to unwind after.

Frequently Asked Questions

Do I need a US entity if I just have US customers paying through Stripe?

Not necessarily. Taking payments from US customers does not by itself create a permanent establishment under the Canada-US Tax Treaty. A US PE generally requires a more fixed presence: an office, dependent agents who can bind contracts, or similar activity. Document your position and revisit it as your US footprint grows.

What is the branch profits tax rate for a Canadian company operating a US branch?

The US statutory rate is 30%, reduced to 5% under the Canada-US Tax Treaty, with a cumulative $500,000 exemption on branch profits. This applies on top of regular US corporate income tax on the branch's earnings.

Does a US subsidiary mean my Canadian parent company has to file a US tax return?

Generally no. Owning a US subsidiary is specifically excluded from the PE definition under the Treaty, so the Canadian parent typically does not need to file a US income tax return solely because the subsidiary exists. The subsidiary files its own return.

If the Canada-US Treaty protects me federally, am I covered for state taxes too?

No. Most US states do not follow federal tax treaties. Hiring employees, storing inventory, or generating enough sales activity in a specific state can trigger that state's own corporate, franchise, or sales tax obligations regardless of your federal treaty position.