Following a one-month consultation, Fastmarkets will proceed to revise the outlier detection method used in the calculation of its copper concentrate TC/RC index to reflect spot market changes.

Changes will take effect on Friday June 4.

The prices involved are: 

Fastmarkets will apply a ±1.96 standard deviation filter which should exclude around 5% of the normalized data points. The standard deviation is calculated with the last two weeks of data and updated weekly.

Data point deviation from the index follows a normal distribution of which 95% lies within 1.96 standard deviations away from the index.

Editorial judgement will still be deployed to determine whether a specific data point is representative of the open and competitive market for the week, and therefore to determine its inclusion in or exclusion from the index calculation.

To provide feedback on the change, or if you would like to provide price information by becoming a data submitter to this index, please contact Julian Luk by email at: Please add the subject heading ‘FAO: Julian Luk re: copper concentrate index.’

To see all Fastmarkets’ pricing methodology and specification documents, go to: