The foreign exchange market has no single physical location or central exchange; it operates as a decentralized, tiered network of banks, financial institutions, and traders connected electronically across the globe. Average daily turnover in this market reached $9.6 trillion in April 2025, according to the Bank for International Settlements' Triennial Central Bank Survey, up 28% from $7.5 trillion three years earlier. Trading flows through a hierarchy: central banks and the largest commercial banks trade directly with each other at the top, while retail traders access prices at the bottom through brokers connected to that upper structure. Understanding this layered structure explains why the price a retail trader sees is never the same price that passes between two major banks.

Four financial centers dominate the geographic distribution of this activity. Sales desks in the United Kingdom, the United States, Singapore, and Hong Kong intermediated 75% of total FX trading in April 2025, with London alone accounting for approximately 38% of the global total and New York contributing roughly 19%. Singapore's share climbed to 11.8% in the same survey, up from 9.5% in 2022, reflecting its growing role as a regional hub for Asian trading hours. This concentration means that market liquidity and volatility follow the clock, shifting from one major hub to the next as each region's trading day begins and ends.

The foreign exchange market is the global venue where currencies are bought, sold, and exchanged, operating continuously without a central exchange building or single clearing venue. Unlike stock markets, which run through exchanges such as the NYSE or LSE, forex activity is conducted over the counter (OTC) — directly between two parties or through electronic networks connecting banks and brokers. This structure means that price formation happens through a web of bilateral relationships and electronic matching systems rather than through a single centralized order book.

The market trades in several instrument types, each serving a different purpose. Spot transactions, which settle the exchange of currencies within two business days, accounted for $3 trillion of daily turnover in April 2025, or 31% of the total. FX swaps remained the largest single instrument category at $4 trillion per day, representing 42% of turnover, while outright forwards reached $1.8 trillion, or 19% of the total — a share that has grown as more participants use forwards to lock in future exchange rates.

This decentralized structure also explains why forex quotes can differ slightly between brokers at the same instant. Since no single exchange sets an official closing or opening price, each liquidity source and broker calculates its own bid and ask based on the feeds it receives from its upstream providers. In highly liquid conditions these differences remain negligible, often less than a tenth of a pip, but they widen during major news events or thin holiday trading when upstream liquidity temporarily contracts.

Forex market structure consists of layered tiers, with access, pricing, and typical trade size decreasing at each level moving away from the center. This tiered design is what separates the forex market from centralized exchanges and explains why different participants receive different prices for the same currency pair at the same moment.

The Interbank Market

The interbank market sits at the top of the tiered structure, consisting of roughly 10 to 15 of the world's largest banks — including JPMorgan, Deutsche Bank, Citigroup, HSBC, and UBS — trading directly with each other via bilateral credit lines and electronic platforms such as EBS and Reuters Matching. This is where exchange rates for major pairs like EUR/USD and USD/JPY are first formed, before spreading outward through the rest of the market. Inter-dealer trading between these institutions accounted for 46% of global FX turnover in April 2025, or $4.4 trillion per day.

No retail trader ever gains direct access to this tier. Every retail order passes through at least one intermediary — typically a broker connected to a liquidity provider, which in turn maintains credit relationships with interbank desks. This layered access explains the pricing difference between what large institutions pay and what individual traders see on their platforms.

Prime Brokers and ECNs

Below the interbank tier, prime brokers and Electronic Communication Networks (ECNs) aggregate liquidity from multiple interbank sources and distribute it to institutional and retail clients. An ECN matches buy and sell orders algorithmically from multiple liquidity providers, without a dealer standing between the trader and the market. This model typically produces spreads between 0.0 and 0.5 pips on major pairs, plus a separate commission per lot traded.

Prime-of-prime brokers occupy a related position, extending interbank-grade credit and pricing access to smaller banks, hedge funds, and larger retail brokers that lack direct interbank relationships. This intermediate layer allows smaller market participants to access institutional-quality pricing without meeting the capital requirements of a direct interbank relationship.

Retail Brokers

Retail brokers form the tier that most individual traders interact with directly, and they generally operate under one of two models. A Straight Through Processing (STP) or ECN broker passes client orders directly to a liquidity provider or aggregated pool, earning revenue through a markup or commission without taking the opposite side of the trade. A market maker broker, by contrast, takes the opposite side of client trades internally, quoting its own bid and ask prices rather than routing orders to external liquidity.

Trading volume in the forex market is distributed unevenly across participant types, and each group trades for a distinct reason. Reporting dealers — largely the major interbank banks — accounted for 46% of turnover in April 2025. Trading with "other financial institutions," a category covering non-reporting banks, institutional investors, hedge funds, and proprietary trading firms, made up 50% of turnover, up from 47% in 2022.

• Non-reporting banks (smaller regional banks): approximately 24% of global turnover, or $2.4 trillion per day.

• Institutional investors, including asset managers and pension funds: 13% of turnover, or $1.3 trillion per day, up from 11% in 2022.

• Hedge funds and proprietary trading firms: 8% of turnover, up from 7% in 2022.

• Non-financial corporate customers: 5% of turnover, continuing a gradual decline from 7% in 2019.

Central banks trade a small fraction of total daily volume directly, yet their influence on price exceeds every other participant category. A single policy rate decision or currency intervention announcement can move a major pair by hundreds of pips within minutes, regardless of the modest volume the central bank itself transacts.

