📚 Exchange Rates | 汇率
Exchange rates play a central role in international economics, linking a country's economy with the rest of the world. For IGCSE Economics, understanding how exchange rates are determined, why they change, and the consequences of those changes is essential. This article provides a focused revision guide covering the key concepts of exchange rates prescribed by the CIE syllabus.
汇率在国际经济中扮演着核心角色，将一个国家的经济与世界其他地区联系起来。对 IGCSE 经济学科而言，理解汇率的决定方式、波动原因及其后果至关重要。本文将围绕 CIE 教学大纲中汇率的关键考点，提供一份精讲复习指南。
1. What Are Exchange Rates? | 什么是汇率？
another. For example, if the exchange rate between the British pound and the US dollar is £1 = $1.30, this means that one pound can buy 1.30 dollars.
汇率是一种货币以另一种货币表示的价格。它告诉我们一单位某种货币能够兑换多少另一种货币。例如，如果英镑与美元之间的汇率是 1 英镑 = 1.30 美元，这就意味着 1 英镑可以购买 1.30 美元。
2. How Are Exchange Rates Quoted? | 汇率如何报价？
Exchange rates can be quoted in two ways: direct quotation and indirect quotation. A direct quote expresses the amount of home currency needed to buy one unit of foreign currency. An indirect quote expresses the amount of foreign currency that can be bought with one unit of home currency. For instance, in the UK, quoting the rate as $1.30 per £1 is an indirect quote, while quoting £0.77 per $1 is a direct quote.
汇率可以有两种报价方式：直接标价法和间接标价法。直接标价表示购买一单位外币所需的本币数量。间接标价表示用一单位本币能够购买的外币数量。例如，在英国，报价 1 英镑兑 1.30 美元属于间接标价，而报价 1 美元兑 0.77 英镑则属于直接标价。
3. The Foreign Exchange Market | 外汇市场
The foreign exchange market (forex) is a global marketplace where currencies are bought and sold. It determines the exchange rates through the forces of demand and supply. Participants in this market include commercial banks, central banks, investment firms, multinational corporations, and individual traders.
外汇市场是一个全球性的买卖货币的市场。它通过供需力量决定汇率。这个市场的参与者包括商业银行、中央银行、投资公司、跨国企业和个人交易者。
4. Demand and Supply for a Currency | 货币的需求与供给
The value of a currency in a free market is determined by demand and supply. The main sources of demand for a currency include:
自由市场中货币的价值由需求与供给决定。货币需求的主要来源包括：
Exports of goods and services: foreign buyers need the domestic currency to pay for exports.
商品和服务出口：外国买家需要本币来支付出口商品。
Capital inflows: foreign investors buying domestic financial assets, such as bonds or shares.
资本流入：外国投资者购买国内金融资产，如债券或股票。
Speculation: if traders expect the currency to appreciate, they buy it now, increasing demand.
投机：如果交易者预期该货币将升值，他们现在就会买入，增加需求。
Higher relative interest rates: attract hot money flows seeking higher returns.
相对利率较高：吸引追求更高回报的热钱流入。
The supply of a currency arises mainly from:
货币的供给主要来源于：
Imports of goods and services: domestic residents need foreign currency to pay for imports, supplying their own currency.
商品和服务进口：国内居民需要外币来支付进口，从而供给本国货币。
Capital outflows: domestic investors buying foreign assets.
资本流出：国内投资者购买外国资产。
Speculation on depreciation: selling the currency in anticipation of a fall in value.
对贬值的投机：预期货币贬值而卖出该货币。
5. Floating Exchange Rate System | 浮动汇率制度
In a floating exchange rate system, the value of a currency is determined entirely by market forces of demand and supply without direct government intervention. When the value of a currency rises due to market forces, it is called an appreciation. A fall in value is called a depreciation. This system provides automatic adjustment of the balance of payments but can lead to volatility and uncertainty for traders and investors.
