Markets Price a 37% Chance of a 2028 US Copper Tariff on Chile

Chile · Mining

The duty is not law yet. But traders read the gap between New York and London metal prices as a live wager on Washington’s next move.

A new US copper tariff is not law yet, but markets are already betting it may come. Traders now put the chance of a 30% duty on refined copper from 2028 at roughly 37%, according to Societe Generale.

For Chile, the world’s top copper producer, that is a number worth watching closely.

What the 37% copper tariff odds really mean

The figure comes from Societe Generale, in a market note dated 10 August. It reads a rough 37% probability that Washington slaps a 30% duty on refined copper by January 2028.

Crucially, this is a market price, not a policy announcement. So it reflects where money is being wagered today, rather than any final decision in Washington.

Where the number actually comes from

The bank does not have a crystal ball. Instead, it reads the odds from the price gap between copper traded in New York and metal delivered against the London benchmark.

When New York trades at a fat premium, it signals traders expect a future import tax. Because that premium can be measured, the implied probability can be backed out from it.

The tariff that is not law yet

A White House proclamation in July 2025 set out the path, yet stopped short of enacting it. It floated a phased duty on refined copper of 15% from January 2027, rising to 30% a year later.

However, that plan was tied to a fresh Commerce Department review, due back by mid-2026. So the refined-copper levy remains a proposal, not a duty already in force.

What is already in force

One copper tariff is real and biting. Since August 2025, the US has charged 50% on semi-finished copper products and copper-heavy goods, under a Section 232 order.

Refined copper, the raw cathode metal, was left out of that first wave. That is why the 2028 question still hangs over the market rather than being settled.

Why Chile has the most to lose

Chile mines more copper than any other country on earth. In 2025 it dug up about 5.3 million tonnes, according to US Geological Survey data.

As a result, any shift in the world’s biggest buyer matters to Santiago. Still, the US is only one customer among many for Chilean metal.

Codelco in the crosshairs

Codelco, the state-owned giant owned by all Chileans, sits at the centre of this. It is widely described as the world’s largest copper producer by output.

In the first eleven months of 2024, Chile sent 544,000 tonnes of cathodes worth US$5.08 billion to the US. Codelco supplied 45% of that flow, so a 30% duty would sting.

How much US business is really at risk

The exposure is real but bounded. The US takes only around 11% of Chile’s copper exports, since Asia and Europe buy the bulk of the metal.

Because America refines little copper itself, Chile can often redirect cargoes elsewhere. So a tariff would pinch margins more than it would shut off sales entirely.

What a 30% duty would actually do

A tariff is a tax at the US border, paid on the metal as it lands. On the 2024 cathode flow, a 30% rate implies about US$1.52 billion in extra duty, before any change in prices or volumes.

In practice, some of that cost lands on American buyers through higher prices. Meanwhile, exporters like Codelco would likely steer more metal toward Asia to soften the blow.

The wider trade-war backdrop

This copper fight is part of a broader US push on metals. Steel, aluminium and copper have all been swept into tougher Section 232 measures since 2025.

For copper-rich Chile, that makes trade policy a first-order market risk. Although the economy is diverse, the metal still drives a large slice of export earnings.

What to watch next

The key trigger is the Commerce review and any presidential decision that follows. If a 15% duty lands in 2027, the market’s 2028 odds would likely jump.

For now, the 37% figure is a live gauge of nerves, not a forecast. Investors should therefore treat it as a mood reading that can move fast with the headlines.

Frequently Asked Questions

Is the US copper tariff on refined metal already in effect?

No. As of August 2026 the refined-copper duty is a proposal for 2027 and 2028, pending a Commerce review. A separate 50% tariff on semi-finished copper goods has been in force since August 2025.

Where does the 37% probability come from?

From Societe Generale’s 10 August note. The bank infers the odds from the premium of New York COMEX copper over metal delivered against the London LME benchmark.

How exposed is Chile to a US copper tariff?

Chile is the world’s top producer, but the US buys only about 11% of its copper exports. That share can often be redirected to Asia, so a duty would squeeze margins more than sales.

What would a 30% tariff cost Chilean exporters?

On the 2024 cathode flow of US$5.08 billion to the US, a 30% rate implies roughly US$1.52 billion in extra duty. Codelco, with 45% of that flow, carries the largest single share.

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