Remarkably, this may actually ease price pressures, because rationing, which had pushed the old black-market price up to 330 kyat a gallon, has been relaxed.

ECONOMIST: Myanmar

But in 2009 attempts predictably missed their mark as producers hoarded stocks and the black-market price soared.

ECONOMIST: Pakistan's populist judges

Prosecutors say the smugglers had ties "with upper echelon Hezbollah officials" and often charged customers a "resistance tax, " in effect, a terrorist fee levied on top of the black-market price.

FORBES: Hezbollah's Hoard

The black market peso price has spiked as the government has tried to close off any and all avenues for people to legally convert out of pesos and into US dollars.

FORBES: Argentina Begins Tracking All Credit Cards

That boosted their price in the black market, disrupting imports and supply chains across the country.

WSJ: Venezuelan Cabinet Tweak Seen Aiding Economy in Short Term

The price of black-market whisky has risen by a similar margin.

ECONOMIST: Kuwait, America and Iraq: My best friend's war | The

Rhino horn now rivals the price of gold on the black market and is trafficked to Yemen, where the horns are fashioned into handles for prized djambia daggers, and to the Far East, where China is the biggest market.

BBC: The rhino wars of central Kenya

In the case of trade bans the price differential has to account for black market risk such as the risk of imprisonment and the cost of bribes.

FORBES: Mitt Romney Is Tough On China, Weak On Reality

Under Abacha, pumps ran dry and the president's friends made fortunes cornering supplies at the low official price and selling them at the much higher black-market rate.

ECONOMIST: A survey of Nigeria

Security researchers will be able to upload hacking techniques, name their price and sell work that until now has been profitable only through the cybercriminal black market.

FORBES: Magazine Article