Does trade creation by social and business networks hold in services?

Recent literature on the border effect has shown that the intensity of trade in goods is positively correlated with the migration stocks between any pair of countries/regions. The number of references for business networks is more limited, but they are also related with a reduction on information costs. In this article we investigate whether such a relation holds also for Spanish domestic trade flows in consumer services. To this end, we use a gravity model rooted in the Dixit--Stiglitz--Krugman theoretical framework and a unique data set on interregional trade flows for some of the main tourism service sectors, namely, accommodations and restaurants. Our industry-specific analysis finds a large positive effect for restaurants but a more limited effect for accommodations. Forces driving the demand in each sector explain this result and suggest the idea that although social networks can act as a substitute of firms in some sectors at the same time they can enhance trade flows in other sectors. We perform the same kind of analysis with a data set (obtained by a similar method) for domestic trade in goods and discover a different response to social and business networks. Finally, we treat the potential endogeneity by taking the instrumental-variable approach of the Poisson pseudo-maximum likelihood estimator and thus obtain consistent results.