The forex market is the largest financial market in the world, trading around $1.5 trillion each day. Trading in the forex is not done at one central location but is conducted between participants through electronic communication networks (ECNs) and phone networks in various markets around the world. 

The market is open 24 hours a day from 5pm EST on Sunday until 4pm EST Friday. The reason that the markets are open 24 hours a day is that currencies are in high demand. The international scope of currency trading means that there are always traders somewhere who are making and meeting demands for a particular currency.

Currency is also needed around the world for international trade, as well as by central banks and global businesses. Central banks have relied on foreign-exchange markets since 1971 - when fixed-currency markets ceased to exist because the gold standard was dropped. Since that time, most international currencies have been "floated", rather than pegged to the value of gold. 

At each second of every day, countries' economies are growing and shrinking because of economic and political instability and infinite other perpetual changes. Central banks seek to stabilize their country's currency by trading it on the open market and keeping a relative value compared to other world currencies. Businesses that operate in many countries seek to mitigate the risks of doing business in foreign markets and hedge currency risk.

To do this, they enter into currency swaps, giving them the right, but not necessarily the obligation to buy a set amount of a foreign currency for a set price in another currency at a date in the future. By doing this, they are limiting their exposure to large fluctuations in currency valuations. Due to the importance of currencies on the international stage there needs to be round-the-clock trading at all times. Domestic stock, bond and commodity exchanges are not as relevant, or in need, on the international stage and are not required to trade beyond the standard business day in the issuer's home country. Due to the focus on the domestic market, demand for trade in these markets is not high enough to justify opening 24 hours a day, as few shares would be traded at 3am, for example.

The ability of the forex to trade over a 24-hour period is due in part to different time zones and the fact it is comprised of a network of computers, rather than any one physical exchange that closes at a particular time. When you hear that the U.S. dollar closed at a certain rate, it simply means that that was the rate at market close in New York. But it continues to be traded around the world long after New York's close, unlike securities.

The forex market can be split into three main regions: Australasia, Europe and North America. Within each of these main areas there are several major financial centers. For example, Europe is comprised of major centers like London, Paris, Frankfurt and Zurich. Banks, institutions and dealers all conduct forex trading for themselves and their clients in each of these markets. 

Each day of forex trading starts with the opening of the Australasia area, followed by Europe and then North America. As one region's markets close another opens, or has already opened, and continues to trade in the forex market. Often these markets will overlap for a couple hours providing some of the most active forex trading. So if a forex trader in Australia wakes up at 3am and decides to trade currency, they will be unable to do so through forex dealers located in Australasia but they can make as many trades as they want through European or North American dealers. With all of this action happening across borders with little attention to time and space, the sum is that there is no point during the trading week that a participant in the forex market can't potentially make a currency trade.

With the improvement in IT and more brokers that allows small denomination (small minimum required amount) as well as high leverage for trading forex has enable the more and more people to join forex market hence th Forex Market can grow at significant percentage recently