As U.S. blockades Iran, its oil still flows ship to ship an ocean away

The financial details surrounding the sale of oil that is transferred ship to ship, including precisely when Tehran is paid, are typically opaque and sometimes deliberately obfuscated, said Petras Katinas, an energy researcher at the Royal United Services Institute, a defense and security think tank in London. Some buyers appear to pay partially in advance, while others settle once a tanker reaches territorial waters or after it reaches port, he said.