This paper theoretically shows that when the trade elasticity is allowed to be country specific and it increases with trade openness across countries, it is possible for the gains from trade to decrease with trade openness across countries under certain conditions, which we call as the diminishing gains from trade. In order to empirically test this possibility, country-specific trade elasticity measures are estimated by using quarterly time-series data for 40 countries, where the model-implied macroeconomic relationship between the home expenditure share and the real income per capita is employed. The average trade elasticity is estimated about 2.7, with a range between 0.3 and 11.9 across countries, which corresponds to the gains from trade of about 30% for the average country. Instead, when a common trade elasticity of 2.7 is used for all countries, the gains from trade are underestimated by about 8% for the average country, showing the importance of using country-specific trade elasticity measures. In a secondary cross-country analysis, the country-specific trade elasticity estimates are shown to increase and the gains from trade are shown to decrease with trade openness measures. It is implied that there are diminishing gains from trade across countries with respect to their trade openness.

本文从理论上表明，当允许贸易弹性因国家而异且随着国家间贸易开放程度的增加而增加时，贸易收益有可能随着贸易的增加而减少特定条件下各国之间的开放程度，我们称之为贸易收益递减。为了实证检验这种可能性，通过使用 40 个国家的季度时间序列数据来估计特定国家的贸易弹性指标，其中采用了模型隐含的家庭支出份额与人均实际收入之间的宏观经济关系。平均贸易弹性估计约为 2.7，各国范围在 0.3 至 11.9 之间，这相当于平均国家约 30% 的贸易收益。相反，当所有国家采用共同的贸易弹性 2.7 时，平均国家的贸易收益被低估了约 8%，这表明使用特定国家贸易弹性指标的重要性。在二次跨国分析中，随着贸易开放措施的实施，特定国家的贸易弹性估计值会增加，贸易收益会减少。这意味着，就其贸易开放程度而言，各国从贸易中获得的收益正在递减。