The Forex Market: The Complete Guide

What Is the Forex Market?

The foreign exchange market — almost universally called forex or FX — is where one currency is exchanged for another. Every time a company pays a foreign supplier, a traveler converts cash at an airport, or a fund manager shifts money between countries, a forex transaction happens. The sheer volume of these transactions, happening continuously all over the world, makes forex the largest financial market on earth by daily turnover.

Unlike the New York Stock Exchange or the London Stock Exchange, forex has no single building, no central exchange, and no official opening bell. It is an over-the-counter (OTC) market — meaning trades happen directly between parties, connected by electronic networks and banking relationships rather than a shared trading floor. You can follow live rates for major, minor, and exotic pairs on the currencies page.

How the Market Stays Open Around the Clock

Forex trades five days a week, essentially without pause, because the market follows the sun. As one financial center closes, another opens, and there is always significant overlap between sessions. The four main sessions are Sydney, Tokyo, London, and New York — and during the overlaps between them, trading activity tends to be heaviest and bid-ask spreads tend to narrow.

The hours above are approximate and shift slightly with daylight saving time changes in different countries. The London–New York overlap, roughly 13:00 to 17:00 UTC, is historically the busiest window of the trading day, as it connects the two deepest pools of liquidity in the world.

Who Trades Forex and Why

Forex participants range from enormous global banks to individual travelers exchanging a few hundred dollars. Each group has different motivations, different volumes, and different effects on the market.

Commercial and Investment Banks

Large banks form the backbone of the forex market. They trade on behalf of clients — corporations, funds, governments — and also trade for their own books. The network of banks quoting prices to one another is called the interbank market, and the rates you see on any data platform ultimately derive from prices formed there.

Corporations (Commercial Hedgers)

A car manufacturer that builds vehicles in one country and sells them in another is constantly exposed to exchange-rate risk. Suppose a European automaker sells cars priced in US dollars but pays its factory workers in euros — if the dollar weakens against the euro (meaning each dollar buys fewer euros), the company's euro revenues shrink even if sales volumes are flat. Corporations use forex to hedge — that is, to lock in exchange rates in advance and reduce that uncertainty. This is one of the most fundamental and economically important uses of the market.

Central Banks

Central banks — institutions like the US Federal Reserve, the European Central Bank, or the Bank of Japan — participate in forex markets to implement monetary policy and, sometimes, to stabilize their currency's value through direct FX intervention. Their actions can move markets dramatically because of the scale of resources at their disposal. The guide on central banks and currencies covers this in depth.

Funds and Institutional Investors

Pension funds, sovereign wealth funds, and asset managers regularly buy and sell foreign assets — foreign stocks, bonds, and real estate. Every such purchase or sale requires a currency conversion, generating large forex flows. Dedicated macro hedge funds also trade currencies as a direct investment, taking positions based on their views about interest rates, economic growth, or political events.

Retail Traders and Tourists

Individual traders access the market through online brokers, and tourists convert money at banks or airport kiosks. In terms of global volume, retail activity is a small fraction of total turnover. However, the growth of retail platforms over the past two decades has made it meaningfully larger than it was historically.

Currency Pairs: The Basic Unit of Forex

In forex, you never simply "buy euros." You always exchange one currency for another, which is why every transaction involves a currency pair. A pair is written as two currency codes separated by a slash — for example, EUR/USD. The first currency (EUR) is called the base currency, and the second (USD) is the quote currency. The price tells you how many units of the quote currency one unit of the base currency is worth. If EUR/USD is quoted at 1.08 (a hypothetical example), one euro buys 1.08 US dollars.

Pairs are grouped by how heavily they trade and which currencies are involved. The guide on currency pairs walks through the full mechanics; the summary below covers the three main categories.

Major Pairs

Major pairs always include the US dollar on one side and pair it with another large, freely traded currency. They are the most liquid pairs in the market — tighter spreads, faster execution, and more data available.

Minor Pairs (Cross Rates)

Cross rates (also called minors) are pairs between two major currencies that do not include the US dollar — for example, EUR/GBP or AUD/JPY. They are generally liquid but slightly less so than the majors.

Exotic Pairs

Exotic pairs combine one major currency with the currency of a smaller or emerging economy — for example, USD/TRY (US dollar vs. Turkish lira) or EUR/ZAR (euro vs. South African rand). These pairs tend to have wider spreads and can be far more volatile, especially during periods of political or economic stress in the smaller economy. The guide on emerging-market currencies explores why.

The US Dollar as Global Anchor

The US dollar is the world's dominant reserve currency — the currency that most central banks hold in their foreign-exchange reserves and that most international commodities, including oil, are priced in. This gives the dollar an outsized role: even a currency pair that does not include the dollar, such as EUR/JPY, is often analyzed by looking at how each currency behaves against the dollar individually.

The US Dollar Index (known by its ticker, DXY) tracks the dollar's value against a basket of six major currencies. When the DXY rises, the dollar is strengthening broadly; when it falls, the dollar is weakening. The dedicated guide on the DXY explains exactly how that basket is constructed and weighted.

What Moves Currency Prices?

Exchange rates shift constantly, driven by a mix of economic data, policy decisions, trade flows, and market sentiment. The detailed treatment is in the guide on what moves exchange rates, but the main categories are worth naming here.

• Interest rates: When a central bank raises its policy rate, the currency of that country often strengthens, because higher rates attract capital from investors seeking better returns. This is the basis of the carry trade.
• Inflation: High inflation erodes a currency's purchasing power over time. Economists often track purchasing power parity — the theory that exchange rates should, in the long run, reflect differences in price levels between countries.
• Economic growth: Strong GDP growth tends to attract foreign investment, increasing demand for a currency. PMI surveys and jobs data are among the high-frequency indicators traders watch for early signals.
• Political and geopolitical events: Elections, policy changes, trade disputes, and conflicts can trigger sharp currency moves, particularly in emerging markets.
• Market sentiment: During periods of global stress, capital tends to flow toward perceived safe-haven currencies — historically the US dollar, Japanese yen, and Swiss franc. The concept of risk-on / risk-off sentiment is central to understanding these flows.

Key economic releases — nonfarm payrolls, CPI reports, and central-bank rate decisions — are scheduled events that can cause large, rapid moves. The economic calendar lists upcoming releases with their expected impact.

Reading Forex Data

When you look at a forex data table, the quoted number is always a price expressed in units of the quote currency per one unit of the base currency. If USD/JPY shows 148.50 (a hypothetical example), that means one US dollar currently buys 148.50 Japanese yen. The base currency is always in the numerator; the quote currency is always the price you see.

The smallest standard unit of price movement in most pairs is called a pip — typically the fourth decimal place for most pairs (0.0001), but the second decimal place for yen pairs (0.01). A full explanation of pips, spreads, and how to read an FX quote is in the guide on reading FX quotes.

Percentage-change columns — showing how much a pair has moved over the day, week, month, year-to-date, and year-over-year — are often more useful than the raw rate for understanding momentum and context. The guide on reading percentage moves explains how to interpret each column without being misled by short-term noise.

A currency rate is always a ratio between two things. A move in EUR/USD can mean the euro is strengthening, the dollar is weakening, or both — the pair alone does not tell you which. Comparing a currency against several others helps isolate what is actually driving the move.

Forex data also appears throughout other markets. Commodity prices quoted in dollars affect the currencies of commodity-exporting nations. Bond yields in different countries signal the interest-rate differentials that drive carry flows. The indicators and countries pages on this site connect those threads across asset classes.