Doesn&#x27;t need to be a bank. You go to a shopfront FX dealer in Vientiane or Tehran or St Petersburg and deposit or withdraw USD against local currency (or anything else that&#x27;s liquid).<p>In the most basic trades, possession is settlement. Much of the third world has significant trade in USD, including countries that the US doesn&#x27;t regard well. In Panama, the USD is a defacto national currency, a choice the crowd has arrived at due to convenience.<p>You can get an armoured van and deliver packs of physical notes.<p>You can use contracts to get more complicated arrangements, including where you have USD on paper but backed by an alternative currency. You can do balance sheet adjustments by contract. You can be a dutch firm ordering agricultural goods from Kenya, and do your leg of the transaction by delivering USD. The banks in the middle might exchange physical USD to make it happen, without any of them being regulated by the US at the time. But - probably - they&#x27;ll just organise the deal in terms of USD using holdings of other currencies or commodities or contract-agreed offsets that are convenient to them.