- Potanin, 61, is the president and largest shareholder at Nornickel, the world's largest producer of palladium and refined nickel. His holding company, Interros - which was also sanctioned - owns 36% of Nornickel, making him one of the most important players in the global market for industrial metals. In 2021 Nornickel was the world's top producer of refined nickel, used to make stainless steel and important for electric vehicle batteries. It also extracted 10% of the world's platinum and 40% of its palladium, which is used in car exhausts. Nornickel itself was not targeted by the U.S. move on Thursday.

- The son of a high-ranking Soviet trade official, Potanin was educated at Moscow's elite diplomatic academy. He was one of a group of tycoons known as the oligarchs who acquired enormous wealth by taking over prize state assets in a flawed privatisation drive in the 1990s. His wife and daughter were also named in the sanctions announcement by the U.S. Treasury.

- Potanin has waged a long-running rivalry with another metals oligarch, Oleg Deripaska. In July he floated the idea of a $60 billion merger of Nornickel with Rusal, formerly controlled by Deripaska, though he said in September that this was on hold.

- Potanin has taken care to stay on the right side of President Vladimir Putin, for instance by accepting a $2 billion fine after Nornickel angered the president by causing Russia's biggest Arctic oil spill two years ago.

- After Russia's invasion of Ukraine and the imposition of Western sanctions against it, Potanin urged the authorities not to confiscate the assets of foreign companies leaving the country - a warning that was largely heeded. He said such a step would shatter investor confidence for decades and isolate the country, as happened after the 1917 Bolshevik Revolution.

- That did not stop Potanin from moving aggressively to snap up departing businesses. Within 10 weeks of the start of the war, he had bought Rosbank from French lender Societe Generale, acquired the Russian unit of U.S.-listed fintech group Global Payments, and purchased 35% of TCS Group Holding, owner of an online bank. The latter was bought from its founder Oleg Tinkov, who had spoken out against the invasion and said he had been forced by the Kremlin into making a "fire sale" to Potanin. Rosbank was also targeted by Thursday's sanctions.

(Writing by Mark Trevelyan, Editing by William Maclean)