Rio Tinto Shares Slide 3.16% with 356th Trading Volume as Glencore Merger Talks Stall Over Coal Price Divergence

Market Snapshot

Rio Tinto (RIO) shares fell 3.16% on March 13, 2026, with a trading volume of 0.33 billion, ranking 356th in market activity for the day. The decline followed a broader market selloff and renewed uncertainty around the stalled merger discussions with Glencore. Despite recent gains in coal prices, which have outpaced iron ore price movements, investor sentiment remains cautious ahead of the six-month regulatory cooling-off period for formal negotiations to resume.

Key Drivers

The primary catalyst for Rio Tinto’s recent volatility is the ongoing speculation about a potential merger with Glencore, a deal that would create the world’s largest mining company. Earlier in 2026, the two firms explored a $240 billion combination of Glencore’s copper and marketing assets with Rio’s operational expertise, but talks collapsed in February due to valuation disagreements. Glencore CEO Gary Nagle has since signaled optimism that rising coal prices—up 26% since January—could rebalance the equation. Coal prices, which heavily influence Glencore’s valuation, have surged as global energy markets adjust to supply constraints, while Rio Tinto’s iron ore exposure has lagged, with prices dipping slightly and shares gaining only 9% over the same period. This shift has increased Glencore’s projected market share in a merged entity to 35%, up from 31.5% at the time of the initial talks, narrowing the gap with the 40% stake Glencore initially sought.

A critical factor in the stalled negotiations was Rio Tinto’s valuation methodology, which anchored Glencore’s worth to January 7’s spot prices for key commodities. Glencore and its supporters argue that forward-looking price projections should have been incorporated to reflect long-term demand trends for copper and coal. The recent price divergence—favoring coal—has strengthened Glencore’s case for a larger equity stake in the combined entity. Additionally, Glencore anticipates that a potential oversupply in the iron ore market could further erode Rio Tinto’s divisional value, creating additional leverage as the six-month regulatory pause under the UK Takeover Code nears its end in August.

However, structural and reputational challenges persist. Australian investors, who hold over half of Rio Tinto’s profits through its domestic operations, remain skeptical. A vocal minority of funds, representing 4% of the shareholder base, raised concerns about Glencore’s past corruption investigations and governance practices. They also question the strategic logic of Rio reacquiring coal assets after years of divesting them to align with environmental, social, and governance (ESG) priorities. Nagle has countered by arguing that Europe has already normalized coal as a transitional energy source, suggesting Australia lags in ESG acceptance. Yet, political and regulatory hurdles remain significant, as any merger would require approval from the Australian government and a supermajority of shareholders under the ASX listing rules.

The timing of the potential revival is also constrained. While Glencore’s recent roadshow in Australia has garnered attention, investors remain divided on the deal’s merits. Some argue that short-term commodity price fluctuations are insufficient to justify a structural overhaul, particularly given the lack of clear operational synergies. Rio Tinto’s CEO Simon Trott previously stated the company could not justify a “value case” for the merger, and that stance has not changed. For the deal to proceed, Glencore must demonstrate not only improved financial dynamics but also a compelling strategic rationale that addresses ESG and governance concerns. Until August, however, formal negotiations remain legally barred, leaving the outcome dependent on market conditions and regulatory developments in the coming months.