The document defines and explains the key concepts of a country's balance of payments (BOP). It states that BOP is the systematic accounting of all economic transactions between a country's residents and the rest of the world over a period, usually a year. For accounting purposes, transactions are grouped under current transactions, capital transactions, reserves accounts, and errors and omissions. Current transactions include exports, imports and unilateral transfers, while capital transactions involve foreign investment, borrowing and lending, and banking transactions. The reserves account shows a country's foreign exchange holdings and the errors and omissions entry balances any reporting discrepancies.