Border effects and the availability of domestic products abroad

Trade between countries could fall short of trade within a country because (1) the volume of international trade is less than the volume of domestic trade for a given product (the intensive margin); or (2) some goods that are sold domestically are simply not exported (the extensive margin). My theoretical model illustrates that either of these two factors could explain a given aggregate 'border effect.' I examine the empirical relevance of this distinction by isolating the fraction of total domestic production attributable only to exporters, finding that around one-half of the border effect may be attributed to each explanation.