No more.

One of Switzerland's largest banks, Credit Suisse, has frozen roughly 5 billion Swiss francs ($5 billion) of money linked to Russia to avoid violating U.S. sanctions, according to its accounts, further increasing pressure on Moscow which today saw the ruble tumble to the lowest level in over two years.

The crackdown on Russian funds by the second largest Swiss bank, which owned aircraft surrendered by Russian tycoon Oleg Deripaska and had lent money to Russian oligarch Viktor Vekselberg before the sanctions, is indicative of the widespread fear among European banks of retaliation by Washington for working with targeted Russian individuals and entities.