一、报告题目：

Gains from Trade with Non-trade Frictions

二、报告人：

张国雄，上海交通大学安泰经济与管理学院

三、报告时间：

2019年5月16日 （周四） 下午 14:00-15:30

四、报告地点：

知新楼B423

五、报告人简介：

张国雄，上海交通大学安泰经济与管理学院助理教授，美国加州大学尔湾分校经济学博士。研究方向包括国际经济学、货币经济学、应用计量经济学等领域。研究论文发表于Australian Economic Review、Economics Letters等国际期刊。主持国家自然科学基金等研究项目。

六、 报告摘要：

In an influential paper, Arkolakis et al. (2012) (hereafter ACR) shows that a class of trade models, including the Melitz model, delivers exactly the same amount of gains from trade. In a following paper, Arkolakis et al. (2018) (hereafter ACDR) extends the framework of ACR by introducing endogenous markup through a general demand function. They show that their model with endogenous markups also delivers the same Gravity equation as previous trade models in ACR. Moreover, the welfare gains from trade are determined by three sufficient statistics. In addition to the two sufficient statistics in ACR, there is a third sufficient statistics that critically depends on the elasticity of markup with respect to productivity, which is typically positive when the demand function exhibits decreasing elasticity. ACDR further estimates the elasticity of markup with respect to productivity to be positive, which indicates that the gains from trade are actually smaller in a heterogeneous firms model compared with a homogenous firms model when markups are endogenous.

This paper incorporates non-trade frictions into the framework of ACDR. We introduce a general form of market friction as a production quantity restriction on monopoly firms, which leads to markup distortion. We then show that our model with non-trade frictions also generates the same Gravity equation as the model in ACDR and that welfare gains from trade in our model are also pin-downed by precisely the same three sufficient statistics in ACDR. Nevertheless, in our model the elasticity of markup with respect to productivity critically depends on the elasticity of markup-distortion with respect to productivity. When the elasticity of markup-distortion is negative, the markup elasticity could be negative even when the demand elasticity is positive. In this case, gains from trade are larger in a heterogeneous firms model compared with a homogenous firms model when markups are endogenous. In our quantitative study, we use highly disaggregate import data of the United States to structurally back out this elasticity of markup-distortion. We find this elasticity to be negative while the resulting markup elasticity is still positive due to the dominant effect of demand elasticity. However, the gains from trade are larger in our model than in ACDR, although it is still smaller than in the model with homogenous firms.

七、主办单位：

yl7703永利官网