Recent years have seen a surge of interest among industrial organization economists in using data on international trade flows as windows into competitiveness. For countries that are at least mid-sized (e.g., Spain), interregional trade tends to be as large as or significantly larger than...

The existence of a large border effect is considered as one of the main puzzles of international macroeconomics. We show that the border effect is, to a large extent, an artefact of geographic concentration. In order to do so we combine international flows with intranational flows data...

Previous studies have shown that, not only countries, but also regions have a preference to trade within their administrative borders. Using unique trade flows data, we also find a large home bias in Spanish intranational trade. However, we show that this home bias tends to disappear once we...