Jason Van Bergen
除了利率和通貨膨脹，匯率是決定一個國家經濟健康水平的最重要因素。匯率在國際貿易中起著至關重要的作用，它對世界上每一個自由市場都非常重要。因為這個原因，匯率受到最廣泛的關註、分析和政府經濟措施的操控。但是匯率同時也能影響更小的事件，他們影響投資者投資組合的實際回報。下面我們來讨論下影響匯率變動的主要因素。
概述
在我們讨論這些因素之前，我們應該簡述匯率運動怎樣影響一個國家和其他國家的貿易關系。高利率使一個國家的出口產品價格昂貴而進口便宜。低利率使一個國家的出口便宜而進口昂貴。高利率通常會降低一個國家的出口額，而低利率將增加出口。
匯率的決定因素
匯率的決定因素有很多，所有這些因素都與兩個國家的貿易關系有關。記住，匯率是相對的，通過兩個國家的貨幣對比表現出來。下面是決定兩個國家匯率的主要因素。這些因素沒有特定順序，像經濟的許多方面一樣，這些因素哪個更重要受到人們的大量讨論。
1.通貨膨脹差異
作為一個一般規則，一個持續低通脹率的國家貨幣會升值，其購買力相對於其他貨幣會上升。在20世紀的後50年，低通脹的國家包括日本、德國和瑞士，而美國和加拿大直到後來才實現低通脹。那些高通脹的國家往往會發現他們的貨幣會相對貿易夥伴貶值。這同時往往會伴隨著高利率。
2.利率差異
利率、通脹率和匯率是高度相關的。通過控制利率，央行可以影響通脹率和匯率，改變利率能影響通脹率和貨幣價值。高利率為借出人提供相對其他國家更高的回報。因此，高利率將會吸引外國資本並引起利率上升。高利率的影響能夠被緩解，然而，一個國家的利率遠高於其他國家，或者其他因素將會使貨幣貶值。降低利率時相反關系也存在，那就是低利率往往會降低匯率。
3.收支赤字
經常收支是一個國家和它貿易夥伴之間的貿易差額，反映出國家之間包括商品、服務、利率和分紅的所有支付。經常收支赤字表明一個國家在國際貿易中的支出比收入多，這個國家正在從國外借款來彌補這一赤字。換句話說，該國需要比出口獲得的外匯更多的外國貨幣，它支付的本國貨幣比國外購買其商品的需要多。這種過多的國外貨幣需求降低該國的匯率，直到該國的商品和服務對外國人來說足夠便宜，國外資產將對國内來說太昂貴導致很難產生利潤。
4.政府債務
國家將參與大型的赤字融資進行政府部門項目和政府資金的支付。雖然這些活動能刺激國内經濟，但是帶有大量政府赤字和債務將降低對國外投資者的吸引力。原因是什麼？大規模債務將會刺激通脹，如果通脹過高，這些債務在未來得到的真正回報將會降低。
在最壞的情況下，政府可能印刷鈔票來償還一部分大型債務，但是增加貨幣供應將不可避免的引起通脹。此外，如果一個政府不能通過國内方式償還債務（出售國内債券、增加貨幣供應），那麼它必須增加出售給外國人的證券，從而降低它們的價格。最後，如果外國人認為一個國家有違約的風險將會引起他們的擔憂。如果風險巨大，外國人將不會願意持有以這種資產計價的證券。因為這個原因，這個國家的債務評級將會成為影響匯率的一個重要因素。
5.貿易比率
貿易比率是出口價格和進口價格的一個比例，貿易比率與經常賬戶和國際收支相關。如果一個國家的出口價格相對進口價格大幅增長，其貿易比率將會得到積極改善。貿易比率增加表明對該國出口商品的需求加大。這將導致出口收入增加，使該國的貨幣的需求量增加（並增加該國貨幣價值）。如果出口價格增長低於進口價格增長，那麼該國的貨幣價值將會相對其貿易夥伴的貨幣價值降低。
6.政治穩定性和經濟表現
外國投資者不可避免的需找經濟表現強勁的穩定國家投資他們的資本。這樣的國家吸引的外國資本將會遠遠多餘那些帶有更多政治和經濟風險的國家。例如，政治動蕩將會引起對貨幣的信心流失並導致資本流向更穩定的國家。
總結
匯率將會決定一個大量投資的投資組合的實際回報。匯率下降將會明顯的減少收入和任何回報資本收益的購買力。而且，匯率影響例如利率、通脹和甚至國内證券資本收益的其他收入因素。而匯率是由大量複雜因素決定的，即使最有經驗的經濟學家也會感到困惑，投資者應該了解貨幣價值和匯率在他們的投資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.
本文翻譯由兄弟財經提供
文章來源：http://www.investopedia.com/articles/basics/04/050704.asp