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

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

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

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