When you trade forex, you're effectively borrowing the first currency in the pair to buy or sell the second currency. With a US$5-trillion-a-day market, the liquidity is so deep that liquidity providers—the big banks, basically—allow you to trade with leverage. To trade with leverage, you simply set aside the required margin for your trade size. If you're trading 200:1 leverage, for example, you can trade $2,000 in the market while only setting aside $10 in margin in your trading account. For 50:1 leverage, the same trade size would still only require about £40 in margin. This gives you much more exposure, while keeping your capital investment down.

An important part of the foreign exchange market comes from the financial activities of companies seeking foreign exchange to pay for goods or services. Commercial companies often trade fairly small amounts compared to those of banks or speculators, and their trades often have a little short-term impact on market rates. Nevertheless, trade flows are an important factor in the long-term direction of a currency's exchange rate. Some multinational corporations (MNCs) can have an unpredictable impact when very large positions are covered due to exposures that are not widely known by other market participants.
In the futures market, futures contracts are bought and sold based upon a standard size and settlement date on public commodities markets, such as the Chicago Mercantile Exchange. In the U.S., the National Futures Association regulates the futures market. Futures contracts have specific details, including the number of units being traded, delivery and settlement dates, and minimum price increments that cannot be customized. The exchange acts as a counterpart to the trader, providing clearance and settlement.

During the 15th century, the Medici family were required to open banks at foreign locations in order to exchange currencies to act on behalf of textile merchants.[10][11] To facilitate trade, the bank created the nostro (from Italian, this translates to "ours") account book which contained two columned entries showing amounts of foreign and local currencies; information pertaining to the keeping of an account with a foreign bank.[12][13][14][15] During the 17th (or 18th) century, Amsterdam maintained an active Forex market.[16] In 1704, foreign exchange took place between agents acting in the interests of the Kingdom of England and the County of Holland.[17]
The FXCM Group is headquartered at 20 Gresham Street, 4th Floor, London EC2V 7JE, United Kingdom. Forex Capital Markets Limited (“FXCM LTD”) is authorised and regulated in the UK by the Financial Conduct Authority. Registration number 217689. Registered in England and Wales with Companies House company number 04072877. FXCM Australia Pty. Limited ("FXCM AU") is regulated by the Australian Securities and Investments Commission, AFSL 309763. FXCM AU ACN: 121934432. FXCM South Africa (PTY) Ltd is an authorized Financial Services Provider and is regulated by the Financial Sector Conduct Authority under registration number 46534. FXCM Markets Limited ("FXCM Markets") is an operating subsidiary within the FXCM Group. FXCM Markets is not regulated and not subject to the regulatory oversight that govern other FXCM Group entities, which includes but is not limited to the Financial Conduct Authority, Financial Sector Conduct Authority, and the Australian Securities and Investments Commission. FXCM Global Services, LLC is an operating subsidiary within the FXCM Group. FXCM Global Services, LLC is not regulated and not subject to regulatory oversight.
Many currency pairs will move about 50 to 100 pips (sometimes more or less depending on overall market conditions) a day. A pip (an acronym for Point in Percentage) is the name used to indicate the fourth decimal place in a currency pair, or the second decimal place when JPY is in the pair. When the price of the EUR/USD moves from 1.3600 to 1.3650, that's a 50 pip move; if you bought the pair at 1.3600 and sold it at 1.3650 you'd make a 50-pip profit.
The need to exchange currencies is the primary reason why the forex market is the largest, most liquid financial market in the world. It dwarfs other markets in size, even the stock market, with an average traded value of around U.S. $2,000 billion per day. (The total volume changes all the time, but as of August 2012, the Bank for International Settlements (BIS) reported that the forex market traded in excess of U.S. $4.9 trillion per day.)