EghtesadOnline: The Trump administration abandoned the Iran nuclear deal this year and is reimposing sanctions. The sanctions leave western companies and banks with a stark choice. If they do business with Iran, they lose access to the American market and financial system. Not surprisingly, businesses and banks have been cutting ties with Iran or shelving plans to invest there. But one important financial link to the country remains: the financial messaging service that plays a crucial role in moving money around the international banking system.