This action targets those people that have been using credit cards as a way to purchase at the official rate rather than the black market rate, in effect creating a dual credit card exchange regime.

FORBES: Argentina Begins Tracking All Credit Cards

In Zimbabwe, the black-market exchange rate is nearly ten times the official one.

ECONOMIST: Zimbabwe

With hyperinflation, a gap of around 10:1 has opened up between the official exchange rate operated by the bank and the true rate reflected in the black market.

ECONOMIST: How to prop up the government

The government has abolished jail terms for those caught dealing in foreign currency, offered extra incentives for private investment and brought the official exchange rate closer to the black-market one.

ECONOMIST: Syria