The pound has undergone something of a roller-coaster ride over the past three and a half years. It was $1.71 in July 2014, fell from $1.49 to $1.32 after the Brexit vote and then again to $1.21 in January, 2017 and has recently risen to $1.38 (20th January 2018). However, it is worth noting that while, historically we usually measure sterling against the dollar, the fall against the euro has been greater. In July 2015, £1 would buy 1.49 euros but by August 2017 the rate had fallen to £1 = 1.08 euros and it is currently at £1 = 1.33 euros.
This post will consider the factors which might cause the value of a currency to fluctuate. (and the next will discuss the impact fluctuations might have on an economy). Over the last 100 years, the world has moved from a system where currencies were fixed to gold (the Gold Standard), to a time when the dollar was fixed to gold while currencies such as sterling were pegged, with limited flexibility, against the dollar (the Bretton Woods Agreement) to a system of flexible exchange rates where, today, in theory, the demand for and supply of the pound in the foreign exchange market determines its value.
In old economics textbooks, the adjustment process was simple. The demand for a currency is determined by foreigners wanting to buy UK exports and needing to pay for them in sterling while the supply of sterling came from UK firms and consumers wanting to buy foreign goods and services, such as overseas holidays, and needing to swap pounds for foreign currency to pay for them. If the UK had a balance of payments deficit, the demand for sterling in the foreign exchange market would be less than the supply and so the value would depreciate against other countries, making UK exports cheaper and imports more expensive, restoring international equilibrium.
Today the situation is far more complex; not only do we have to consider the impact of a currency such as the euro which has replaced the individual currencies of the members of the eurozone, making it impossible for them to use depreciation to improve their balance of payments, it is now no longer the sale and purchase of exports and imports of goods and services which determines the exchange rate, it is the trade in financial assets which is far more important as banks, businesses, governments and individuals buy and sell foreign shares and government securities and move money between countries to gain higher interest rates or profit from speculative movements in currencies. To put this into perspective, the World Trade Organisation estimated that in 2015, total international trade in goods and services amounted to $20 trillion while $5 trillion was traded on the foreign exchange market EACH Day.
Therefore factors which influence speculators’ views of the economy will have a major short-term impact on the value of the currency. Hence, immediately after Brexit, the general view was that leaving the EU would have detrimental effects on the economy (or at least on those dealing in financial assets and currencies) and this reduced the demand for sterling from overseas and increased its supply from UK holders seeking to purchase foreign financial assets. Similarly if the political situation changes and that affects views of the economy, then the value of the currency will change. Other things which will affect the value of the currency will be changes (or expected changes) in our rate of interest or the rate of interest in other major currencies, the economic performance of our economy or other major countries since if, for example, the US economy weakens, then relatively, the UK economy will be stronger and this will encourage a movement of money from the dollar to the pound.