The U.S.-Canada tariff war is raising costs across North American supply chains. Canada's additional retaliatory tariffs took effect on September 8, 2026. The impact on Korean companies' profits depends on where they produce goods and where they export them.
The tariff figures are based on official announcements by both countries in August and September 2026.
What tariffs have the United States and Canada imposed?
Both countries' additional tariffs apply to designated products. They do not impose the same rate on all traded goods. The relationship between existing tariffs and the new measures must also be checked for each product.
| Measure | Effective date | Confirmed details |
|---|---|---|
| Additional U.S. tariffs on designated Canadian products | August 22, 2026 | Additional 50% tariff on designated products |
| Canadian retaliatory tariffs on designated U.S. products | September 8, 2026 | 15%, 25%, or 50%, depending on the product |
| Changes to products subject to additional U.S. tariffs | September 15, 2026 | Addition and removal of some products and changes to rules on overlapping tariffs |
| U.S. import ban on certain Canadian products | September 29, 2026 | Applies to products designated in the annex to a separate proclamation |
Initial U.S. implementation guidance is available in the CBP notice. Canada announced that the targeted imports were worth 27.6 billion Canadian dollars. This is not the amount of tax revenue the tariffs would generate.
Canada also announced 7.5 billion Canadian dollars in support measures. This is the combined amount for several measures supporting businesses and workers. The distinction between retaliatory tariffs and support measures is set out in the Canadian Department of Finance announcement.
Other existing counter-tariffs, including against U.S. autos, continue to apply.
This wording appears in the Canadian Department of Finance's “Complete list of U.S. products subject to counter tariffs.” It means that existing retaliatory tariffs, including those on U.S. automobiles, remain in effect. The new product list does not replace all existing measures.
Tariff rates alone cannot determine how much consumer prices will rise.
What else changed from September onward?
The United States continued to change the scope of the tariffs after its initial announcement. Calculating subsequent import costs using only the August tariff schedule can therefore lead to errors. Announcement dates must also be distinguished from actual effective dates.
The September 8, 2026 proclamation added or removed targeted products. The revised rules apply from September 15 of the same year. The proclamation also includes rules on applying these tariffs together with tariffs under Section 232 of the Trade Expansion Act. Details of the scope are available in the White House proclamation modifying product coverage.
A separate proclamation banned imports of certain Canadian products. Its effective date is September 29, 2026. This differs from allowing imports upon payment of additional tariffs. The covered products must be checked against the annex to the import ban proclamation.
Why did negotiations between close allies break down?
Both countries argued that the other's demands and measures were unfair. The United States considered Canada's automobile-related measures discriminatory. Canada says U.S. demands undermine its industries and sovereignty.
Prime Minister Mark Carney explained the reasons for suspending negotiations on August 22, 2026. He said Canada had sought tariff reductions for key industries. He also stated that protection of the French language and culture was nonnegotiable. This is Canada's account as presented in the Canadian prime minister's speech.
However, specific figures in negotiating proposals are different from agreed tariff rates. Discussion of a proposal to lower automobile tariffs does not mean it took effect. A final agreement or implementation notice is needed to determine the applicable conditions.
Why are automobile supply chains sensitive to tariffs?
Automobile production involves parts and finished vehicles moving across borders. A factory in one country may still use imported parts. The tariff burden is difficult to assess solely from where a finished vehicle is assembled.
Just-in-time production means receiving the necessary parts according to the production schedule. Low inventories leave less room to absorb customs delays. If tariff-related price renegotiations occur at the same time, supply schedules come under pressure.
| Supply chain stage | How costs increase | What to check |
|---|---|---|
| Steel and aluminum procurement | Higher procurement prices for imported materials | Material origin and applicable tariff rates |
| Parts production | Intermediate goods import costs and paperwork burden | Product codes and processing history for each part |
| Finished vehicle exports | Automobile tariffs imposed by the importing country | Finished vehicle origin and separate automobile rules |
| Factory operations | Parts delays and production volume adjustments | Inventory levels and alternative suppliers |
Multiplying the tariff rate by the number of border crossings will not give the actual burden. The taxable goods and their value are not necessarily the same at every crossing. Separate rules may also apply to reimports or processed goods.
Production restructuring was underway even before these retaliatory tariffs. Stellantis announced its U.S. investment plan on October 14, 2025. The plan at the time called for 13 billion U.S. dollars over the following 4 years. Interpreting the company announcement solely as a result of the September 2026 measures does not fit the timeline.
Breakdown by scenario: Impact on Korean automobile and battery companies
The impact on Korean companies depends more on the routes their goods take than on corporate nationality. Higher costs for competitors may create a relative opportunity. Any benefit diminishes if a company's own parts costs or market demand worsen.
The table below is a conditional analysis based on supply chain structures. It is not a forecast of actual profits or losses for individual companies. Hyundai Motor and Kia must also be assessed by separating production locations and sales markets for each model.
| Production and sales conditions | Possible impact | Other variables to check |
|---|---|---|
| Production in the United States for U.S. sales | Possible opportunity in price competition with imported finished vehicles | Imported parts costs and local production capacity |
| Production in Korea for export to the United States | Possible change in competitive conditions relative to Canadian vehicles | Separate tariffs applicable to Korean vehicles |
| Production in the United States for export to Canada | Possible exposure to Canadian measures on U.S. automobiles | Origin and vehicle-specific exemptions |
| Battery production in Canada for export to the United States | Possible direct costs if the product is covered | Battery classification and whether exemptions apply |
| Parts supply to North American automakers | Customers' production cuts may lead to fewer orders | Revenue by customer and factory capacity utilization |
Electric vehicle demand alone is also insufficient to explain the battery business. NextStar Energy announced battery pack production on June 25, 2026. The company described it as an expansion to meet demand for energy storage systems, or ESS. The company announcement at the time states that it is a wholly owned subsidiary of LG Energy Solution.
The end use of the products therefore also affects the profitability of Canadian battery factories. Order trends for electric vehicles and ESS cannot be assumed to be the same. Nor should the same tariff be applied to all products simply because they are made in Canada.
Is crude oil excluded from the tariff war?
It cannot be assumed that crude oil is permanently excluded from the dispute. However, the two countries' refining infrastructure makes changing suppliers difficult. Even high crude oil production does not mean that all the types of crude needed are the same.
Heavy crude accounts for a large share of Canadian oil. Refineries in the U.S. Midwest specialize in processing this type of crude. An analysis by the Federal Reserve Bank of Kansas City also explains these refinery characteristics.
Under this structure, supply restrictions could raise costs for U.S. refiners. Canadian producers would also face the burden of finding different buyers. Which side loses more depends on transport networks and alternative demand.
The scale of U.S. crude oil production and its ranking in crude oil exports are also different indicators. Exports that include petroleum products must likewise be distinguished from crude oil exports alone. A ranking for one indicator should not be applied directly to another.
