Competition and Pass-Through: Evidence from Isolated Markets
利用希腊小岛加油站日度定价数据，研究消费税意外变化在不同竞争程度的市场中如何传导给消费者，发现传导率从垄断市场的0.4上升至四个及以上竞争者市场的1，且竞争更激烈的市场价格调整速度高出约60%。
We measure how pass-through varies with competition in isolated oligopolistic markets with captive consumers. Using daily pricing data from gas stations on small Greek islands, we study how unanticipated and exogenous changes in excise duties are passed through to consumers in markets with different numbers of retailers. We find that pass-through increases from 0.4 in monopoly markets to 1 in markets with four or more competitors and remains constant thereafter. The speed of price adjustment is about 60 percent higher in more competitive markets. Finally, we show that geographic market definitions based on measures of distance across sellers often result in signifi-cant overestimation of the pass-through.