Due to the extremely high volume traded on a daily basis — some estimate it around $5.1 trillion, but we will never actually know with precision — and the number of online (and offline) brokers residing and operating all around the world, it would be inherently difficult for any central organization to impose a definite regulation that is valid and accepted by all the major players.
For this and other reasons, there is actually no main regulatory body for this business. Just take a moment and think about it, $5.1 trillion being traded every day and there is not a single, central authority that anyone can rely on: traders are by themselves. There is no set of rules on a global scale that any given online broker has to follow in order to operate on the market, only rules or guidelines set by each and every single country, of course with varying degrees of restriction. Now, how does that sound? Not very encouraging, that is for sure. However, in recent times, the Bank for International Settlements (BIS) have expended some efforts to construct some international rules for Forex market participants — the FX Global Code.
In the USA, the internal regulatory body for every activity related to currency trading is the Commodity Futures Trading Commission (CFTC). We certainly invite you to have a good look at their website, especially at their Forex Fraud consumer advisory section. It contains some general but nevertheless useful tips to sort out honest and reliable companies from scammers whose only aim is to take your money away.
A Forex broker in America should be registered as a Futures Commission Merchant (FCM) with the CFTC, and also to be a member of the National Futures Association (NFA). Our strong suggestion is to stay away from non-regulated firms! You can check whether any given broker is registered with the NFA from their search page. If you are thinking about depositing money with a US firm, we strongly encourage you to check that page first!
Needless to say, for the reasons explained above, it becomes a matter of extreme importance, whenever you are considering investing your money via a certain broker, to always keep an eye on which country such broker operates in. Knowing that your broker operates in countries such as the USA, Switzerland, or some European Union nation can generally be seen as some sort of guarantee — not a definite one, but still one worth looking for — of a solid legislative background, meaning that your money is less likely to suddenly "disappear" into their hands. It is also important to understand how different regulatory institutions regulate the brokers' operating from their countries.
Such data should always be present on the company's website and, if not, you should be able to contact the support personnel via chat or email and ask them for some definite proof. If for some reason, you cannot access this information, or you are given it only to find out that the company is based in the British Virgin Islands or some other offshore jurisdiction, you will have a strong argument against "securing" your money with them.
Just to be clear: the fact alone of being based in a fiscal paradise does in no way mean that the company is dishonest and is not legit, but it does mean that you will have less guarantees. In these cases, the least you can do to protect your investment if you actually mean to deposit money with them, is to google the name of their company and see for yourself what other users and traders think about them.