What moves currency prices? Rates, inflation, growth, risk and flows

Currency prices move when demand for one currency rises or falls relative to another. The biggest single influence is usually expectations about interest rates, because they set the return on holding a currency. Inflation, economic growth, risk sentiment, trade and capital flows, politics and occasional government intervention all feed into those expectations or act on demand directly. Over hours and days, news and positioning dominate; over years, inflation, productivity and the health of a country's institutions matter more.

This guide explains each driver in turn, how they interact, and why the same piece of news can push a currency up one month and down the next. It builds on the short overview in how the forex market works and links to deeper guides on each topic.

Start with supply and demand

An exchange rate is a price, and like any price it moves when buyers and sellers change their minds. Someone buys euros and sells dollars for a reason: a German exporter converting dollar revenue, a US pension fund buying European bonds, a tourist, a hedge fund betting on the European Central Bank, a central bank managing its reserves. Each of them is a flow of demand for one currency and supply of another.

Every driver in this guide works through that channel. Higher interest rates attract investors who need the currency to buy local bonds. Strong exports bring foreign buyers who need the currency to pay for goods. A political crisis makes holders sell. The useful question for any piece of news is always: who now wants to buy or sell this currency, and how much?

Two more points before the drivers themselves:

• Every pair has two sides. EUR/USD can rise because the euro is strong or because the dollar is weak. News from the US often moves EUR/USD as much as news from the euro area. See currency pairs explained.
• Prices reflect expectations. Much of what is known or widely expected is already in the price. Markets move on the gap between what was expected and what happens.

Interest rates and central banks

Interest rates are the most watched driver because they set what you earn for holding a currency. If one central bank pays 4% and another pays 1%, money tends to drift towards the higher yield, other things being equal. The difference between two countries' rates, the interest rate differential, is one of the main things currency analysts watch.

Three refinements matter more than the headline rate:

1. Expectations beat decisions. A rate rise that everybody expected is already priced in. What moves a currency is a change in the expected path of rates, often triggered by a central bank's statement, a speech or a data release.
2. Real rates matter. A 5% interest rate with 6% inflation leaves a negative real return. Investors care about rates after inflation, and a currency with high nominal but negative real rates may not attract much money.
3. Forward guidance moves markets. When a central bank signals what it is likely to do next, the market adjusts immediately, long before any decision.

Our dedicated guide to central banks and interest rates covers the Fed, ECB, Bank of England and Bank of Japan in detail. Rate differentials also show up in your own costs: they set the nightly swap you pay or receive on a position.

Worked example: the differential changes

Imagine (illustrative numbers) that the US policy rate is 4.5% and the euro area rate is 2.5%, a differential of 2 percentage points in the dollar's favour. The market expects both central banks to hold rates for the next year.

Now US inflation data comes in well above forecast, and traders start pricing one more US rate rise. The expected differential widens. Investors who hold euro deposits now have a slightly better reason to switch to dollars, and EUR/USD tends to fall, other things being equal. If a week later the ECB signals it is also considering a rise, the expected gap narrows again and some of that move may reverse.

Notice that nothing about the current rates changed in this example. Everything happened through expectations.

Inflation

Inflation affects currencies in two opposite ways, which confuses many beginners.

• In the short run, higher-than-expected inflation often strengthens a currency, because the market expects the central bank to raise rates or keep them high to fight it.
• In the long run, persistently higher inflation tends to weaken a currency, because each unit buys less over time. This is the idea behind purchasing power parity: over long periods, exchange rates tend to drift towards levels that equalise the cost of the same goods in both countries.

Purchasing power parity is a poor guide to where a currency will trade next month, and currencies can stay far from it for years. It is more useful as background, explaining why countries with persistently high inflation have tended to see their currencies weaken over decades.

The inflation numbers that matter most for markets are the monthly consumer price index releases and, in the US, the PCE price index that the Federal Reserve targets. How economic data moves forex explains how those releases are read.

Economic growth and data

Strong growth tends to support a currency for two reasons: it raises the chance of higher interest rates, and it attracts investment into local businesses and assets. Weak growth does the reverse.

Markets track growth through a stream of data releases: GDP, employment figures such as US non-farm payrolls, purchasing managers' indices (PMIs), retail sales and many others. Each release is compared with a consensus forecast, and the currency moves on the surprise. A strong number that was fully expected can do nothing, while a merely decent number that beats a gloomy forecast can lift the currency sharply. Our guide to using an economic calendar shows how to find the schedule, the consensus and the previous figure in one place.

Relative growth matters more than absolute growth. If both the US and euro area economies are slowing at the same pace, EUR/USD may hardly move. If one slows much faster, its currency usually feels it.

Risk sentiment

Sometimes currencies move together for reasons that have little to do with their own economies. When investors are confident, they tend to buy riskier, higher-yielding assets and currencies. When they are frightened by a financial crisis, a war or a sharp fall in share markets, they tend to sell those and move money towards perceived safety. Traders describe this as "risk-on" and "risk-off".

