“Academics Esfandyar Batmanghelidj and Axel Hellman have argued, for example, that during a previous Iranian SWIFT ban in 2012-16, several European banks were able to maintain their relationships with Iranian financial institutions by using “ad hoc messaging systems” and this could be revived. The two academics posit a rise in the use of so-called gateway banks — which have access to the ECB’s value payments system, Target2, and limited exposure to the US financial system — which would conduct euro transactions on behalf of buyers and sellers of Iranian oil. Instead of using SWIFT bank identifier codes to indicate account number, Batmanghelidj and Hellman point to the possibility of using IBAN numbers, a different international standard.”