Norwegian export of farmed salmon - trade costs and market concentration

While variation in unit value most commonly has been associated with quality in the trade literature, observed differences in prices between markets might also be explained by variation in market concentration and the degree of competition. Using transaction data on Norwegian exports of salmon, we introduce a Herfindahl index as a measure of competition in a standard gravity model. We find that competition typically is weaker in small and distant markets that due to high trade costs are served by relatively few firms. We argue that the anti-competitive impact of trade costs may explain price differentiation between markets even for homogeneous products.