The evaluation of the Single European Market requires a better knowledge of the level of integration both between and within the EU countries. While some institutions are pushing for greater integration between EU countries, others may be introducing—purposely or collaterally—additional barriers to interaction. Several reports have reported the high levels of market fragmentation prevailing within Spain. This paper aims to determine whether regional borders influenced the patterns of intra- and interregional trade between the 18 regions of Spain (Nuts 2) over a long period of time (1995–2017). While trade is more intense within regions than between them, our results suggest the presence of spatial and temporal heterogeneity in the estimated home bias. We also investigate empirically the effect that the quantity and quality of national, regional and local regulations have on the economic performance of firms, in both the industrial and the service sectors. We use different non-spatial and spatial-gravity models, which yield robust results.

对单一欧洲市场的评估需要更好地了解欧盟国家之间和内部的一体化水平。虽然一些机构正在推动欧盟国家之间更大程度的融合，但其他机构可能会有意或间接地引入额外的互动障碍。几份报告报告称，西班牙内部市场高度分散。本文旨在确定区域边界是否在很长一段时间内（1995-2017 年）影响了西班牙 18 个地区（坚果 2）之间的区域内和区域间贸易模式。虽然区域内的贸易比区域之间的贸易更加激烈，但我们的结果表明，估计的本土偏差存在空间和时间异质性。我们还实证研究了国家的数量和质量的影响，区域和地方法规对工业和服务部门的公司的经济业绩都有影响。我们使用不同的非空间和空间重力模型，它们产生了稳健的结果。