Stocks of Rusal collapse 50% after U.S. sanctions

Separately, Rusal warned that the sanctions impact "may result in technical defaults in relation to certain credit obligations of the group, and the company is now evaluating the impact (if any) of such technical defaults on the financial position of the group".

Julius Baer analyst Carsten Menke said "This is a further hit to Russian aluminium exports to the US They come after the tariffs (US President Donald) Trump introduced in March".

Deripaska, whose wealth Forbes magazine estimates at $6.7bn, meets Putin regularly and has said his own interests can not be separated from those of the Russian state.

The latest wave of sanctions also saw Russian stock market indices plummet around 10 percent.

The US Treasury sanctioned Russian individuals, officials, state-owned firms and companies, including Rusal, the world's second largest maker of aluminum, under provisions of a law Congress passed past year to retaliate against Moscow for meddling in the 2016 USA presidential election, last Friday.

Rusal and seven other companies linked to Deripaska were the main targets when the U.S. imposed sanctions created to punish Vladimir Putin's inner circle for "malign activity", including support for Bashar al-Assad's government in Syria and interfering with the USA election in 2016. The company, also listed in Moscow, is the biggest aluminum maker outside China, and the measures could hurt access to financial markets and disrupt shipments to world buyers.

The Kremlin slammed the sanctions.

The sanctions also hit Norilsk Nickel, whose shares were down 16 percent.

The company which supplies seven percent of the world's aluminum supply, is now at risk of defaulting on part of its debt, the AFP reported.

The rouble suffered its biggest one-day fall in...

Russia's prime minister, Dmitry Medvedev, told his government to draw up possible retaliatory steps.

The company said the sanctions were likely to have a "materially adverse" impact on its business and finances. He said the new U.S. sanctions were unacceptable and illegitimate, and that the government would come up with plans to support the companies affected.

  • Wendy Palmer