By Executive Order, the United States has sanctioned the use of the Iranian Rial by financial institutions located outside of Iran. It has prohibited, upon pain of sanctions:
(1) The maintenance of significant funds or accounts, outside the territory of Iran, denominated in the Iranian Rial.
(2) Any significant transaction related to the purchase, sale, swap, derivatives, futures, forward, or any other contract whose value is based upon the exchange rate of the Rial.
The consequences for violators are dire:
(A) The US will deny the financial institution the ability to hold correspondent accounts in American financial institutions, and will close those that exist. This will, in effect, deny the foreign bank access to the US financial structure, and would cause clients to move to the competition, possibly causing the bank to be forced to close.
(B) The US would block assets and interests, of the foreign bank, located in America.
Of course, the question arises; what about the caches of Rial notes held in safe deposit boxes worldwide, owned by heroin traffickers, hedge and vulture funds, currency speculators, corrupt Iranian PEPs, and other criminal elements ? How will they now be able to convert their holdings to US Dollars, Pounds, or other stable currencies ?
Nevertheless, these individuals or entities may be able to unload their Rials, at a discount, somehow, which will result in cash that they may seek to launder through the global financial structure. It is suggested that you bear this in mind, should you see any unusual cash deposits, particularly from Iranian expats, or Iranians who are now residents or citizens in your jurisdiction .