Though most bankers refuse to talk about OFAC, one insider told me it operates like this. “OFAC tells the British bank that it will suffer consequences (for example, loss of a US banking licence, or blacklisting) if it doesn’t agree to a settlement. The bank must agree to cooperate with the authorities by ceasing all business with Iran. It must then pay a penalty stretching to millions of dollars. It is also made to promise not to reveal the terms of the agreement or the process that led to it – even though the US authorities can do so if they wish.