Cross-border landed cost between the United States and Canada changed twice in one weekend. If any of your inventory crosses that border, the number in your cost sheet is already out of date.
What happened
Talks collapsed late on Friday, August 21, 2026. The following day the United States imposed 50% tariffs on roughly $20 billion of Canadian goods, and Prime Minister Mark Carney announced dollar-for-dollar retaliatory tariffs starting September 8 (AP News, August 23, 2026).
Reported Canadian targets span steel, dairy, appliances, agricultural equipment, pulp and paper, and electronics (BBC News, August 23, 2026). Carney set out the government's position in remarks published the same weekend (Prime Minister of Canada, August 22, 2026).
The US measure is live now. The Canadian measure has a two-week runway, which is the only piece of good news in the sequence.
Why it matters
Duty is one of the few costs that can move by tens of percentage points overnight and still be invisible in a seller dashboard, because it usually gets folded into a landed cost figure that was set months ago. When that happens, the margin drop appears weeks later and gets blamed on advertising or on a fee change that had nothing to do with it.
The exposure is also asymmetric. A US seller shipping into Canada for Amazon.ca has a September 8 problem. A Canadian manufacturer selling into the US has an immediate one.
What to change in the next 72 hours
- List the SKUs that actually cross the border. Country of origin on the customs paperwork, not the address of your supplier's sales office.
- Match HS codes against the published lists. Category names in press coverage are approximations. The tariff schedule is not.
- Recalculate contribution margin per unit at the new duty rate before touching prices. Some SKUs will still clear their floor.
- Decide what to pre-ship before September 8 where inventory is already on the correct side of the border and storage cost is tolerable.
- Keep duty as its own cost line. Buried inside COGS, it destroys your ability to attribute the next margin move.
The Nova angle
Nova lets you attach your own cost inputs per SKU and see profit per marketplace rather than as a blended average, so a Canadian duty change is visible as a Canadian duty change. See Nova Profit & Loss and custom breakdowns.