We use detailed data on exporters from Costa Rica, Ecuador and Uruguay as well as on their buyers to show that: aggregate exports are disproportionally driven by few multi-buyers exporters; and each multi-buyer exporter's foreign sales of any product are in turn accounted for by few dominant...

Trade barriers have been declining around the world over the last five decades. Countries reduced their tariffs unilaterally as well as concertedly in the framework of regional integration agreements. As a consequence, trade flows among economies have substantially intensified. According to...