中国国务院在7月末暗示，进一步扩大人民币汇率浮动区间可能是支撑出口一揽子措施的一部分。单这项措施不会提振海外销售，除非该措施还伴随着人民币走弱。彭博的投资组合流动分析显示，人民币贬值会带来利弊难以权衡的处境，因为人民币走弱虽然可能促进出口，但也会带来资本外逃风险。国际货币基金组织(IMF) 即将决定是否将人民币纳入特别提款权 (SDR) 一篮子货币，增加了人民币维持稳定的压力。
人民币汇率水平对出口的影响很明显。2005年，中国放弃了盯住美元的人民币汇率制度，开始升值过程时，出口约同比增长30%。现在出口同比增长为近零水平。彭博经济学家基于模型的预估显示，在其它条件一样的情况下，人民币实际有效汇率下跌1%，就意味着三个月后出口增长会提高一个百分点。人民币实际有效汇率下跌10%，会让出口增长恢复至双位数。
为分析汇率和资本流动之间的关系，彭博经济学家使用了基于银行购汇的投资组合流动每月预估。分析显示，
人民币(6.2098，0.0001，0.00%)兑美元下跌10%可能引发4370亿美元的资本外流——相当于GDP的4%。虽然汇率和资本流动之间的因果关系不是那么一清二楚，但是资本外逃的潜在强度是显著的。
由于中国渴望
人民币(6.2098，0.0001，0.00%)被纳入IMF的SDR货币篮子，加深了
人民币(6.2098，0.0001，0.00%)汇率的两难困境。SDR篮子货币是储备货币地位的象征。IMF 8月初公布的一份详细报告读上去模棱两可。该报告表明仍对
人民币(6.2098，0.0001，0.00%)“可自由使用的”——纳入SDR篮子货币的一个前提条件——存有疑问，并且提议SDR货币篮子调整可以从2016年1月份推后至9月份。
人民币(6.2098，0.0001，0.00%)被纳入SDR一篮子货币是件好事，但非必须，因而IMF的评估对汇率政策的影响力将不及对出口和资本外逃的担忧。并且，IMF评估也需要人民币稳定。人民币显著贬值会打击国际投资者持有人民币的意愿——偏离了IMF关于可自由使用的标准。由于IMF最近不再认为人民币被低估，所以人民币贬值也会是一项糟糕的政治举措。
对于中国来说，理想情况是人民币兑走弱的美元保持稳定，从而使人民币兑一篮子货币走低。不幸地是，由于美联储朝着首次加息靠近，美元走强的压力势将上升。这让中国面对难以接受的选择——保持人民币强势并且牺牲出口，或者允许人民币贬值同时承担伤害金融稳定和难以获得储备货币地位的风险。我们相信，中国将继续选择前者。
INSIGHT: Capital Flight Risk, SDR Ambitions Favor Yuan Stability
Fielding Chen and Tom Orlik, BLOOMBERG ECONOMIST
China's State Council suggested at the end of July that a further widening of the yuan trading band could be part of a package of measures to support exports. In itself that would do nothing to boost overseas sales unless it's accompanied by a weakening of the currency. Our analysis of portfolio flows suggests depreciation presents a difficult trade-off, with a weaker yuan likely to lift exports only at the risk of capital flight. The International Monetary Fund's impending decision on including the yuan in its SDR reserve currency basket adds to the pressure for stability.
Real Effective Exchange Rate and Exports
The impact of the yuan's strength on exports is clear. In 2005, when China broke the yuan’s peg to the dollar and began the process of appreciation, export growth was about 30 percent year on year. Now it is close to zero. Our model-based estimation shows that a 1 percent drop in the yuan's real effective exchange rate would mean 1 percent more export growth three months later, all other things being equal. A 10 percent real effective depreciation of the yuan would take exports back to double-digit expansion.
Capital Flows and the Yuan
To analyze the relationship between the exchange rate and capital flows, we used a monthly estimate of portfolio flows based on banks’ FX purchases. Our analysis shows that a 10 percent drop in the yuan against the dollar could trigger $437 billion in capital outflows -- equivalent to 4 percent of GDP.
While the causality between the exchange rate and capital flows is less clear cut, the potential magnitude of capital flight is significant.
China's exchange rate dilemma is deepened by its aspiration for yuan inclusion in the IMF's Special Drawing Right currency basket -- a symbol of reserve currency status. A detailed report from the IMF, published at the start of August, sounded an equivocal note. The report suggests the yuan's status as "freely usable" -- a pre-requisite for SDR inclusion -- remains in question and proposes that any shift in the SDR basket could be pushed back from January to September 2016.
SDR status for the yuan is a "nice to have," not a "must have," so we don't think the IMF review is as important a driver of exchange rate policy as concerns about exports and capital flight are. That said, the IMF review also argues for stability.
A pronounced depreciation of the yuan would discourage international investors from holding China's currency -- a move away from meeting the IMF's freely usable criteria. With the Fund recently dropping its characterization of the yuan as undervalued, it would also be bad politics.
The goldilocks scenario for China is stability against a weaker dollar allowing the yuan to fall against a basket of currencies. Unfortunately for China, as the Federal Reserve moves toward a first rate hike, pressure for a stronger dollar is set to increase. That leaves China facing an unpalatable choice -- keep the yuan strong and sacrifice exports or allow it to fall and risk financial stability and reserve currency status. We believe they will continue to choose the former.
责任编辑：forex
