What is the ruling on working in currency exchange companies?

Working in currency exchange companies is permissible if the company adheres to Shariah guidelines, and the employee's work does not involve direct forbidden acts or aiding therein.

For currency exchange when the denominations are of the same type (e.g., dollar for dollar), it is required that they be equal in value and exchanged hand-to-hand immediately (spot exchange), whether literally or constructively. Constructive possession is valid through bank transfers or certified checks.

If the two currencies are different (e.g., dollar and Japanese yen), immediate possession, either literally or constructively, is required, but not equality in value, based on the Prophet Muhammad's (peace be upon him) saying: "Gold for gold, silver for silver, hand to hand, like for like, and any excess is usury (riba). But if these types differ, then sell as you wish, provided it is hand to hand."