在浮动汇率制度下，货币价值完全由市场的供需力量决定，政府不直接干预。当货币价值因市场力量上升时，称为升值。价值下跌称为贬值。该制度能够自动调节国际收支，但可能给贸易商和投资者带来波动性和不确定性。
6. Fixed Exchange Rate System | 固定汇率制度
Under a fixed exchange rate system, the government or central bank pegs its currency to another major currency (such as the US dollar) or to a basket of currencies. The central bank intervenes in the foreign exchange market to maintain the fixed rate. Changes in the official rate are rare: an upward adjustment is called a revaluation, while a downward adjustment is a devaluation. This system provides certainty for international trade but requires large foreign exchange reserves and may restrict domestic monetary policy.
在固定汇率制度下，政府或中央银行将其货币与另一种主要货币（如美元）或一篮子货币挂钩。央行在外汇市场进行干预以维持固定汇率。官方汇率的调整很少：向上调整称为法定升值，向下调整称为法定贬值。这种制度为国际贸易提供了确定性，但需要大量外汇储备，并可能限制国内货币政策。
7. Managed Float (Dirty Float) | 管理浮动汇率（肮脏浮动）
A managed float, also known as a dirty float, is a system where the exchange rate is predominantly determined by market forces, but the central bank occasionally intervenes to smooth out excessive fluctuations or to achieve specific economic objectives. Most major economies today operate some form of managed float, as pure floating or fixed systems are rare.
管理浮动汇率，也称为肮脏浮动，是指汇率主要由市场力量决定，但中央银行偶尔进行干预，以平抑过度波动或实现特定经济目标的制度。当今大多数主要经济体都实行某种形式的管理浮动，因为纯粹的浮动或固定制度已很少见。
8. Causes of Exchange Rate Movements | 汇率变动的原因
Exchange rates can change due to several factors. A change in any of the determinants of demand or supply will cause the currency to appreciate or depreciate in a floating system. Key causes include:
汇率可因多种因素而变动。在浮动汇率制度下，任何需求或供给决定因素的变化都会导致货币升值或贬值。主要的原因包括：
Differences in inflation rates: a country with a lower inflation rate tends to see its currency appreciate as its exports become more competitive.
通货膨胀率差异：通胀率较低的国家，由于其出口变得更有竞争力，其货币往往会升值。
Differences in interest rates: higher interest rates offer lenders a higher return, attracting foreign capital and causing the currency to appreciate.
利率差异：较高的利率为贷款人提供更高回报，吸引外资流入并导致货币升值。
Current account position: a persistent current account deficit may put downward pressure on the currency, as the country needs to supply more of its own currency to pay for imports.
经常账户状况：持续的经常账户赤字可能使货币承受贬值压力，因为该国需要供给更多本币来支付进口。
Public debt and political stability: high levels of government debt or political uncertainty can deter foreign investment, reducing demand for the currency.
公共债务与政治稳定性：高额政府债务或政治不确定性可能阻碍外国投资，降低对货币的需求。
Speculation: if markets expect a currency to weaken, they will sell it, causing a self-fulfilling depreciation.
投机：如果市场预期一种货币将走弱，他们就会卖出，导致其自我实现式的贬值。
9. Effects of an Exchange Rate Change | 汇率变动的影响
Changes in the exchange rate have significant effects on an economy. The impact depends on whether the currency appreciates or depreciates, and on the price elasticity of demand for exports and imports.
汇率变动对经济有重大影响。影响如何取决于货币是升值还是贬值，以及进出口需求的价格弹性。
A depreciation makes exports cheaper for foreign buyers and imports more expensive for domestic consumers. This can boost export volumes and reduce import volumes, potentially improving the current account balance, provided the Marshall-Lerner condition holds (the sum of price elasticities of demand for exports and imports is greater than 1).
贬值使出口对外国买家来说更便宜，进口对国内消费者来说更昂贵。这可以增加出口量并减少进口量，有可能改善经常账户收支，前提是满足马歇尔-勒纳条件（出口和进口需求的价格弹性之和大于1）。
An appreciation has the opposite effect: exports become more expensive abroad and imports become cheaper, likely worsening the current account.
