(Bloomberg) -- The London Bullion Market Association has barred MMC Norilsk Nickel PJSC from its annual precious metals conference due to Russia’s invasion of Ukraine.

The Russian firm, which is the world’s top palladium miner, was asked not to attend the event in Lisbon this year, a spokesperson for the LBMA confirmed. Norilsk Nickel isn’t currently sanctioned by the US or Europe, but stigma against Russian companies has gone beyond entities targeted by official measures.

“With regret the LBMA felt it inappropriate to accept Norilsk Nickel’s registration due to the international situation,” the LBMA spokesperson said.

The association’s annual conference is viewed as the highlight of the precious metal industry’s calendar, and a crucial opportunity for firms to meet clients. Traders, refiners and miners are currently gathering in Portugal’s capital for three days of events, seminars and dinners

While Russian gold has largely been cut out of the mainstream supply chain, the treatment of industrial metals like palladium has been mixed. Some European firms, including Norsk Hydro ASA and Novelis Inc., have avoided signing new contracts for aluminum from the country. And the London Metal Exchange is discussing whether to ban new deliveries of Russian metals to its warehouses.

Norilsk Nickel produces around 40% of the world’s palladium, which is largely used in catalytic converters. Its major shareholder is Russian billionaire Vladimir Potanin. Other major producing nations include South Africa and the US.

Norilsk Nickel declined to comment. 

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