Official reserve transactions refer to the transactions carried out by the monetary authorities (such as the Reserve Bank) involving the buying and selling of foreign exchange reserves. Specifically, the central bank sells foreign exchange when there is a deficit in the balance of payments, known as an official reserve sale.

These transactions are of great importance as they act as accommodating items ('below the line' items) in the BoP. They are specifically undertaken to bridge the gap created by autonomous transactions. A decrease in official reserves indicates an overall balance of payments deficit, while an increase indicates a surplus. Thus, monetary authorities act as the ultimate financiers of any deficit through these transactions.