Here's one:
[Excerpt] It is illegal in Cuba for anyone except the regime to employ workers. That means that foreign investors cannot hire or pay workers directly. They must go to the Cuban government employment agency, which picks the workers. The investors then pay Castro in hard currency for the workers, and Castro pays the workers in worthless pesos.
Here is a real-life example: Sherritt International of Canada, the largest foreign investor in Cuba, operates a nickel mine in Moa Bay (a mine, incidentally, which Cuba stole from an American company). Roughly 1,500 Cubans work there as virtual slave laborers. Sherritt pays Castro approximately $10,000 a year for each of these Cuban workers. Castro gives the workers about $18 a month in pesos, then pockets the difference.
The net result is a subsidy of nearly $15 million in hard currency each year that Castro then uses to pay for the security apparatus that keeps the Cubans enslaved.[End Excerpt] Source
The US...Archer Daniels Midland has a food processing plant in Cuba.