How foreign exchange markets work: structure, participants, and price discovery

The foreign exchange market is the largest and most liquid financial market in the world, with daily trading volumes exceeding USD 7.5 trillion. Understanding how forex markets work—their structure, participants, and pricing—is the foundation for understanding currency investing, the FX risk embedded in international equity portfolios, and the mechanics of the hedging instruments used to manage it.

What the foreign exchange market is

The foreign exchange market is not a single centralised exchange. Unlike equity markets, which route trades through organised exchanges such as the NYSE or London Stock Exchange, the FX market is an over-the-counter (OTC) market. Trading takes place directly between participants via telephone and electronic networks, without a central matching facility or clearing house for spot transactions. This decentralised structure means there is no single quoted price for a currency pair at any moment—prices are quoted bilaterally, and the spread between buy and sell prices varies across participants and platforms.

The market operates continuously for five days a week, following the sun across time zones. It opens in Wellington, New Zealand on Monday morning and closes in New York on Friday afternoon. The most active trading hours are when the London and New York sessions overlap—typically 13:00–17:00 UTC—when both the world's largest financial centre and its most important currency market are simultaneously open.

How it works

The FX market is structured in tiers. At the top is the interbank market, where large commercial banks trade currencies with each other in very large sizes—typically USD 1 million or more per transaction. The interbank market sets the reference prices that flow downstream to other participants. Below it are non-bank financial institutions (hedge funds, asset managers, pension funds), corporations using FX for trade and investment payments, and at the retail end, individual investors and brokers who access the market through banks or electronic trading platforms.

Price discovery in the interbank market is continuous and competitive. When a market participant wants to buy euros with dollars, they request a two-way quote from a bank. The bank quotes a bid (the rate at which it will buy euros) and an offer (the rate at which it will sell euros), and earns the spread between the two. In the wholesale interbank market, spreads on major currency pairs such as EUR/USD are fractions of a basis point. At the retail level, spreads are larger—typically 1–10 basis points for major pairs, and significantly more for minor or exotic currency pairs.

Three main instrument types are traded in FX markets. The spot market handles transactions for immediate delivery, conventionally settled two business days after the trade date. The forward market handles transactions for delivery on a specified future date, with the exchange rate agreed now. The swap market handles simultaneous spot and forward transactions in opposite directions—a foreign exchange swap involves selling a currency spot and simultaneously buying it forward (or vice versa), and is used primarily for short-term funding and hedging.

What the evidence shows

Data published by the Bank for International Settlements (BIS) in its triennial FX survey tracks the evolution of the market over time. The 2022 survey found average daily turnover of USD 7.5 trillion, up from USD 6.6 trillion in 2019 and less than USD 1 trillion in 1992. The growth reflects the expansion of global trade and investment flows, the rise of electronic trading, and the increased participation of non-bank financial institutions such as hedge funds and asset managers.

The EUR/USD pair is the most actively traded, accounting for approximately 22% of global turnover. USD/JPY and GBP/USD are the next most active. The US dollar appears on one side of approximately 88% of all FX transactions, reflecting its role as the world's primary reserve currency and the default invoice currency for commodity contracts and international trade.

Limitations and trade-offs

The OTC structure of the FX market means that transaction costs and execution quality vary significantly across participants. Institutional investors with direct interbank market access pay spreads of fractions of a basis point; retail participants accessing the market through brokers or banks pay spreads that may be 10–100 times wider. The lack of a consolidated tape—a single authoritative record of all trades and prices—also makes it difficult to assess execution quality in the way possible on organised exchanges.

The 24-hour structure of the FX market creates gaps in liquidity. During off-hours—late Friday afternoon New York time through Sunday evening Wellington time—volumes drop sharply, spreads widen, and large trades can move prices more than they would during peak hours. Events that occur over weekends (elections, central bank announcements) can produce sharp price moves at the market open on Sunday evening before liquidity has fully returned.

FX markets in pfolio

Currency appears in pfolio both as an asset class—where FX exposure is taken as a deliberate return driver—and as an incidental risk embedded in international equity and fixed income positions. The currency assets in pfolio's investable universe are listed in the Assets section. Currency asset class performance and exposure are tracked in pfolio Insights.

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