Forex, or the foreign exchange market (also called FX for short) is the marketplace where currencies are traded. At its simplest, a foreign exchange transaction might be, for example, when you transfer your local currency to a new one for an upcoming holiday. Across the market as a whole, an estimated 5.3 billion USD is traded every day between governments, banks, corporations, and speculators.
These cover the bulk of countries outside Europe. Forex brokers catering for India, Hong Kong, Qatar etc are likely to have regulation in one of the above, rather than every country they support. Some brands are regulated across the globe (one is even regulated in 5 continents). Some bodies issue licenses, and others have a register of legal firms.
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.
Currency trading and exchange first occurred in ancient times. Money-changers (people helping others to change money and also taking a commission or charging a fee) were living in the Holy Land in the times of the Talmudic writings (Biblical times). These people (sometimes called "kollybistẻs") used city stalls, and at feast times the Temple's Court of the Gentiles instead. Money-changers were also the silversmiths and/or goldsmiths of more recent ancient times.
Forex is a portmanteau of foreign currency and exchange. Foreign exchange is the process of changing one currency into another currency for a variety of reasons, usually for commerce, trading, or tourism. According to a recent triennial report from the Bank for International Settlements (a global bank for national central banks), the average was more than $5.1 trillion in daily forex trading volume.