Spreads should always be considered in conjunction with depth of book. Oddly enough, when it comes to economies of scale, forex doesn't even act like most other markets. On the inter-bank market, for example; the larger the ticket size, the larger the spread is. So when you see a 1-pip spread on an ECN platform, you have to wonder if that spread valid for a $2M, $5M or $10M trade, which it probably isn’t. In many cases, the tight spread that is offered applies only to a capped trade sizes that are very inadequate for most of the common trading strategies.
Spread policies change a great deal from broker to broker, and the policies are often difficult to see through. This certainly makes comparing brokers much more difficult. Some brokers actually offer fixed spreads that are guaranteed to remain the same regardless of market liquidity. But since fixed spreads are traditionally higher than average variable spreads, you are paying an insurance premium during most of the trading day so that you can get protection from short-term volatility
Spreads are tighter when there is good market liquidity but they will widen as liquidity dries up.
When it comes to choosing between fixed and variable rates, the choice depends on your individual trading pattern. If you trade primarily on news announcements that you hear, you may be better off with fixed spreads. But only if quality of execution is good.
Some brokers have different spreads for different clients based on their accounts. For example; those clients that have larger accounts or those who make larger trades may receive tighter spreads, while the clients that are referred by an introducing broker might receive wider spreads in order to cover the costs of the referral. Some offer the same spreads to everyone.