升值则有相反效果：出口在国外变得更贵而进口更便宜，可能导致经常账户恶化。
A depreciation can lead to higher inflation because imported goods and raw materials cost more, raising production costs and consumer prices.
贬值可能导致更高的通货膨胀，因为进口商品和原材料成本上升，推高生产成本和消费者价格。
Exchange rate changes also influence economic growth. A weaker currency may stimulate growth by increasing net exports, but could also reduce real incomes if inflation rises.
汇率变动也会影响经济增长。货币疲软可以通过增加净出口刺激增长，但如果通胀上升也可能降低实际收入。
10. Government Intervention in Foreign Exchange Markets | 政府对外汇市场的干预
Governments and central banks can intervene to influence the exchange rate. Common methods include:
政府和中央银行可以进行干预以影响汇率。常见的方法包括：
Buying or selling their own currency in the forex market. To prevent depreciation, the central bank can buy its own currency using foreign reserves. To prevent appreciation, it can sell its currency.
在外汇市场买卖本币。为避免贬值，央行可以使用外汇储备买入本币。为避免升值，可以卖出本币。
Adjusting interest rates. Raising interest rates attracts capital inflows, increasing demand for the currency and causing appreciation. Lowering rates has the opposite effect.
调整利率。提高利率会吸引资本流入，增加对货币的需求并导致升值。降低利率则效果相反。
Exchange controls: imposing restrictions on the amount of foreign currency individuals or businesses can buy or sell.
外汇管制：对个人或企业买卖外汇的数量施加限制。
Moral suasion: encouraging commercial banks to act in ways that support the currency without formal regulations.
道义劝告：鼓励商业银行以支持货币的方式行事，而不采取正式监管措施。
11. Real vs Nominal Exchange Rate | 实际汇率与名义汇率
The nominal exchange rate is the rate we see quoted in the market, such as $1.30 per £1. However, it does not account for differences in price levels between countries. The real exchange rate adjusts the nominal rate by the ratio of domestic to foreign price levels, providing a more accurate measure of a country's international competitiveness.
名义汇率是我们在市场上看到的报价，例如 1 英镑兑 1.30 美元。但它并未考虑国家之间价格水平的差异。实际汇率通过国内与国外价格水平的比率对名义汇率进行调整，能更准确地衡量一个国家的国际竞争力。
Real exchange rate = Nominal exchange rate × (Domestic price level ÷ Foreign price level)
If the real exchange rate rises, the country's goods have become relatively more expensive, indicating a loss of price competitiveness. If it falls, the country's exports become relatively cheaper.
如果实际汇率上升，意味着该国商品变得相对更贵，表明价格竞争力下降。如果下降，则该国出口商品变得相对更便宜。
12. Exchange Rates and the Balance of Payments | 汇率与国际收支
Under a floating exchange rate system, the exchange rate should theoretically move to eliminate any imbalance in the balance of payments. A current account deficit implies that the country is supplying more of its currency (to buy foreign goods) than is being demanded, leading to depreciation. That depreciation then makes exports cheaper and imports more expensive, helping to correct the deficit. This automatic adjustment mechanism is a key argument in favour of floating rates.
在浮动汇率制度下，理论上汇率的变动会消除国际收支的任何不平衡。经常账户赤字意味着该国货币的供给（用于购买外国商品）大于需求，导致贬值。贬值随后使出口更便宜、进口更昂贵，有助于纠正赤字。这种自动调节机制是支持浮动汇率的一个关键论据。
However, this process is not instantaneous and depends on the responsiveness of trade flows. In the short run, a depreciation may worsen the current account before improving it (the J-curve effect), because import prices rise immediately while export and import volumes adjust slowly.
然而，这一过程并非瞬间完成，并依赖于贸易流的反应程度。在短期内，贬值可能在改善经常账户之前使其恶化（J 曲线效应），因为进口价格立即上升，而出口和进口量调整缓慢。
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