Borders, Geography, and Oligopoly: Evidence from the Wind Turbine Industry
利用丹麦和德国风力涡轮机安装的微观数据，估计了一个包含跨境贸易和异质性企业的结构寡头模型，发现国家边界成本解释了企业市场份额在边界处大幅下降的40%至50%，消除边界摩擦可使两国行业总福利分别提高4%和6%。
Using a microlevel data set of wind turbine installations in Denmark and Germany, we estimate a structural oligopoly model with cross-border trade and heterogeneous firms. Our approach separately identifies border-related from distance-related variable costs and bounds the fixed cost of exporting for each firm. In the data, firms' market shares drop precipitously at the border. We find that 40 percent to 50 percent of the gap can be attributed to national border costs. Counterfactual analysis indicates that eliminating national border frictions would increase total welfare in the wind turbine industry by 4 percent in Denmark and 6 percent in Germany.