Like any other business in the history of business, your broker’s raison d’etre, is to make as big a profit as possible. There are about as many ways to go about this as there are brokers. For those who are in it for the long haul, however, it is generally best to adopt a set of practices which are deemed fair by their clients: certain boundaries are set, and operating beyond them can cost a brokerage its reputation, and along with it its clients. Straying outside these boundaries, therefore, is not considered as being in line with the long term goals of the business. How strictly these boundaries are enforced, especially when there is little chance of clients ever even becoming aware of any transgression, again varies from business to business. For the sake of simplicity, in this article we assume that everyone in the business is squeaky clean, as if every client could peek into the broker’s back office at any time and dissect every trade. This is obviously not the case, and many brokers do take advantage of this opaqueness, but the details of that are best left for another discussion.

So without further ado, let’s get into the details of how forex brokers function. Somewhat removed from the top-tier interbank market, retail forex brokers are there to provide a service that would otherwise not be available, that is, giving an investor with a $10,000 bankroll the chance to speculate in the up-until-recently very exclusive forex market. There are generally considered to be 2 types of brokers providing access at the retail level: Electronic Communications Networks (ECNs) and Market Makers. ECNs are generally somewhat more exclusive, requiring larger deposits to get started, but are seen as providing more direct access to the interbank market. As we will see, there are certainly advantages to this, but some disadvantages as well. Market makers, on the other hand are more often than not, the counter party to their clients’ trades, creating somewhat of a conflict of interest, whereas ECNs profit from commission fees charged directly to the clients, regardless of the result of any trade, they are seen as being completely impartial – an ECN has no incentive for a client to lose money. In fact, one could argue that an ECN stands to profit more if a client is successful, meaning that s/he will stay around longer and they will be able to collect more commission fees from them. A market maker, on the other hand, being the counterparty to a client’s trade, makes money if the client loses money, providing an incentive for some shady practices, particularly in an unregulated market. The extent to which this happens varies among individual brokers. There are also some benefits to trading with a market maker (see our ECNs vs. Market Makers article) Some brokers also provide a service that doesn’t quite fit into either category – they route different orders differently, depending on complex algorithms, or on a dealing desk, that analyze each order and attempt to fill it in the way that will be most beneficial to the broker’s bottom line. They can offset some client orders against one another, effectively creating an in-house market, they can choose to be the counterparty to a client’s trade (trade “against” the client), or they can offset their position with a hedge through a higher-tier counterparty. Note that the market maker is mainly concerned with managing its net exposure, and NOT with any single individual’s trades. They are NOT gunning for your stop losses specifically, but may be gunning for clusters of stops.

If you have already read the first article in the series, Structure of the Forex Market, you will recall that market mechanics are responsible for the variation in bid/ask spreads, and also for slippage. So it seems the two biggest novice traders’ pet peeves are not so much a function of who their broker is, but rather their lack of understanding of the way the forex market operates. A broker that offers a fixed spread tends not to fill orders during periods of low liquidity because this would expose them to undue risk, and as much as their job is to cater to their clients, remember they are in business primarily to make money for themselves. Some brokers also offer guaranteed order fills, such as “guaranteed stop losses”. Again, if there is no counter party to take the trade, they have to expose themselves to risk in order to fulfill this guarantee, so don’t be surprised if you see such a broker quoting different/delayed prices around important trend lines or support/resistance levels. Be especially aware of brokers who offer both guaranteed fills AND fixed spreads. When a broker offers something that seems too good to be true, you would be wise to question how exactly their business model is able to support such a risky practice. As a general rule, a broker will help you only when your interests are aligned with theirs. On the other hand, brokers provide a very valuable service, without which you wouldn’t have the opportunity to profit from the forex market, so please think about how it all comes together before blaming your broker for everything.

http://www.forextradingzone.org/articles-How_Forex_Brokers_Work