Definition
A fixed exchange rate system is a policy in which a government or central bank ties its currency to a foreign currency (usually the U.S. dollar) and holds it at a set value or within a very narrow range. Think of an amusement park that always sells one token for exactly $1. Instead of letting supply and demand make the rate bounce around, the government steps in and holds it steady.
An Exchange Rate With the Price Tag Taped Down
If exchange rates move up and down every day, anyone doing business abroad has to worry constantly. Say $1 costs 1,000 won today, and tomorrow it suddenly costs 1,500 won. A factory that imports raw materials from overseas could take a huge loss overnight.
A fixed exchange rate system is meant to stop that chaos. The country ties its exchange rate to one specific number. The government declares, "From now on, $1 trades for 1,000 won," and then sticks to that promise.
When the rate barely moves, companies that trade abroad and people who invest overseas can predict their future costs much more easily. It's like shopping at a fixed-price store, where you can trust the price tag. Trade between countries becomes steadier and easier to plan.
The Price of Keeping the Rate Fixed
In a market, prices naturally rise when more people want to buy and fall when more people want to sell. The foreign exchange market works the same way. When more people want dollars, the dollar's value tries to shoot up on its own.
To keep its promised rate, the government has to jump into the market itself. When so many people want dollars that the price starts to climb, the government sells dollars from its stockpile to push the price back down. When dollars are flooding in, it does the opposite: it prints its own currency and buys up the extra dollars.
That's why a country with a fixed exchange rate needs plenty of foreign currency reserves ready for emergencies. Suppose foreign investors pull their money out all at once and the government's stash of dollars runs dry. The country can't defend its rate, and it can fall into a severe economic crisis.
A Closer Look: Every Gain Has a Cost
In economics, there's a principle called the "impossible trinity" (or trilemma). It says a country can't catch all three rabbits at once. The three goals are free movement of capital, independent control of interest rates (independent monetary policy), and a stable exchange rate (a fixed rate). You can only pick two of the three at the same time.
If a country keeps its borders open to money flows and also fixes its exchange rate, it basically has to give up the right to set interest rates to suit its own economy. Imagine the U.S. raises interest rates sharply to fight inflation. What happens if we worry about our own economic slump and leave our rates where they are?
Money chasing higher returns drains out of our country and flows to the U.S. like a receding tide, and that threatens the fixed rate. In the end, to protect the peg, we have to follow the U.S. and raise rates, even if our own economy is struggling. In exchange for a stable exchange rate, we sacrifice the freedom of independent monetary policy.
Common misconceptions
Under a fixed exchange rate system, the government doesn't have to do anything to keep the rate in place.
To hold the rate at a fixed value, the central bank has to step in and buy or sell dollars in the market whenever needed. If it left things alone, supply and demand would push the exchange rate around on its own.
Where you meet it
Hong Kong has used a currency peg since the 1980s, keeping the Hong Kong dollar within a set range against the U.S. dollar.
Saudi Arabia pegs its currency, the riyal, to the U.S. dollar to protect the stable value of its oil export revenue.
In one sentence
A fixed exchange rate system greatly reduces the uncertainty of exchange rate swings. But it requires large foreign currency reserves, and if capital moves freely, the country basically has to give up control over its own interest rates.