Historically, in risk-off periods:

• the US dollar has tended to gain, because it is the world's main reserve and funding currency and investors need dollars to repay dollar debts;
• the Japanese yen and Swiss franc have tended to gain, partly because Japan and Switzerland are large net creditors whose investors bring money home in a crisis, and partly because those currencies have often been used to fund carry trades that get unwound;
• currencies linked to growth and commodities, such as the Australian, New Zealand and Canadian dollars, and many emerging-market currencies, have tended to weaken.

These are tendencies, not rules. The safe-haven role of a currency can weaken if its own economy is the source of the stress, and the pattern has broken down in some episodes. Risk sentiment is also why correlations between pairs can jump suddenly: in a panic, many positions that looked independent turn into the same trade. See currency correlation.

The carry trade and its unwinding

A carry trade means borrowing in a low-interest currency and holding a high-interest one, earning the difference. When markets are calm, carry trades can build up over months and support high-yielding currencies. When volatility rises, traders close them in a hurry, buying back the low-yielding funding currency. That is why yen strength has often coincided with market stress. In early August 2024, for example, a sharp rise in the yen after the Bank of Japan raised rates at the end of July coincided with a rapid unwinding of yen-funded positions and a wider sell-off in equity markets.

Trade and the current account

A country that exports more than it imports earns foreign currency that its exporters mostly convert back into the home currency, creating steady demand for it. A country that runs a persistent current account deficit needs to attract foreign capital to pay for its imports, which can leave its currency vulnerable if that capital becomes harder to attract.

Commodity prices are a specific case. Some currencies have tended to move with the prices of their main exports:

• the Canadian dollar and Norwegian krone with oil;
• the Australian dollar with metals such as iron ore, and with demand from China;
• the New Zealand dollar with dairy and other agricultural exports.

The link works through the terms of trade: when the price of what a country sells rises relative to what it buys, more foreign money flows in. As with every driver here, the relationship is loose and can disappear for long periods.

Trade flows tend to matter more over months and years than over minutes. Daily currency trading volume is vastly larger than the value of goods traded across borders, so on any given day financial flows and expectations dominate.

Capital flows

Most of the money moving through the currency market is investment money rather than trade payments. Pension funds, insurers, asset managers and companies buy and sell foreign bonds, shares, property and businesses. Their decisions can move currencies for long periods.

• Portfolio flows: international investors buying a country's bonds or shares need its currency. A large index inclusion or a shift in global bond allocations can create sustained demand.
• Mergers and acquisitions: a large cross-border takeover paid in cash can require billions in one currency to be bought on a specific date.
• Hedging: when foreign investors decide to hedge more or less of their currency exposure, they buy or sell the currency without changing their underlying investments.
• Calendar flows: month-end, quarter-end and year-end portfolio rebalancing can push currencies around in the final days and hours of a period, often regardless of news.

These flows are rarely visible in advance to retail traders. They are one reason a currency can move for no reason you can see on the news.

Politics, fiscal policy and institutions

Investors want to know that they will be repaid in a currency that holds its value, and that the rules will not change against them. Politics affects all of that.

• Elections and referendums can move a currency if the outcome changes the likely path of policy. After the UK voted to leave the EU in the referendum of 23 June 2016, sterling fell sharply against the dollar in the following hours.
• Fiscal credibility matters. In September 2022, the UK government's "mini-budget" of unfunded tax cuts triggered a sell-off in UK government bonds, and sterling fell to a record low against the dollar a few days later. The episode showed that a country with a respected central bank can still see its currency punished if markets doubt its public finances.
• Central bank independence: if markets suspect that a central bank will be pressured to keep rates lower than inflation warrants, they tend to demand a higher return for holding the currency, or sell it.
• Sanctions, conflicts and capital controls can cut a currency off from normal flows altogether.

Political risk is hard to model, and it often shows up as a sudden gap in price rather than a gradual move. Gap risk and weekend risk explains why your stop-loss may not protect you as expected in those moments.

Intervention and pegs

Governments and central banks sometimes act directly on their currency, buying or selling it in the market.

• Japan intervened to support the yen in September and October 2022, and again in 2024, when the yen had fallen to levels the Ministry of Finance judged excessive. Those interventions produced sharp moves within minutes.
• Switzerland: the Swiss National Bank held a minimum exchange rate of 1.20 francs per euro from 2011 and abandoned it without warning on 15 January 2015. The franc jumped dramatically within minutes, and some brokers and many clients suffered large losses because prices skipped past stop-loss orders.
• Coordinated action: in the Plaza Accord of September 1985, the major economies agreed to push the dollar lower, a reminder that policy can override market forces for a time.
• Pegs and bands: some currencies, such as the Hong Kong dollar, are held within a narrow band against the US dollar. They move little until the peg is challenged.

