Top global copper producer Codelco on Friday agreed a contract with a major Chinese buyer for copper supply at a premium of $88 a tonne in 2021, two sources at the Chilean company said.

The premium, which Codelco kept steady on the 2020 level in its recent offer to state-run Chinese clients, is paid on top of London Metal Exchange copper prices for physical delivery of copper cathodes and is a widely watched industry benchmark.

The sources asked not to be named as the information was not public and also declined to identify the buyer.