Jason Van Bergen
除了利率和通货膨胀，汇率是决定一个国家经济健康水平的最重要因素。汇率在国际贸易中起着至关重要的作用，它对世界上每一个自由市场都非常重要。因为这个原因，汇率受到最广泛的关注、分析和政府经济措施的操控。但是汇率同时也能影响更小的事件，他们影响投资者投资组合的实际回报。下面我们来讨论下影响汇率变动的主要因素。
概述
在我们讨论这些因素之前，我们应该简述汇率运动怎样影响一个国家和其他国家的贸易关系。高利率使一个国家的出口产品价格昂贵而进口便宜。低利率使一个国家的出口便宜而进口昂贵。高利率通常会降低一个国家的出口额，而低利率将增加出口。
汇率的决定因素
汇率的决定因素有很多，所有这些因素都与两个国家的贸易关系有关。记住，汇率是相对的，通过两个国家的货币对比表现出来。下面是决定两个国家汇率的主要因素。这些因素没有特定顺序，像经济的许多方面一样，这些因素哪个更重要受到人们的大量讨论。
1.通货膨胀差异
作为一个一般规则，一个持续低通胀率的国家货币会升值，其购买力相对于其他货币会上升。在20世纪的后50年，低通胀的国家包括日本、德国和瑞士，而美国和加拿大直到后来才实现低通胀。那些高通胀的国家往往会发现他们的货币会相对贸易伙伴贬值。这同时往往会伴随着高利率。
2.利率差异
利率、通胀率和汇率是高度相关的。通过控制利率，央行可以影响通胀率和汇率，改变利率能影响通胀率和货币价值。高利率为借出人提供相对其他国家更高的回报。因此，高利率将会吸引外国资本并引起利率上升。高利率的影响能够被缓解，然而，一个国家的利率远高于其他国家，或者其他因素将会使货币贬值。降低利率时相反关系也存在，那就是低利率往往会降低汇率。
3.收支赤字
经常收支是一个国家和它贸易伙伴之间的贸易差额，反映出国家之间包括商品、服务、利率和分红的所有支付。经常收支赤字表明一个国家在国际贸易中的支出比收入多，这个国家正在从国外借款来弥补这一赤字。换句话说，该国需要比出口获得的外汇更多的外国货币，它支付的本国货币比国外购买其商品的需要多。这种过多的国外货币需求降低该国的汇率，直到该国的商品和服务对外国人来说足够便宜，国外资产将对国内来说太昂贵导致很难产生利润。
4.政府债务
国家将参与大型的赤字融资进行政府部门项目和政府资金的支付。虽然这些活动能刺激国内经济，但是带有大量政府赤字和债务将降低对国外投资者的吸引力。原因是什么？大规模债务将会刺激通胀，如果通胀过高，这些债务在未来得到的真正回报将会降低。
在最坏的情况下，政府可能印刷钞票来偿还一部分大型债务，但是增加货币供应将不可避免的引起通胀。此外，如果一个政府不能通过国内方式偿还债务（出售国内债券、增加货币供应），那么它必须增加出售给外国人的证券，从而降低它们的价格。最后，如果外国人认为一个国家有违约的风险将会引起他们的担忧。如果风险巨大，外国人将不会愿意持有以这种资产计价的证券。因为这个原因，这个国家的债务评级将会成为影响汇率的一个重要因素。
5.贸易比率
贸易比率是出口价格和进口价格的一个比例，贸易比率与经常账户和国际收支相关。如果一个国家的出口价格相对进口价格大幅增长，其贸易比率将会得到积极改善。贸易比率增加表明对该国出口商品的需求加大。这将导致出口收入增加，使该国的货币的需求量增加（并增加该国货币价值）。如果出口价格增长低于进口价格增长，那么该国的货币价值将会相对其贸易伙伴的货币价值降低。
6.政治稳定性和经济表现
外国投资者不可避免的需找经济表现强劲的稳定国家投资他们的资本。这样的国家吸引的外国资本将会远远多余那些带有更多政治和经济风险的国家。例如，政治动荡将会引起对货币的信心流失并导致资本流向更稳定的国家。
总结
汇率将会决定一个大量投资的投资组合的实际回报。汇率下降将会明显的减少收入和任何回报资本收益的购买力。而且，汇率影响例如利率、通胀和甚至国内证券资本收益的其他收入因素。而汇率是由大量复杂因素决定的，即使最有经验的经济学家也会感到困惑，投资者应该了解货币价值和汇率在他们的投资中占有非常重要的角色。
6 Factors That Influence Exchange Rates
By Jason Van Bergen
Aside from factors such as interest rates and inflation, the exchange rate is one of the most important determinants of a country's relative level of economic health. Exchange rates play a vital role in a country's level of trade, which is critical to most every free market economy in the world. For this reason, exchange rates are among the most watched, analyzed and governmentally manipulated economic measures. But exchange rates matter on a smaller scale as well: they impact the real return of an investor's portfolio. Here we look at some of the major forces behind exchange rate movements.
