If allowing a currency to appreciate freely is costly, the second option is unsterilized foreign-exchange intervention. This is effective in stemming upward exchange-rate pressure, but it feeds the beast: it exacerbates overheating in already fast-growing emerging markets, causing inflation and leading to excessive credit growth, which can fuel dangerous asset bubbles.
如果允许本币自由升值意味着高昂代价，那么第二种办法是非冲销式外汇干预（unsterilized foreign exchange intervention）。这一措施在抵消汇率升值压力方面很有效，但它也是养虎为患：它会令本已处于快速增长中的新兴市场出现严重的经济过热，加剧通货膨胀、促使信贷过度增长从而酝酿资产泡沫危险。