An economic embargo imposed by the United States after the Iranian revolution nearly 30 years ago has kept American firms from doing business in the oil-rich theocracy.
And with the recent saber-rattling over Iran's nuclear program, and its alleged links to insurgents in Iraq, there's little hope that embargo will be lifted soon.
But even if it was, experts say doing business in Iran is tough. Its government is thought to squeeze foreign oil firms for all the concessions it can, despite an oil sector that many say is in desperate need of modernization.