MOSCOW (Reuters) – The new round of U.S. sanctions against Russia will have a “severe effect” on targeted companies and will limit Russia’s potential economic growth, Fitch Ratings said on Friday.

The U.S. Treasury on April 6 announced sanctions on seven Russian oligarchs and 12 companies they own or control, saying they were profiting from a Russian state engaged in “malign activities” around the world.

“The sanctions are likely to have a profound effect on the designated companies, which would be unable to transact in U.S. dollars – the standard denomination currency in commodities trading and the main currency in counterparty transactions in international trading,” Fitch said.

The sanctions hit Russian markets hard, denting the rouble and sending shares in four publicly listed companies with links to those sanctioned plummeting both in Russia and elsewhere: Rusal , EN+ Group, GAZ group, GAZA. and Polyus.

Fitch said it stopped rating Rusal and EN+ Group, describing the latest round of sanctions as “the most significant affecting Russian corporates” since 2014 when the West first imposed sanctions against Russia for the annexation of Crimea and Moscow’s role in the Ukrainian crisis.

According to Reuters calculations, three Russian tycoons targeted by a new list of U.S. sanctions may have lost a combined $7.5 billion in less than a week since the list was announced.

Fitch noted Russia’s strong external balance sheet, saying it means Russia is well positioned to meet forex needs from other parts of the economy, while the free-floating rouble provides a shock absorber, something that was not available in 2014.

“However, uncertainty stemming from the sanctions and their possible extension could deter investment and thereby undermine potential economic growth,” Fitch said.

This year, the economy is on track to grow by up to two percent, the central bank forecast, after expanding by 1.5 percent in 2017.

Fitch revised Russia’s sovereign rating outlook to positive from stable in September and said the rating itself would be one notch higher than its current BBB- level if not the U.S. sanctions.

(Reporting by Andrey Ostroukh; Editing by Richard Balmforth)