London, Jan 30, 2026, 08:01 GMT — Regular session
- Rio Tinto shares fell in early London trade after agreeing to buy control of Brazil’s CBA with China’s Chinalco
- Investors are also counting down to a Feb. 5 decision point on any potential Glencore bid
- A sharp copper rally this week has added momentum — and noise — to big miners
Rio Tinto (RIO.L) shares fell 1.9% to 6,718 pence in early London trading on Friday, paring gains from the previous session as investors weighed a new aluminium deal against an approaching takeover deadline.
The miner said late Thursday it would join China’s Chinalco to buy control of Brazilian aluminium producer Companhia Brasileira de Aluminio (CBA), a move that nudges Rio further into so-called low-carbon aluminium.
That matters now because Rio is simultaneously running down the clock on whether it makes a play for Glencore, while metals prices — especially copper — have been swinging hard and dragging big miners with them.
Chinalco and Rio agreed to acquire a 68.6% stake in CBA for 4.69 billion reais ($903.6 million) and will then launch a tender offer — an offer to buy the remaining shares — that could lead to CBA being delisted from Brazil’s B3 exchange, they said. “I like it, it’s a very bullish signal,” said CLSA analyst Baden Moore, pointing to offshore investment by Chinese aluminium producers and Rio’s tilt toward low-carbon aluminium. Reuters
The bigger question for traders sits with Glencore. The market is awaiting a possible Rio takeover offer for Glencore that is expected to be announced by Feb. 5, Reuters reported, a deal that would create a mining group valued above $200 billion.
Commodity prices are not making it easier. Copper jumped to a record above $14,000 a metric ton on Thursday before giving back part of the move, and Reuters quoted Britannia Global Markets’ Neil Welsh as saying: “Investors are piling into base metals on expectations for stronger U.S. growth and more global spending on data centres, robotics and power infrastructure.” Reuters
Rio’s slide on Friday also comes after the stock pushed toward its recent highs this week, leaving it exposed to any wobble in the broader metals trade and to position-trimming ahead of next week’s M&A deadline.
But there are clear risks. The CBA transaction still hinges on local process and pricing for the mandatory offer, and any broader Rio-Glencore tie-up would invite regulatory scrutiny, possible asset sales and financing questions, particularly if copper prices cool sharply and the sector’s risk appetite fades.
Next up is the Feb. 5 cut-off under the UK Takeover Code for Rio to declare whether it will make an offer for Glencore, followed by Rio’s 2025 annual results on Feb. 19, when investors will be looking for cost and production signals for 2026. 1
