How National Interest Rates Affect Currency Values and Exchange Rates

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Higher national interest rates usually strengthen a currency, and lower rates usually weaken it. When a central bank raises its policy rate, yields on deposits, bills and bonds in that currency tend to rise. Investors at home and abroad then have more reason to hold assets denominated in it, and to buy them, foreign investors must first buy the currency. That extra demand pushes the exchange rate up. A rate cut works in reverse: returns fall, some capital moves elsewhere, and the currency tends to depreciate. The relationship is a tendency, not a law. Inflation, market expectations, political risk, debt levels and safe-haven demand can override it, sometimes for long periods.

What currency interest rates are

Each currency has its own interest rates, anchored by its central bank’s policy rate: the federal funds rate for the U.S. dollar, the European Central Bank’s deposit and refinancing rates for the euro, Bank Rate for the British pound. Commercial banks, money markets and bond markets price off that anchor, so a change in the policy rate spreads to savings accounts, loans and government bond yields in the same currency.

Central banks set these rates for domestic goals, typically price stability and, in some mandates (including the Federal Reserve’s), maximum employment. The exchange rate effect is a side consequence of those choices, but in an open economy it is one of the fastest channels through which monetary policy reaches the real economy.

For currency traders, the number that matters is the interest rate differential: the gap between the rates of the two currencies in a pair. A U.S. rate of 4% means little on its own; a U.S. rate of 4% against a euro rate of 2% gives a 2 percentage point advantage to holding dollars, all else equal.

How raising interest rates affects a currency

The chain runs like this:

1. The central bank raises its policy rate.
2. Short-term market rates and yields on fixed-income securities in that currency rise.
3. Assets in that currency now pay more relative to assets elsewhere.
4. Domestic investors have less reason to send money abroad, and foreign investors have more reason to bring money in.
5. To buy those assets, foreign investors sell their own currency and buy the higher-yielding one.
6. Increased demand for the currency raises its price in the foreign exchange market.

So when the Fed raises rates, the dollar usually strengthens. Yields on Treasury bills, notes and other dollar fixed-income products tend to rise with the federal funds rate. Investors worldwide may sell holdings in their own currencies to buy those dollar assets, and the U.S. Dollar Index (DXY), which measures the dollar against six major currencies, tends to rise.

Higher rates can also support a currency indirectly. A central bank that hikes to fight inflation signals that it intends to protect the currency’s purchasing power, and that credibility can make the currency more attractive to hold.

Why lower interest rates cause currency depreciation

Cutting rates reverses each step. Yields on deposits and bonds in that currency fall, so the return on holding it falls. Some investors move money into currencies that pay more, selling the lower-yielding currency to do so. Lower rates also encourage domestic borrowing and spending, which can raise inflation expectations and further reduce the currency’s appeal.

A cheaper currency makes exports less expensive for foreign buyers and imports more expensive at home. Some central banks welcome that when the economy is weak, but higher import prices can feed inflation, which limits how far a central bank can cut without losing control of prices.

Expectations move currencies more than decisions

Foreign exchange markets trade on anticipated rate paths. If traders are confident that a central bank will raise rates by a quarter point next month, that expectation is usually reflected in the exchange rate before the meeting. On the day, a hike that matches expectations may barely move the currency, and it can even fall if the accompanying statement suggests fewer hikes ahead than the market had assumed.

What tends to produce sharp moves is a surprise: a larger or smaller change than expected, an unexpected pause, or guidance that shifts the expected path of future rates. For this reason, analysts follow central bank statements, meeting minutes, inflation reports and employment data closely, because each changes the probability of future moves. Volatility around rate announcements can be large.

Example: the rate differential in practice

A hypothetical forward rate

Interest rate differentials are built directly into forward exchange rates through covered interest rate parity. The one-year forward rate equals the spot rate multiplied by the ratio of the two currencies’ interest rates:

Forward = Spot × (1 + quote currency rate) / (1 + base currency rate)

Hypothetical inputs: EUR/USD spot at 1.1000, a one-year U.S. dollar rate of 5%, and a one-year euro rate of 2%.

