Optimal Exchange Rates: A Market Microstructure Approach
分析央行在外汇市场不完全、代理人无法完全对冲汇率波动风险时，如何通过平滑汇率提供保险，但平滑汇率会引发投机，央行无法同时实现两者，托宾税可能提供解决方案。
We analyze exchange-rate management by the central bank when it makes the FX market for the sake of social-welfare objectives. It is assumed that markets are incomplete, so that agents are exposed to exchange-rate volatility against which they cannot fully hedge. It follows that the central bank may provide insurance by smoothing the exchange rate. However, smoothing the exchange rate also creates arbitrage opportunities for spec-ulators. We show that the central bank cannot smooth the exchange rate and deter speculation at the same time. A Tobin tax may provide a way out. 1