For traders, the lesson is that intervention risk is real in currencies that officials are watching closely, and that it arrives without a timetable.

Short run versus long run

Putting the drivers on a timeline helps make sense of them.

• Seconds to hours: scheduled data releases, central bank statements, headlines, large orders and stop-loss clusters. Prices react to surprises and to how traders are positioned. Spreads often widen around these moments.
• Days to weeks: shifts in rate expectations, risk sentiment, positioning and month-end flows.
• Months to years: interest rate cycles, relative growth, inflation, trade balances, capital flows and political events.
• Decades: productivity, inflation differences (the purchasing power parity idea), demographics and the quality of institutions.

A short-term trader needs to know what is scheduled and how markets are positioned. A long-term view is about the slow forces. Both are working all the time, which is why a currency can rally for a week against what looks like a weak long-term outlook.

Positioning and "priced in"

Two currencies can receive the same news and react completely differently, depending on how traders were already positioned.

If most speculators are already long a currency because they expect rates to rise, good news may produce only a small gain: everyone who wanted to buy has bought. Mildly disappointing news can then cause a sharp fall as those positions are closed. Traders call this "buy the rumour, sell the fact". It is also why a currency sometimes falls after a central bank raises rates: the rise was expected, and the accompanying statement hinted that it might be the last.

Positioning data such as the weekly US Commitments of Traders report gives a rough picture of how futures speculators are positioned, but it is delayed and covers only part of the market.

Worked example: one week, several drivers

Here is an illustrative week for a fictional pair, showing how drivers combine. No real data is implied.

1. Monday: share markets fall sharply after a banking scare. Risk-off flows push the safe-haven currency up 0.8% against the commodity currency.
2. Tuesday: markets calm. Half the move reverses as traders conclude the scare is contained.
3. Wednesday: inflation in the commodity country comes in above forecast. Traders bring forward expectations of a rate rise and the commodity currency gains 0.5%.
4. Thursday: the price of the country's main export falls 4%, and the currency gives back some of Wednesday's gain.
5. Friday: month-end rebalancing produces a burst of selling in the final hour, unrelated to any news.

By Friday the pair might be roughly where it started. Each driver was real; they simply pushed in different directions. This is normal, and it is why explaining the market after the fact is much easier than trading it in advance. Recaps such as our weekly forex reviews show this pattern in real weeks.

Common mistakes

• Reading news as simply good or bad. What matters is the surprise versus expectations and how the market was positioned.
• Looking at one side of the pair. A strong euro area figure may not lift EUR/USD if US data on the same day is stronger still.
• Assuming relationships are permanent. Commodity links, safe-haven roles and correlations change over time.
• Treating fundamentals as timing signals. A currency can look overvalued for years. Long-run drivers say little about next week.
• Trading through big events at full size. Spreads widen, slippage increases and prices can gap. If you hold positions over scheduled releases, size them for the possible move.
• Confusing explanation with prediction. Every move gets a story afterwards. That does not mean the story could have been used beforehand.

How to use this as a trader

You do not need to be an economist to trade currencies, but you do need to know when the big drivers are likely to show up:

• Check the economic calendar each week for central bank meetings and major releases for both currencies in your pair.
• Know the current interest rate stance of each central bank and roughly what the market expects next.
• Notice the general risk mood: are share markets calm or stressed?
• Keep your position size small enough that a surprise you did not see coming cannot do serious damage.

Most retail CFD accounts lose money, and understanding the drivers does not change that on its own. It helps you avoid being surprised by scheduled events and helps you interpret what you see on the chart.

Frequently asked questions

What is the most important factor for exchange rates?

Over most periods, expectations about interest rates have the strongest influence on major currencies, because they determine the return on holding them. But risk sentiment, politics or intervention can dominate for a time, so no single factor always wins.

Why did a currency fall when the economic data was good?

Usually because the data was weaker than the market expected, because something more important happened on the other side of the pair, or because traders were already heavily positioned for good news and took their gains.

Why does the yen often rise when markets fall?

Japan is a large net creditor, so Japanese investors have tended to bring money home in a crisis, and the yen's low interest rates have made it a popular funding currency for carry trades that get closed when volatility rises. This has been a common pattern, not a fixed rule.

Do commodity prices affect currencies?

Some currencies have historically moved with the prices of their main exports, such as the Canadian dollar with oil and the Australian dollar with metals. The relationships are loose and vary over time.

How do politics affect forex?

Elections, budgets and other political events can change the expected path of interest rates, government borrowing and economic policy, and can raise doubts about a country's institutions. Large political surprises often show up as sudden moves or gaps.

Can you predict currency movements from fundamentals?

Fundamentals help explain why currencies move and what might matter, but they do not reliably predict short-term prices. Much information is already in the price, and surprises by definition cannot be known in advance.