Rio Tinto CEO Jakob Stausholm has expressed caution regarding the potential impact of US President Donald Trump’s proposed 25% import tax on all steel and aluminium, stating that the ultimate effect on the company remains uncertain.

Speaking from Washington DC, Stausholm said on Wednesday that Rio Tinto operated within the US and other countries, making the tariff's implications complex. 

“The economic impact on tariffs to Rio Tinto might be both pluses and minuses, and we don't know whether the net will be positive or negative. But it really depends on how the tariff hit,” he said.

He pointed out that if all countries face tariffs equally, the impact on Rio Tinto would be zero. However, if tariffs target specific countries, such as Canada, the company may need to redirect shipments to other markets while other producers fill the US supply gap.

“So, new balances will arise,” said Stausholm, but stressed that it was “far too early to conclude” how the tariffs would ultimately shape global trade flows.

“At the end of the day, tariffs are only an instrument,” he said, stating the need to first understand Washington’s broader objectives before determining the full impact on Rio Tinto’s business. Stausholm presented the UK-headquartered group’s earnings from Washington where he is meeting with officials.

Trump has ordered a a 25% import tax on all steel and aluminium entering the US, ending previous exemptions for allies including Canada and the EU and marking a major expansion of trade barriers. The US President said he was "simplifying" the rules and the measures would boost domestic production. The measures would come into force on March 12.

Canada accounts for about half of aluminium imported into the US. Rio Tinto operates aluminium operations in Saguenay-Lac-Saint Jean and the BC Works in Canada.

Despite the uncertainty surrounding trade policies, Stausholm reaffirmed Rio Tinto’s commitment to investing in both the US and Canada. “We are very keen to invest in the US,” he said, citing the company’s involvement in the Resolution copper project, which could supply 25% of the country’s copper needs, as well as its position as one of only two operators of a copper smelter in the US.

At the same time, Stausholm highlighted Rio Tinto’s ongoing investment in Canada, including the AP60 aluminium smelter project. “I’m very pleased to inform you that the project is on schedule,” he said, adding that it is the first new smelter in the Western world in 16 years.

While acknowledging some uncertainty in the short term, Stausholm framed the situation as an opportunity rather than just a challenge. “When you have fairly seismic change, opportunities arise, and it's really the opportunities I'm looking for right now,” he stated.