The Current Account Balance [CAB] is a record of money flowing into a national economy through foreign trade, minus money flowing out through foreign trade. It is shown as a percentage of GDP. For more detail, see the Glossary. Source: International Monetary Fund.
When a nation's CAB is positive, foreign trade is pouring money into its economy, making more available for investment, consumption and taxation. When the CAB is negative, foreign trade is draining money out of its economy, diminishing the stock of wealth available for these activities.