Glencore, the world’s largest commodities trader, has begun cutting its ties with the Russian aluminium tycoon Oleg Deripaska after new US sanctions against his business empire.

Glencore said it had cancelled the planned swap of its 8.75% stake in the Russian aluminium maker Rusal, which is controlled by Deripaska, for shares in the London-listed En+ Group, another of the oligarch’s companies.

Glencore’s chief executive, Ivan Glasenberg, has also resigned from the Rusal board. The Swiss-based commodities trader said it was evaluating other contracts with Rusal. It bought $2.4bn (£1.7bn) of aluminium from Rusal in 2017 under a multi-year deal that is due to be renegotiated this year.

“Glencore is committed to complying with all applicable sanctions in its business and is taking all necessary measures in order to mitigate any risks to Glencore’s business,” it said.

“Glencore is still evaluating the position under its contracts with Rusal, but notes that these contracts are not financially material to Glencore.”

The rouble has lost about 4% against the dollar, its second day of heavy losses, falling to its lowest level since December 2016.

The plunge came even though the Russian central bank chief, Elvira Nabiullina, said the country’s economy could withstand the latest US sanctions.

“The central bank has a broad spectrum of instruments in order to act in such situations, if risks arise to financial stability. In our view, there are not such risks now,” Nabiullina told a conference in Moscow.

“There is no need to take some kind of systemic measures. Of course we will follow the situation and possibly introduce some revisions if necessary.” Russia’s 50 richest men lost more than $16bn in value on Monday according to Bloomberg, with the biggest loser, Vladimir Potanin, not even on the sanctions list.

A senior Russian official on Tuesday said the government was ready to step in if necessary to prevent bankruptcies or mass layoffs in some of the business empires targeted by the sanctions.

“What’s most important now is to minimise uncertainty, above all by providing for the stable, calm operations of enterprises which employ hundreds of thousands of people … if necessary, we will facilitate the preservation of these enterprises’ stable operations,” said Arkady Dvorkovich, a deputy prime minister whose portfolio includes the economy, at a session of the Moscow Exchange Forum on Monday.

The US sanctions have thrown Russian markets into some of its worst turmoil since 2014, threatening to derail the country’s shaky economic recovery.

How the government will protect those targeted is still unclear. The Russian business daily Vedomosti reported that the government is discussing plans to set up offshore zones inside the country to relieve financial burdens on sanctioned companies. And the government has threatened to punish companies that refuse to do business with those targeted by sanctions.

In the past, the Russian government has offered means for sanctioned companies blocked out of markets to refinance their debt. More likely, sanctioned oligarchs will begin to cut formal ties with their companies.

Shares in Glencore fell 2% on Friday when US sanctions on seven Russian oligarchs and 17 top government officials were announced, and a further 3.4% on Monday, with investors fretting over the impact on the company’s aluminium business. On Tuesday, the shares rallied as much as 4.6% after some analysts said there would be little impact.

Glencore’s involvement in Rusal dates back to 2007, when Deripaska and fellow Russian billionaire Viktor Vekselberg, who has also been sanctioned, merged their companies with Glencore’s aluminium plants.

Last October, when Deripaska wanted to float his holding company En+ Group in London, Glencore stepped in as a cornerstone investor, pledging to swap its 8.75% stake in Rusal for En+ shares.

The sanctions announced last Friday ban US individuals and companies from doing business with Deripaska and his firms. While Glencore is not a US company, the penalties make it harder for anyone to work with the oligarch.

Deripaska has called the sanctions “groundless, ridiculous and absurd”.