Gravity with History: On Incumbency Effects in International Trade
研究发现，较早进行贸易自由化的国家之间贸易量更大，原因是沉没市场进入成本产生了在位效应。量化分析表明，该机制可解释高达25%的国内份额，且考虑在位效应后贸易收益平均增加10%。
Abstract Countries trade more if they liberalized their trade relationship earlier. We derive a gravity equation featuring this path dependence due to sunk market-access costs that generate incumbency effects. We provide supporting evidence for the underlying mechanism and derive an augmented ACR (Arkolakis, Costinot, and Rodríguez-Clare 2012) formula for the gains from trade that accounts for incumbency effects. A quantification suggests our mechanism explains up to 25% of countries’ home shares, and the gains from trade are, on average, 10% larger when allowing for incumbency effects. The analysis further reveals novel distributional effects of trade, boosting real wages but reducing profits.