The potential merger between the two mining heavyweights, if successful, would be the industry's largest deal and create a combined company with a market value of around $US158 billion ($A254 billion), surpassing top miner BHP's $US126 billion ($A203 billion) valuation.
The report on Thursday said it was unclear whether the talks were still live.
Both the companies declined to comment. Rio Tinto's US-listed shares fell 2.5 per cent, while Glencore stock was up 7.4 per cent.
A source familiar with the matter told Reuters that Glencore approached Rio late in 2024, but the talks were brief and no longer active.
This would not be the first time the two companies have considered combining. In 2014, Rio Tinto rejected a merger offer from Glencore that would have allowed the combined company to surpass BHP as the world's biggest miner.
The latest discussions come as iron ore demand in China, the world's largest consumer of the commodity, takes a hit from a slowdown in the country's debt-laden property sector.
Consolidation has also picked up in the mining industry as companies race to secure supplies of metals essential for electric-vehicle batteries and the clean energy transition.
Rio in 2024 agreed to buy US-listed lithium producer Arcadium for $US6.7 billion ($A10.8 billion) as the world's largest producer of iron ore sought to transform itself into a processor of high-end, low-carbon raw materials.
Still, Rio Tinto faces challenges with depleting primary mines and is resorting to increased production of lower-grade iron ore to maintain output levels.
These challenges have hit Rio Tinto's performance, with the company reporting its lowest annual iron ore shipments in two years on Thursday.
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