Rio Tinto Ltd (ASX: RIO) shares are back in focus on Tuesday after climbing to a new all-time high at market open.
The mining giant's shares are currently up 1.8% to $175.16, after briefly touching $175.82 earlier in the session. By comparison, the S&P/ASX 200 Index (ASX: XJO) is 0.6% higher to 8,977 points.
That gain leaves the stock up about 20% in 2026 and more than 58% over the past 12 months, among the sector's strongest runs.
With the shares now sitting at the top of their 52-week range, the market appears to be backing stronger commodity prices and a broader earnings base.
Here's what could be driving the latest move.
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Copper strength is adding a new growth layer
A big part of the recent optimism appears tied to copper.
While Rio Tinto remains best known for its Pilbara iron ore operations, copper has become a much larger contributor to earnings over the past year.
At its full-year 2025 results, the miner revealed that copper earnings had doubled and were contributing close to 30% of group profits. The increase was driven by stronger prices and increased production at Oyu Tolgoi.
Copper also remains a long-term market favourite, with electrification, data centres, grid investment, and EV demand continuing to support sentiment.
Investors may also be increasingly viewing Rio Tinto as more than an iron ore business, with its broader commodity mix adding to the growth outlook.
Iron ore is still doing the heavy lifting
Even with copper growing quickly, iron ore remains the key earnings engine.
Prices around the US$100 per tonne mark have stayed firmer than many analysts expected heading into 2026. That is helping support cash generation from Rio's low-cost Pilbara operations.
The strong cash flow continues to support dividends, expansion plans, and the balance sheet.
The market is also watching Simandou in Guinea closely, with the project remaining one of the world's most significant long-term iron ore developments.
Foolish Takeaway
I still think Rio Tinto remains one of the highest-quality large-cap miners on the ASX. The latest record high reflects growing confidence in its earnings base from investors.
Iron ore is still driving strong cash flow and dividends. Copper is also giving the business a stronger long-term growth angle tied to electrification and grid demand.
After a 20% gain this year and another record high, the easy re-rating may already be behind it. From here, I would expect gains to be steadier and more closely tied to commodity prices and project execution.
