Intra-trade is trade between economies belonging to the same group.
According to UNCTAD, extra trade is the trade of economies in the same group with all economies outside the group.
It represents the difference between the total trade and the internal trade of a group.
In theory, economy A’s exports to economy B should be equal to economy B’s imports from economy A recorded FOB.
In practice, however, the values of the two flows tend to be different. The reasons for these commercial asymmetries include: different registration times, different treatment of transit trade, insufficient notification, measurement errors and incorrect pricing or billing.
Intra-trade
Exports to (imports from) all the world’s economies do not always exactly add up to total exports (imports). The difference is due to ship depots, bunkers and other minor exports.