Some brokers may also charge a very small commission, perhaps two-tenths of one pip, and then will pass the order flow received from you on to a large market maker with whom he or she has a relationship. In such an arrangement, you can receive a very tight spread that only larger traders could otherwise access.
Different Brokers, Different Levels of Service
So what is the bottom line effect of each type of commission on your trading? Given that all brokers are not created equal, this is a difficult question to answer. The reason is that there are other factors to take into account when weighing what is most advantageous for your trading account.
For example, not all brokers are able to make a market equally. The forex market is an over-the-counter market, which means that banks, the primary market makers, have relationships with other banks and price aggregators (retail online brokers), based on the capitalization and creditworthiness of each organization. There are no guarantors or exchanges involved, just the credit agreement between each player. So, when it comes to an online market maker, for example, your broker's effectiveness will depend on his or her relationship with banks, and how much volume the broker does with them. Usually, the higher-volume forex players are quoted tighter spreads. (For more, see Getting Started In Forex.)
If your market maker has a strong relationship with a line of banks and can aggregate, say, twelve banks' price quotes, then the brokerage firm will be able to pass the average bid and ask on to its retail customers. Even after slightly widening the spread to account for profit, the dealer will be able to pass a more competitive spread on to you than competitors that are not well capitalized.
If you are dealing with a broker that can offer guaranteed liquidity at attractive spreads, this may be what you should look for. On the other hand, you might want to pay a fixed pip spread if you know you are getting at-the-money executions every time you trade. Slippage, which occurs when your trade is executed away from the price you were offered, is a cost that you do not want to bear.
In the case of a commission broker, whether you should pay a small commission depends on what else the broker is offering. For example, suppose your broker charges you a small commission, usually in the order of two-tenths of one pip, or about $2.50 - $3 per 100,000 unit trade, but in exchange offers you access to a proprietary software platform that is superior to most online brokers' platforms, or some other benefit. In this case, it may be worth paying the small commission for this additional service.