Fastmarkets updates consultation proposal on Asia-Pacific copper concentrates TC/RC index

Fastmarkets proposes to introduce a dynamic volume weighting of trader and smelter purchases in the final index calculation, adjusted weekly based on reported price and volume data over a rolling six-month period. The proposed change affects only the weighting between traders’ and smelters’ purchases to calculate the copper concentrates TC/RC index, cif Asia Pacific. Currently, Fastmarkets applies a fixed 50:50 weighting for the calculation, meaning that the smelters’ and traders’ indices have equal weighting in the index, regardless of market liquidity and observed trading patterns.

The proposed dynamic volume weighting would apply greater influence on the market side with the largest reported transactions and their volumes, thereby aligning the index with the prevailing spot market trades.

Under the change, only reported transactions and their volumes will be used to calculate the weighting. This weighting would be adjusted weekly and on a rolling 6-month basis, to ensure the weighting — and as a result the index — reflect the latest spot market conditions while maintaining sufficient data liquidity to support a market-reflective price.

The following indices would be affected:

MB-CU-0287 Copper concentrates TC index, cif Asia Pacific, $/tonne

MB-CU-0288 Copper concentrates RC index, cif Asia Pacific, US cents/lb

The individual smelter and trader indices (MB-CU-0508, MB-CU-0509) would not be impacted by this proposed change in weighting.

For greater transparency regarding the potential pricing impact, Fastmarkets has modeled a price history to illustrate how the proposed weighting change would have been reflected between January 1, 2026, and June 19, 2026. Please note that this data analysis is not a prediction of future values, and supply-demand fundamentals and source behavior may change. The modeled analysis is also not reflecting any gold or silver normalization change that Fastmarkets has proposed. During this analytical period, Fastmarkets’ copper concentrates TC index, cif Asia Pacific would have been on average $17.60 per tonne higher (less negative), had the proposed weighting methodology been applied.

Fastmarkets has also proposed to normalize gold and silver content and payables within the index calculation to base specifications. Where gold or silver content is below the payable threshold, the reported treatment and refining charges (TC/RCs) may reflect a credit or deduction relative to material at the base specification.

As part of the normalization, Fastmarkets will normalize the reported gold and silver content, the applicable deduction or payable threshold, the payable percentage, the prevailing precious metal price on the day of the reported transaction, and standard unit conversions used in the market.

As part of this, Fastmarkets also proposes to change the gold (Au) base specification from 1.1 grams per dry metric tonne to 1.0 g per dmt, and the silver (Ag) base specification from 75 g per dmt to 30 g per dmt. The maximum specifications for gold and silver would remain unchanged at 30 g per dmt and 350 g per dmt respectively.

This change came from sustained, unprecedented tightness since late 2023 in the copper concentrates market, fierce competition and the surge in gold and silver prices.

The following indices would be affected:

MB-CU-0287 Copper concentrates TC index, cif Asia Pacific, $/tonne

MB-CU-0288 Copper concentrates RC index, cif Asia Pacific, US cents/lb

MB-CU-0508 Copper concentrates TC implied smelters purchase, cif Asia Pacific, $/tonne

MB-CU-0510 Copper concentrates RC implied smelters purchase, cif Asia Pacific, cents/lb

MB-CU-0509 Copper concentrates TC implied traders purchase, cif Asia Pacific, $/tonne

MB-CU-0511 Copper concentrates RC implied traders purchase, cif Asia Pacific, cents/lb

The proposal was first published on April 8 and the feedback period was extended to July 31 in a subsequent notice. The proposal was preceded by an open consultation on the copper concentrated index weighting and gold and silver normalization, published on February 3.

Please send any questions or comments by July 31 to pricing@fastmarkets.com and basemetals@fastmarkets.com. Please add the subject heading “Re: Copper Concentrates TC/RC Index.”

Please indicate if comments are confidential. Fastmarkets will consider all comments received and will make comments not marked as confidential available upon request.

To see all Fastmarkets pricing methodology and specification documents, go to the Fastmarkets methodology page.