The Role of Trade Flows in Exchange Rate Determination: A Rational Expectations Approach
在资产组合方法和理性预期框架下，分析汇率与贸易余额的互动，发现即期汇率与长期均衡的差异与贸易顺差成正比，支持顺差国货币低估的假设。
The purpose of this paper is to examine the interaction between the exchange rate and the trade balance within the framework of the portfolio approach to exchange rates and rational expectations. In a simplified linear version, it is shown that the difference between the spot exchange rate and its long-run equilibrium value is proportional to the current level of the trade-balance surplus normalized by the current stock of foreign-asset holdings. Therefore, the analysis provides some evidence in favor of the presumption that surplus country should have an undervalued currency (relative to its long-run level). The basic idea behind the analysis is that, in a world of high capital mobility,current flow payments disequilibria can be accommodated by capital flows without need, in principle, for exchange rate movements. Only if the public expects lasting change in the required rate of capital flows will exchange rates adjust, since in this case the expected time path of net foreign assets will be significantly affected.