Trade, Firm Selection and Innovation: The Competition Channel
研究了在异质性企业、可变加成和内生增长的经济中，贸易如何通过竞争渠道影响福利，发现贸易自由化降低加成、强化企业选择并激励创新，从而提升生产率和增长率，且增长使福利收益翻倍。
We study the welfare gains from trade in an economy with heterogeneous firms, variable markups \nand endogenous growth. Variable markups arise from oligopolistic competition, and cost-reducing \ninnovation is the engine of long-run growth. Trade liberalisation stiffens competition by reducing \nmarkups, generating tougher firm selection and increasing the aggregate productivity level. Selection \nincreases firms’ incentives to innovate, thereby leading to a higher aggregate productivity growth \nrate. Endogenous productivity growth boosts the selection gains from trade, leading to substantial \nwelfare improvements. A calibrated version of the model shows that growth doubles the welfare gains \nobtainable in models with static firm-level productivity.