By Zimbabwean law, all official foreign-currency transactions must go through the central bank.

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Among the tax options on the table, which also include a global financial transaction fee (called a "Tobin tax" after Nobel-winning economist James Tobin, who proposed a tax on foreign-currency transactions in the 1970s) and a Bonus Tax, a risk-based fee is the most efficient solution.

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The Bank Secrecy Act of 1970 (or BSA, or otherwise known as the Currency and Foreign Transactions Reporting Act) requires financial institutions in the United States to assist U.S. government agencies to detect and prevent money laundering.

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Since December 2002, the euro has been North Korea's official currency for all foreign transactions.

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Since the mechanism of a currency transactions levy is supposed to be based on taxing the net position of foreign exchange transactions, it could represent a restriction of the free movement of capital and payments (Article 63 TFEU).

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All this contributes to economic collapse, relieved mainly by a burgeoning underground economy based on barter or transactions involving precious metals, stable foreign currency or whatever else might be commonly accepted.

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Desperate for hard currency, the government imposed curbs on imports and foreign-exchange transactions.

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That free ride is over now: Banks have extended currency exchange fees and usage fees to transactions made in foreign countries.

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New rules allowing foreign enterprises to more freely change yuan into their own currency are likely to affect only large transactions.

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