Exchange Rates

A depreciation is a fall in the value of a currency relative to another currency (1), under a floating exchange rate system, caused by market forces (a fall in demand for, or rise in supply of, the currency) (1).

Before: £20,000 × 1.50 = $30,000** (1). After: £20,000 × 1.20 = **$24,000 (1). The dollar price of the UK car has fallen from $30,000 to$24,000 (1). The pound has depreciated (fallen in value against the dollar), which makes UK exports cheaper for American buyers (1).

An appreciation means the currency rises in value against others, which makes the country's goods more expensive in foreign-currency terms (the 'ED' of SPICED — Exports Dearer). Because exports now cost foreign buyers more, they tend to buy fewer of them, so exporters' sales volumes fall. With lower export sales, exporting firms earn less revenue and may have to cut production, which can lead them to reduce their workforce, raising unemployment in export industries. Exporters also face a squeeze on profit margins: to keep foreign customers, they may lower their foreign prices, accepting less profit per unit. This is especially damaging for an economy that relies heavily on exports. So an appreciation harms exporters by making their goods less price-competitive abroad, reducing sales, revenue and possibly jobs.

In a floating system the exchange rate is set by the demand for and supply of the currency. When foreigners want to buy more of a country's exports, they must first buy that country's currency to pay for them, so the demand for the currency rises. On a foreign-exchange diagram, the demand curve for the currency shifts to the right. With higher demand and an unchanged supply, the price of the currency rises — that is, the currency appreciates. For example, if demand for UK goods rises, foreigners buy more pounds, so the pound appreciates. The appreciation then makes the country's exports dearer and imports cheaper (SPICED), which can partly offset the original rise in export demand. The same logic works in reverse: weaker export demand means less currency is bought, so the currency depreciates. So stronger export demand raises demand for the currency and causes it to appreciate.

A strong, appreciating currency has both benefits and costs, so whether it is 'good' depends on the situation. Benefits: an appreciation makes imports cheaper, which lowers inflation (cheaper imported goods, raw materials and energy) and raises consumers' purchasing power — they can buy more foreign goods; it makes importing capital equipment and inputs cheaper, helping firms that rely on them; and a strong currency can reflect confidence in the economy. Costs: an appreciation makes exports dearer abroad, so exporters sell less, which can reduce output and jobs in export industries and widen a trade deficit (imports rise, exports fall); an economy that depends heavily on exports could suffer slower growth. Judgement: a strong currency is good for controlling inflation and raising purchasing power, which benefits consumers and import-dependent firms, but it can be bad for exporters, growth and the trade balance. Whether it is good overall depends on the economy's structure — for an economy reliant on exports, a strong currency is more harmful, whereas for one reliant on imported essentials and fighting inflation, it is more beneficial. So a strong currency is neither simply good nor bad; it depends on circumstances.

Speculation — buying a currency expected to appreciate and selling one expected to depreciate, to profit — dominates daily currency trading, and whether it harms an economy is debatable. Why speculation can be harmful: it can make exchange rates volatile and unpredictable, as large speculative flows move a currency sharply up or down regardless of trade fundamentals; this uncertainty makes it hard for exporters and importers to plan and price, deterring trade and investment; speculation can also drive a currency away from its 'true' value, and sudden speculative attacks can trigger a currency crisis (rapid depreciation, lost reserves), as seen in past emerging-market crises. Why it may not be harmful (or can help): speculation adds liquidity to currency markets, making it easier for genuine traders to buy and sell quickly; speculators who correctly anticipate changes can help the rate adjust smoothly towards its market level; and in a deep market, one speculator's buying is offset by another's selling. Judgement: speculation is harmful when it causes excessive volatility or destabilising attacks, which damage trade and confidence — a real risk for small or fragile economies. But in large, stable markets it mainly provides liquidity and helps prices adjust, so it is not always harmful. So whether speculation harms an economy depends on its scale and on how stable and deep the currency market is — destabilising speculation is harmful, stabilising speculation is not.