The US dollar sits at the center of forex market structure, appearing on one side of 89.2% of all trades in April 2025, up from 88.4% in 2022. This dominance makes the dollar the world's primary vehicle currency — a currency used as an intermediary step even when converting between two other currencies. The euro held the second-largest share at 28.9%, down from 30.6% in 2022, while the Japanese yen's share remained steady at 16.8%.

The renminbi and Swiss franc gained market share notably between 2022 and 2025, rising to 8.5% and 6.4% of global turnover respectively. Sterling's share fell to 10.2% from 12.9% in 2022, dropping below its average of roughly 13% across the three preceding surveys, reflecting reduced trading activity relative to other major currencies.

Forex market structure includes a time dimension: trading runs continuously across four overlapping regional sessions, each centered on a major financial hub. This continuous cycle exists because as one region's business day ends, another's begins, keeping the market open five days a week without a full close.

The London and New York sessions overlap from 12:00 to 16:00 UTC, producing the deepest liquidity window of the trading day because both major hubs are active simultaneously. The Sydney and Tokyo sessions overlap earlier in the cycle, but with materially lower combined turnover than the London-New York window, since London alone handles more than a third of global volume.

Trading volume and spread behavior follow a predictable pattern tied to this session structure. Spreads on major pairs tend to be tightest during the London-New York overlap, when the largest number of liquidity providers are simultaneously active and competing for order flow. Conversely, spreads widen during the transition between the New York close and the Sydney open, a window with comparatively few active participants and reduced depth across most currency pairs.

Forex market structure supports several distinct instrument types beyond simple spot currency exchange, each occupying a different position in the tiered system. FX swaps combine a spot transaction with an offsetting forward at a later date, and remain the single largest instrument category by turnover despite a declining share of the total. Outright forwards let a participant lock in an exchange rate for a future date without an accompanying spot leg, a structure heavily used by corporations hedging receivables or payables in foreign currency.

Currency options add a further layer of complexity, granting the buyer the right, but not the obligation, to exchange currency at a set rate before a specified expiration. Average daily turnover in FX options more than doubled between 2022 and 2025, reaching approximately 7% of global turnover, up from 4% three years earlier — growth driven largely by institutional investors and corporations using options to hedge against currency volatility without committing to a fixed forward rate. Currency swaps, used mainly for longer-term funding needs across currencies, held a stable 2% share of turnover, reflecting their role as a specialized instrument for multi-year currency and funding management rather than short-term trading.

Unlike equities, options, or exchange-traded futures, most forex transactions settle bilaterally between two counterparties rather than through a central clearinghouse. This over-the-counter structure means that credit risk, pricing, and execution terms depend on the specific relationship between the two parties in each trade, rather than on standardized exchange rules. FX swaps, spot transactions, and the majority of forwards all trade this way, while only a small share of currency derivatives clear through central counterparties.

Cross-border trading made up 63% of global FX turnover in April 2025, reflecting how routinely participants in one country transact with counterparties located elsewhere. This cross-border characteristic, combined with the absence of a single exchange, is why forex market structure depends so heavily on the credit relationships and technology connections that link each tier to the one above it.

Regulatory oversight varies significantly by tier, which affects the protections available to each type of participant. Interbank trading between major banks falls under prudential banking regulation, including capital and liquidity requirements set by national regulators and international bodies such as the Basel Committee. Retail forex brokers face separate rules depending on jurisdiction — the FCA in the United Kingdom, CySEC in Cyprus, and ASIC in Australia each impose licensing, client fund segregation, and leverage limits on brokers serving retail clients.

These jurisdictional differences directly affect trading conditions available to retail participants. A broker regulated in the European Union under ESMA rules, for example, caps leverage on major currency pairs at 30:1 for retail clients, while some offshore-regulated brokers offer leverage exceeding 500:1. This regulatory patchwork means that two brokers offering access to the same underlying interbank liquidity can present very different risk profiles to their retail clients, based solely on which regulatory regime governs their operations.

Liquidity providers occupy a critical function between the interbank tier and the retail-facing brokers, supplying continuous two-way pricing that brokers then pass on to clients. A liquidity provider typically maintains direct credit relationships with multiple Tier 1 banks, allowing it to aggregate several competing quotes for the same currency pair and select the tightest available price at any given moment. Retail brokers operating an ECN or STP model connect to one or more of these liquidity providers rather than to the interbank market directly.

This aggregation process explains why spreads on major pairs like EUR/USD can compress to fractions of a pip during peak liquidity hours. When dozens of liquidity providers compete to fill the same order flow, the resulting price reflects the tightest bid-ask spread across that entire pool, rather than a single dealer's quote. During periods of low liquidity, such as the gap between the New York close and the Sydney open, fewer liquidity providers remain active, which widens spreads even on the most heavily traded pairs.

Forex market structure determines the price, spread, and execution quality available to every participant, from the largest interbank desk to the smallest retail account. A trader who understands the tiered system — interbank, prime broker, ECN, and retail broker — can better interpret why spreads widen during low-liquidity hours or why execution during the London-New York overlap tends to be faster and tighter. With $9.6 trillion in daily turnover concentrated through four major financial centers and dominated by a handful of major currency pairs, the forex market's structure directly shapes the trading conditions every participant experiences.