What Is a Currency Peg?

Most major currencies, including the pound, the dollar and the euro, float freely, rising and falling with supply and demand. But many countries take a different path and lock their currency to another at a fixed rate. That decision shapes their entire economy, from inflation to interest rates, and occasionally produces dramatic crises when the lock is tested. Here is what a currency peg is, how a government keeps one in place, the trade-offs involved, and what happens when a peg finally breaks.

What a currency peg is

A currency peg is a policy of fixing a country's exchange rate to another currency, or to a basket of currencies, rather than letting it move freely on the market. A government with a pegged currency commits to keeping its exchange rate at, or very close to, a set target.

For example, a country might peg its currency to the US dollar at a fixed rate, promising that one unit of its money will always be worth a particular number of dollars. Instead of the rate drifting up and down each day, it stays put, anchored to the chosen reference currency.

Pegs sit at one end of a spectrum of exchange-rate systems. At the other end is a free float, where the market sets the rate with no official target. In between are managed floats, where a central bank lets the currency move but intervenes to smooth large swings. A peg is the most rigid of these arrangements, and the strength of the currency it is tied to feeds directly into a country's credit rating.

How a peg is held in place

A peg is a promise, and promises need backing. A central bank maintains its peg using two main levers.

1. Buying and selling currency. This is the front line. If the pegged currency starts to weaken below its target, the central bank sells its foreign reserves, dollars or other strong currencies it has stockpiled, to buy up its own currency, supporting the price. If the currency threatens to rise above the target, it does the reverse, selling its own currency to keep the rate down.
2. Interest rates. Higher interest rates attract foreign money seeking better returns, which strengthens demand for the currency. So a central bank defending a weakening peg may raise rates to make holding the currency more attractive, even if the wider economy would prefer lower rates.

The crucial point is that a peg demands deep foreign-exchange reserves and a willingness to subordinate domestic priorities to the exchange-rate target. The market knows this, which is why pegs are constantly tested by traders judging whether a central bank has the firepower and the resolve to hold the line.

Types of peg

Not all pegs are equally rigid. The main varieties are:

A currency board is the most extreme version, where the central bank backs every unit of local currency with foreign reserves and gives up almost all discretion. The most flexible arrangements blur into a managed float.

Why governments use pegs

Countries choose pegs chiefly for stability and credibility.

• Predictability for trade and investment. When the exchange rate cannot lurch overnight, businesses can price contracts, plan imports and exports, and invest with more confidence. For economies that depend heavily on trade, this is a major attraction, and it links to the broader logic of how tariffs and trade flows shape an economy.
• Taming inflation. A country with a history of high inflation can "import" the credibility of a more stable currency by pegging to it. If the peg holds, prices of imported goods stabilise, and the discipline can help break an inflationary cycle.
• Reassuring investors. Foreign lenders and companies often feel safer putting money into a country whose currency will not suddenly collapse in value, which can lower borrowing costs.

For small, open or trade-dependent economies, these benefits can be substantial, which is why pegs remain common despite their risks.

The cost: losing control

The central trade-off of a peg is the loss of an independent monetary policy.

A central bank can defend its exchange rate, or it can set interest rates to suit its own economy, but it cannot fully do both at once. A peg forces it to choose the exchange rate.

Consider a country in recession that pegs to a stronger economy. Its own situation calls for lower interest rates to encourage spending. But if defending the peg requires higher rates to keep the currency attractive, the central bank's hands are tied. It must prioritise the peg, even at the cost of deepening the downturn. The currency's stability comes at the price of flexibility, the very flexibility that floating currencies use to cushion shocks.

What happens when a peg breaks

Pegs can hold for decades, but they can also collapse, sometimes spectacularly.

A peg comes under pressure when markets begin to doubt that it reflects the currency's true value, or that the central bank can keep defending it. Traders may sell the currency aggressively, betting it will be forced lower. To hold the line, the central bank burns through its reserves buying its own currency, but reserves are finite. If they run low and confidence keeps draining, the government may have no choice but to abandon the peg.

When that happens, the result is often a sudden, sharp devaluation as the currency snaps to a lower market level. The consequences can be severe:

• Imported goods become more expensive, fuelling a spike in inflation.
• Businesses and governments with foreign-currency debts suddenly owe far more in local-currency terms, which can trigger defaults.
• Confidence is shaken, sometimes spreading to neighbouring economies.

History offers several painful examples of currency crises that began when a peg cracked under speculative pressure. The lesson is that a peg is only as strong as the reserves and credibility behind it.

The bottom line

A currency peg fixes a country's exchange rate to another currency to deliver stability, predictability and, often, lower inflation. A central bank holds the peg by buying and selling currency and adjusting interest rates, which requires substantial foreign reserves. The price of that stability is the loss of an independent monetary policy, because defending the exchange rate must come first. Pegs can serve trade-dependent economies well for years, but when markets lose faith and reserves run thin, a forced break can bring a sharp devaluation and serious economic disruption. Stability, in other words, is bought at the cost of flexibility.