How Do Interest Rates Affect Exchange Rates? Central Bank Decisions Explained

Higher interest rates tend to strengthen a currency because they make holding it more rewarding, and lower rates tend to weaken it for the opposite reason. On decision day, though, markets react mainly to the gap between what a central bank does and what was expected, and to what it signals about the future. A widely anticipated rate rise can leave a currency flat or even lower.

Why interest rates matter to a currency

Money moves around the world looking for a return. If deposits and government bonds in one currency pay more than comparable assets elsewhere, investors have a reason to buy that currency to hold them. When the return falls, some of that money leaves. The key variable is not one country's rate in isolation but the rate differential — the gap between two countries' rates — and the expected direction of that gap.

That differential is also what drives the strategy explained in the article on the carry trade, and it is why interest rates sit at the top of most lists of what affects exchange rates.

Who makes the decision

Each currency area has a central bank that sets a benchmark rate, usually through a committee that meets on a published schedule. Well-known examples include:

• the Federal Reserve (US dollar), whose rate-setting body is the Federal Open Market Committee;
• the European Central Bank (euro);
• the Bank of England (British pound), through its Monetary Policy Committee;
• the Bank of Japan (Japanese yen);
• central banks in Switzerland, Canada, Australia, New Zealand and elsewhere.

Most have a mandate built around price stability, sometimes alongside employment or growth. Their rate decisions are the main tool for steering inflation, and the effect on the currency is a side effect they watch closely.

Expectations do most of the work

Long before a meeting, markets form a view of what the central bank will do. Interest-rate futures and similar instruments are priced to reflect the probability of a hike, a cut or no change, and that view is already reflected in the exchange rate. On the day, the reaction depends on the surprise:

Market expected	Bank delivered	Common first reaction
A rise	A rise of the expected size	Little change; attention shifts to the statement
A rise	No change	Currency often weakens
No change	An unexpected rise	Currency often strengthens
A cut	A larger cut than expected	Currency often weakens

These are tendencies, not rules. Other news on the same day, or the tone of the accompanying message, can produce a completely different result.

The words matter as much as the number

A rate decision usually arrives with a statement, and many central banks follow it with a press conference, published forecasts or the minutes of the meeting a few weeks later. Markets read these for forward guidance: hints about the likely path of future rates.

• Hawkish language suggests concern about inflation and a readiness to keep rates high or raise them. It tends to support the currency.
• Dovish language suggests concern about growth and a readiness to cut. It tends to weigh on the currency.

A bank can raise rates and still see its currency fall if the statement signals that this was the last rise for a while. Equally, a decision to hold can lift the currency if the tone is firmer than expected. The vote split, where it is published, is read for the same reason.

Beyond the headline rate

Central banks have other tools that can influence currencies. Large-scale bond purchases, often called quantitative easing, add money to the financial system and push down longer-term yields, which tends to weigh on the currency. Reversing those purchases works in the opposite direction. Some banks also intervene directly in the currency market from time to time.

What a decision day looks like

1. The days before: analysts publish previews and expectations settle. Price moves can be muted as participants wait.
2. The announcement: the decision and statement are released at a fixed time. Prices can jump within seconds, spreads may widen and orders can be filled away from the requested price.
3. The press conference: a second wave of movement is common as officials answer questions.
4. The following days: analysts digest forecasts and minutes, and the initial move is sometimes partly or fully reversed.

Dates and times of these meetings appear on any economic calendar, usually marked as high-importance events.

Common questions

Does a rate rise always strengthen a currency?

No. If the rise was fully expected, or if markets think it will damage growth, the currency may not gain at all. Over longer periods, inflation, growth and global risk appetite also play a large part.

Why does the market sometimes move before the decision?

Because expectations shift as new data and speeches arrive in the weeks beforehand. By meeting day, much of the adjustment has often already taken place.

Do rate decisions matter outside trading?

Yes. They affect the cost of foreign holidays, import prices, the value of overseas income and the repayments on loans in another currency.

A general explainer on monetary policy and currencies, not a forecast or a trading recommendation. Trading around rate announcements can lead to fast, large losses; seek guidance from a qualified adviser before making financial decisions.