Rio Tinto and Glencore abandon merger plans that once promised to forge a $260 billion mining behemoth, ending months of high-stakes negotiations amid an industrywide scramble for copper and other metals powering the artificial intelligence boom.

After weeks of intense but cordial talks, the two global miners reached a stalemate over valuation and corporate control as a key regulatory deadline loomed Thursday. What could have become the world’s largest mining group instead unraveled at the negotiating table.

Price and Power Struggles Doom Deal

Rio Tinto said it had “determined that it could not reach an agreement that would deliver value to its shareholders,” effectively drawing a line under more than 18 months of intermittent discussions between the companies.

People familiar with the talks described a gap too wide to bridge. “The gap was too big,” one person said, while another noted that negotiations stretched to the final hours before the deadline. Even after weeks of sustained engagement, the companies failed to align on valuation, according to those close to the matter.

Earlier reports had highlighted significant divisions over both price and governance — fault lines that ultimately split the deal.

Glencore, in its own statement, signaled frustration with Rio’s insistence on keeping its chair and chief executive in charge of the combined entity. It also argued that Rio’s proposal “significantly undervalued Glencore’s underlying relative value,” particularly failing to properly reflect the strength of its copper business.

Sources said Glencore had pushed for a premium that would grant its shareholders roughly 40% ownership of the merged group. Bloomberg first reported details of the premium sought.

Market Reaction: A Sharp Jolt

Investors reacted swiftly. Glencore shares tumbled as much as 10% in late-afternoon trading in London before closing down 7% at £4.75. Rio Tinto’s London-listed stock was comparatively steady, slipping about 2.6% to £68.26.

The companies had publicly confirmed merger discussions in early January and faced a Feb. 5 “put up or shut up” deadline — the point by which Rio needed to make a firm offer or walk away unless both sides agreed to extend negotiations. With talks now terminated, they are barred from revisiting a merger for six months.

Still, people close to the discussions did not entirely dismiss the possibility of renewed talks after a cooling-off period. In mining, as in geology, pressure can reshape outcomes over time.

Copper at the Center of the Storm

The collapse marks another failed megamerger in the mining sector, following BHP’s unsuccessful attempts to acquire Anglo American.

At the heart of the drama lies copper — the red metal increasingly viewed as the bloodstream of electrification and artificial intelligence infrastructure. Mining groups are racing to secure new supply as demand accelerates.

Glencore, the world’s sixth-largest copper producer, announced in December a strategic pivot to focus more heavily on copper, aiming ultimately to become the world’s top producer.

Rio Tinto, whose profits are still dominated by iron ore, has been working to expand its copper portfolio through projects including the Resolution Mine in Arizona.

“A deal of this size, and with the egos involved, was always going to be a significant challenge,” said Ben Davis, an analyst at RBC. “We are surprised it was revisited so quickly — clearly something had brought the two back together, and it is unclear what has driven them apart again.”

For now, the dream of a mining colossus straddling iron ore, copper and global commodity flows has fractured. In a sector defined by scale and ambition, Rio Tinto and Glencore’s aborted union underscores a simple truth: even giants can fail to align when value — and control — are on the line.