The settlement currency is the currency in which funds actually move to complete a transaction. It may differ from the transaction currency, the one in which the price was set or the card was charged. A customer may pay a merchant in Thai baht, while the card network settles with the issuer in the issuer's billing currency and with the acquirer in a currency agreed with it, such as US dollars; the merchant may then be paid in yet another currency after currency conversion.
Merchants and payment platforms often choose a settlement currency to match their costs and avoid repeated conversions, and some acquirers offer multi-currency settlement into separate accounts. In foreign exchange and trade, the settlement currency is the one delivered on the value date, and contracts such as non-deliverable forwards settle only the difference in a convertible currency. Choosing a settlement currency determines who bears foreign exchange risk and which nostro accounts a firm must fund.