Foreign exchange trading increased by 38% between April 2005 and April 2006 and has more than doubled since 2001. This is largely due to the growing importance of foreign exchange as an asset class and an increase in fund management assets, particularly of hedge funds and pension funds. The diverse selection of execution venues have made it easier for retail traders to trade in the foreign exchange market. In 2006, retail traders constituted over 2% of the whole FX market volumes with an average daily trade volume of over US$50-60 billion (see retail trading platforms). Because foreign exchange is an OTC market where brokers/dealers negotiate directly with one another, there is no central exchange or clearing house. The biggest geographic trading centre is the UK, primarily London, which according to IFSL estimates has increased its share of global turnover in traditional transactions from 31.3% in April 2004 to 34.1% in April 2007. The ten most active traders account for almost 80% of trading volume, according to the 2008 Euromoney FX survey. These large international banks continually provide the market with both bid (buy) and ask (sell) prices. The bid/ask spread is the difference between the price at which a bank or market maker will sell ("ask", or "offer") and the price at which a market-maker will buy ("bid") from a wholesale customer. This spread is minimal for actively traded pairs of currencies, usually 0–3 pips. For example, the bid/ask quote of EUR/USD might be 1.2200/1.2203 on a retail broker. Minimum trading size for most deals is usually 100,000 units of base currency, which is a standard "lot".
These spreads might not apply to retail customers at banks, which will routinely mark up the difference to say 1.2100/1.2300 for transfers, or say 1.2000/1.2400 for banknotes or travelers' checks. Spot prices at market makers vary, but on EUR/USD are usually no more than 3 pips wide (i.e., 0.0003). Competition is greatly increased with larger transactions, and pip spreads shrink on the major pairs to as little as 1 to 2 pips.
Unlike a stock market, where all participants have access to the same prices, the foreign exchange market is divided into levels of access. At the top is the inter-bank market, which is made up of the largest investment banking firms. Within the inter-bank market, spreads, which are the difference between the bid and ask prices, are razor sharp and usually unavailable, and not known to players outside the inner circle. The difference between the bid and ask prices widens (from 0-1 pip to 1-2 pips for some currencies such as the EUR). This is due to volume. If a trader can guarantee large numbers of transactions for large amounts, they can demand a smaller difference between the bid and ask price, which is referred to as a better spread. The levels of access that make up the foreign exchange market are determined by the size of the “line” (the amount of money with which they are trading). The top-tier inter-bank market accounts for 53% of all transactions. After that there are usually smaller investment banks, followed by large multi-national corporations (which need to hedge risk and pay employees in different countries), large hedge funds, and even some of the retail FX-metal market makers. According to Galati and Melvin, “Pension funds, insurance companies, mutual funds, and other institutional investors have played an increasingly important role in financial markets in general, and in FX markets in particular, since the early 2000s.” (2004) In addition, he notes, “Hedge funds have grown markedly over the 2001–2004 period in terms of both number and overall size” Central banks also participate in the foreign exchange market to align currencies to their economic needs.
The interbank market caters for both the majority of commercial turnover and large amounts of speculative trading every day. A large bank may trade billions of dollars daily. Some of this trading is undertaken on behalf of customers, but much is conducted by proprietary desks, trading for the bank's own account. Until recently, foreign exchange brokers did large amounts of business, facilitating interbank trading and matching anonymous counterparts for small fees. Today, however, much of this business has moved on to more efficient electronic systems. The broker squawk box lets traders listen in on ongoing interbank trading and is heard in most trading rooms, but turnover is noticeably smaller than just a few years ago.