Overview
Before we look at these forces, we should sketch out how exchange rate movements affect a nation's trading relationships with other nations. A higher currency makes a country's exports more expensive and imports cheaper in foreign markets. A lower currency makes a country's exports cheaper and its imports more expensive in foreign markets. A higher exchange rate can be expected to lower the country's balance of trade, while a lower exchange rate would increase it.
Determinants of Exchange Rates
Numerous factors determine exchange rates, and all are related to the trading relationship between two countries. Remember, exchange rates are relative, and are expressed as a comparison of the currencies of two countries. The following are some of the principal determinants of the exchange rate between two countries. Note that these factors are in no particular order; like many aspects of economics, the relative importance of these factors is subject to much debate.
1.Differentials in Inflation
As a general rule, a country with a consistently lower inflation rate exhibits a rising currency value, as its purchasing power increases relative to other currencies. During the last half of the 20th century, the countries with low inflation included Japan, Germany and Switzerland, while the U.S. and Canada achieved low inflation only later. Those countries with higher inflation typically see depreciation in their currency in relation to the currencies of their trading partners. This is also usually accompanied by higher interest rates.
2.Differentials in Interest Rates
Interest rates, inflation and exchange rates are all highly correlated. By manipulating interest rates, central banks exert influence over both inflation and exchange rates, and changing interest rates impact inflation and currency values. Higher interest rates offer lenders in an economy a higher return relative to other countries. Therefore, higher interest rates attract foreign capital and cause the exchange rate to rise. The impact of higher interest rates is mitigated, however, if inflation in the country is much higher than in others, or if additional factors serve to drive the currency down. The opposite relationship exists for decreasing interest rates - that is, lower interest rates tend to decrease exchange rates.
3.Current-Account Deficits
The current account is the balance of trade between a country and its trading partners, reflecting all payments between countries for goods, services, interest and dividends. A deficit in the current account shows the country is spending more on foreign trade than it is earning, and that it is borrowing capital from foreign sources to make up the deficit. In other words, the country requires more foreign currency than it receives through sales of exports, and it supplies more of its own currency than foreigners demand for its products. The excess demand for foreign currency lowers the country's exchange rate until domestic goods and services are cheap enough for foreigners, and foreign assets are too expensive to generate sales for domestic interests.
5.Public Debt
Countries will engage in large-scale deficit financing to pay for public sector projects and governmental funding. While such activity stimulates the domestic economy, nations with large public deficits and debts are less attractive to foreign investors. The reason? A large debt encourages inflation, and if inflation is high, the debt will be serviced and ultimately paid off with cheaper real dollars in the future.
In the worst case scenario, a government may print money to pay part of a large debt, but increasing the money supply inevitably causes inflation. Moreover, if a government is not able to service its deficit through domestic means (selling domestic bonds, increasing the money supply), then it must increase the supply of securities for sale to foreigners, thereby lowering their prices. Finally, a large debt may prove worrisome to foreigners if they believe the country risks defaulting on its obligations. Foreigners will be less willing to own securities denominated in that currency if the risk of default is great. For this reason, the country's debt rating (as determined by Moody's or Standard & Poor's, for example) is a crucial determinant of its exchange rate.
5.Terms of Trade
A ratio comparing export prices to import prices, the terms of trade is related to current accounts and the balance of payments. If the price of a country's exports rises by a greater rate than that of its imports, its terms of trade have favorably improved. Increasing terms of trade shows greater demand for the country's exports. This, in turn, results in rising revenues from exports, which provides increased demand for the country's currency (and an increase in the currency's value). If the price of exports rises by a smaller rate than that of its imports, the currency's value will decrease in relation to its trading partners.
6.Political Stability and Economic Performance
Foreign investors inevitably seek out stable countries with strong economic performance in which to invest their capital. A country with such positive attributes will draw investment funds away from other countries perceived to have more political and economic risk. Political turmoil, for example, can cause a loss of confidence in a currency and a movement of capital to the currencies of more stable countries.
The Bottom Line
The exchange rate of the currency in which a portfolio holds the bulk of its investments determines that portfolio's real return. A declining exchange rate obviously decreases the purchasing power of income and capital gains derived from any returns. Moreover, the exchange rate influences other income factors such as interest rates, inflation and even capital gains from domestic securities. While exchange rates are determined by numerous complex factors that often leave even the most experienced economists flummoxed, investors should still have some understanding of how currency values and exchange rates play an important role in the rate of return on their investments.
本文翻译由兄弟财经提供
文章来源：http://www.investopedia.com/articles/basics/04/050704.asp