美元弱势调整对中美双边贸易的影响

The Effects of US Dollar Exchange Rate Adjustment on Sino-US Bilateral Trade

2002—2012年美元弱势调整对中美双边贸易产生怎样影响?本文构建出完全替代和不完全替代的美中产品贸易模型,使用统计比较和GMM估计表明:(1)美国对华同质品出口占比较高,若直接使用不完全替代模型会导致美国对华同质品和异质品出口加总对汇率变化的估计偏差。本文依据Rauch分类匹配出美中最细化的5分位及光头4分位同质品和异质品贸易数据,最大限度上消减了产品贸易加总对汇率变化的估计偏差。(2)数理模型证实,不完全替代的美国对华异质品实际出口的汇率敏感度不同于完全替代的美国对华同质品实际出口的汇率敏感度;美国从华产品实际进口也是如此。(3)美元弱势调整会使美国对华交易所同质品贸易差额显著改善、参考价格同质品贸易差额不明确,而异质品贸易差额显著恶化,致使美国对华产品贸易收支恶化。实际汇率波动上升不利于美国对华同质品、异质品及全样本产品出口,也不利于美国从华异质品和全样本产品进口,但并未能抑制从华同质品进口增加。因此,不能夸大美元弱势调整对改善美中贸易失衡的作用,平稳好双边实际汇率波动对促进美中产品贸易更加有利。

What effect does a weakening US dollar（USD） have on Sino-US bilateral trade during 2002-2012 ？ Constructing the perfect and imperfect substitute trade models of homogeneous goods（HG） and differentiated goods（DG） between US and China, this paper uses statistical comparison and GMM estimation to show that firstly, US export of HG to China occupies a large share, and if the imperfect substitute model were used directly, such a study would induce the estimation bias of US HG and DG export aggregation to China to exchange rate change. Using Rauch classification, I match the most disaggregated 5 - digit and naked 4 - digit HG and DG trade data, which reduces the bias of product trade aggregation response to exchange rate change to the utmost extent. Secondly, the mathematical model confirms that the exchange rate sensitivity of US real export of DG to China under imperfect substitute model is different from that of US real export of HG to China under perfect substitute model, and so is US real import from China. Thirdly, the weakening USD can improve US trade balance of organized exchange HG （OHG） with China, make US trade balance of referenced price HG （RHG） indefinite, whereas worsen US trade balance of DG with China, and result in the deterioration of US trade balance with China. The rise of real exchange rate volatility works against US exports of HG, DG and full goods to China, and also works against US imports of DG and full goods from China, but cannot hinder the increase of US import of HG. Therefore, it is difficult to exaggerate the role of weakening USD on improving US-China trade imbalance, and it would be more favorable for promoting US-China product trade if real exchange rate volatility were better smoothed.