News & Market Analysis: Copper’s Benchmark Is Breaking Down – And A Replacement Is Already Emerging

Spot treatment and refining charges (TC/RCs) for copper concentrate have fallen deep into negative territory, according to market participants, with trader-to-smelter transactions during New York Copper Club Week reportedly reaching as low as minus $220 per tonne. That figure is not a market anomaly. It is a verdict on the benchmark system itself.

The copper concentrate market operates on a simple commercial logic. Miners pay smelters to process ore into refined metal. The fee is the TC/RC. When that fee turns negative, the logic inverts: smelters are paying for access to feedstock, not being compensated for processing it. This is what a structural feedstock deficit looks like.

Antofagasta has now drawn the explicit conclusion. The Chilean miner has proposed shifting concentrate sales to spot-market index pricing in negotiations with Chinese buyers covering the second half of 2026 and through the first half of 2027. The proposal has been presented to at least two buyers. As of 12 June 2026, it had not been accepted,¹ but whether or not it succeeds is less significant than what it represents.

Antofagasta is not alone. Freeport-McMoRan, which previously played a central role in setting the annual benchmark, has also indicated it may break away from the traditional structure entirely.² Their positions are not identical. Antofagasta is explicitly proposing index pricing. Freeport has signalled a preference for individual supply deals if benchmark conditions deteriorate further. What both share is the balance sheet and contracted volume to absorb pricing uncertainty through a transition.

Smaller producers, junior miners and producers with financing or offtake arrangements built around long-term sales certainty are in a different position. For a mid-tier miner, an annual benchmark, however unsatisfactory its level, may still provide planning visibility and lender comfort that a spot-linked contract cannot. When two of the largest copper producers are simultaneously questioning the benchmark mechanism, the debate moves beyond annual TC/RCs. Instead, it becomes a debate about whether annual contracts serve any remaining purpose.

The cause is not difficult to locate. China now refines approximately 45% of the world’s copper.³ It has built that capacity at pace, expanding smelter throughput well ahead of growth in global mined supply. By March 2026, active Chinese smelting capacity had reached a record 10.73 million tonnes, running at 96.1% utilisation.⁴ The result is a structural imbalance that the benchmark system was never designed to accommodate.

The 2026 annual benchmark has already settled at zero dollars per tonne and zero cents per pound, the lowest in the history of the system.⁵ That level now sits materially above spot conditions.

The Chinese smelter perspective on this shift is more complicated than it may appear. Annual benchmark pricing has historically given smelters something the spot market cannot: cost certainty. A fixed TC/RC agreed in advance allows a smelter to underpin capital expenditure decisions, model refining margins over a planning horizon, and, in some cases, secure project financing against a known feedstock cost. For smelters with less sophisticated treasury functions, the ability to hedge feedstock price risk through an annual contract has been a structural advantage. A move toward spot-linked or index pricing removes that floor. In the current environment, where spot TC/RCs are deeply negative, smelters would face direct exposure to market conditions they have been partially insulated from. That exposure is partly mitigated by by-product economics. Revenues from sulphuric acid, along with credits from precious metals such as gold and silver, can offset negative TC/RCs and sustain operations even when concentrate processing appears uneconomic on a headline basis. The irony of the benchmark’s collapse is that it may accelerate a transition that disadvantages the very party that triggered the surplus in the first place.

The precedent the industry will reach for is iron ore. In early 2010, Vale and BHP moved first, abandoning a four-decade-old annual benchmark in favour of quarterly pricing. Rio Tinto followed within weeks.⁶ The proximate cause was a market that had become too dynamic for once-a-year negotiations to track. When markets grow in liquidity, benchmark pricing periods tend to get squeezed. The second-order effect was to deliver leverage to producers that the old system could not.

Copper concentrates are not at that point yet. The market remains less liquid than iron ore, and the transition to index pricing would require settlement infrastructure that does not currently exist at scale. There is also a product complexity that the iron ore analogy elides. Iron ore became easier to benchmark partly because grades converged over time toward a relatively standardised seaborne specification.

Copper concentrates vary substantially by mine of origin: copper head grade, moisture content, and the presence of deleterious elements including arsenic, antimony, and bismuth. These differences are currently handled through penalty and credit clauses negotiated alongside the TC/RC. An index-linked pricing system would need to replicate that functionality or standardise around a reference specification, neither of which is straightforward to construct at the scale and speed that producers are pushing for.

But the direction is clear: mined supply growth remains constrained, Chinese smelters remain dependent on imported concentrates, and producers retain pricing leverage that the benchmark system has structurally undervalued. With continued demand growth, each of these conditions is more likely to intensify than to reverse.

The annual benchmark survived commodity cycles, smelter closures, and periods of acute surplus because it delivered something both sides valued: predictability. That implicit trade is breaking down. Miners are being asked to accept fixed-price contracts in a market where spot conditions offer them a structurally better outcome. The incentive to sustain the benchmark no longer operates symmetrically.

Antofagasta’s proposal may be rejected this cycle. The benchmark may persist for several years in its modified form. But the question facing the copper concentrate market is no longer where the annual benchmark should be set. It is whether miners will continue offering one at all.

Sources

1  Julian Luk, “Copper Miner Antofagasta Seeks to Link Ore Sales to Spot Market,” Bloomberg, 17 June 2026.

2  “Freeport to Break Away from Copper Benchmark It Set for Decades,” Bloomberg / Mining.com, 14 October 2025.

3  UNCTAD Global Trade Update, May 2025: “China imports 60% of global copper ore and produces more than 45% of the world’s refined copper.” CME Group, September 2025: “China processed 45% of the world’s copper in 2024.”

4  Earth-i satellite monitoring data, March 2026, as reported by Recycling Today, 15 April 2026, and corroborated by multiple secondary sources.

5  Antofagasta agreed zero TC/RCs with Jiangxi Copper and Tongling for 2026. Sources: Mining.com, 19 December 2025; BigMint, 7 April 2026.

6  “Annual iron ore contract system collapses,” Financial Times, 30 March 2010; “Rio sounds death knell for annual iron ore pricing,” Reuters, 8 April 2010; “Rio Tinto Goes to Quarterly Pricing on Iron Ore,” New York Times, 9 April 2010.