Forward = 1.1000 × 1.05 / 1.02 ≈ 1.1324

The forward price of the euro is higher than spot because the dollar pays more interest. An investor who earns the extra 3 points on dollars and locks in the exchange rate with a forward gives the advantage back through the forward price. Uncovered positions are different: an investor who holds the higher-yielding currency without hedging keeps the extra interest but carries the exchange rate risk. This unhedged trade is called the carry trade.

The Federal Reserve from 2020 to 2023

In March 2020, at two unscheduled meetings at the start of the COVID-19 pandemic, the Federal Reserve cut the federal funds rate by a combined 1.5 percentage points to a target range of 0% to 0.25%, to make credit cheaper as businesses closed and unemployment claims surged.

As inflation rose quickly after the pandemic, the Fed moved earlier and more aggressively than many other central banks. It began raising rates in March 2022 and continued into 2023, reaching a target range of 5.25% to 5.50% by July 2023. The dollar strengthened during the hiking cycle: in October 2022 the U.S. Dollar Index reached a 20-year high. The widening differential between U.S. rates and rates in other major economies was a key part of that move. The Fed began cutting in 2024 as inflation eased.

Exceptions that change the answer

Inflation outpacing interest rates

Investors care about real returns, roughly the nominal interest rate minus inflation. A country paying 5% while inflation runs at 7% offers a real return of about minus 2%. If inflation rises faster than rates, the currency’s purchasing power erodes faster than interest compensates holders, and the currency can weaken even as the central bank hikes. Rate increases that look like they lag behind inflation can be read as a sign of weakness rather than strength.

If high inflation results from stimulus policy, foreign investors may conclude the economy is fragile. A currency tends to firm up when the central bank clearly prioritizes fighting inflation.

Why a high interest rate currency can depreciate

Uncovered interest rate parity, a standard theory in international finance, says a high-yield currency should depreciate over time by roughly the interest rate differential, cancelling the carry advantage. Over short and medium horizons this prediction has often failed, which is why the carry trade exists. Over longer stretches, though, currencies of countries with persistently high rates frequently do lose value, because those rates usually compensate investors for high inflation or default risk rather than offering a free return.

High rates can also accompany sudden reversals. When global risk appetite drops, investors often exit high-yield currencies at once and buy safer ones, and the high-yielder can fall sharply despite its rate advantage.

Safe-haven demand

In uncertain periods, money often flows into currencies perceived as safe regardless of yield. The U.S. dollar, the world’s main reserve currency, is the leading example: safe-haven demand supports it even when U.S. rates are low, and at times has mattered more than interest rates or inflation.

Debt and credibility

High government debt can be manageable for a while, but over time it can lead to higher inflation, pressure on the central bank to keep rates low, and in extreme cases an official devaluation. If markets believe a central bank is raising rates under political pressure, or will reverse course soon, a hike may do little for the currency.

Other factors that influence exchange rates

Interest rates sit inside a wider set of drivers, many of which also shape the central bank’s rate decisions:

• Political stability. Instability in government, institutions or policy raises the risk premium investors demand.
• Economic growth. GDP growth and currency value often move together, and central banks weigh GDP when deciding future rate changes.
• Balance of trade. Strong demand for a country’s exports means foreign buyers need its currency. A persistent current account deficit is generally viewed as a weight on a currency.
• Debt relative to growth. Currencies of countries whose debt is not outpacing economic growth, with stable unemployment, are generally viewed more favorably.
• Monetary expansion. Loose policy that inflates the money supply tends to reduce a currency’s value.

Does an appreciating currency affect interest rates?

The influence runs both ways. A stronger currency makes imports cheaper, which lowers inflation pressure and can slow the economy by making exports less competitive. Both effects tighten financial conditions much as a rate hike would, so a central bank facing a sharply appreciating currency may have less reason to raise rates, or more room to cut. A rapidly falling currency does the opposite: it raises import prices and can push a central bank to hike to defend purchasing power. This feedback is one reason exchange rates are a standard input in central bank deliberations.

FAQs

The Bottom Line

Currency traders and investors holding foreign assets should treat higher rates as a tendency that supports a currency. It does not guarantee a stronger exchange rate. Inflation, the credibility of the central bank, debt levels, and safe-haven flows can override the rate advantage, sometimes for long periods. Expected rate paths and real returns usually tell more about where a currency is heading than any single rate decision.